Sciencemadness Discussion Board

Hydrazine

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Praxichys - 7-10-2015 at 09:33

Improvements to GB1153483, in lieu of GB392845 on the manufacture of Hydrazine Sulfate: A Chlorourea-Ketazine Process not involving Cl2.

I decided to give GB1153483 a try, just to see whether their 75% claimed yield held any vestiges of truth.

12.6g (0.2 mol) urea was dissolved in 18.9g water. 1.6g of 50% NaOH (0.01 mol) was stirred in and the mixture was placed in the freezer.

When the mixture had dropped to -10C (it froze), 125g of 12.5% commercial NaClO (0.2 mol) at 0C was added in roughly 10ml portions evenly over an hour. Vigorous stirring and re-chilling followed each addition. The reaction is not very exothermic but any rise in temperature above 5C results in bubbling, undoubtedly signalling the decomposition of the chlorourea intermediate. The bubbling was most pronounced on the first and last additon, suggesting that thermal control is difficult with a low reaction mass, and decomposition of the intermediate is fast at high concentrations. The mixture does not foam.

After the last addition of NaClO, 30.4g of 50% NaOH (0.38 mol) with 0.1g Knox gelatin was added with rapid stirring, causing the light green mixture to begin foaming. The reaction was heated as quickly as possible, reaching 60C in about 10 minutes and causing foam to add another 1/3 to the volume of the reaction mix (total about 300ml incl. foam at peak). The color of the liquid gradually became orange/amber. After approximately a minute of exotherm the foam rapidly subsided, leaving a straw colored, foam-free, hot liquid characteristic of a hydrazine prep.

This was allowed to cool with stirring with a watch glass over the top of the erlenmeyer until it reached approximately 30C. 28.8g (0.4 mol) methyl ethyl ketone was added and the mixture was allowed to stir for an hour for the azine to form, cooling to room temperature in the process.

The azine layer was extracted and immediately run into 19.6g H2SO4 in 20.9g H2O at about 30C. Hydrazine sulfate precipitated immediately. This was stirred for 10 minutes, then heated with stirring for about 30 minutes to drive off the MEK. After a loss of 1/3 of its volume, the mixture was placed in the freezer and chilled to 0C. It was then vacuum filtered and washed twice with 30ml portions of ice water.

The dried filtrate weighed 6.26g, or 21% of theoretical yield, and consisted of dense, pearlescent crystals consistent with hydrazine sulfate.

Some notes:

-All percentages listed are w/w.
-Satuating the reaction mix with NaCl after extracting the azine (30g was added and did not fully dissolve) yielded no more extractable azine, after 24h.
-Theoretical yield would net a volumetric efficiency of 96g hydrazine sulfate per liter of flask volume, including room for foam. The 75% yield in the patent would net 72g/L, 50% would net 48g/L and the current yield was 20.9g/L. The "Mr Anonymous" method requires about 6 liters of volume for at max 236g of product, an efficiency of 39g/L. Achieving the same yield as Mr. Anonymous (ca. 60%) using this method would result in a volumetric efficiency 1.48 times greater. The yield stated in the patent would achieve 1.85x over the M.A. method - a marked improvement in both volumetric efficiency and safety, albeit with judicious temperature control.
- I prefer the ketazine extraction method over direct precipitation. I feel like M.A.'s method has a high level of Na2SO4 contamination.

Things to try on the next run:

- Spread out the addition of the NaClO. Ideally the mix should never rise over -5C. Use a bowl of 30% CaCl2/H2O chilled to -20C as a thermal buffer to surround the flask and absorb the heat. Regrettably, my lab freezer is too small to set up an addition funnel/stirrer inside, so additions are limited to small-volume aliquots.
- Make a schedule of additions starting and ending small, max 10ml.
Schedule, ml/5 min intervals, total 1h10m: 5, 5, 5, 10, 10, 10, 10, 10, 10, 10, 10, 5, 5, 5. A volumetric pipette stored in the freezer will help with this.
- Use fresh NaOCl. The commercial 12.5% has been in my freezer for a year. I went out and purchased 4 gallons of 10% today. The slightly lesser concentration of hypochlorite will also help with thermal management.
- Stir overnight with MEK to fully form the azine. Not sure about rate of reaction on this.
- Use 10% more MEK to make up for unwanted products formed with unreacted urea/hypochlorite in the basic environment.
- Use a separate gelatin solution rather than the NaOH solution. Gelatin clumping was a problem in the NaOH and its effectiveness as a chelator was probably compromised. I feel that this is a big factor, per US1959503(A)/GB392845. It may also significantly increase the foam volume, reducing volumetric efficiency to a point where this method will be inferior to others.

Failing this, I will try a third time with recrystallized urea. It's a pain in the ass to do, so that will be a last resort. I will also double the scale, and split the reaction mass into two equal portions prior to the hydrazine extraction. One will be azine-extracted and the other will be directly neutralized/precipitated with HCl/H2SO4, to check the efficiency of the azine process.

A possibly interesting experiment:

- What happens if all NaOH is added to urea to form essentially cold conc. ammonia first, then add hypochlorite slowly at -10C? What happens when this is done with MEK present in the ammonia?

[Edited on 8-10-2015 by Praxichys]

Pimmental - 10-5-2016 at 09:38

Quote: Originally posted by vmelkon  
COPPER IS EVIL! Cu2+

Just for your info:

I redid this experiment --- the Nurdrage method : mix 2-butanone and ammonia solution. Then drip NaClO slowly.
The glassware in which I had my NaClO was contaminated by a copper compound.

My yield was 0%.
Definitely, the presents of Cu2+ messes it up.
------------------------
From
http://www.lookchem.com/Chempedia/Chemical-Technology/Inorga...

2 NH2Cl + N2H4 → N2 + 2 NH4Cl
This reaction is particularly catalyzed by copper. A large excess of ammonia and the addition of complexing agents such as ethylenediaminetetra-acetic acid (EDTA) are used as countermeasures.



lookchem.com is a business network from the Chinese government to earn more money from Western countries with their own asian companies. For professional business profiles only, NOT a website for chemists. Not a good source of information. ;)

The last post: ammonia dissolve better in cold water but what is the reaction mechanism between urea and sodium hydroxide, without hypochlorite ?...

chemplayer... - 17-5-2016 at 07:21

Praxichys - thanks, that is an interesting experiment.

We also tried a variant method from the literature (don't have the exact reference though) which involved bubbling Cl2 gas through a urea solution containing some dissolved gelatine in order to produce chlorourea. The chlorine was absorbed pretty well and a yellow coloured solution resulted. We tried to use about 1.1 x the stoichiometric amount of Cl2 gas needed.

The solution was fairly concentrated - about 30g of urea in 60ml of water, plus about 0.3g gelatine.

Then this was added to a chilled solution of sodium hydroxide (24g in 50ml deionised water). There was a STRONGLY exothermic reaction at this point (easily reached 90C without much difficulty) and some foaming.

Once this died down, HCl was then added until gas evolution stopped, at which point there was a crystalline white precipitate (we assume NaCl) which we filtered off.

The filtrate was then acidified with 50% sulfuric acid and chilled. We got some crystalline hydrazine sulfate, but not much, probably only a few grams.

Rosco Bodine - 17-5-2016 at 13:37

Quote: Originally posted by Praxichys  

I feel like M.A.'s method has a high level of Na2SO4 contamination.


Uh huh ....I see, you "feel" .....say what ? ! Hmmmph

Try the improved method with the bulk neutralization using HCl followed by the H2SO4 ....that was designed to soothe feelings :D

The interesting thing for followup would be the use of a manganese salt to increase yields as reported by Russians.
See these posts linked

http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

http://www.sciencemadness.org/talk/viewthread.php?tid=1128&a...

Praxichys - 27-5-2016 at 05:32

Quote: Originally posted by Rosco Bodine  
Quote: Originally posted by Praxichys  

I feel like M.A.'s method has a high level of Na2SO4 contamination.


Uh huh ....I see, you "feel" .....say what ? ! Hmmmph

Try the improved method with the bulk neutralization using HCl followed by the H2SO4 ....that was designed to soothe feelings :D

I "feel" things when I can't be bothered to generate data. :D

I only have concerns about contamination because the solubility curves of the two suggest that they probably coprecipitate to some degree. Precipitating hydrazine sulfate from a sodium sulfate or even sodium chloride solution is going to warrant recrystallization at the least. I'd be curious to assay the hydrazine content of that, just to see. It would be virtually impossible to judge the purity of such a mixture by eye since the crystals can be made similarly dense and granular using the precipitation methods given.

The azine extraction method removes pretty much all ionic contaminants by nature. Granted, it does use more glass and has some toxic intermediates, but I'd rather do a L/L extraction over a recrystallization anyway. I do not doubt that your method is optimized for high yield - I just prefer to work it up differently out of concern for contamination.

nitro-genes - 27-5-2016 at 13:25

Also prefered the MEK-azine extraction, really brings peace of mind to know there are no contaminants in there! ;) Besides... during acid neutralization of the entire reaction mixture, the CO2 effervescence is really strong and creates an aerosol which will likely also contain some hydrazine. So this is not something that should be performed without safety measures IMO.

Rosco Bodine - 27-5-2016 at 20:10

Trace sodium chloride as a spectator ion is a pretty low concern in most reactions where the hydrazine sulfate would be later used. And there is a chance some of the hydrazine is sequestered as carbonate disrupted by acidification, which could benefit yield.

Rhodanide - 10-10-2016 at 08:02

Quote: Originally posted by Al Koholic  
The fumes smelled relatively ammoniacal but also had a distinct sweetish component. /rquote]
In my experience, N2H4 smelled of Ammonia mixed with woodsmoke.
Like a sweet mesquite BBQ undertone. Too bad it's so toxic. :(

The jersey rebel - 20-4-2017 at 10:13

Quote: Originally posted by Al Koholic  
As a matter of fact, I ran into exactly the same problems. The bubbling upon supposed neutralization of the hopefully hydrazine solution is most perplexing. I did not notice a green gas but more of a thick cloudy white vapor of some kind during my neutralization. I also used a somewhat large excess of NH3...

Lets think about this...I did not use gelatin or EDTA and still I get the bubbling upon warming of the solution and neutralization. You used both gelatin and EDTA and notice similar bubbling although noting the presence of chlorine by smell which I did not notice. Perhaps some side reactions are occuring in both of our cases with different outcomes? Seems unlikely...

Did you notice a really bad smell when you added the H2SO4 to the solution for neutralization? It was bad in the sense that rotting food is bad...nauseating...not like the pungent sting of Cl2.

[Edited on 3-12-2003 by Al Koholic]
The bleach could have chlorate prehaps. So the gas could be chlorine dioxide


[Edited on 20-4-2017 by The jersey rebel]

Dihydrazine Sulfate

Rexona - 4-5-2018 at 23:54

How to prepare Dihydrazine Sulfate(H10N4O4S) ?:)

Protocol: Synthesis of hydrazine sulfate from bleach and urea

RadicallyStabilized - 10-10-2018 at 06:27

I recently made hydrazine sulfate from household bleach and urea according to NileRed's method (posted on Youtube).

TL;DR: The bleach had a much lower concentration than expected but in the end it worked out.

Experimental:
About 500 ml of < 5% household bleach (assumed to be about 5% concentration) were put into a 1 l beaker and stirred in an ice bath. 32 g of sodium hydroxide pellets were added in small portions, not allowing the temperature to rise beyond 14 °C. The solution was then left to cool to 7.5 °C. A solution of 22 g of urea (Honeywell, p. a.) in about 25 ml of water was prepared and heated in the microwave for about 30 seconds to dissolve everything. A solution of 0.75 g of gelatin powder in about 10 ml of water was made and warmed in the microwave for about 15 seconds. After cooling these two solutions were combined.
In the fume hood: The cooled alkaline sodium hypochlorite solution was strongly stirred on a hotplate. The gelatin/urea solution was added all at once and the beaker covered with plastic foil. After a short while strong bubbling occurred which gave the solution a turbid appearance. Foaming was not a problem. The bubbling gradually subsided after about one hour of stirring, so the hotplate was turned on and the solution (which was slightly yellow) was heated up to 85 °C. After a few minutes at this temperature the solution gradually lost its yellow hue. When no change in color could be observed any more the solution was taken off the hotplate and left to cool to room temperature. It was put into an ice bath and cooled to about 7 °C. About 120 ml of cold 50% sulfuric acid (-15 °C) was added carefully with stirring and the solution gradually warmed up to about 25 °C. No precipitate formed. The solution was again put into an ice bath. At about 10 °C white crystals began to form. More sulfuric acid was added but there was no additional precipitation. The solution was kept in a fridge for about an hour but no more crystals formed. The precipitate was vacuum filtered off. The yield when wet was 9.60 g. The mass was put into a vacuum desiccator and dried over calcium chloride for about two days. The final yield of white crystals was 9.05 g corresponding to about 21.4% of the theoretical.

Titration of the bleach:
To help explain the low yield the concentration of the bleach was determined as follows:
The sodium hypochlorite solution was titrated using sodium thiosulfate after mixing with a potassium iodide/starch indicator, according to the procedure specified in [2].
The volume of the samples was 5 ml. 40 ml of indicator solution were added to each sample.
The necessary volume of 0.1 mol/l Na2S2O3*5H2O solution was 31.5 ml in each run.
The concentration of active chlorine was determined to be (see [2]):
C(Cl2) = 31.5 ml * 0.1 mol/l * 35.4257 g/mol / 5 ml = 22.32 g/l = 2.23% [wt% available Cl2]
According to [3] this corresponds to a weight content of NaOCL of 1.05 * 2.23 [wt% NaOCl] = 2.34%.
The specific gravity of the bleach was found to be 1.04 g/ml which is off the chart in [3] but the value seems to work out.

It is therefore obvious that the sodium hypochlorite concentration was much lower than expected.
NileRed's yield in [1] was 20.25 g (48%) when using a bleach concentration of 4.9%. This corresponds to a gram yield per bleach concentration percent of 20.25 g / 4.9% = 4.13 g/%.
The value in this experiment was 9.05 g / 2.34% = 3.86 g/% which is a bit lower but quite close (6.5% difference).

Testing the result:
A small amount of the product was heated in a test tube. The mass began to foam and smoke emerged. In the upper portion of the test tube white and yellow precipitates began to form and there was a smell of sulfur dioxide. A little transparent, colorless residue remained that was soluble in water and gave no color with phenolphthalein.
As a comparison a sample of anhydrous sodium hydrogen sulfate was subjected to the same test. There was little white precipitate but no yellow could be seen. The salt melted in the bottom of the test tube and left a white residue that was soluble in water and gave no color with phenolphthalein.
A tiny amount of the hydrazine sulfate was burned in a bunsen flame which showed the typical color of sodium. The sample evaporated quickly without leaving any residue. It was concluded that there was at least some small amount of sodium contamination.
The Tollens test was done by adding about 2 ml of a weak ammonia solution to about 1 ml of silver nitrate solution, until the white precipitate of silver hydroxide had dissolved. To this was added a small spatula of the hydrazine sulfate. Immediately a silver mirror began to form in the test tube even in the cold. There was slight evolution of gas. It was concluded that the substance was indeed highly reducing and likely to be hydrazine sulfate of a reasonable purity.

To determine the purity of the hydrazine sulfate the following iodometric titration was performed using the solutions made for titration of the bleach:
5 ml of bleach were put into an Erlenmeyer flask and about 30 ml of the potassium iodide/starch solution were added. The solution took on a dark color. Some more solid potassium iodide was added to ensure that all iodine was fully liberated (KI/starch solution had run out). With strong stirring sodium hydrogen carbonate was added until the foaming stopped, plus an additional spatula for a slight excess of NaHCO3[4]. The approximate amount of hydrazine sulfate necessary for reduction of the formed iodine was calculated as follows:
Titration with sodium thiosulfate:
2 S2O3(2-) + I2 => S4O6(2-) + 2I-
Therefore two moles of sodium thiosulfate reduce one iodine molecule.
The amount of I2 in the solution can be reduced by 31.5 ml * 0.1 mol/l Na2S2O3*5H2O = 31.5 * 0.1/1000 mol/ml = 0.00315 mol. Therefore, 0.001575 mol of I2 were released by the bleach.

Hydrazine reduces iodine to iodide according to the following equation:
N2H5+ + 2 I2 => N2 + 4 HI
One mole of hydrazinium ion is required to reduce two moles of iodine. Therefore, 0.0007875 mol of hydrazine sulfate (130.12 g/mol) are required which is about 0.102 g. To account for possible impurities the amount was chosen to be 0.20 g.
0.20 g of hydrazine sulfate were dissolved in 50 ml of distilled water. The iodine solution was titrated. Though the endpoint was kind of hard to determine because the solution remained slightly pink titration was stopped when 22.2 ml had been added. After this point no color change could be noticed any more.
This result was a bit surprising because this amount was less than the theoretical minimum amount (about 25 ml). The solution might have contained less than the theoretical amount of iodine, possible due to the reaction with the alkaline solution. Perhaps the excess of sodium hydrogen carbonate had been too great, and pH had not been checked (according to [4] the pH should be 7.4 for optimum results). It is also possible that the sodium thiosulfate titration (which is said to be unreliable, see [4]) was not very accurate.
In any case the hydrazine sulfate was assumed to be pure enough to further work.
Some of the hydrazine sulfate was further used in the synthesis of 2,4-dinitrophenylhydrazine with satisfactory results.

Conclusions:
- It is better to know the concentration of your starting solutions beforehand.
- Even though urea was present in large excess this didn't seem to influence the yield very much.
- The excess of sulfuric acid might have been helping with purifying the hydrazine sulfate by converting the sodium sulfate into sodium hydrogen sulfate which has more than six times greater solubility in water. Also, there was about twice the volume of water in the solution. Together, this might have reduced the sodium sulfate impurities even though the solution had been cooled in the fridge (contrary to original recipe recommendations).

Next time:
- Use twice the amount of this bleach or half of the other reagents.
- Use EDTA instead of gelatin to avoid foaming.
- Use battery acid instead of making 50% sulfuric acid from concentrated acid.

References:
[1] NileRed (Youtube): Making Hydrazine Sulfate from Urea and Bleach
[2] Titration Of Active Chlorine, Antenna Foundation; https://www.antenna.ch/wp-content/uploads/2017/03/Titration-...
[3] OxyChem Sodium Hypochlorite Handbook; https://www.oxy.com/OurBusinesses/Chemicals/Products/Documen...
[4] K. S. Panwar, N. K. Mathur, S. P. Rao, Hydrazine As A Titrimetric Reagent in Iodometry Part 1, Jodhpur, 1960 (doi:10.1016/0003-2670(61)80114-1)

[Edited on 10-10-2018 by RadicallyStabilized]

Hydrazine Sulfate synthesis with Calcium Hypochlorite

Σldritch - 5-8-2019 at 12:42

Reagents:
50g Ca(OCl)2 (granules, pool chlorine)
100g KOH (90%)
40g Urea (granules, deiceing agent)
80g NaHSO4 (pool ph lowering agent, probably the monohydrate)
HCl (30%, technical with green impurity)

Procedure:
50g of Calcium Hypochlorite granules were mostly dissolved at room temperature in 300ml of tap water. 100g of KOH was dissolved in a small amount of tapwater (estimated 200ml total volume after dissolution). A small amount of Potassium Hydroxide solution was added to the Calcium Hypochlorite solution and both solutions were then placed in a freezer to cool. After some time addition of Potassium Hydroxide was completed. It too was placed in a freezer to cool but this time for several hours. At the same time 40g of Urea granules were also placed in a freezer to cool.

40g of cold urea granules were added to the hypochlorite solution with vigorous stirring after both were removed from the freezer and placed on a magnetic stirrer. Manual stirring was used as well to beat down foam. After some time the reaction slowed down and the solution was heated until the reaction was completed with continued stirring. The resulting hydrazine solution was left to cool in a freezer.

Calcium Carbonate was vacuum filtered off the solution and to the filtrate the Sodium Hydrogen Sulfate was added carefully. The solution was then acidified with hydrochloric acid until it cleared and cooled in a freezer. 26g of dense white crystals were filtered of the cooled solution giving a yield of 28%.

Discussion:
This is my second successful attempt of Hydrazine Sulfate with Calcium Hypochlorite so some mistakes were made: I did not use cold water to dissolve the Calcium Hypochlorite which may have prevented some decomposition and similarly i was too hasty with the addition of the Hydroxide and allowed to solution to heat up a lot. Likely with a similar outcome. Also i did not use distilled water but it seems to work anyway, which is nice.

And here are some observations: when the urea reactions with the hypochlorite solution it goes through a color change even with no gelatin present. First it turns slightly yellow and then towards reddish just before the colour disappears. Final volume before filtering the Hydrazine Sulfate was 600ml. Foam reached only 800ml. Heating the product leaves a small amount of nonvolatile residue therefore real yield is probably lower.

And some notes for anyone who may try this: make sure to cool the hydrazine solution well before you filter of the Calcium Carbonate so that you do not vaporize any more toxic hydrazine than necessary. Using distilled water is probably better too even though it seems to work without it.

And some general thoughts: I think i prefer using Calcium Hypochlorite over Sodium Hypochlorite/Gelatin. Calcium Hypochlorite is so easy to get at good concentration and it does not need gelatin. Which also means it is possible to add solid urea reducing the amount of water even further. And butanone is incredibly expensive here too so i think this procedure is much more accessible.

[Edited on 5-8-2019 by Σldritch]

Boffis - 6-8-2019 at 02:13

Nice work Eldritch. Why does the calcium hypochlorite method not need gelatine or something similar? Does gelatine precipitate with calcium salts? Given the way calcium hypochlorite is produced industrially I would have thought that there was more likelyhood of heavy metal contaiminents in this salt than in sodium hypochlorite.

Pumukli - 6-8-2019 at 05:28

Congrats for the synth!

I'd like to second Boffis' amazement on omitting gelatine. My exact thoughts were as he stated, the way Ca-hypochlorite is produced makes it more likely to get contaminated with various metal ions. My understanding is gelatin is used as a complexing agent to hold up these ions which would otherwise accelerate the decomposition of hydrazine!

Σldritch - 6-8-2019 at 05:34

In short; it is because Calcium Hydroxide is in fact something similar to gelatine, why it works im not entirely sure.

Long answer is that gelatine is believed to chelate metal or immobilize transition metals preventing their catalytic decomposition of hydrazine or some intermediate(s). Calcium Hydroxide should act in a similar way by some combination of incorporation of transition metals into its crystal structure (many transition metals are +2 just as calcium) and intercalation of transition metals between the layers in its crystal structure (check the crystal structure on wikipedia). Any transition metals present in the Calcium Hypochlorite should meet the same fate as those in the tap water when alkali hydroxide is added. Also if it is in fact an intermediate that is decomposed tap water may not actually make a difference to the reaction as long as you do not add more water before the reaction and your urea is pure. Assuming all metal ions are trapped in the Calcium Hydroxide too.

hydrazine from chlorourea, failure report

Diachrynic - 23-9-2019 at 05:19

Based on the posts by garage chemist and ordenblitz as well as patent US3454361A I attempted the chlorourea process with the change of using MEK instead of direct neutralization with sulfuric acid.

Disclaimer:
I found this process unreliable, but maybe I am just missing a crucial detail.

Silver mirror test:
A small sample is dissolved in 9% ammonia with some drops of silver nitrate solution. After a while a silver mirror forms and confirms the reducing agent.

Attempt 1:
Following garage chemists post, I used the same amounts and just adjusted for using sodium dichloroisocyanurate (NaDCCA) instead of TCCA.

Chlorine: 15.2 g NaDCCA, 30 g 30% HCl
Urea: 20.5 g CO(NH2)2 + 0.2 g gelatin in 40 ml
Sodium hydroxide: 16 g NaOH in 40 ml of water
Extraction using MEK, yielded 33 g of ketazine phase

The gelatin was first dissolved into the boiling hot water, which was dumped onto the urea, instantly dissolving and giving a luke-warm solution which was left to cool to room temp. for a bit.

The chlorine absorption was great and even tho the chlorine bubbled fast through the solution, no chlorine smell was observed, as well as next to no suckback. After all acid was added, the chlorine generator was heated until no more gas evolved.

The chlorourea was added into the lye solution inside a 1000 ml erlenmeyer flask, the foam only filled up about 200 ml. It was left stirring then heated, turing yellow and then more clear again, was left cooling in the water bath and then stirred with the MEK for a short time.

Yield was about 4.56 g of hydrazine sulfate after hydrolyzing the ketazine with 38% sulfuric acid, 25% based on chlorine (the limiting reagent).

Then I attempted the procedure from the patent.

Attempt 2:
Slightly modifying the procedure from the patent, I increased the ratio of chlorine to urea to about 1/1. I also added some NaHCO3 to catch some of the HCl that forms. The foaming was unbearable and the addition of chlorine took almost 3h when it took half an hour before.

Chlorine: 36.4 g NaDCCA, 63 g 30% HCl
Urea: 20 g urea + 0.2 g gelatin + 9 g NaHCO3 in 40 ml
Sodium hydroxide: 16 g NaOH in 40 ml of water
Extraction using MEK, yielded 44 g of ketazine phase

The chlorourea solution had an unpleasant chlorine-like smell, somewhat sweeter, possible the smell of chloramines. It evolved gas on its own, nearly blowing out a stopper once. It foamed strongly when pouring it into an addtion funnel.

Addition into the hydroxide produced a massive amount of foam and lots of white smoke and a lot of heat. It had to be added in several small amounts, yet the foam almost reached the top of the 1000 ml erlenmeyer flask several times.

After the hydrolysis nothing could be recovered from the hydrolyzed ketazine.

Upset about this I thought about giving this a last chance.

Attempt 3:
Following garage chemists post again but on 2x scale and with some modifications I used these amounts:

Chlorine: 30.4 g NaDCCA, 60 g 30% HCl
Urea: 41 g CO(NH2)2 + 0.4 g gelatin in 40 ml
Sodium hydroxide: 32 g NaOH in 80 ml of water
Extraction using MEK, yielded 22 g of ketazine phase

This time I cooled the urea solution in the freezer before passing the chlorine into it.

The reaction flask for the final addition was a three necked 1000 ml RBF with addtion funnel and reflux condenser. Both the chlorourea and the lye solutions were cooled to about 5 °C beforehand. With strong stirring, the chlorourea solution in the addition funnel was drained into the lye, heating the soltion to 40 °C instantly and foaming up to roughly about 2x the liquid volume. The solution was stirred for a bit, but no change in bubbling seemed to occur, so the mix was heated to about 80 °C for a few minutes. Still barely any change, it was cooled to 70 °C before I added the (ca. 40 g) MEK via the addition funnel. The mix turned first yellow and then red. Cooling in the water bath to 20 °C and stirring strongly for 2h (I suspected the earlier attempt to fail because I didn't stir long enough to form the ketazine) gave a very red solution (should have let the solution cool more) and a yellow layer on top. To improve the recovery of ketazine, some K2CO3 was added and 25 ml of washing gasoline which gave 30 ml of slightly yellow liquid, another washing gave 27 ml from 24 ml. The gasoline washes were processed separately.

On hydrolysis the this time very yellow ketazine phase gave nothing but a deeply red, awfully smelling solution. The gasoline washes deposited a small amount of what looked like hydrazine sulfate which was confirmed using the silver mirror test.

Attempts at saving the hydrolyzed ketazine solutions:
I suspected I added not enough sulfuric acid, so I added some more and boiled the ketazine from attempt 2 and 3 down even further. This yielded bigger crystals that didn't look like the small crystals of hydrazine sulfate.

However, the silver mirror test confirmed both crystals to contain hydrazine.

Conclusions:
A big issue is the self-heating when mixing the chlorourea and the lye.

I have found this method to be unreliable and low yielding, giving 25%, 0% and 0% in the three attempts as well as something that doesn't seem to be hydrazine sulfate but still reducing somehow.

Maybe there is also some issue with the ketazine extraction. Maybe the crystals are some different salt of hydrazine, maybe they just look different. Maybe the gelatin gets destroyed by the chlorine and should be added later. Overall I think making bleach from the chlorine is more worthwhile.

However, urea seems to at least work as a good chlorine scrubber.

Left to right: Samples of the products of attempt 1, 2 and 3.

hydrazine_attempt1.jpg - 1.1MB hydrazine_attempt2.jpg - 1.1MB hydrazine_attempt3.jpg - 1.1MB

improvement of the ketazine extraction using washing gasoline

Diachrynic - 29-9-2019 at 03:26

I have run the synthesis of hydrazine sulfate from NileRed and Chemplayer with the change of using MEK to extract the hydrazine.

I found two improvements to the process:

The first is to let the MEK stir in for a longer time like several hours.
The second one is after the ketazine layer is drained from the aqueous solution, the solution can be reextracted with washing gasoline, I did this two times with 40-50 ml each.

I did the synth. with a total of 1325 ml of 4% NaOCl.

Using this, I obtained 27.44 g of hydrazine sulfate from the ketazine phase and additional 6.69 g from the gasoline upon adding sulfuric acid.

For purity reasons for recovering the MEK, the washing gasoline extract should be treated separately.

Note: I didn't come up with this idea, in this thread Nurdrage suggested toluene, but as washing gasoline is cheaper and OTC for me I used that. It seems to be higer boiling stuff tho. Despite boiling at 110 °C it seems quite volatile. Odd.

B.D.E - 8-1-2020 at 08:26

I'm not sure if anyone posted it here yet, but I found a new book(2014) dedicated only to Hydrazine and some of its Derivatives.

Inorganic Hydrazine Derivatives: Synthesis, Properties and Applications

f936c2d44ce90b02568a1c474c27be3e-d.jpg - 38kB
http://gen.lib.rus.ec/book/index.php?md5=F936C2D44CE90B02568...

Hydrazine And Its Derivatives

MadHatter - 9-1-2020 at 03:13

I had the book once before and it
was lost due to unfortunate circumstances.
I found another copy on eBay and
awaiting its arrival. I'll let you know.

Your book

MadHatter - 9-1-2020 at 14:14

B.D.E, anytime you can find a book who's
focus is 1 compound and its derivatives,
that's definitely a KEEPER ! I wish there
more books like that around. I'm still waiting
on Hydrazine And Its Derivatives. I consider
myself very lucky to have found this treasure
again. I'll be scanning this 1 in - AGAIN !

Let me know about the details of your
book when you have a chance. I would
be very grateful and certainly appreciate
any effort on your part.

Next replacement book - The Merck Index

Thank You

The Merck Index

MadHatter - 12-1-2020 at 14:43

The Merck Index should arrive within the
next few days. It'll be scanned in if I can't
find any comparable link online. These
materials will be available under the REFERENCE
section of the LIBRARY when I get the FTP
server booted up. Wish me luck !

Wild speculation on the function of gelatin

Σldritch - 7-2-2020 at 02:06

I have been thinking on and off on the origin of the yellow and red color i observed when making hydrazine and i think i may have come up with a good candidate: the red and yellow color is from the aminoxyl radical. Look at the color of TEMPO:

https://en.wikipedia.org/wiki/TEMPO#/media/File:Sample_of_TE...

Almost identical, and in dilute solution it could very well be yellow. With this i speculate that gelatine actually has two functions in the hydrazine synthesis because of the difference of the colour i observed in my gelatine free hydrazine synthesis and what is usually reported from the hydrazine synthesis.

1. Trapping radical producing transition metals.

2. Trapping radicals by reacting with them (probably oxidation of proline, other amines and sulfur)

If it is not present, such as in the Calcium Hypochlorite version i did, the solution turns red because the concentration of the radicals is high while with gelatine a yellow color is usually observed because the concentration is lower. The unstable aminoxyl radical seems to quickly decompose, probably yielding nitrogen gas and carbamic acid which further decomposes to ammonia and Carbon Dioxide:

2 CO(NH2)NHO* ---> 2 COOHNH2 + N2 (1)
COOHNH2 ---> CO2 + NH3 (2)

But really there are a lot of stuff that can form when radicals is involved, hydrazine(derivatives) too but in the Hoffmann degredation i think it is undesireable. So if this is true we should not only be looking for chelating agents but radical scavengers too. While i have not had much success finding a readily available radical scavenger i did find this paper which is quite interesting assuming radicals is a major reducer of yield:

https://www.ncbi.nlm.nih.gov/pubmed/30243703

While they use Hydrogen Peroxide similar chemistry should be seen with hypochlorite though chloride may compete more with chelating agents for complexation with copper. After some quick searching for the catalyzed decomposition of hypochlorite by transition metal i did not find much except that it likely follows the reaction:

2 ClO- ---> Cl- + O2 (3)

Now imagine singlet oxygen is formed, not too far-fetched considering the reaction of Hydrogen Peroxide and hypochlorite, and consider the following reaction producing the aforementioned aminoxyl radical:

CO(NH2)2 + 1O2 ---> CONH2NHO* + H2O (4)

Neat, but i do not think this makes that much sense unless the aminoxyl radical has an extremely strong color or reaction 3 is an equilibrium and the removal of singlet oxygen causes an increased rate of decomposition of hypochlorite according to le chatlier's principle. Option one seems somewhat reasonable but i can not make a strong argument for it. Anyway i should probably stop now seeing as i can not test any of this right now.

Synthesis and Questions

artemov - 7-4-2020 at 22:58

My hydrazine sulfate synthesis using the standard urea+bleach+sulfuric acid method. This is the 2nd run, I was too scared during the 1st run to take any pic :)

Pic 1 30g of NaOH is first dissolved in 30ml of DW
Pic 2 (which is then added to ) ~550ml cold household bleach (assumed 5% concentration)
Pic 3 ~22g of urea and <1g of gelatine is dissolved in 20ml of warm DW
Pic 4 the initial foaming started in about 5 seconds after combination of reactants
Pic 5 heating in water bath after initial foaming died down; solution turned a darker shade with more foaming
Pic 6 stop heating after foaming ceased; solution is pale yellow
Pic 7 ppt before neutralization; NaCl? Na2CO3?
Pic 8 neutralization with 110ml of 55% cold sulfuric acid; ppt disappeared!; extra sulfuric acid will not affect yield right?
Pic 9 "yield" from 1st run; very fine crystals, frankly I can't tell if it's hydrazine sulfate, Na2SO4 or NaCl ...

I am assuming there will be Na2SO4 impurity, this will not affect the freebasing of hydrazine with NaOH/ethanol right?

Cheers. It was fun.


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20200408_145128.jpg - 31kB

[Edited on 8-4-2020 by artemov]

B(a)P - 8-4-2020 at 02:53

What was your percentage yield?
You can use the silver mirror test if you have silver nitrate (or can readily make it) http://www.sciencemadness.org/smwiki/index.php/Hydrazine_sul...
As long as you filtered before it got too cold you won't get much Na2SO4.
Na2SO4 is what you will be filtering out after the freebasing so it does not matter.

edit, fixed the link

[Edited on 8-4-2020 by B(a)P]

artemov - 8-4-2020 at 03:58

Quote: Originally posted by B(a)P  
What was your percentage yield?
You can use the silver mirror test if you have silver nitrate (or can readily make it) http://www.sciencemadness.org/smwiki/index.php/Hydrazine_sul...
As long as you filtered before it got too cold you won't get much Na2SO4.
Na2SO4 is what you will be filtering out after the freebasing so it does not matter.

edit, fixed the link

[Edited on 8-4-2020 by B(a)P]


Unfortunately I dun have any silver salts, too expensive lol ....

I haven't dry them yet, and I'll be combining yields from both runs. Hoping to get >30g (with impurity) for the azide synthesis.
I'm cooling them down to ~5C in the fridge, since Na2SO4 doesn't matter in the freebasing, I'll try to get as much hydrazine sulfate out of the solution as possible. Too tired to do a 3rd run :P

Thanks, will update with the final yield.



[Edited on 8-4-2020 by artemov]

Belowzero - 24-5-2020 at 22:55

Failure


Hello Sciencemadness,
It's been close to 10 years since I was active here and I am glad to see SM is going strong!
Anyway recently I got a new lab up and running and decided to synthesize a small batch of HS which seemed to have failed.

Since I had a hardcopy of this procedure and since it is similar to Rosco's method I gave it a go.
https://www.designer-drug.com/pte/12.162.180.114/dcd/chemist...

I used roughly 1/6th of the amounts used.
Which comes down to:

Urea 22.0g
Bleach 230.0ml 12.5 %
NaOH 32.3g
Pig Gelatine 0.3g
Sulfuric acid 183ml 37%


I didn't confirm the concentration of the bleach however I know this batch is relatively fresh and should be very near to 12.5%
This is 20ml less than the procedure to compensate for its higher concentration.

Now I know the neutralization step is suboptimal compared to the HCl route and took this for granted.
I might just have made very expensive glaubers salt because the procedure did not go as planned.


The dissolving of the NaOH was quite tedious, to buffer the temperature of the bleach I used a large cold water bath.
The temperature never rose above 10 degrees C.

After adding all the reactants a large evolution of gas was witnessed, the temperature rose strongly (no measurements)
almost too hot to touch the flask.
Expecting the foaming as described and seen in my earlier days of making this substance I was surprised hardly any foam was produced at all, only a very small whiteish layer above the liquid. This subsided entirely after a few minutes.

The production of gas stopped entirely after an hour or so and I decided to kick up the heat to just below boiling.
More gas was produced and the heat was turned off again.

I called it quits because no distinct coloration nor foaming was witnessed and dumped the content in a large beaker in a cold water bath. The sulfuric acid was added and left to cool in the same bath, ~10-15 degrees C.

The next day a layer of white precipitate was formed.


No tests have been conducted yet on the product.
I suspect I have made really expensive sodium sulfate.
Now the question is why didnt the reaction foam excessively like it should?


I suspect it is due to metal traces in the reaction , the groundwater contains quite some iron. I use this to wash my glassware.
Of course knowing this I took extra care and flushed it with both NaOH solution and HCl as an attempt to get rid of traces.
Looks like it still was not enough to get rid of it.
Or perhaps I messed something else up like using too much hypochlorite.

Any suggestions ?




[Edited on 25-5-2020 by Belowzero]

woelen - 25-5-2020 at 00:50

Did you test the white solid? Does it dissolve in cold water easily? If not, then it might be hydrazinium sulfate (that compound only dissolves with difficulty in cold water). Another test for hydrazinium sulfate is to add this to an acidified solution of KMnO4. This will lead to nearly instantaneous loss of color of the solution. If it is just sodium sulfate, then there will be no loss of color and if it is urea, then there will only be slow disappearance of color.

You could also add some of the solid to a concentrated solution of an acidified chlorate, bromate or iodate. With hydrazinium sulfate you will have a very violent reaction.

Belowzero - 26-5-2020 at 08:11

Quote: Originally posted by woelen  
Did you test the white solid? Does it dissolve in cold water easily? If not, then it might be hydrazinium sulfate (that compound only dissolves with difficulty in cold water). Another test for hydrazinium sulfate is to add this to an acidified solution of KMnO4. This will lead to nearly instantaneous loss of color of the solution. If it is just sodium sulfate, then there will be no loss of color and if it is urea, then there will only be slow disappearance of color.

You could also add some of the solid to a concentrated solution of an acidified chlorate, bromate or iodate. With hydrazinium sulfate you will have a very violent reaction.



Thanks Woelen!
I conducted the test with KMnO4 , I dissolved a few crystals in 10 ml of water with a drop of H2SO4.
When I dropped in a few supposed HS crystals the solution went to light pink and then white almost instantly.

Also the material is poorly soluble in cold water, I attempted to dissolve a few wet crystals in 20ml which didnt go into the solution upon stirring.

The wet crystals are now washed ,vacuum filtered and put in a dessicator, I'll conduct more tests to rule out any false positives.

It seems the synthesis did produce HS after all.
I am still clueless as to why the foaming was practically absent, if the yield is good it might be worth investigating since the foaming is the worst part of this procedure and it would be great if this could be prevented.

More results later.


[Edited on 26-5-2020 by Belowzero]

B(a)P - 26-5-2020 at 15:29

Quote: Originally posted by Belowzero  


It seems the synthesis did produce HS after all.
I am still clueless as to why the foaming was practically absent, if the yield is good it might be worth investigating since the foaming is the worst part of this procedure and it would be great if this could be prevented.

More results later.


[Edited on 26-5-2020 by Belowzero]


The amount of foaming you get is very variable and depends on the additives in the bleach. I switched to pool chlorine for my HS thinking it would not have many additives and it has a high NaClO concentration. However, it foams more than any other NaClO source that I have used before. It does produce a good yield though.

Belowzero - 28-5-2020 at 22:23

Quote: Originally posted by B(a)P  
Quote: Originally posted by Belowzero  


It seems the synthesis did produce HS after all.
I am still clueless as to why the foaming was practically absent, if the yield is good it might be worth investigating since the foaming is the worst part of this procedure and it would be great if this could be prevented.

More results later.


[Edited on 26-5-2020 by Belowzero]


The amount of foaming you get is very variable and depends on the additives in the bleach. I switched to pool chlorine for my HS thinking it would not have many additives and it has a high NaClO concentration. However, it foams more than any other NaClO source that I have used before. It does produce a good yield though.


NaClO is actually the only thing it contains according to the label , I'll have another look at what the manufacturer mentions.
The precursors used are all quite pure in fact.
Externally introduced impurities is the only thing I can think of at this point.

Fyndium - 15-1-2021 at 05:32

I was about to bump an old topic, but noted that there is actually a major thread on this matter.

Hydrazine forms 68.5% azeotrope according to wiki ( https://en.wikipedia.org/wiki/Azeotrope_tables ) which would indicate that distilling it would proceed as with nitric acid.

https://www.prepchem.com/synthesis-of-hydrazine-hydrate/

This source depicts that it is practically done as said, but with very little water, apparently to gain over 90% concentration, and without vacuum, so apparently at least vacuum is not necessary. I presume that adding more water to the azeotrope balance would yield to collection of azeotropic hydrazine. They note that the major corrosive contributor is the hydroxide, not the hydrazine itself. The trouble of getting a copper/silver/tantalum retort equals to ordering a dozen or two of 500-1000mL flasks from china, so a potential sacrificial flask would be a much better choice. Running without vacuum could make things easier, as no active exhaust of hydrazine fumes happens, and it can just simply put behind a trap.

[Edited on 15-1-2021 by Fyndium]

Jebby - 26-4-2021 at 06:41

I followed the procedure from NileRed’s video scaled down by half. I tried to add the urea gelatin mix to the basic bleach solution all in one go and it almost immediately started foaming uncontrollably spilling everywhere. The temperature of the bleach solution was around 8 to 10°C and the gelatin+urea was still slightly warm. The bleach I am using is about 7% and I’m using tech grade NaOH drain cleaner. I’ve tried the reaction 3 times and had one run that gave me a few mg of hydrazine sulfate. I was wondering if anyone had any ideas as to what I’m doing wrong.

clearly_not_atara - 26-4-2021 at 09:46

I think you could make methyl carbazate via the reaction of hydroxyurea with dimethyl carbonate as described in the attached. Assuming that DMC doesn't react with the other side of the hydroxyurea, it should be fine.

Hydroxyurea is itself produced by the rearrangement of hydroxylammonium cyanate produced by salt metathesis (hydroxylammonium X + M cyanate).

This adds up to a laborious but OTC and "clean" prep of hydrazine by hydrolysis of methyl carbazate. The Lossen has successfully been performed on substituted hydroxyurea via carbonates as well, cf:

https://pubs.acs.org/doi/full/10.1021/acs.orglett.9b01742

Attachment: kreye2012.pdf (196kB)
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clearly_not_atara - 10-9-2021 at 08:49

Found this while looking up something unrelated:
https://pubs.acs.org/doi/abs/10.1021/ja01063a013

Oxidation of benzhydrylamine [...] in hot excess permanganate, benzophenone azine (VII) is formed.

ManyInterests - 25-10-2021 at 08:15

This thread is fascinating. I've been looking into various ways to make hydrazine sulfate, but I have one simple question:

When you use HCl to reduce the alkalinity of the solution before adding the 50% H2SO4, would hardware store muriatic acid suffice? I have some ro-tyme muriatic acid at 31.25% concentration, but I am not sure about other possible impurities.

I bought a bottle of 10% Sodium hypochlorite pool chlorinator, but that was months ago. I hope it didn't degrade too much.

ManyInterests - 27-10-2021 at 19:02

So I have my first batch of hydrazine in the freezer that is around 20 or 21 c. I have one question: Does Hydrazine retain it's own heat so well? I've never seen a substance take so long to cool down before.

Edit: No it's fine. It came out. It just took a lot longer than I thought. My freezer is also OK.

[Edited on 28-10-2021 by ManyInterests]

Belowzero - 28-10-2021 at 01:20

Quote: Originally posted by ManyInterests  
This thread is fascinating. I've been looking into various ways to make hydrazine sulfate, but I have one simple question:

When you use HCl to reduce the alkalinity of the solution before adding the 50% H2SO4, would hardware store muriatic acid suffice? I have some ro-tyme muriatic acid at 31.25% concentration, but I am not sure about other possible impurities.


One thing that comes to mind is that metal contaminants can be responsible for significantly lowering the yield.
Without knowing which impurities are present it is hard to say anything resonable here.
Perhaps you can boil down some of the stuff to see if it leave solids behind.

Basically any acid will do, iirc HCl(instead of H2SO4) is used to prevent other sulfates from coming out of solution.

ManyInterests - 28-10-2021 at 16:39

OK that is good. I was not aware of that.

BTW, I finally dried my yield, and I think it seems awfully high. I used 50% of the amounts used in this video:

https://youtu.be/K4p8zHuPVIM

But while I was expecting a similar yield of 20 grams or so, I got a yield of 29 grams. I am wondering if I have a lot of sodium sulfate contamination in it. I did put it in the freezer and peroidically checked my glass thermometer until it hit around 13 or 14 c. It took an awful long time to cool down, but It did. What could have happened for my yield to be so high?

Also if I may, can I draw your attention to another thread I made on disposing of the hydrazine and the byproducts of the synthesis in this thread. I want to make sure I disposed of everything correctly.

https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

Thanks.

ManyInterests - 11-12-2021 at 16:42

OK so I attempted to freebase some hydrazine... but I am pretty sure something was off. It is possible that my hydrazine sulfate was far too contaminated with sodium sulfate. I added around 30 grams of sodium hydroxide gradually to 40 grams of hydrazine sulfate, with 110ml of ethanol added. I mixed them for about 20 minutes and let them sit in an ice bath (covered with plastic wrap) for almost an hour now and the liquid is milky white with no clear liquid out there. I added more ethanol and the ethanol solution is still very milky white.

Was my hydrazine sulfate a dude or what?

B(a)P - 11-12-2021 at 22:15

Quote: Originally posted by ManyInterests  
OK so I attempted to freebase some hydrazine... but I am pretty sure something was off. It is possible that my hydrazine sulfate was far too contaminated with sodium sulfate. I added around 30 grams of sodium hydroxide gradually to 40 grams of hydrazine sulfate, with 110ml of ethanol added. I mixed them for about 20 minutes and let them sit in an ice bath (covered with plastic wrap) for almost an hour now and the liquid is milky white with no clear liquid out there. I added more ethanol and the ethanol solution is still very milky white.

Was my hydrazine sulfate a dude or what?


Do you have any of your initial product left? There are tests you can do to identify hydrazine sulfate.
In my experience you sometimes need a little water to kick the reaction off. Were you using absolute ethanol or aziotropic?

ManyInterests - 11-12-2021 at 22:37

Quote:
Do you have any of your initial product left? There are tests you can do to identify hydrazine sulfate.


I used 40 grams and I think I have about 20 grams left. I don't have much faith in them to extract enough hydrazine freebase in order to finish my NHN synthesis. But I can test it if you like. I need to take a break from this for a bit before I do another synthesis of hydrazine. I have enough experience with it so I can use the 'normal' quantities instead of half quantities.

I will be using hydrochloric acid in addition to sulfuric in making it. If that will free up more hydrazine sulfate. This failure was extremely frustrating to me.
Quote:
In my experience you sometimes need a little water to kick the reaction off.


When I opened my hydrazine container (I store it in a plastic tupperware) I noticed that the coffee filter I put under it was quite moist, so I assume it was not 100% dry even if I thought it was. How much water are we talking about here?
Quote:
Were you using absolute ethanol or aziotropic?


I used 95% denatured ethanol. Every guide I looked at in freebasing (including chemplayer, who I followed as closely as possible). I also have 99% isopropyl alcohol to use if that will yield a better result.

I need to ask this one question about my failed NHN synthesis. While I do believe I made excellent nickel nitrate (it was very dry, no nitric acid, and extremely green). When I added it to the rather... non-freebased hydrazine, the color turned green and some kind of green goo percipitated. I am not sure what it is, but I don't think it's an explosive of any kind and I need to dispose of it. I poured 10% sodium hypochlorite solution and calcium hypochlorite solution and it turned black. Did the left over liquid (which had hydrazine as evident when I poured the sodium hypochlorite in it.

I also poured some bicarbonate solution in case there is any acid. What other precaution should I take before putting this stuff in the trash?

B(a)P - 12-12-2021 at 03:20

Quote: Originally posted by ManyInterests  
Quote:
Do you have any of your initial product left? There are tests you can do to identify hydrazine sulfate.


I used 40 grams and I think I have about 20 grams left. I don't have much faith in them to extract enough hydrazine freebase in order to finish my NHN synthesis. But I can test it if you like. I need to take a break from this for a bit before I do another synthesis of hydrazine. I have enough experience with it so I can use the 'normal' quantities instead of half quantities.

I will be using hydrochloric acid in addition to sulfuric in making it. If that will free up more hydrazine sulfate. This failure was extremely frustrating to me.
Quote:
In my experience you sometimes need a little water to kick the reaction off.


When I opened my hydrazine container (I store it in a plastic tupperware) I noticed that the coffee filter I put under it was quite moist, so I assume it was not 100% dry even if I thought it was. How much water are we talking about here?
Quote:
Were you using absolute ethanol or aziotropic?


I used 95% denatured ethanol. Every guide I looked at in freebasing (including chemplayer, who I followed as closely as possible). I also have 99% isopropyl alcohol to use if that will yield a better result.

I need to ask this one question about my failed NHN synthesis. While I do believe I made excellent nickel nitrate (it was very dry, no nitric acid, and extremely green). When I added it to the rather... non-freebased hydrazine, the color turned green and some kind of green goo percipitated. I am not sure what it is, but I don't think it's an explosive of any kind and I need to dispose of it. I poured 10% sodium hypochlorite solution and calcium hypochlorite solution and it turned black. Did the left over liquid (which had hydrazine as evident when I poured the sodium hypochlorite in it.

I also poured some bicarbonate solution in case there is any acid. What other precaution should I take before putting this stuff in the trash?


Test your hydrazine sulfate, you can't freebase hydrazine if you don't have it in the first place.
The reaction for the liberation of hydrazine needs a little water to get it started because of the limited solubility of hydrazine sulfate in ethanol. Once started the reaction generates water so no more is needed. It is a finicky reaction that requires close and careful observation. If there are no signs of the reaction commencing after the first sodium hydroxide addition then there is not point in adding more until you can get the reaction started. On the flip side if the reaction gets going to quickly/vigorously it will also fail.

ManyInterests - 12-12-2021 at 08:12

OK so I think the problem is that my synthesis went wrong somehow. I will go through the thread I commented on and pyrotechnical science's video again (where he uses hydrochrloric acid. I think it was you in another thread that said that even the technical grade muratic acid is good enough for this stuff. I want to extract good hydrazine sulfate. Just one good batch and I should have enough for a single NHN synthesis. At least my nickel nitrate synthesis went good!

What test can I do to make sure I have hydrazine sulfate? I was told I jst need a test tube and a blowtorch. I don't have any test tubes and just a barbique lighter.

fredsci93 - 12-12-2021 at 11:58

One test for hydrazine is to heat the hydrazine sulfate with nitric acid to ~70C and pass the produced vapours through lead, copper or silver nitrate, it should produce hydrogen azide fumes which will make the metal nitrate solution precipitate metal azides.
But I would not recommend this unless you can handle highly explosive and highly toxic gasses since hydrogen azide is very toxic and very explosive.

B(a)P - 12-12-2021 at 13:19

Quote: Originally posted by ManyInterests  
OK so I think the problem is that my synthesis went wrong somehow. I will go through the thread I commented on and pyrotechnical science's video again (where he uses hydrochrloric acid. I think it was you in another thread that said that even the technical grade muratic acid is good enough for this stuff. I want to extract good hydrazine sulfate. Just one good batch and I should have enough for a single NHN synthesis. At least my nickel nitrate synthesis went good!

What test can I do to make sure I have hydrazine sulfate? I was told I jst need a test tube and a blowtorch. I don't have any test tubes and just a barbique lighter.


You can distinguish between sodium sulfate and hydrazine sulfate very easily by testing the melting point. Hydrazine sulfate has a much lower melting point and will decompose with further heating.
A more specific test was mentioned above.
You can also react silver nitrate with hydrazine sulfate in a glass vessel to make a silver mirror, you would need to research the specifics of the reaction.

ManyInterests - 12-12-2021 at 14:45

That sounds good. I have around 20 grams of sulfate remaining (but I seriously doubt it's purity). I will try test a bit of it. Maybe even try to freebase it, but I won't hold my breath... or maybe I will, as breathing in any hydrazine fumes is no good! :D

ManyInterests - 13-12-2021 at 18:57

My goodness! I think I figured out why my hydrazine sulfate synthesis went wrong before! No wonder I couldn't freebase any hydrazine. My first two synths failed to synthesize anything other than sodium sulfate or whatever.

So what happened is when I put in the urea/gelatin solution I didn't wait for the thing to fully react, or it didn't react correctly before I turned up the heat. This is the first problem. The second problem is that I avoided HCl, which probably affected the yield a lot.

That being said. This time I did my synthesis (It's cooling as I write this) and now I see the sulfate already forming like in all the videos I have seen, and it isn't even 20 C yet. I will harvest the moment it hits 15C

the only thing I might have done wrong this time is let the temperature hit 20C for a brief bit, but it never went beyond that and it cooled to 19 C and below in a minute or less.

fredsci93 - 13-12-2021 at 23:46

That's good that you sorted the problem, hopefully the hydrazine freebasing will go better with the new source of hydrazine sulphate.

ManyInterests - 14-12-2021 at 02:57

Yeah. I should have noticed that I didn't get any sulfate precipitate like in the videos, but this time I got a lot of precipitate the moment I finished adding the sulfuric acid. In fact I got no precipitate at all until the temperature dropped below 15... So that stuff was mostly, if not entirely, sodium sulfate.

Now it looked like all the videos. I will wait 24 hours or so to let it dry at room temperature and try to squeeze out as much liquid as possible. I did see pyrotechnical science dry his on a hot plate, but that sounds very excessive to me. A bit of hand squeezing with paper towels should be sufficient.

S.C. Wack - 4-2-2022 at 16:29

Quote: Originally posted by S.C. Wack  
Sauron seems to have deleted where he doubted making hydrazine from urea and hypochlorite, which makes my looking up DE164755, US1959503 (the above GB patent), DE729105, and DE735321 seem pointless.


Quote: Originally posted by Sauron  
I will happily look at those patents.


The 1939 Inorganic Syntheses entry for hydrazine sulfate begins with "The only satisfactory method for synthesizing hydrazine was devised by Raschig [1907] and involves the oxidation of ammonia by sodium hypochlorite in the presence of some such catalyst as glue or gelatin." They go on to say "Although it has long been known that benzaldehyde reacts with hydrazine in alkaline solution to give a yellow, insoluble precipitate of benzalazine and that the latter when steam distilled in the presence of mineral acids is hydrolyzed to give the corresponding hydrazine salts*, no previous attempt has been made to apply these facts to the recovery of hydrazine residues.", their *citation being Zhurnal Russkago Fiziko-Khimicheskago Obshchestva 37, 1 (1905) and its JCS abstract.

IS fails to mention that the cited Russian article (its title, ~ "The action of hypochlorites on urea: a new synthesis of hydrazine" is also unsaid) is not about benzalazine but is in fact a synthesis of hydrazine from urea and 7.5% sodium hypochlorite in 60% yield, by way of benzalazine, and also that the JCS abstract says nothing of benzalazine or much of anything at all. The IS authors must have read a better abstract at the least for that detail, and would have been aware of the yield, and certainly that benzaldehyde was applied to the recovery of hydrazine. The use of benzaldehyde can't be unsatisfactory since IS employs it, and their yield from ammonia is 35%, based on hypochlorite.

Dr. Petr Ivanovič Šestakov (Czech? published from St. Petersburg) /P. J. Schestakoff/P. J. Schestakow (let's call him Shestakov in this language) obtained DE and FR patents for the process in 1903, and he might have been frustrated by such treatment from these and other writers, if he survived 1905 (the 1905 revolution); I couldn't find any information about him. Hofmann and Raschig stole all his thunder; he gets only a little love for this (mostly through Houben-Weyl) with the "Shestakov Rearrangement" of hydantoic acids to hydrazino acids.

The Chem. Centr. abstract says that without the benzaldehyde, Shestakov's yield was 20%; thus the benzaldehyde (and, "30-40 g of hydrazine sulfate can be prepared from 1 liter of urine"). It's rather amazing that it took 25 years for someone to consider using Raschig's additives with Shestakov's substrate; urea was dismissed by several experimenters before IS took things so far as to disappear it. US1959503, using urea with glue, gelatin, etc. without benzaldehyde, was issued to Germans in 1932. (it is said that hydrazine was not produced in the USA until 1938, and then only for boiler water treatment) Yield is still 60+%. Doubly ironically, it was Raschig GmbH (which still exists) who held the patent to a later additive for further improving Shestakov's discovery, employing Mn, said years earlier to be detrimental to the Raschig method.

Beispiel
Zu einer Lösung von 74,5 g Natriumhypochlorit in 1000 ccm Wasser werden zunächst 280 g NaOH 45° Baume gegeben. Dann wird das Gemisch mit 15 ccm einer 1/2 %igen Mangansulfatlösung versetzt. Nach Kühlung auf etwa 15° werden 60 g Harnstoff zugesetzt. Hierauf wird zum Kochen erhitzt und die Lösung etwa 5 Minuten lang bei dieser Temperatur gehalten. Aus der Reaktionslösung kann man das Hydrazin in bekannter Weise als Sulfat oder als Hydrat gewinnen. Die Ausbeute beträgt 78 bis 90 g Hydrazinsulfat = 60 bis 70% der Theorie.

Lately, I've been optimizing that for my hands, as I have some interest in hydrazine in organic chemistry. 70%+ yield has only been possible when the yield is based on hypochlorite, and less than 1 mol. of it is added. The ceiling based on urea, using the cheapest 7.5% bleach, is 64%. 60% based on urea should be considered a minimum, even though 56% would be higher than anyone's book, video, or internet recipe using gelatin.

Not overlooking hepatotoxic/genotoxic/carcinogenic/mutagenic hydrazine vapors or sulfate mist, a kitchen stove with 4 burners and large pots of water can accomodate perhaps 16 loosely sealed Mason jars of quart size, yielding a kg of hydrazine sulfate, using 7.5% bleach and with acidification in 2 5-gallon buckets. The entire process to dry crystals can be performed in an hour if one is in a hurry (if washed with volatile solvent), and has pre-cooled reagents.

Further regarding toxicity, anyone who says that there is a conspiracy to not cure cancer with hydrazine sulfate is a proven idiot, who is wet clay in the hands of conspiracy theorists and shameless profiteers, plus either willfully ignorant of or hostile to over 120 years of science. Someone who sells or advises using this to ingest obviously isn't taking it themselves.

Reproducible results are challenging when using different bottles of bleach, without titration. Bottles from the same grocery shelf can have obviously different color and clarity. I suggest starting with a theoretical 10% deficiency of hypochlorite and 10% excess of NaOH, which appears to be the most economical plan. If the yield is still not good with equimolar hypochlorite and excess NaOH, more bleach will not help because chloric acid and chlorine will not help, and titration will probably indicate that the bottle has gone bad. A homemade hypochlorite with the amount of free NaOH required for the process will store and yield better than any commercial product.

To produce 1.3 kg of the sulfate (500 g of the hydrate, theoretically), I'd need roughly 1 kg urea, 14 l "7.5%" bleach, 4 l conc. sulfuric acid, and 1.5 kg NaOH. So, it would not be an inexpensive mission. Stop reading here if you're uninterested in these experiences, because those concise six sentences of patent are transformed even further to a long dull story of questionable value.

Elsewhere in the patent, they say that the form of Mn is not particularly important. The specified concentration is not randomly chosen. The solution is completely decolorized after heating with their amount of Mn. It may be convenient to use this decolorization as the end point of heating, but I prefer to double their amount, and this is not decolorized. Either way, the Mn precipitates and can be filtered after cooling, but it's not easy or obviously beneficial.

Stirring is not mentioned in the example, which I suspect is not accidental. I also suspect that a flaw of other investigators using urea and gelatin is employing stirring (and, maximizing hypochlorite concentration, and, adding solid NaOH to hypochlorite regardless of temperature, and, bad ratios). Using considerably more NaOH, or less, is not necessarily detrimental to the yield of hydrazine or its sulfate, but then I'm not using M hypochlorite (not deliberately at least), as the patent describes.

The overall concentration is perhaps similar however, as my urea is a solution (the eutectic), cooled as far as possible in a RBF (as is the bleach, in a stoppered FBF) in the freezer, with the Mn solution and 42% NaOH stored in the fridge. This is out of habit, but the temperature does not seem particularly critical, and in fact many aspects of all this can be varied without changing the yield much. The NaOH is prepared and kept in a plastic container. First the bleach is added to it, and with some agitation, the Mn solution. This mixture is shaken hard and immediately dumped into the urea. A drying tube packed with damp paper towel is added to absorb vapor. The RBF with drying tube is clamped and lowered into boiling water. There are 2 separate stages with vigorous gas evolution, yet 85% of the volume of the reactor can be filled with liquid if desired. Much gas at both stages (and probably also during acid addition) is a sign of not enough Mn and/or NaOH, too much hypochlorite, or bad hypochlorite.

After heating, the flask is chilled, then sulfuric acid from the freezer (1:2 v/v conc. acid/water) is added from a pressure-equalized addition funnel topped with the drying tube from earlier, just until about neutral, with magnetic stirring. This requires 3 minutes, and caution while adding the last 25% of the acid. The liquid is transferred to a FBF of the same size and shake-swirled by hand to degas until the solution is cleared. The flask is a bit warm to the touch. Half of the desired amount of conc. sulfuric acid is dumped in. When no more precipitation seems imminent, the other half is added and the FBF is left to sit while loosely stoppered. When the flask no longer feels warm, the mixture is filtered with vacuum, with the RBF as receiver. Once the crystals are sucked dry, they're washed twice in the filter with more of the cold 1:2 sulfuric acid, adding to the filtrate which is then put in the fridge for a time. A second washing follows with 91% IPA, repeated twice. After cooling, a second crop of crystals are washed as before. These crystals sparkle, but are less pure than the first. It's entirely possible to not use a filter at all, or to use a coffee filter. After the crystals have digested some, they fuse a bit and can stick to the flask, even if the whole mass moves about. With enough care, the flask can be inverted completely without any crystals coming out.

If the acid is added all at once, there is a tendency for the liquid to turn green (especially if warm), which is probably not a good thing. If there is stirring after neutralization, a dull powdery snow falls, not sparkling in the light at all. This is full of Na even if precipitated warm. If one intends to recrystallize anyways, go ahead and use magnetic stirring, but I prefer a fog turning to a rain of thousands of little sparkles which then stick together to form shaved ice of good purity. There is no danger of sodium (bi)sulfate crystals if the hydrazine sulfate is mostly precipitated before cooling below 30C, and the amount of acid is not excessive, although of course increasing the sulfate ion concentration also benefits the precipitation of the hydrazine. A large excess of NaOH requires a large excess of acid, and when this acid is sulfuric, particularly good precipitation of clean nicely crystalline product may occur, contrary to expectation that the increased Na in solution is an issue.

In other words, good yields are easy, but the highest yield requires some care.

It's possible that a more dilute solution works just as well, when water is removed after partial acidification, or more acid is added. It's also possible that a more dilute hypochlorite gives better hydrazine yield; I haven't explored it, nor the use of lab grade chemicals.

Recrystallization leads to over 20% of the hydrazine sulfate remaining in solution at room temperature (10% if a modest amount of conc. sulfuric acid is added after dissolving) so is best avoided. Obviously, good overall recovery may occur after some evaporation, if the amount of sodium contamination is small. The pure sulfate leaves no nonvolatile residue when heated to decomposition in an evaporating dish with enough flame. In a crucible or test tube, a S residue, etc. condenses on the walls. Weighing the residue left in an evaporating dish is faster than titration with iodate.

S.C. Wack - 9-2-2022 at 14:44

BTW none of that applies to Name Brand 7.5% hypochlorite.

Now 90% of all the bleach bottles in the store are "low splash" and/or scented. Perhaps the remainder on the bottom shelf are old stock which will be replaced with the modern, advanced, state of the art (i.e. shit) merchandise that everyone is clamoring for (how many times a day do you hear people complain about bleach not being syrupy).

"Cloromax technology" (no, really) results in the Mn not decolorizing or precipitating, a persistent haze, and a different precipitation of the sulfate. Perhaps this bleach has the same additive as the "low splash" product, just less of it. When combined with Dr. Thönnessen's amounts above, the yield is 61%, and the product is inferior to the cheap hypochlorite sulfate.

Repeating without any additive (other than Thönnessen's 50% excess of NaOH and whatever secret ingredient is in the bleach) gave a clear colorless liquid in which the haze did not appear until at the neutral point. This time, the magnetic stirring was continued as the conc. portion of the acid was slowly added dropwise. The resulting first crop sulfate was the dull uniform fine powder of earlier stirring trials, yet this material was of quite good purity. Unfortunately, 22% of the total was in the second crop, which had much more Na (and no organic residue) in it. There was none of the gas which always evolved from the sulfate in contact with the mother liquor when using Mn. 64.6%.

Sodium bisulfate would have been tested if I or the stores had the prill in stock.

S.C. Wack - 17-3-2022 at 15:59

Lobry de Bruyn wrote in 1895-6 of adding barium chloride to hydrazine sulfate to form the dihydrochloride (insoluble in methanol), which is heated to form the monohydrochloride, which is dissolved in methanol and basified with sodium methoxide, or barium bromide is added to the sulfate, followed by KOH with the KBr precipitating with alcohol, or the sulfate is basified with KOH or NaOH, and the alkali sulfate is precipitated with alcohol. (Adams and Marvel write in 1921 that this last method gives 50% hydrate in 50-60% yield after vacuum distillation) He also makes anhydrous hydrazine from the "hydrate" with BaO.

Given all of that, it's striking that the professor did not mention basifying in part with barium hydroxide and in part with NaOH, followed by precipitation of sodium sulfate with alcohol.

Most posters here seem to prefer NaOH at both stages, with a lot of salt at the end. Going for less salt, I converted hydrazine sulfate to dihydrazine sulfate by adding barium hydroxide (112% of the theoretical weight of freshly recrystallized, vacuum filtered, undried octahydrate) to a pH around 4.4, obviously in hot solution followed by some workup. An interesting optical phenomenon was noted during the magnetic stirring of barium sulfate in dihydrazine sulfate (with fluorescent tube light): the center of the vortex was blue. The barium sulfate was washed more by decantation than filtering.

Distillation of the water was stopped at the theoretical weight of 50% concentration, and 105% of the theoretical amount of 50% NaOH was added. Less than 62% of the expected weight of sodium sulfate was collected by vacuum filtration. Instead of precipitating the rest with methanol, distilling it off, and vacuum distilling the remaining volatiles, the filtrate was distilled with aspirator vacuum. This distillate was found to be 17.3% hydrazine (27% hydrazine hydrate), in 81% yield, by titration with iodate.

This concentration could have been higher if the dihydrazine solution had been properly analyzed, because it could have been boiled down further with less NaOH added. It's unclear at which stage the missing hydrazine was lost, due to this overall sloppiness. The last portion of hydrazine to come over was of presumably high concentration (oily drops in the receiver), so it's not unlikely that some was lost in the apparatus and residual hydroxide and sulfate.

So, the whole process has to be repeated with more care, and this is in progress. What I was really interested in was this last part: the distillate was concentrated in a desiccator with lime. If the initial daily water loss held steady, it would be hydrazine hydrate at 15 days and anhydrous hydrazine at 21 days, this was however not the case, and the loss slowed some, even with fresh lime. Titration today indicates exactly 25% hydrazine w/v.

There were plans to take this further before posting, but I made the mistake of mentioning this in a thread where I argued with an admin, who just hours later totally by coincidence announces his intention to lock this thread, and immediately this thread magically became the frontrunner in voting to be the very first of all threads locked. (a lot of people spent a lot of time writing posts in this thread, just for it to be locked and unstuck, and for their posts to be reduced to a much more important "summary" written by someone else, if mentioned at all...so why bother writing anything in the first place?)

artemov - 23-3-2022 at 05:03

Tried the urea + bleach + MEK method on a half-molar scale with 750ml of 5% bleach ...

After the solution is cooled for an hour or so (it retains heat really really well!), MEK is added and stirred for about 3-4 hours.
Unlike what Doug's Lab said, my mixture didn't become cloudy, clear, then cloudy again (ketone -> hydrazone -> ketazine?); it stayed cloudy (and warm!) throughout.

Organic layer on top is separated, and 36% sulfuric acid is added.
White flaky ppt is formed almost immediately. An organic layer (MEK+ketazine?) floats on top of the aqueous/sulfuric acid layer (red line) ...

Will continue tmr and do a decantation/filtration to get an initial batch of hydrazine sulfate, then do a distillation with the filtrate to remove the MEK/water to get a second batch, fingers crossed.

What can I use to wash the hydrazine sulfate after filtration?

20220323_203218.jpg - 49kB

20220323_203037.jpg - 75kB

Colleen Ortiz - 30-3-2022 at 00:41

Hydrazine has the chemical formula N2H4 and is an inorganic substance. It is a colorless flammable liquid with an ammonia-like scent that is a simple pnictogen hydride. Hydrazine is extremely hazardous unless it is handled in solution, such as hydrazine hydrate (NH2NH2 xH2O). The global hydrazine hydrate market was worth $350 million in 2015. Hydrazine is primarily employed as a foaming agent in the preparation of polymer foams, but it is also utilized as a precursor to polymerization catalysts, medicines, and agrochemicals, and as a long-term storable propellant for in-space spacecraft propulsion. In 2015, around two million tonnes of hydrazine hydrate were used in foam blowing agents. In addition, hydrazine is employed in the preparation of gas precursors used in airbags, as well as in other rocket fuels. Hydrazine is utilized as an oxygen scavenger in both nuclear and conventional electrical power plant steam cycles to manage dissolved oxygen concentrations in an effort to minimize corrosion. Hydrazines are a type of organic compounds formed by substituting an organic group with one or more hydrogen atoms in hydrazine.

vano - 26-7-2022 at 01:23

Nickel and cobalt hydrazine nitrates. Cobalt is a much better explosive material than nickel, but also unstable. two days later it became very weak because of decomposition.

unnamed.jpg - 1.2MB

Sir_Gawain - 15-10-2022 at 16:45

I made hydrazinium hydrogensulfate using 250 ml of 12.5% pool shock(actually 10%). I mostly followed NileRed's procedure except I used HCl to neutralize sodium carbonate. My final yield was 26g. I'm going to do a titration to make sure it's not half sodium sulfate.:)

[Edited on 16-10-2022 by Sir_Gawain]

Keras - 15-10-2022 at 23:06

Is there any reason why sulphuric acid is preferred over hydrochloric acid in the neutralisation of hydrated hydrazine? Couldn't both be used?

Sir_Gawain - 16-10-2022 at 12:06

Hydrazine hydrogenchloride is about 10 times more soluble than hydrazine hydrogensulfate. Hydrochloric acid is sometimes used to neutralize the sodium hydroxide and carbonate, then sulfuric acid to precipitate hydrazine hydrogensulfate. Sulfuric acid can be used for both (as NileRed did), but sodium sulfate has a low solubility at low temperatures and can precipitate out and contaminate your product.

[Edited on 16-10-2022 by Sir_Gawain]

[Edited on 17-10-2022 by Sir_Gawain]

[Edited on 17-10-2022 by Sir_Gawain]

Keras - 16-10-2022 at 22:33

Quote: Originally posted by Sir_Gawain  
Sulfuric acid can be used for both (as NileRed did), but sodium sulfate has a low solubility at low temperatures and can precipitate out and contaminate your product.


Yeah, I saw that in hindsight, and came upon a recipe clearly stating that filtering hydrazine hydrosulphate should not be done below 25 °C to limit sodium sulphate contamination.

That being said, is it possible to use sodium bisulphate instead of sulphuric acid?

Sir_Gawain - 17-10-2022 at 10:09

You could try it but I don't think that would work. Even if it would, it would add a massive amount of sodium sulfate that would likely precipitate out with your hydrazine hydrogensulfate. To neutralize 32g hydrazine you would need 240g NaHSO4. 2NaHSO4 + N2H4 = Na2SO4 + N2H5(HSO4) This would produce 140g of sodium sulfate and only 130g of hydrazine hydrogensulfate.

[Edited on 17-10-2022 by Sir_Gawain]

Keras - 17-10-2022 at 10:21

Quote: Originally posted by Sir_Gawain  
You could try it but I don't think that would work. Even if it would, it would add a massive amount of sodium sulfate that would likely precipitate out with your hydrazine hydrogensulfate.


Solubility of sodium sulphate at 25 °C seems to be one order of magnitude higher than that of hydrazine sulphate.

Sir_Gawain - 17-10-2022 at 10:57

It might work if you use hydrochloric acid to neutralize the sodium carbonate, then sodium bisulfate to precipitate hydrazine hydrogensulfate. If you use sodium bisulfate for both steps there would be too much sodium sulfate produced. Try it and report back. If it does work it would be great for people who can't get sulfuric acid.

[Edited on 17-10-2022 by Sir_Gawain]

Keras - 17-10-2022 at 22:39

Quote: Originally posted by Sir_Gawain  
… If it does work it would be great for people who can't get sulfuric acid.

[Edited on 17-10-2022 by Sir_Gawain]


Will do.

Cubane538 - 1-8-2023 at 19:17

I've 50% conc. Hydrogen peroxide, Acetone & Liquid ammonia and I want to make hydrazine hydrate using these raw material..
Please guide.

B(a)P - 1-8-2023 at 19:56

Quote: Originally posted by Cubane538  
I've 50% conc. Hydrogen peroxide, Acetone & Liquid ammonia and I want to make hydrazine hydrate using these raw material..
Please guide.


You have responded to a thread with 23 pages of posts about the synthesis of hydrazine, reading through these posts will give you a good start. Is there a reason you want to use these specific reagents? What concentration is your ammonia? Do you have access to methyl ethyl ketone?
When reading up on various routes to hydrazine, make sure you take in the safety aspects of the synthesis, hydrazine is a compound to be taken seriously.

Cubane538 - 2-8-2023 at 19:06

Quote: Originally posted by B(a)P  
Quote: Originally posted by Cubane538  
I've 50% conc. Hydrogen peroxide, Acetone & Liquid ammonia and I want to make hydrazine hydrate using these raw material..
Please guide.


You have responded to a thread with 23 pages of posts about the synthesis of hydrazine, reading through these posts will give you a good start. Is there a reason you want to use these specific reagents? What concentration is your ammonia? Do you have access to methyl ethyl ketone?
When reading up on various routes to hydrazine, make sure you take in the safety aspects of the synthesis, hydrazine is a compound to be taken seriously.



My ammonia is 30% concentrate and yes I've access of Methyl ethyl ketone.
I tried Hofmann degradation method 3 times in which I got some Hydrazine sulphate in first attempt and no precipitation in second and third attempt!!!

Then I came to know about Ketazine process.
Also I've enough amount of 50% Hydrogen peroxide
So, I thought Ketazine process would work..

B(a)P - 2-8-2023 at 20:45

Quote: Originally posted by Cubane538  
Quote: Originally posted by B(a)P  
Quote: Originally posted by Cubane538  
I've 50% conc. Hydrogen peroxide, Acetone & Liquid ammonia and I want to make hydrazine hydrate using these raw material..
Please guide.


You have responded to a thread with 23 pages of posts about the synthesis of hydrazine, reading through these posts will give you a good start. Is there a reason you want to use these specific reagents? What concentration is your ammonia? Do you have access to methyl ethyl ketone?
When reading up on various routes to hydrazine, make sure you take in the safety aspects of the synthesis, hydrazine is a compound to be taken seriously.



My ammonia is 30% concentrate and yes I've access of Methyl ethyl ketone.
I tried Hofmann degradation method 3 times in which I got some Hydrazine sulphate in first attempt and no precipitation in second and third attempt!!!

Then I came to know about Ketazine process.
Also I've enough amount of 50% Hydrogen peroxide
So, I thought Ketazine process would work..


There are plenty of posts here on the ketazine process. Nurdrage also posted a pretty detailed video on this process. What were you going to use the hydrogen peroxide for? Are you proposing the peroxide ketazine process? I think this requires a catalyst, hypochlorite is a lot easier. If you look through this thread you will also find a method that was trialed fairly successfully using chloroacetone. You will get more help if you pick an approach, research it, then come back with more targeted questions.

Cubane538 - 2-8-2023 at 21:59

Yes, I'm talking about peroxide ketazine process. And I want to use Hydrogen peroxide as oxidising agent.
I know about hypochlorite ketazine process, but I don't know how much concentration of hypochlorite is best for good yield. Also I don't have much hypochlorite.

Can you tell me which process yields better,
Peroxide ketazine process or Hofmann degradation?

ManyInterests - 6-4-2024 at 19:58

I have a question: This is concerning saving my sanity when it comes to making hydrazine sulfate, and I will need to make a lot more very soon. Also entirely about the Hoffman rearrangement of urea.

When adding the sodium hydroxide to the bleach solution (while cool and maintaining a temperature below 15C). Is it possible to store the solution for later before adding the gelatine/urea mix to the whole thing and heating? I'm asking this because it often takes me a long time to add the sodium hydroxide solution and keep it all cool. If I could do this step and complete the others in another day it would make my life a lot easier.

Would there be any degradation of the material if it happens?

Sir_Gawain - 6-4-2024 at 20:46

It’s perfectly fine to store the bleach/lye solution. If anything, it should slow degradation.

ManyInterests - 7-4-2024 at 08:01

Quote: Originally posted by Sir_Gawain  
It’s perfectly fine to store the bleach/lye solution. If anything, it should slow degradation.


Good, making hydrazine sulfate is a lengthy and fairly stressful process for me. Doing this allows me to spread a synthesis over a few days when needed (adding the sodium hydroxide to the bleach, then doing the urea/gelatine addition with heating later and then after cooling I can add the muriatic acid + sulfuric acid to get the sulfate to crash and allow it to cool to ambient temperature of 10-15C overnight to maximize yield).

That'll make things easier.

fx-991ex - 7-4-2024 at 12:12

Do you think using drain opener will work for hydrazine sulfate? i think i saw some video where people did it and it worked but am not sure if my memory is correct on this.

dettoo456 - 7-4-2024 at 12:49

Drain opener as H2SO4 for the neutralization or NaOH as the base in the Hoffmann rearrangement?

Dilute concentrations of H2SO4 (50% or higher) will be fine for neutralization and NaOH in crystal form or highly concentrated ‘gel’ should be fine for the Hoffmann step as well.

The preparation in general can tolerate H2O in excess, and only a slight yield drop would be noticed since N2H5HSO4 decently insoluble.

Sir_Gawain - 7-4-2024 at 12:55

Quote: Originally posted by fx-991ex  
Do you think using drain opener will work for hydrazine sulfate? i think i saw some video where people did it and it worked but am not sure if my memory is correct on this.

I use 93% sulfuric acid drain opener. It’s pretty pure and I’ve gotten over 60% yields using it.

ManyInterests - 7-4-2024 at 17:02

I got one question about freebasing. This is because I am sure my NHN (Nickel-hyrazine-nitrate) synthesis failed due to improperly freebased hydrazine.

In the past the ingredients were at room temperature and mixed in an ice bath (50% of the sodium hydroxide solution put in at first with the other half later) and mixed with 95+% ethanol.

I guess the last times I did it, I made a huge mistake of putting them in the fridge for 24h (all ingredients. the hydrazine sulfate, the sodium hydroxide, and the ethanol) and I was informed that the temperature was far too low for a proper hydrazine freebasing to occur. I suppose if I took the mixture outside of the additional ice bath and let the temperature rise for an additional 15 or 20 minutes I would have had the proper freebasing.

I never took a temperature reading while freebasing before. When I filtered out the stuff I failed at it was at 9C. Was that too low a temperature? What is a decent range to free base it?

Sir_Gawain - 7-4-2024 at 17:49

The temperature is less important than the presence of enough water to start the reaction. There should be a visible reaction and temperature spike. I’m not the best at the freebasing myself, and I blame my low sodium azide yields on that.

ManyInterests - 7-4-2024 at 18:15

Quote: Originally posted by Sir_Gawain  
The temperature is less important than the presence of enough water to start the reaction. There should be a visible reaction and temperature spike. I’m not the best at the freebasing myself, and I blame my low sodium azide yields on that.


Hmm, that could also be a major problem, since the ingredients were dry and the alcohol was also dry.

So what do you recommend? I will give my previous successful synthesis from 2022:

30.15 grams of hydrazine sulfate
18.43 grams of sodium hydroxide
105ml of 95% ethanol (put 55ml first, then the 30 ml later and finally 25ml)

I took the above from my old notes.

So please tell me what you did to get a good freebase? I have never added water to my freebasing before. All videos I see on the matter all use alcohol, sodium hydroxide, and hydrazine sulfate and nothing more. Should I add like 15ml of water or something?

Sir_Gawain - 7-4-2024 at 18:25

IIRC, alchemystery uses some water in his potassium azide video. You just add the hydrazine sulfate to the ethanol and slowly add sodium hydroxide while stirring. If the reaction doesn’t start, you add water a few drops at a time until it does. If you add all the sodium hydroxide at once, then initiate the reaction with water, it heats up so much it boils. I’ve had this happen once, and it was terrifying.

ManyInterests - 7-4-2024 at 18:34

I will look up that video if I don't already have it (I download any chemistry video I find interesting).

I think this was my mistake in the previous two synthesis. added everything all at once, which was wrong, and then made everything too cold. I will stand that the coldness is a factor, too.

In all honesty I am not sure how the reaction would look like, or I have seen it but I forgot. I made some hydrazine sulfate that I am still precipitating out. I moved my setup indoors as it is mostly hydrazine sulfate, but I have my apartment well ventillated (and the beaker is well covered) in order to allow all the stuff to precipitate at 15C and not allow it to go under 10C. By next weekend I should have everything fully ready to try again.

B(a)P - 7-4-2024 at 19:14

Quote: Originally posted by ManyInterests  
I will look up that video if I don't already have it (I download any chemistry video I find interesting).

I think this was my mistake in the previous two synthesis. added everything all at once, which was wrong, and then made everything too cold. I will stand that the coldness is a factor, too.

In all honesty I am not sure how the reaction would look like, or I have seen it but I forgot. I made some hydrazine sulfate that I am still precipitating out. I moved my setup indoors as it is mostly hydrazine sulfate, but I have my apartment well ventillated (and the beaker is well covered) in order to allow all the stuff to precipitate at 15C and not allow it to go under 10C. By next weekend I should have everything fully ready to try again.


Once you have added the first portion of hydroxide you need to stir until you see the reaction start (some white vapour will be visible and the vessel will warm), note that it takes a long time to get going. If you have been stirring for 15 minutes with no evidence of a reaction starting, try a little water (maybe 5% of your ethanol volume), keep stirring until you see the reaction commence. The formation of the sodium sulfate hydrate with later additions of sodium hydroxide will remove the water.

ManyInterests - 8-4-2024 at 05:06

Thank you for that information. So adding all the ethanol and mixing the hydrazine sulfate first. Then the hydroxide piecemeal. If I don't see what you are describing, add water dropwise until something reacts.

Yesterday I did the longest hydrazine sulfate synthesis I ever did. Most of the time it was waiting for things to cool down. My.mantle overshot the temperature again (it peaked at 91C) but I saw plenty of sulfate formation. I let it cool until it was at 23C before it got too late. I brought the setup inside (with lots of plastic wrap to prevent any gas escape. Overnight it cooled down to 14C and currently I still have it unfiltered at 16C since I had to go to work. Once I return to it I will put it in a ice bath and cool to just barely over 10C before filtering to prevent much sodium sulfate formation.

I was extremely patient with this one and I hope for a high yield.

ManyInterests - 12-4-2024 at 08:50

I'm going to get ready for an NHN synthesis and I will do follow your instructions and do everything slowly and steadily. If water is needed I will do slightly less than 5% of the ethanol. I really want this to succeed. I want to make one final NHN synthesis and get it all done. I want to make more hydrazine sulfate as it will be useful in the future, but for now I just want to make one final bit of high quality NHN and call it a day for NHN synthesis.

Sir_Gawain - 12-4-2024 at 10:35

What was your hydrazine sulfate yield?

ManyInterests - 12-4-2024 at 13:03

Quote: Originally posted by Sir_Gawain  
What was your hydrazine sulfate yield?


69.65g. My best yet. Doing it slowly and patiently paid off.

but what didn't pay off was using to make nickel hydrazine nitrate. I really don't understand it, but this time I am confident it is not a failure of freebasing, I am certain it did freebase. What I did see happening as I was heating the ethanolized hydrazine was that when my mantle switched off heating at 58C. It went completely nuts and shot up to 75C (AGAIN! Third time!) and I saw some kind of steam coming out of my flask which I thought I covered up and a lot of bubbling in the flask.

This has to be the reason: My hydrazine got fucked from the heat and simply escaped. When I added some nickel nitrate solution it went straight to green again and with none of the purple goodness. Meaning all the hydrazine was destroyed in the process.

This is entirely the result of my new mantle. I need to find a work around for this. I simply cannot afford to keep having these failures.

For my hydrazine sulfate synth, I followed the instructions in a video that is no longer on youtube. But here are the reagents:
Quote:
355 ml pool bleach (or 500 ml regular bleach selection)
75 ml 50% H2SO4 (add 37.5ml 98% H2SO4 to 37.5ml super cold water)
47.8 g NAoh
34.1 g urea (30ml or 40ml of distilled water to dissolve. use absolute minimum and make sure water is warm.)
0.75 g gelatine (takes 15 ml of warm water to dissolve this)
122 ml HCI


I did 3 times that amount to great success. It worked quite well the last time as well. I filtered after I cooled everything down to 10C and no more, so the amount of sodium sulfate left is minimal.

I'm sorry, but I am very upset right now, and I must apologize for the foul language but I am VERY unhappy at this I made NHN successfully many times and these failures are costing me and frustrating me. I did everything right, but the heating did it in and destroyed my hydrazine. Please tell me I am correct...

[Edited on 12-4-2024 by ManyInterests]

Sir_Gawain - 12-4-2024 at 14:21

What’s the purity of your nickel nitrate? That’s about the only major variable I can think of.

ManyInterests - 12-4-2024 at 14:40

I bought it from a chemical supplier. It is very pure. I dissolved it in distilled water with 0.04% the weight of the nitrate with dextrin.

It is not the nickel nitrate, I am very confident that it isn't. So far I've done this three times. The first time I did it it worked... but I got a very poor yield. Only 4g when I was expecting around 15g or so. The second time there was also a big nothing. Then there was this time, and this time I am very confident that the problem is the heating now, since I am certain that the hydrazine freebased well. There was heat coming out and I saw a clear change in the hydrazine sulfate to look like the sticky thing I'd expect out of sodium sulfate in that situation.

It is the heating. The first time I tried to heat them I used a cheap hotplate stirrier, but it never went beyond 40C. Probably due to it being very cold outside. So I transferred it to my mantle to get it to heat to the necessary temperature but I also had a similar runaway. I've had those runaways in all instant.

I am prepping for another hydrazine sulfate synthesis, the next time I do this, I will use my cheap hot plate stirrer again since the weather is MUCH warmer than the last time. If I need to heat it up. I will only use my mantle until it reaches 45 or 50C (I set my mantle temp to 51C, but it did not stop until 58C, then the runaway happened at 60C. This means my thermometer is probably not accurate. I will use a hot water bath to get it to the appropriate temperature.

It was probably the heat and the destruction of the hydrazine that was the culprit in all cases. NHN can be made at room temperature, but the results will be chunky and will need additional crushing. When done at a higher temperature it will have the consistency of talcum powder and will need very little grinding.

At this point I am willing to compromise, I'm sick and tired of all these failures, especially for something that I thought I had accomplished years ago.

clearly_not_atara - 13-4-2024 at 06:13

Yields aside, there are basic safety reasons not to make energetics with a heating system that malfunctions and overheats. I'd recommend you take a break until you have some equipment that turns off properly.

ManyInterests - 13-4-2024 at 08:03

Quote: Originally posted by clearly_not_atara  
Yields aside, there are basic safety reasons not to make energetics with a heating system that malfunctions and overheats. I'd recommend you take a break until you have some equipment that turns off properly.


I agree. This needs to be taken care of as it can cause very deadly errors. I intend to make some more picric acid in the future, and part of that involves several heating steps. It needs to not exceed a certain temperature or else it might go to an explosive runaway. Not something I want or wish anyone to have.

Sir_Gawain - 13-4-2024 at 19:28

Quote: Originally posted by ManyInterests  


69.65g. My best yet. Doing it slowly and patiently paid off.
For my hydrazine sulfate synth, I followed the instructions in a video that is no longer on youtube. But here are the reagents:

Quote:
355 ml pool bleach (or 500 ml regular bleach selection)
75 ml 50% H2SO4 (add 37.5ml 98% H2SO4 to 37.5ml super cold water)
47.8 g NAoh
34.1 g urea (30ml or 40ml of distilled water to dissolve. use absolute minimum and make sure water is warm.)
0.75 g gelatine (takes 15 ml of warm water to dissolve this)
122 ml HCI


I did 3 times that amount to great success. It worked quite well the last time as well. I filtered after I cooled everything down to 10C and no more, so the amount of sodium sulfate left is minimal.
[Edited on 12-4-2024 by ManyInterests]
Using that method, you should be getting twice that amount. The synthesis is from a writeup by Rosco Bodine. Here it is:https://www.sciencemadness.org/talk/viewthread.php?tid=15091
The single most important thing to get a good yield is to use the exact right amount of hypochlorite. Use concentrated bleach or, even better, liquid pool chlorinator and test the concentration. Even a little extra hypochlorite and it will destroy the hydrazine. Not quite enough and the excess urea will also react with hydrazine. I’ll take a picture of my lab notebook where I got 41.5g hydrazine sulfate from 34g urea and post it tomorrow.

ManyInterests - 14-4-2024 at 04:12

That sounds incredible. I will be sure to use it next time.

Right now I just want to make sure that the current yield I made to make another NHN doesn't go to waste.

Edit: I looked over at the thread. It seems identical to the way I normally do it. I wonder what would be different other than giving it an alcohol wash to drive out the water.

[Edited on 14-4-2024 by ManyInterests]

Sir_Gawain - 14-4-2024 at 12:47

Here it is:
IMG_0460.jpeg - 2.9MB
Apologies for the bad handwriting.

ManyInterests - 14-4-2024 at 19:19

Your handwriting is fine. The only thing that got me off was I wasn't aware that carbamide was also another name for urea. It is identical to what I normally do. In the past I had poor yields due to prematurely filtering out the hydrazine before it sufficiently cooled. I did that because I was afraid of sodium sulfate formation, but I realize that it actually needs to get a lot colder than I thought and for longer for the sodium sulfate to start forming.

One other problem is that when I added the sodium hydroxide I didn't sufficiently cool back the solution to 8C again. I did that in my current synthesis and I never saw that much foaming before. I had a mild overflow but I was able to prevent my heating mantle from being damaged. The only thing I did differently is that I went to bed while letting it cool down after heating it to 85C. I added the chilled acids the morning after (chilled in the fridge, not the freezer, but they were ice cold) I used a slight excess of the HCl And H2SO4, but the yield was good enough that I needed to change filters on my funnel as one was not sufficient to hold all the sulfate.

So with this, I'll split it into two parts after it fully dries since I know that it is going to be plenty.

I will also review the freebasing with it. I now know that I need to start at room temperature, mix the ethanol in the hydrazine sulfate first (it will not dissolve) and then add the hydroxide piece meal, also adding a little distilled water (less than 5% the ethanol content) anyway to assure a reaction takes place. One thing I've done to fully contain any would be fumes is to cover up the beaker entirely and instead of using a stir rod or stirbar I would simply shake and swirl the beaker around to dissolve everything does work.

I did see a video of someone who also put his beaker in the freezer for an hour after shaking it to allow all the stuff to precipitate. I did that after stirring and seeing a reaction take place when I felt it was getting hotter and I saw the solids start to gel up and the ethanol clearly separating from everything. I hope I am doing this right. I know it is weird, but it is my autism and anxiety taking over.

dettoo456 - 15-4-2024 at 13:16

If the extraction in EtOH presents issues for you, you can always revert to Ca(OH)2 instead of NaOH. Just dissolve up the Hydrazine sulfate, add req’d (or even excess) Ca(OH)2, heat with vigorous stirring for an hour or two, and then decant/filter while hot.

And if the resulting N2H4 conc% is too low, you can always pull out excess water w/ sieves since they won’t react with any of the hydrazine.

If you need the Hydrazine in Ethanol alone for whatever reason, you can just add EtOH to the N2H5OH, add a shit ton of sieves, and then filter.

[Edited on 15-4-2024 by dettoo456]

clearly_not_atara - 15-4-2024 at 14:38

Carbamide is a popular name for urea when you don't want people to think about urine. Like when it appears in cosmetics or medicine.

But it makes me wonder. Could you perhaps achieve the desired rxn with carbamide peroxide and a little catalytic bromide salt? The peroxide converts the bromide to hypobromite which reacts with the urea to give hydrazine and regenerate bromide, etc.

ManyInterests - 16-4-2024 at 17:35

Quote: Originally posted by dettoo456  
If the extraction in EtOH presents issues for you, you can always revert to Ca(OH)2 instead of NaOH. Just dissolve up the Hydrazine sulfate, add req’d (or even excess) Ca(OH)2, heat with vigorous stirring for an hour or two, and then decant/filter while hot.

And if the resulting N2H4 conc% is too low, you can always pull out excess water w/ sieves since they won’t react with any of the hydrazine.

If you need the Hydrazine in Ethanol alone for whatever reason, you can just add EtOH to the N2H5OH, add a shit ton of sieves, and then filter.

[Edited on 15-4-2024 by dettoo456]


I bought some calcium hydroxide since you mentioned that, if that is a more sure way of freebasing hydrazine, then I will use that method.

I also thank you for all the help you're giving me. I think the reason why it is all happening like this is due to the heating issue. I think my last time I was too quick in filtering out my hydrazine (I was afraid it would volatilize really fast and I need to hurry as fast as possible) I think like with making hydrazine sulfate has become more fruitful when I slowed everything down I think I also need to slow down the heating and the whole process, too.

I made 97.97g from my last synthesis. So things are improving quite well in making hydrazine sulfate. I obviously cannot use all of it once (nor should I!) but I know I can make a lot of good quality hydrazine sulfate for whatever I need.

ManyInterests - 20-4-2024 at 09:45

Just to drop in an update. I did finally do a successful freebase as I did before. The only thing I needed to do differently was simply add the hydroxide piecemeal and not let things get TOO cold. It was an incredibly basic process.
Quote:
But it makes me wonder. Could you perhaps achieve the desired rxn with carbamide peroxide and a little catalytic bromide salt? The peroxide converts the bromide to hypobromite which reacts with the urea to give hydrazine and regenerate bromide, etc.


Possibly. That is something to consider. For now I have a 48g of extra hydrazine sulfate. Given how much I got in terms of practice, I am thinking of doing one more synthesis to give me over a hundred grams of the stuff to add to it, then I will say I got a good stock.

Keras - 21-4-2024 at 11:49

I tried the hydrazine sulphate classic synthesis (the one you find everywhere on YouTube) with NileRed quantities, except that I replaced gelatine with 1g of EDTA (which is too much, it doesn’t totally dissolved I had to filter the residue) anddddd… I got 50 g of hydrazine sulfate????

Something went wrong?

Sir_Gawain - 21-4-2024 at 12:12

Quote: Originally posted by Keras  
I tried the hydrazine sulphate classic synthesis (the one you find everywhere on YouTube) with NileRed quantities, except that I replaced gelatine with 1g of EDTA (which is too much, it doesn’t totally dissolved I had to filter the residue) anddddd… I got 50 g of hydrazine sulfate????

Something went wrong?

From how much urea? You may have just gotten a good yield. Did you test the purity?

ManyInterests - 21-4-2024 at 18:14

Quote: Originally posted by Keras  
I tried the hydrazine sulphate classic synthesis (the one you find everywhere on YouTube) with NileRed quantities, except that I replaced gelatine with 1g of EDTA (which is too much, it doesn’t totally dissolved I had to filter the residue) anddddd… I got 50 g of hydrazine sulfate????

Something went wrong?


I'm curious as how much of your other reagents you used as well. For me the formula I use (and it is also used by Magpie as linked earlier by Sir Gawain) is 34.1g. My last synthesis used triple that, 102.3g and I ended up with 96.96g. My best synthesis yet.

I never heard of EDTA before this. Why did you opt to use it in the place of gelatin? unflavored gelatin is ubiquitous and cheap.
Quote: Originally posted by Sir_Gawain  

From how much urea? You may have just gotten a good yield. Did you test the purity?


I wanted to ask this question and I should have asked it a long time ago: How do you test the purity of hydrazine sulfate? In the past when I was still inexperienced with hydrazine sulfate synthesis, I was so afraid of sodium sulfate synthesis that I would not allow it to sufficiently cool to 10C and I would filter it at 15C, thus losing a lot of potential yield (and I mean a LOT). Once I allowed it to slowly cool to 11C over the course of several hours (using the ambient temperature outdoors) my yield improved considerably.

But I am curious as how to test for purity.

Sir_Gawain - 21-4-2024 at 18:54

Quote: Originally posted by ManyInterests  
I wanted to ask this question and I should have asked it a long time ago: How do you test the purity of hydrazine sulfate.

One way I know is to heat it. Hydrazine sulfate should decompose leaving little residue behind. Another way would be to react with copper sulfate. It form an insoluble complex that can be weighed to calculate the purity.
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