Sciencemadness Discussion Board - help make white fuming nitric acid.

help make white fuming nitric acid.

Pages: 1 2

NeonPulse - 25-2-2015 at 15:59

Quote: Originally posted by Hawkguy

Quote: Originally posted by hissingnoise

If you need water-white HNO3 just add a small pinch of urea as a last resort.

decentn't the resulting Urea nitration cause the release of more NOx, which might be redissolved?

I made a video on the tube called cleaning NO2 from RFNA. It outlines the process I use to get my distilled acid totally clean. Since I don't use a vacuum I fund this necessary for a decent clear acid and it works well.
https://www.youtube.com/watch?v=chGiOsQBlMY

[Edited on 26-2-2015 by NeonPulse]

greenlight - 26-2-2015 at 04:47

Thanks for the replies guys, i made a mistake with the type of pump though. It is a ILMvac 400082-03 chemical resistant membrane pump not a diaphragm pump. Its quite hard to find much information on it but it does pull a reasonably good vacuum and boils warm water from the tap when placed under vacuum with it.
Molecular manipulations, I wanted to neutralize the vapours with a basic solution in the dreschel bottle. Will this make damage to the pump minimal considering that it is chemical resistant already?

[Edited on 26-2-2015 by greenlight]

Molecular Manipulations - 26-2-2015 at 06:47

It will certainly help, put so glass wool in the tip of the bubbler to increase the surface area of the bubbles.

markx - 9-3-2015 at 16:13

Glass wool on the tip of the bubbler tube will not make much of a difference to the efficiency of the scrubber under the given circumstances...trust me. What will make a difference though is mechanical agitation. Put the scrubber onto a magnetic stirrer and add a suitable stirrer bar into the dreschel bottle, that will increase the active neutralising surface area and retention time manyfold and hence also increase the survival chances of your vacuum pump,

greenlight - 10-3-2015 at 07:19

Thanks, I will use a Dreschel bottle filled with either a saturated solution of Sodium bicarbonate or Sodium hydroxide base and place the bottle on a magnetic stirrer as well to increase the surface area.

Mr.Greeenix - 16-5-2015 at 12:40

Is is possible to dry about 95% nitric acid to 99% in an desiccator with a normal drying agent.

Because I think I have read somewhere it isn't possible.

NeonPulse - 16-5-2015 at 15:44

Quote: Originally posted by Mr.Greeenix

Is is possible to dry about 95% nitric acid to 99% in an desiccator with a normal drying agent.

Because I think I have read somewhere it isn't possible.

To dry HNO3 you need to distill it with an equal amount of concentrated sulfuric acid. Preferably under a vaccum. It can't be dried any further in a dessicator. What did you need it for? In most instances 95% will do just fine.

Mr.Greeenix - 17-5-2015 at 05:05

Why it isn't actually possible to dry it in a dessicator? It know that you can dry it by distilling, but it's annoying

I need it for nitrating Glycoluril to the TetraNitro compound with Engagers method.
-> HNO3 + acetic anhydride therefore you really need 99% ?

PHILOU Zrealone - 17-5-2015 at 07:15

The concentrated acid has a vapour tension and the vapour contains both water and HNO3...that's why dessicator won't work.
If you understand the concept of distillation plates and negative azeotropic mix, you will understand that below 68% HNO3 it is possible to concentrate HNO3 up to 68% because the vapour is richer at water than the condensed phase; but above 68% the vapour is richer at HNO3 than the condensed phase.

You thus need to catch the water chemically.

[Edited on 17-5-2015 by PHILOU Zrealone]

Rosco Bodine - 17-5-2015 at 08:03

It is possible to break the azeotrope by adding to the aqueous HNO3 a nitrate salt which is hygroscopic and will form a hydrated salt having greater affinity for the water than does the HNO3. Dehydrated calcium nitrate or magnesium nitrate or anhydrous or nearly anhydrous mixtures of magnesium nitrate with potassium nitrate, sodium nitrate, or ammonium nitrate are useful for breaking the azeotrope of HNO3 and H2O and other anhydrous salts such as zinc nitrate or others may work also.

Some of the nitrates which cannot be dehydrated by baking out the H2O without decomposition to the metal oxides will dehydrate without decomposition when mixed with another nitrate which forms a lower melting point mixture of nitrates, so the water will escape more easily from the melt at a lower temperature. This method avoids the thermal decomposition of a nitrate such as magnesium nitrate which otherwise can't be dehydrated by heat alone. Heating such mixtures under vacuum speeds the dehydration. A complication occurs that some mixtures will form glasses on cooling, instead of crystallizing and crumbling on solidification on cooling, falling apart as loose crystals which are desirable to make easy collection and removal of the dehydrated nitrate salts. Such anhydrous nitrate mixtures are likely also useful in nitration schemes where a solid nitrate is added to sulfuric acid to produce HNO3 as an alternative or in conjunction with using neat HNO3 made separately.

nitric acid of 19.century

Thraxx - 15-10-2016 at 12:13

I would like to tell something about very old method for to make 100 % HNO3 without destilation.
You have KNO3 + conc. H2SO4 as usually,you can heat it for 70 C,but after you should cold the bottle to 0C .There will crystalised the KO.4SO4.6HO with big long crystals in a good shape.
And you will do this: On the open end of the bottle with freezed crystals you give the second bottle.Now you revers this two bottels and stay it in the easy hand centrifuge and turn it quickly in the hand.The crystals stay in the bottle and the liquid-100% HNO3 is going out to the second bottle.
(Or you can do it with pressure or vacuum)
An because is it without heating and without destillation,it will be free of noxes.
Described by Richard Escales,used by Nobel and I self did it.

nitro-genes - 15-10-2016 at 13:41

Interesting, any original reference? What is KO.4SO4.6HO? Hard to believe any hydrate salts would be formed, in which case the nitric will only be as strong as the starting sulphuric. Wouldn't just potassium bisulfate precipitate, along with a small amount of potassium nitrate? What ratios did you use and did you test the amount of sulfates present in the resulting nitric by dilution and neutralization with calcium carbonate for example?

[Edited on 15-10-2016 by nitro-genes]

Thraxx - 15-10-2016 at 23:20

It will be better,if I will give here picture of the Book of Escales and you can self read it in original.
The method has two ways.Either 100 % HNO3 or watterless nitration acid (HNO3+H2SO4)My experience is with the watterless nitration acid.And it look like long needles in solid trajectory in all hole of the bottle.The acid flow easy out without moving crystals.
May be it was not 0 C ,I cooled in freezer ,may be it was more cold.

Thraxx - 16-10-2016 at 02:10

Thraxx - 18-10-2016 at 03:36

yeasterday I did experiment for to explain,if this HNO3 production is possible.I gave 20 g KNO3(1Gewichtteil)
to 38,25 ml H2SO4 /96%/ (3 and 1/2 Gewichtteile).Together was it thick like honey.After one hour was it clear and after them I put it into freezer.After 3 hours was it dense solid substance without crystal needles.Absolute inseparable.
Did I mistake? Yes,befor many years as I did this experiment first time,I took volumen parts not weights parts like Escales wrote.
What now?May be,if I will give there more SA,can it work,but not economical.Unfortunatelly.

kratomiter - 18-10-2016 at 07:11

Try to heat it for 1 hour or more before putting it in the freezer. KNO3 needs time to fully dissolve, it tends to form lumps in sulfuric acid.

Thraxx - 18-10-2016 at 09:51

Thank you,I will do. Now I gave 10g KNO3 to 38ml H2SO4.Its a half of "1 Gewichtteil".I freezed and separated (!) big crystals on the bottom of bottle and acid ,better to tell something like thick pink honey.To this pink honey I gave the second half of "1 Gewichtsteil"( =10 g KNO3) Now I will use your advice and will heate and after freeze.

Thraxx - 19-10-2016 at 03:57

The frozen substance is inseparable,sticky and dense .In other condition,with more liquid part,could it be helpful for lowering of water content in the nitration acid,but the described method by Escales doesnt work.

XeonTheMGPony - 20-10-2016 at 08:50

Allow it to warm to room temp after it sat in the freezer, the crystals will remain! if you have a glass fritted funnel you can remove any smallish crystals that may come over, but they will be inert any ways so not much to be worried about.

Alternatively you can filter with clean fiber glass mating.

if it is gelling bad you have too much water in your acid too bty! Dry Acid can be at -25 and still flow smoothly albeit viscus.

PHILOU Zrealone - 20-10-2016 at 10:17

If you have a lot of tiny crystals, then by capillarity the acid may remain stuck to it and forming like a gel.

Also the shape of the crystals has an importance...sometimes needle like crystals intricates into such a mess that it is hard to get the liquid out of it...

--> centrifugation
--> vaccuum filtration
--> extract the anhydrous HNO3 with CH2Cl2

Thraxx - 20-10-2016 at 10:40

Into the crystal poridge content 20g KNO3 + 38ml H2SO4 I gave 5 g of Sorbitol and 48 hours stooud it out of window without cooling.The acid stood crystalline. Surprisingly was the yield good.The same like with fuming acid.(With the conc. 65%HNO3 is such reaction impossible).
Now I will repeat the experiment. Escales wrote about cooling to 0 C,perhaps was the cooling to quickly and the shape of crystals look it.
(Could be the DCM extract usable for Hexamine nitrolysis? )

Thraxx - 29-10-2016 at 05:33

This could be an economical way:
1)Mg(NO3)2 x 6 H2O-- heat for to lose the water.It melt at 89 C and destroy at 300 C.Therefore heat between 100- 200 C should be sufficient.
2)Destilation of 300g burned Mg(NO3)2 for each 100 ml HNO3 65%.
3)Over burning of the Mg(NO3)2

(Unfortunatelly it is only my idea now.)

PHILOU Zrealone - 31-10-2016 at 06:20

Quote: Originally posted by Thraxx

This could be an economical way:
1)Mg(NO3)2 x 6 H2O-- heat for to lose the water.It melt at 89 C and destroy at 300 C.Therefore heat between 100- 200 C should be sufficient.
2)Destilation of 300g burned Mg(NO3)2 for each 100 ml HNO3 65%.
3)Over burning of the Mg(NO3)2

(Unfortunatelly it is only my idea now.)

This Mg(NO3)2 process for increasing HNO3 concentration has been covered many times onto the forum. Did you use the forum search engine?

PHILOU Zrealone - 31-10-2016 at 06:23

Quote: Originally posted by Thraxx

Into the crystal poridge content 20g KNO3 + 38ml H2SO4 I gave 5 g of Sorbitol and 48 hours stooud it out of window without cooling.The acid stood crystalline. Surprisingly was the yield good.The same like with fuming acid.(With the conc. 65%HNO3 is such reaction impossible).
Now I will repeat the experiment. Escales wrote about cooling to 0 C,perhaps was the cooling to quickly and the shape of crystals look it.
(Could be the DCM extract usable for Hexamine nitrolysis? )

The initial subject was to make concentrated HNO3, not to make sorbitol hexanitrate.
DCM/HNO3 concentrated may eventually be used for Hexamine nitration...not nitrolysis what means replacing a group (like acetyl or formyl) by a nitro group from HNO3 solvent.

Tsjerk - 31-10-2016 at 07:46

I find this German text a bit strange, as it talks about concentrated sulfuric acid and anhydrous nitrate salts, but describes the salts and the acids produced as being hydrates. The acids are described as either a mix of sulfuric and nitric acid, or in the last sentence as the mono hydrate of nitric acid

Thraxx - 31-10-2016 at 09:06

-Hi,the german text is nonsense(lie?),R.Escales had the same sulfuric acid and kalium nitrate like we today and therefore was the mix the same inseparable solid mass in his time like today.
-Why the HNSorbitol? it was proof of strength of the acid or better potency of the Nitrate/SA method.I did it many times and I know,that the strongest fuming acid has with sorbitol problems.And what I found? That this nitrate/SA method (first publicate by Axt?)is (for Sorbitol)the best .Because is slow.I keeped the reaction mix frozen for one week without oxidation and the product was solid stuff,not a liquid of lower nitrates like usually .I did it with fuming acid and it blow after one day in fridge.
-my idea about destillation of Mg nitrate with diluted HNO3 is nonsense( Mg nitrate lose water before it melt by 89 C and acid destilate at 120 C).You are right I should first read what was written.
-The DCM methods look expensive or it need vacuum destilation.
The DCM metod for the nitrate/SA mix is described by Ledgard.
-I will try the vacuum destillation of Mg nitrate /HNO3 but now I am waiting for the nitrate.

[Edited on 15-10-2016 by Thraxx]

Thraxx - 5-11-2016 at 11:32

Experiment asking answer for question,if the use of Mg nitrate and his doublesalt with Amon.nitrate is able to substitute some part of fuming nitric acid by the nitrolysis of RDX.

RDX is building by 1:4 -1: 500 ratio with yield by 1:8-1:30 and maximum at 1:26 and optimum temperature 20C .In the range 1:3,5 and 85% HNO3 will appear the DPT .
// 1:8=140,2 + 504 (=336 ml) HNO3//vol. 1g : 2,4 ml.

Therefore ratio 1:3,2 should make it impossible and therefore the possible activity of nitrates will be visible.

Mg (NO3)2 = m.w.= 148,31 anhydrate
+ 6 waters = 148,31 + 108,12 = 256,43 for hexahydrate.

Mg nitrate hexahydrate was melted and dryied at 165 c and cooled.

Experiments
1)14 g Hexamine into 30 ml (45g)Nitric acid (1:3,2) + melted and cooled on the bottom of the beaker 20 ml of Mg N anhydrate = 5g of product

2)14 g H + 30 ml (45g)Nitric acid (1: 3,2) without Mg nitrate= 4g of product

3) 14 g H + 30 ml Nitric acid + melted 15 ml of Mg nitrate togegther with 15ml Amanium nitrate on the bottom of the beaker = 3g of product

4) 25 ml melted (liquid) Mg nitrate poured into 25 ml nitric acid ,cooled and into this acid gaved 14 g of Hexamine= 0 without product.

Discusion:
Mg nitrate is something like mushroom-it is full of watter and you never know,if is already dry or not yet. If I melt it in the beaker and covered it with glas, now it steamed up.Therefore is necessary to have it melted in the heat for some time.

Conclusion- application of Mg nitrat for concentration of nitric acid in the laboratory is complicate and not convincing .

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

Thraxx - 17-11-2016 at 09:01

The Escales method is possible with Mg(NO3)2.
I had 70 g of Mg nitrate and I melted it half an hour at 170 C.There was 50 ml melt and at 100 C I put it into 100 ml of cold H2SO4.The reaction was a bit fuming,but it was not too bad. After adition it was white warm poridge,it was not clear like KNO3/Sulf.acid.After one h. I put it into freezer .After one hour there was two layers- very white sulfate on the bottom and not clear,but good separated acid . The acid was about 50 ml and I was able without problems drain it into other beaker.
I wanted to know what is the acid able to do and therefore I gave it back to the beaker with sulfate and misced there 20 g of sorbitol. This beaker I want to keep in freezer for one week,but after 24 h. there was two layers and red fumes.I pour it into warm watter and there was very good separated HNS(poor yield) with higher melting point,because at the RT was it solid.Therefore I expect,that this method is very strong nitrating way,stronger than KNO3/Sulfuric.
I think and hope,that(vac.) destilation of liquid melt of Mg nitrate and sulfuric acid could give fuming nitric acid of more than 100% concentration.(with N2O5).

[Edited on 15-10-2016 by Thraxx]

PHILOU Zrealone - 17-11-2016 at 11:27

Quote: Originally posted by Thraxx

I think and hope,that(vac.) destilation of liquid melt of Mg nitrate and sulfuric acid could give fuming nitric acid of more than 100% concentration.(with N2O5).

Sadly theorically and practicaly not possible to make N2O5 from H2SO4 and Mg(NO3)2...
Think twice to the problem by writting the chemical equations:
1°)Mg(NO3)2.xH2O -heat-> Mg(NO3)2 + MgO + H2O + NxOy

2°)H2SO4 + Mg(NO3)2 --> 2 HNO3 + MgSO4

3°)MgO + 2 HNO3 --> Mg(NO3)2 + H2O

4°)MgO + H2SO4 --> MgSO4 + H2O

You already see that at best you get HNO3 and you may even add water if Mg(NO3)2 was heated too strongly...

Why would N2O5 and H2O split appart form HNO3 and where would the water go? Without P2O5 or SO3 hard to get N2O5...

Maybe B2O3 since H3BO3 + nitrate when heated produces HNO3 of medium concentration and borax ... and B2O3 results from calcinating H3BO3...so maybe direct heating of B2O3 and nitrate may lead to N2O5?

[Edited on 17-11-2016 by PHILOU Zrealone]

Thraxx - 18-11-2016 at 08:33

Thank you for advice and good idea.N2O5,they write,is solid stuff sublimating at 30 C.If it will retain in cooler,then it could make problems.
I repeated the experiment with Mg nitrate in Escaless method-60 g Mg nitrate hexahydrate was melted at 170 C.It was abbout 25 ml.In other beaker was 100 ml of cold sulfuric acid.The hot Mg nitrate melt was added to the SA.After one h. was it filtered on vacuum-frita.There was 65 ml acid.
Now there is a question,what is this acid able to nitrate.But we can say,that this conc. nitration acid was prepared without destillation.

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

PHILOU Zrealone - 19-11-2016 at 13:16

Quote: Originally posted by Thraxx

Thank you for advice and good idea.

N2O5,they write,is solid stuff sublimating at 30 C.
If it will retain in cooler,then it could make problems.

I repeated the experiment with Mg nitrate in Escaless method-60 g Mg nitrate hexahydrate was melted at 170 C (It was about 25 ml).
In other beaker was 100 ml of cold sulfuric acid.
The hot Mg nitrate melt was added to the SA.
After one h. was it filtered on vacuum-frita.There was 65 ml acid.

Now there is a question,what is this acid able to nitrate.
But we can say,that this conc. nitration acid was prepared without destillation.

If you know your initial product to be an hexahydrate...this means:
Mg(NO3)2.6H2O --heat--> Mg(NO3)2 + 6 H2O
So for each mole of the hexahydrate, you get 1 mole of Mg(NO3)2 and 6 mole of vapour.
A simple weight loss analysis may give you a good idea at what point of the dehydration you are (assuming you don't overheat to decompose the Mg(NO3)2 partially into MgO and NxOy)

1 mole Mg nitrate = 148.31g
6 mole water = 18g*6 = 108g
1 mole Mg nitrate hexahydrate = 256.31g = 148.31g +18g*6
So 148.31/256.31*100%= 57,86% dry matter = 42,14% weight loss as vapour.

--> Heating but moderate
--> Patience
--> Regular mixing and agitation
--> Regular venting of the above layer with dry/hot air

Thraxx - 20-11-2016 at 06:49

Then I must it all repeat,because if the weight loss is 42%,then it was 34,8g nitrate and there should be not 100 ml sulfuric acid,but 66,9 ml.
But there is the MgO problem.On the bag with nitrate they wrote,that there is 15% of MgO and other MgO will there appear through decomposition during melting.
15 %of 34,8 is 5,22,therefore it shoud be somethig over 40g nitrate and 15% of acid is 10ml,therefore 77 ml.

[Edited on 15-10-2016 by Thraxx]

PHILOU Zrealone - 20-11-2016 at 15:40

Don't make things more complicate than they look...

You can dissolve the nitrate in the minimum amount of warm water and filtrate...owing to common ion effect, the solubility of Mg(OH)2/MgO what is already weak, will be even less and thus remain solid onto the filter.

You may also add a slight exces HNO3 to make Mg(NO3)2 out of the MgO/Mg(OH)2...the tiny excess will volatilise during evaporation/crystallization.

--> Many simple solutions.

[Edited on 20-11-2016 by PHILOU Zrealone]

Thraxx - 23-11-2016 at 02:25

Back to the white nitric acid.
I heard about very economic method :One man have vacuum destilation with 4 l bottle and destillate only Nitric 65% + sulfuric conc.First he fill there 2 l sulfuric acid and write the surface.After he put there the nitric acid and destillate.It does he one day and the second day he recovery the sulfuric acid-he is heating such long,as the surface of sulfuric acid is on the same place like before.

PHILOU Zrealone - 23-11-2016 at 04:15

Quote: Originally posted by Thraxx

Back to the white nitric acid.
I heard about very economic method :One man have vacuum destilation with 4 l bottle and destillate only Nitric 65% + sulfuric conc.First he fill there 2 l sulfuric acid and write the surface.After he put there the nitric acid and destillate.It does he one day and the second day he recovery the sulfuric acid-he is heating such long,as the surface of sulfuric acid is on the same place like before.

Yes economical,

Only noticeable inputs are 65% HNO3, electricity (for vaccuum and heat).
The conc H2SO4 is recycled and thus input = Price H2SO4 conc/number of cycli.

[Edited on 23-11-2016 by PHILOU Zrealone]

markx - 23-11-2016 at 06:14

Quote: Originally posted by Thraxx

It is economical as long as you get to the part of concieving a viable vaccuum apparatus for this setup. And forget about practical regeneration of the sulfuric under atmospheric pressures. If one is not willing to invest top dollar for a chemically resistant vaccuum pump (teflon coated) then the only other option is a water operated suction pump. Basically all other types of mechanical vaccuum pumps will fail very quickly due to the acidic vapours discharge from the flask (scrubbers and traps will not help much). Also please consider the matter of safety....I would be extremely cautios about pulling a considerable volume containing hot sulfuric (up to 300C hot that is) under vaccuum and being nearby at the time. Should that flask fail for some reason then the results will be catastrophic. And these reasons are numerous...thermal shock, backflush of water from flow pump, mechanical influence, internal defect in glassware just to name some. Building a failsafe for the ones that you can spot will already complicate the system to a point that makes it unreasonable for occasional amateur use. I've been contemplating about this matter for quite some time and finally arrived at the revelation that simple atmospheric distillation of nitrate salt+concentrated sulfuric is the most reasonable approach after all. Truly the cost in time, money and just plain technical complications is not worth to construct a sulfuric regenerating system compared to the cost of discarding the acid through the simple salt distillation. It's not like you need gallons of WFNA after all....

Thraxx - 23-11-2016 at 13:48

All what you wrote is true.Grave true. I destilled with vacuum only one time and have a 1 l scrubber with two cocks before and after the scrubber.But my pump was not too strong.
Conc.sulfuric acid is expensive and may be,that in the future they will it not sell.Possibility to concentrate it from diluted sulf. for cars could be important.
I did once the concentration of sulfuric ac. in atmospheric pressure and it was a lot of blows and the last blow up was the biggest.Better not remember.
Perhaps could be good to construct destillation machine from steel with threads,sealed with teflon tape , with two motors ,one for cooler and second for vacuum.Thermometer external.It could be nice small machine.

[Edited on 15-10-2016 by Thraxx]

PHILOU Zrealone - 24-11-2016 at 14:42

Quote: Originally posted by Thraxx

All what you wrote is true.Grave true. I destilled with vacuum only one time and have a 1 l scrubber with two cocks before and after the scrubber.But my pump was not too strong.
Conc.sulfuric acid is expensive and may be,that in the future they will it not sell.Possibility to concentrate it from diluted sulf. for cars could be important.
I did once the concentration of sulfuric ac. in atmospheric pressure and it was a lot of blows and the last blow up was the biggest.Better not remember.
Perhaps could be good to construct destillation machine from steel with threads,sealed with teflon tape , with two motors ,one for cooler and second for vacuum.Thermometer external.It could be nice small machine.

[Edited on 15-10-2016 by Thraxx]

I would go for SO3 production from sulfate salt pyrolysis.

Then add two moles of SO3 (approx 160g) per 100g of HNO3 64%...
HNO3 64% is 64g HNO3 and 36% H2O (or two moles).
HNO3 + 2 H2O + 2 SO3 --> HNO3 + 2 H2SO4 + a lot of heat
(the HNO3 will probably boil off)

The final mix is HNO3 (100%) (64g) and H2SO4 (100%) (196g).
Then distill into glass rod distill apparatus (eventually under mild vaccuum) to recollect the conc HNO3.

Thraxx - 26-11-2016 at 06:23

Pyrolysis of sulfate( Fe2(SO4)3 need over 480C.There is a question,if such work is possible to do in glass.
And if yes,then would be better to sent the smell shortest way (without cooling) into the sulfuric acid for to make oleum.

PHILOU Zrealone - 26-11-2016 at 08:59

Quote: Originally posted by Thraxx

Pyrolysis of sulfate( Fe2(SO4)3 need over 480C.There is a question,if such work is possible to do in glass.
And if yes,then would be better to sent the smell shortest way (without cooling) into the sulfuric acid for to make oleum.

Pyrex glass resist quite wel heat ... up to melting point thus 480°C is no troubles. Of course normal glass would break due to dillatation coefficient and resulting stress.

Sulfur trioxide from laboratory process by two-stage pyrolysis of sodium hydrogenosulfate via intermediary sodium pyrosulfate
1°)Dehydration at 315 °C:
2 NaHSO4 → Na2S2O7 + H2O

2°)Cracking at 460 °C:
Na2S2O7 → Na2SO4 + SO3

Procedure is wel documented into the forum.

[Edited on 26-11-2016 by PHILOU Zrealone]

markx - 28-11-2016 at 01:26

Calling SO3 into the equation will hardly make things easier from a practical point of view

Working with a highly corrosive volatile matter that needs a huge amount of work and custom made equipment to produce is a route that I would not really want to wander in the amateur realm. I've been involved in a process that produced TiCl4 as a sideproduct and this being vaguely similar to SO3 in properties I can say that it means the end of basically all materials and equipment that came in to contact with it or the fumes for any considerable time.
Basically all the methods to obtain WFNA rely on the principle of removing water from the precursor mix or releasing HNO3 via the action of a strongly water affinic substance. Be it SO3, conc, H2SO4, nitric oxides or Mg(NO3)2. None of the water binding agents are practically regenerable under atmospheric pressures. This also goes for magnesium nitrate. But out of the bunch the Magnac (magnesium nitrate based method) process is perhaps the only one that I would consider of any practical purpose for an amateur setup. At least the dehydrating agent there is not a volatile highly corrosive liquid or gas, but just magnesium nitrate that has been partly freed from its crystal water by vaccuum drying and posesses a huge affinity towards water because of that. If I remember correctly then it is possible to dehydrate the magnesium nitrate to its dihydate form under vaccuum and heat, but never to the anhydrous state without decomposing the salt. It is quite cheap to obtain in the hydrated form and poses no trouble storing. Of course the trouble starts at the vac system again....all of the same old woes return: pump failures, temperature hazards, failure of vac flask, backflush etc. Also the time spent on the whole experiment is of consideration here....one can fiddle around a complicated "seemingly profitable" method for months to end up with a mediocre result at a huge cost or just go a simple route and leap to further experiments with the quickly obtained product. So the question is wether the objective is to obtain WFNA for some further purpose or to study the acid production process itself? If the goal is to obtain the acid for further experiments, then the simplest KNO3+H2SO4 is definately the practical way to go.....if not, then one can think about getting involved in the regenerative methods on a level that involves more than just theoretical contemplations. But doing this on any physical scale truly calls for an expendable facility of its own....forget about performing this in your kitchen. Choose something you can burn down to the ground with all contents and not mourn the losses.

Thraxx - 29-11-2016 at 02:42

About the nitric acid:
Properties:
HNO3 ,Mr.63,are white crystals,stable below its f.p. or m.p. at – 41 C.at higher temperature take place the slow decomposition :4HNO3 ==4NO2+2H2O+O2 .Boiling point for anhydrous acid is at 83-87 C,for aquous (68%)at 121 C. The decomposition is slowly and cause noxes.The higher is the temperature,the higher are lost of acid and more noxes.
Some authors told,that only Au,Pt , Cr steel and Al are stable in the fuming nitric acid.Other autors told,that iron is stable too.(?)

Manufacture:

Either we manufacture the nitric acid or we concentrate it.And between are clever pathways which combine this two sources of fuming nitric acid for to optimalising the waste problem how to throw the sulfate out from the bottle.
Simultaneously or after we have the fuming acid can we use one of three ways to the wanted white fuming nitric without noxes-adding urea,air bubbling and vacuum preparation of step I.

I. Glaubers fuming nitric acid 1648
-heating 85 parts kalisalpeter with 98 parts sulfuric acid below 150 C to avoid loss by decomposition of the nitric acid.(Kalisalpeter was there to y.1900,after was it Chilesalpeter.)(1)
I. – 1- manufacture:
Theoretically:

NaNO3 + H2SO4 == NaHSO4 + HNO3
Mr=85 98 120 63
53,6ml 42ml
mp=306,8C 58,5C

KNO3 KHSO4
Mr=101 136,17
mp=334C 197 C

NH4NO3 NH4HSO4
Mr=80 115,11
mp= 169,5 C 121-145C

In the praxis today there was described these rations:

900 g KNO3 + 500ml H2SO4 (2)/need 22ml SA/
400 g NaNO3 + 500ml H2SO4 == 150-200 fuming NA after 2,5 h destillation (3)/remain 252ml SA,could be added 144ml nitric ac./
68 g KNO3 + 32 g H2SO4 (4) /need 4 ml SA/
58 g NaNO3 + 32 g H2SO4 destilled at temperature 80-90C (5)
(to the NaNO3-could be manufactured from Ca(NO3)2 and Na2CO3 and give 15% more HNO3 than KNO3)
80 g NH4NO3 + 100 g H2SO4 = unsatisfactory concentration (1,22 g/cm3)(6)
80 g NH4NO3 + 100ml H2SO4= unsatisfactory concentration,doesnt work with hexamin(7)

The waste beginn to crystalise after 10 min after heating.It is necessary to disassemble the distill. Ap.

I. 2 : Concentration of nitric acid to highest concentration:

- Frenchman and Rouelle 1750- concentration of weak nitric acid with conc. sulfuric acid by distillation.
Today ration:
200ml 65% HNO3 + 350ml 96% H2SO4 at 110-120 C give 108-110 ml fuming NA
280g 640,5g
of 1,51g/cm3 (8)
( spent acid is 440 ml of 72% sulfuric acid,therefore was used 3,57ml conc. sulfuric acid for every ml of watter in the nitric acid or 1,75ml sulfuric acid for every ml of nitric acid.In according to Valentiners proces it schould be 280gNA : 560 gSA)

-concentration without distillation with help of anhydrous magnesium nitrate or calcium nitrate:
- Escales method of cold separation of misced nitric and sulfuric acid-although by author described method with Na or K nitrates (1 weight part of Na or K nitrate + 31/2 weight part of conc. sulfuric acid cooled at 0 C and separate )was impracticable,but there was found an other way with anhydrid of Magnesium nitrate. (9)

- Valentiners vacuum proces-19.century(Basil Valentinus lived in 17.c.?)Distillation at 15-25 mm Hg.
Today:
Laboratory preparation of 99%+
1 part of HNO3 (1,4 g/cm3) +2parts of sulfuric acid (1,84g/cm3)dist. under vacuum.(10)

Combined methods:
140ml 65%HNO3 +170ml 96% H2SO4+70g NaNO3== 110ml fuming NA(11)/there should be 72 ml HNO3/
350 g NaNO3 + 500ml H2SO4 + 150 ml HNO3== 200-250ml fuming NA(12)/there should be 18ml SA less/

I. 3 : Extraction of nitric acid with DCM -20.century like patent 549198 or 3981975.Ledgard described manufacture of absolute nitric acid : 94ml sulfuric acid +106 ml 70% HNO3+ extraction 7x 200 ml DCM and after this vac.destillation of DCM. (13)

II.-White fuming nitric acid – because the Noxes are allowed to 4% and more could make explosion of hexamine or oxidation of other reaction,is better to have NA without noxes.
-Bubbling ,air gurgling (14)
-vacuum destilation (Valentiners proces)
-adding of urea –1)hot-should be at 60 C but it is very exothermic reaction with some delay.Adding 10g of urea into 250 ml fuming NA for 15 min need to wait 2 h for to be sure,that the reaction is ended.During adition are huge amount of noxes outgoing,which could do explosion and are highly toxic .(15)
2)atRT-the same reaction like hot adding,can explode.(16)
3) cold urea -for every 100ml nitric ac. 2 g urea at 0 C-outgoing are CO2 and N.(17)
- boiling - stupid like hot adding of urea .

III.-Fuming nitric in situ:

-Different methods of nitration with sulfuric acid and nitrates Na,K, or Ca (18)
------------------------------------------------
Numbers (1)to(18) are numbers of pathways
------------------------------------------------
What I allowe me to suggest is 1) iron distillation apparatus and 2) one iron flask with pipe for cracking of NaHSO4 (destillation waste).
The iron apparatus should have two iron flasks connected through threads with long pipe of U shape which one arm is going through watter bath .Connected to strongest vacuum pump.
Questions about waste:
To the waste,called "nitro cake"-if it is NaHSO4,could it react with Ca(CO3)2 to NaNO3??
-at how temperature will be possible reaction: NaNO3 + H2SO4 ==Na2SO4 + 2 HNO3 if it will be done under vacuum?
At atmos. pressure it isnt possible,because the temperature is need too high and the HNO3 will be decomposed to noxies.But under vacuum? This reaction need only half of amount of sulf.acid and the nitrocake could be converted with Ca nitrate.

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

PHILOU Zrealone - 30-11-2016 at 09:14

@Thraxx,
Iron becomes passivated by contact with conc HNO3 alone...but contact with other metals may deactivate the passivation; I don't know what happens when lower % HNO3 is involved nor what happens when conc HNO3 and H2SO4 are together into contact with iron.

QUOTED From you:
"To the waste,called "nitro cake"-if it is NaHSO4,could it react with Ca(CO3)2 to NaNO3??"
1°) Ca(CO3)2 doesn't exist, it is CaCO3...Ca is bivalent and H2CO3 is diprotic acid.
2°) If it is NaHSO4 then reacting it with CaCO3 will never make NaNO3...that would call for nuclear chemistry (transmutation of one atom into another ... C into N)

Wait! I read into your mind...

--> I guess you meant Ca(NO3)2 instead of Ca(CO3)2
Indeed:
NaHSO4 + Ca(NO3)2 --> CaSO4(s) + HNO3(v) + NaNO3
Because transciently:
2NaHSO4 <==> Na2SO4 + H2SO4
so
Na2SO4 + Ca(NO3)2 <--==> CaSO4(s) + 2 NaNO3
H2SO4 + Ca(NO3)2 <--==> CaSO4(s) + 2 HNO3 (v)

Thraxx - 30-11-2016 at 11:45

If we havent KNO3 more and if we have a lot of time and money,then could we do this manner:
Distillation:
Ration: 500 ml H2SO4 (915g=9,33 mol)+ 950 g KNO3 (9,33 mol)
The nitro cake will have 1270 g and need to throw it out from bottle either like solid or with 3 l of hot watter to other bottle of 10 l volume.There add 2203 g of Ca(NO3)2 in 2 l hot watter and after some hours add there solution of 500 g KOH in 1l watter . After a longer time for decantation of plaster of paris there could be solution of 1884 g KNO3 in 6000 ml watter,which need to be evaporate.

DISTILLATION :
KNO3 + H2SO4 == KHSO4 + HNO3
Mr= 101 98(53,6ml) 136,17
mp= 334C mp=197 C
solubility= 49g/100ml at 20 C

WASTE-NITRO CAKE:
KHSO4 + Ca(NO3)2== HNO3 + KNO3 + CaSO4
Mr=236,15/tetrahydrate/
m.p.=42,7C
Solubility =444,3g/100ml at 20 C
Neutralisation:
HNO3 + KOH ==KNO3 +H2O
Mr=56,1
m.p.=406 C
Solubility= 121g/100ml at 20 C

----------------------------------
Today I did the "white fuming nitric"-
Some days ago I distilled NaNO3 + SA at vacuum-there stood something like stone from NaNO3,because the low vac.temperature was unsufficient for the reaction .So I added there new SA + nitric acid and distillated it at atm pressure. It worked well,but there was amount of brown noxies and the fuming acid was dark yellow.
First I cold to O C in ice bath and added there 2g urea for 100 ml of acid.What happened? nothing,no fumes,no bubbles it diluted mild and easy and the acid stood yellow.
I found it unsufficient and put there an air through glass pipe.It was good pressure,acid gurgled in the bottle and really a lot of fumes ,White fumes get out.It was a few minutes,may be 5 min. and after it gurgled but there was the white fume no more.And the acid stood yellow.
Before I ever throwed urea to warm acid with gasmask,respirator was unsufficient.Acid squirted out of bottle and there was a very much of brown fumes .And the acid was then really like watter.It was total bad -I decomposed me my acid.
It seems me,that right was the method of cool bubbling,and the bad noxies diluted in HNO3 are the white fumes and not brown fumes,which are from decomposed HNO3.And the acid may be yellow.
---------------------------------------------------------
If the Sulfuric acid need to be concentrate,then perhaps could be such way:
Generally:
- Sulfuric acid H2SO4.Mr= 98,m.p. 10,36 C ,boiling point 273 for 100% and 310-335 for 98 %,Decomposition up 338C.
- SO3-melting point 16,8C,boiling point 44,8C
- KHSO4-melting point 197 C,boiling point with decomposition 300 C
- K2S2O7-mellting point 325 C and decomposition between 460 up to 600C

1. Step- making Potassium hydrogensulfate through Distillation at higher degrees to 150 C of KNO3 800 g + H2SO4 500ml== KHSO4 1078,5 g + H2SO4 in one bottle and HNO3 + noxies in the second bottle which we turn for other bottle with Sulf acid which should be concentrate .
2.Step- making Potassium pyrosulfate through heating.
-At 240 C there will be decomposition to K2SO4 +H2SO4,but the sulf.acid should stay in the bottle.
-At 320 C there will be decomposition of sulfate to pyrosulfate :
2 KHSO4 ==K2S2O7 + H2O
…and the sulf.acid will distillate,but it must stay there like catalysator.
3. Step-pyrolysis of pyrosulfate at 460 C .First melt the pyrosulfate and after boiling are white fumes of SO3 outgoing from melt to cooler.
K2S2O7 == SO3+ K2SO4
Video here:
http://www.prepchem.com/synthesis-of-sulfur-trioxide/

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

[Edited on 15-10-2016 by Thraxx]

markx - 1-12-2016 at 07:03

Thraxx....you need to do a bit of fraction cutting during the simple acid distillation. Majority of nitric oxides come over in the "heads" or the first fraction that boils over. It is mostly less than 10% of the total acid yield. You need to collect these nitric oxide rich heads separately and discard. The rest of acid comes over quite pure after that. It will still have a slight yellow hue to it, but that is not a problem for nitramines in direct nitrolysis route and even less in Bachmann route. The urea addition makes quite a mess as you can conclude from your previous experienece. Also there is no need to really go slow with the distillation....as long as you separate the first bad fraction, you can turn up the boil rate and run quite fast. That is provided your flask and other equipment can handle the thermal shock with no trouble. I suggest you do not use an oil bath to heat the acid flask.....if it breaks then the resulting mix will most definitely burst into a raging fireball. I have found that hanging the flask directly over a hotplate, but not in direct contact is perhaps the safest way to do it when using glassware.

PHILOU Zrealone - 1-12-2016 at 11:09

@Thraxx,
Na pyrosulfate is better than K pyrosulfate to make SO3... the K version favors decomposition of the SO3 into SO2 and 1/2 O2...so yield will be lower /amount will be less.

[Edited on 1-12-2016 by PHILOU Zrealone]

Microtek - 2-12-2016 at 01:40

In the EU, sulfuric acid is becoming a restricted chemical in concentrations above 30 or 50 %, so the ability to produce or recycle is more important than ever.
I have experimentet with boiling down dilute sulfuric at atmospheric pressure and obtained acid of ca. 90-93 % concentration without exceedingly high temperatures or particularly long heating time.
While this concentration is not as high as would be preferred, it is still high enough for concentrating dilute HNO3 (though you may need more than one distillation).
Of course, nitric acid is also becoming restricted (above 10% IIRC), so that is another chemical that will be necessary to produce.

Thraxx - 2-12-2016 at 04:45

Quote: Originally posted by Microtek

I have experimentet with boiling down dilute sulfuric at atmospheric pressure and obtained acid of ca. 90-93 % concentration without exceedingly high temperatures or particularly long heating time.

If I understand,you didnt boil the acid,you only heated and for the concentration or evaporation it was sufficient?

Microtek - 4-12-2016 at 14:01

No, I did boil it, but it wasn't at an extremely high temperature. I simply heated it strongly until the temp reached somewhere around 200 C. Then turned off the heating and sealed the container.

Pages: 1 2