Triflic Acid
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Making alcohol solutions of hydrazine.
I need an alcoholic solution of freebase hydrazine, and I have hydrazine sulfate. How should I go about making the solution? I don't want to have to
vacuum distill the hydrazine.
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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macckone
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Add calcium hydroxide or sodium hydroxide.
Both calcium and sodium sulfate are insoluble in ethanol and isopropanol.
Sodium bisulfate disproportionates to sodium sulfate and sulfuric acid in alcohols.
Don't use methanol if trace sodium sulfate is a problem.
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Triflic Acid
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But isn't hydrazine sulfate also insoluble in ethanol/isopropanol? So how do I get the sodium hydroxide in ethanol solution to react with the sulfate?
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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macckone
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They will react unless your solution and your reagents are bone dry.
Mix them intimately and then add the ethanol if you are using calcium hydroxide.
If you are using sodium hydroxide, mix it with the alcohol then add the hydrazine sulfate.
Two phase reactions are a thing.
Same with isopropanol, except you are going to have to add both in stages as there are solubility issues.
One of the sodium azide preps uses isopropanol, sodium hydroxide and hydrazine sulfate.
Sodium sulfate will absorb any water present.
It also gets quite hot so good ventilation is absolutely mandatory.
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S.C. Wack
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It seems more likely to be less convenient than that. IIRC the original preparation of anhydrous hydrazine was the methanolic HCl + sodium methoxide.
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macckone
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The HCl is not very soluble either.
In methanol it is about 0.2g/100ml.
It is worse in ethanol and isopropanol.
The one that I know works right is sodium hydroxide in alcohol and add the hydrazine salt.
The calcium method, like everything involving calcium would be a pain the butt to filter.
Any biphasic reaction is going to require a lot of time and stirring.
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S.C. Wack
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Weird how no one else seems to have heard the news.
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Triflic Acid
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What do you mean?
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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S.C. Wack
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Where has hydrazine sulfate been used in this way in the past 130 years?
If something is insoluble in alcohol, that doesn't rule out solublility in alcoholic hydroxide, but how is the sulfate going to dissolve if sodium
sulfate is also insoluble? Perhaps some hydrate could be made in water with an equimolar amount of hydroxide and the sulfate precipitated with alcohol
and most water removed as the azeotrope, but it seems unlikely that the expected amount of sulfate or hydrate will be found.
What is the solubility of the hydrochloride in hot alcohols? More than the sulfate.
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Bedlasky
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Quote: Originally posted by macckone  | The HCl is not very soluble either.
In methanol it is about 0.2g/100ml.
It is worse in ethanol and isopropanol. |
????
https://en.wikipedia.org/wiki/Hydrogen_chloride
Solubility of HCl in MeOH 47 g/100 ml, which is more than in ethanol and isopropanol (MeOH is more polar so just from logic it dissolve more HCl than
longer chain alcohols).
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Boffis
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No Bedlasky, they are talking about hydrazine hydrochloride not hydrogen chloride!
If you convert hydrazine hydrogen sulphate (the normal stuff called hydrazine sulphate to the dihydrazine sulphate it is very soluble in water and
ethanolic hydrazine solution can then be produced by carefully adding sufficient ethanolic sodium hydroxide solution. The resulting solution is not
super strong and will contain a little sodium sulphate and water but it depend what you want to do with it. If you want anhydrous hydrazine in
anhydrous ethanol I have posted details before on SM; try the search engine.
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Gargamel
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The usual problem seems to be that there is still leftover hydroxide in the freebased hydrazine solution.
How do you get rid of that other than by destillation?
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clearly_not_atara
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^bubble CO2? AFAIK hydrazinium carbonates are not stable and will decomp to the freebase.
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Triflic Acid
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Well, I seem to have found a prep:
| Quote: |
Anhydrous hydrazine is more easily prepared by adding a solution of sodium methoxide in methyl alcohol to a solution of hydrazine hydrochloride in,
methyl alcohol. Sodium chloride produced is filtered off
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I don't need anhydrous, so I'm going to use NaOH instead of NaOCH3. Also, anyone know a quick way of evaporating hydrazine hydrochloride solution,
since I'm going to be making it by reacting calcium sulfate with hydrazine sulfate.
[Edited on 3-7-2021 by Triflic Acid]
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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macckone
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I assume you mean calcium chloride with hydrazine sulfate.
Filtering calcium sulfate is a pain in the butt.
Anything quick with hydrazine is going to be dangerous.
This is not something you want airborne even in salt form.
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macckone
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S.C. Wack
The hydrazine sulfate solubility in ethanol is 0.04g/100ml.
I could not find good figures for both the sulfate and hydrochloride in both solvents.
Again hydrazine salts are not tremendously soluble.
I can tell you that sodium hydroxide dissolves just fine in alcohol.
Calcium hydroxide does not but it is more soluble than the sulfate.
Biphasic reactions are usually slow and require a lot of stirring and sometimes a PTC.
The best example of this is nurdrage's sodium synthesis.
It uses sodium hydroxide and magnesium in mineral oil with methanol as a PTC.
In the hydrazine salt case, with sodium hydroxide, it is soluble so you don't need a PTC as it is direct contact with the material, you just need
stirring to expose 'fresh' material.
In the calcium hydroxide case, you are going to need a lot more time and stirring but there is some solubility without a PTC. If you start with a
good mixture of powders, you don't need nearly as much time.
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Triflic Acid
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Wait. Doesn't nurdrage produce freebase hydrazine in this video: https://www.youtube.com/watch?v=58Ve69s0qD0&ab_channel=N...
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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Oxy
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No, he's making hydrazine acetate.
If you need it really clean then you will probably need to distill it. What do you want to do with it? For some usages the contamination may not be a
problem.
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Triflic Acid
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This might work if you have a feasible way of making large-ish amounts of liquid ammonia, or if you only need a small amount of hydrazine.
| Quote: |
In the treatment of hydrazine sulfates with liquid ammonia at about 33 C., i. e., the boiling point of liquid NI-la, the reaction products are free
hydrazine and an ammonia addition product or complex known as the triammonate of ammonium sulfate. With the acid sulfate it is formed according to the
following equation:
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From patent US2680673A
Letting it warm up removes the ammonia(or, if you are really stingy about ammonia, you can add a gas adapter and recycle it for another batch or
dissolve it into water.) Anyway, after that, adding some ethanol to the mix will dissolve out only the freebase hydrazine with very little byproduct.
The ammonium sulfate isn't soluble in ethanol either, according to the patent.
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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macckone
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If you need larhe amounts of ethanoic hydrazine, distill it.
Although it is toxic, working with large amounts of liquid ammonia is going to be toxic as well.
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Triflic Acid
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I'm going to need only a few grams worth, so this should work for me.
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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