Sciencemadness Discussion Board

Hydrazine

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ManyInterests - 22-4-2024 at 06:36

By heating I assume you mean fire? How much temperature are we talking about? What are the byproducts released? I need to make sure so I can take the safety precautions needed.

Keras - 22-4-2024 at 07:38

Quote: Originally posted by ManyInterests  


I'm curious as how much of your other reagents you used as well.


I used NileRed’s quantities.
Quote: Originally posted by ManyInterests  

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.


I have EDTA on my shelf. I bought it a long time ago together with Eriochrome Black T to do potable water titrations. Since EDTA is known as a powerful chelator, I decided to use it instead of gelatine.

I will definitely try to recrystallise it when I have time, but I was surprised.

[Edited on 22-4-2024 by Keras]

EF2000 - 22-4-2024 at 07:58

Quote: Originally posted by ManyInterests  
By heating I assume you mean fire? How much temperature are we talking about? What are the byproducts released? I need to make sure so I can take the safety precautions needed.


According to ChemSpider it decomposes at melting point 254-255 °C: https://www.chemspider.com/Chemical-Structure.23225.html (Properties tab)

Products of decomposition should be N2, H2O and SO2. Only the last one is of concern, being a lung irritant. But if you test a tiny quantity outside or in your balcony-turned-into-fume-hood, it should be fine.

Keras - 22-4-2024 at 08:37

Quote: Originally posted by ManyInterests  
But I am curious as how to test for purity.


This might help:

Attachment: kolthoff1924.pdf (504kB)
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EF2000 - 22-4-2024 at 09:35

Quote: Originally posted by Keras  
Quote: Originally posted by ManyInterests  
But I am curious as how to test for purity.


This might help:

Also this: Quantitative Determination of Hydrazine
Attachment: penneman1948.pdf (550kB)
This file has been downloaded 172 times

ManyInterests - 23-4-2024 at 07:09

Quote: Originally posted by Keras  
Quote: Originally posted by ManyInterests  


I'm curious as how much of your other reagents you used as well.


I used NileRed’s quantities.
Quote: Originally posted by ManyInterests  

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.


So I am assuming that you used 22g of urea and 500ml of 5% bleach? Yeah, you will need to recrystallize or something since the amount you got, 50g, would be impossible. Nilered got 20.25g, a 48% yield. If he got 100% he might have gotten close to 41g or so, but I highly doubt anyone could get 100% yield on a lab scale.

I remember the first few synthesis I tried, I used Magpie's quantities but I was lead to believe by a YouTuber that the hydrochloric acid was optional. It wasn't. I didn't bring the pH down enough for hydrazine sulfate to form. I don't know what the white powder I got ultimately was, but it wasn't enough to be either sodium sulfate or hydrazine sulfate.

I have EDTA on my shelf. I bought it a long time ago together with Eriochrome Black T to do potable water titrations. Since EDTA is known as a powerful chelator, I decided to use it instead of gelatine.

I will definitely try to recrystallise it when I have time, but I was surprised.

[Edited on 22-4-2024 by Keras]


I think you should. I looked up Nile Red's video on hydrazine sulfate (I found other methods more superior to his) and he used 22g of urea. I am assuming you used the same reagents as well (500ml 5% bleach, 100ml 50% sulfuric acid, etc) and his yield was 20.25g or 48%. Meaning a 100% yield would be around 41g at the absolute most. I highly doubt anyone could get that high in a lab setting.

This reminds me of the first few times I was making hydrazine sulfate. I used the Magpie quantities (a YouTuber also did it, but without the alcohol wash) and I was originally lead to think that the hydrochloric acid was optional. It wasn't. But due to that, I didn't add enough acids to even fully neutralize it. Something did come out, but it wasn't hydrazine sulfate.

Keras - 23-4-2024 at 11:06

Quote: Originally posted by ManyInterests  

So I am assuming that you used 22g of urea and 500ml of 5% bleach? Yeah, you will need to recrystallize or something since the amount you got, 50g, would be impossible. Nilered got 20.25g, a 48% yield. If he got 100% he might have gotten close to 41g or so, but I highly doubt anyone could get 100% yield on a lab scale.

I think I used 9.6% bleach instead. I don’t have 5% bleach. Maybe I scaled down the volume accordingly. Can’t remember, didn't really write anything down since it was reproducing what many other people had already done (and redone, and re-redone…)

Sir_Gawain - 23-4-2024 at 12:02

Since you used the sulfuric acid neutralization method and that small volume of liquid, it’s most likely just sodium sulfate.

ManyInterests - 24-4-2024 at 14:41

Quote: Originally posted by Sir_Gawain  
Since you used the sulfuric acid neutralization method and that small volume of liquid, it’s most likely just sodium sulfate.


That is what I am thinking. I remember (I posted it here on this thread a few years ago) when I only used sulfuric acid. What came out when it was very, very cold was sodium sulfate and not hydrazine sulfate.

The one thing I would be looking for now after I finish adding the HCl and start with the sulfuric acid is what I call 'the snow globe effect'. It's when you see bits of the shiny hydrazine sulfate start to form and swirl around (if you're using magnetic stirring) even if the solution is still warm after the addition of all the acids. That stuff is hydrazine sulfate.

Keras - 24-4-2024 at 22:21

Quote: Originally posted by ManyInterests  


That is what I am thinking. I remember (I posted it here on this thread a few years ago) when I only used sulfuric acid. What came out when it was very, very cold was sodium sulfate and not hydrazine sulfate.


I don’t really put the solution in the fridge, given the video warned about lowering the temp under 15 °C.

I’m going to dissolve my 50 g of mixture in 100 mL of water at 30 °C. Apparently this is enough to dissolve 50 g of sodium sulphate, while I'd lose only 3 g of hydrazine sulphate. What does not dissolve should therefore be pure hydrazine sulphate.

Keras - 4-5-2024 at 22:45

Quote: Originally posted by Keras  

I’m going to dissolve my 50 g of mixture in 100 mL of water at 30 °C. Apparently this is enough to dissolve 50 g of sodium sulphate, while I'd lose only 3 g of hydrazine sulphate. What does not dissolve should therefore be pure hydrazine sulphate.


By the way, yes, this worked. I ended up with 12 g of what I think is mostly pure hydrazine sulphate. Not much left, but at least I’m fairly confident this is the real McCoy now.

Sir_Gawain - 5-5-2024 at 20:12

Yeah, with higher concentrations of hypochlorite, you just have to use the hydrochloric acid neutralization. I’ve used 12% bleach, cooled to <10C and gotten no sodium sulfate precipitation.

ManyInterests - 8-5-2024 at 16:20

Quote: Originally posted by Sir_Gawain  
Yeah, with higher concentrations of hypochlorite, you just have to use the hydrochloric acid neutralization. I’ve used 12% bleach, cooled to <10C and gotten no sodium sulfate precipitation.


Thanks for mentioning that, when I do my next hydrazine synthesis, I'll also let it cool to a little below 10C since you mentioned that. I wanna do one final hydrazine sulfate synthesis since I finally got a handle on freebasing it. I just don't want to have to bother with making more for a good long time.

Keras - 8-5-2024 at 23:57

Quote: Originally posted by ManyInterests  

Thanks for mentioning that, when I do my next hydrazine synthesis, I'll also let it cool to a little below 10C since you mentioned that. I wanna do one final hydrazine sulfate synthesis since I finally got a handle on freebasing it. I just don't want to have to bother with making more for a good long time.


By the way, it is mentioned in the famous book Small Scale Synthesis of Laboratory Reagents that: ‘Neutralisation is performed with HCl rather than the more commonly used H₂SO₄, reducing the exothermicity of the reaction and thermal loss of hydrazine, as well as co-precipitation of Na₂SO₄.10H₂O on cooling, due to NaCl forming part of the salt load.’

ManyInterests - 25-5-2024 at 08:11

Quote: Originally posted by Keras  
Quote: Originally posted by ManyInterests  

Thanks for mentioning that, when I do my next hydrazine synthesis, I'll also let it cool to a little below 10C since you mentioned that. I wanna do one final hydrazine sulfate synthesis since I finally got a handle on freebasing it. I just don't want to have to bother with making more for a good long time.


By the way, it is mentioned in the famous book Small Scale Synthesis of Laboratory Reagents that: ‘Neutralisation is performed with HCl rather than the more commonly used H₂SO₄, reducing the exothermicity of the reaction and thermal loss of hydrazine, as well as co-precipitation of Na₂SO₄.10H₂O on cooling, due to NaCl forming part of the salt load.’



And NaCl is quite soluble in water, hence it's ease of purification. :)

I did it one more time. Albiet when I add the acid I don't take break, I only wait for the fizzing to subside between additions. I did cool down my solution to 10C before filtering. I got a 101 grams this time. I probably will not need any more hydrazine sulfate for a long time, as I have 148g in total now.

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