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Salt metathesis


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#1 willowchar

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Posted 06 January 2021 - 06:06 PM

Wondering if sodium perchlorate and ammonium nitrate can be used to produce ammonium perchlorate and what mass of each should be combined in solution?

Also, what would be the theoretical yield of AP. in such reaction?

Thanks



#2 MadMat

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Posted 06 January 2021 - 07:31 PM

It's been a long time since I did any chemistry, but I think this wouldn't work because the solubility of ammonium perchlorate is higher in a water solution than sodium perchlorate. In a double displacement reaction, you need your desired end product to precipitate out of solution and unless there is a different solvent that I don't know of, that just won't happen



#3 RichardH08

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Posted 09 January 2021 - 09:39 AM

I have to disagree. Ammonium perchlorate is the least water-soluble salt that can form from sodium perchlorate and ammonium nitrate, so the method will work. Perhaps MadMat was thinking of starting with potassium perchlorate, which is far too insoluble.

 

Theoretically, 100g of ammonium nitrate will react with about 150g of sodium perchlorate (each dissolved in as little hot water as will just completely dissolve them) yielding, when the solutions are mixed and left to cool, about 140g ammonium perchlorate. In practice, some will remain in solution and I reckon you would do well to extract 100g. Also bear in mind that the product will be heavily contaminated with sodium salts. If that is an issue, you would have to recrystallize the product a couple of times, which would further reduce the final yield.



#4 MadMat

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Posted 09 January 2021 - 03:14 PM

Opps! You are exactly right! I was thinking of potassium perchlorate. I checked back and when I was looking up solubilities, it was potassium perchlorate that I looked at and not the sodium salt.... Sorry for the confusion


Edited by MadMat, 09 January 2021 - 03:16 PM.


#5 willowchar

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Posted 10 January 2021 - 06:44 PM

Thanks for the response,

Would the sodium contamination in this method be any worse than if ammonium chloride were used instead of ammonium nitrate?

My gut feeling is that it would be the same? 



#6 davidh

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Posted 11 January 2021 - 11:49 AM

Your best bet would be to research the industrial process, and from that research determine the other common processes for producing AP. Then you can adapt one of those processes, although I suspect they may all prove prohibitive to the amateur.



#7 Mumbles

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Posted 12 January 2021 - 01:16 AM

This should produce ammonium perchlorate.  One thing I would keep in mind is all of the relative solubilities.  Sodium perchlorate and ammonium nitrate are by far the most soluble of the species involved.  As RichardH said, ammonium perchlorate is the least soluble, which will favor it's precipitation.  The thing to keep in mind, to help minimize sodium contamination is the solubility of the resulting sodium nitrate.  It's less soluble than both ammonium nitrate and sodium perchlorate.  If you just mix saturated solutions of each, which honestly would be my first instinct as well, you'd precipitate sodium nitrate too.

 

Sodium perchlorate - 2090g/L @ RT, 3290g/L @ 100C

Ammonium nitrate - 1500g/L @ RT, 10240g/L @ 100C

Sodium nitrate - 912g/L @ RT, 1800g/L @ 100C

Ammonium perchlorate  - 208.5g/L @ RT, 570g/L @ 100C

 

As a first start, I'd go backwards from sodium nitrate and add in a buffer of water to try to minimize it's precipitation.  As a gut instinct, I'd say 850g of sodium nitrate, which conveniently makes the math real easy.  850g is almost exactly 10 moles.  To do this, I'd mix 1224g sodium perchlorate in 500mL water and 1696g ammonium nitrate in 500mL water.  This would make 1174g ammonium perchlorate.  Even at boiling, you'd see an immediate precipitate.  Whether at RT or hot, it wouldn't really matter.  While that's the total produced, you'd lose some to solubility at RT.  In theory, you'd get about 966g of ammonium perchlorate precipitated out.  You'd likely get a lot more than that though due to all the sodium nitrate pushing more of it out of solution. 

 

That might not be a bad place to start.  You'd almost certainly need to recrystallize it, which unfortunately comes with fairly heavy mass loss.  Depending on what things are looking like, methanol is decent at washing out low levels of sodium ntirate, assuming its not trapped inside the crystal.  The other concern is how hygroscopic all the products and reactants are.  Any slightly contamination might yield some product that could be hard to work. 

 

I'm happy to help if you really want to move forward with this.  Let me know if there's any questions, or if I messed up some of the figures.  It's not he be-all, end-all procedure, but hopefully is a good starting point.


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#8 eb666

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Posted 16 January 2021 - 10:46 PM

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The Chlorate and Perchlorates

 

http://www.pyrobin.c...erchlorates.zip

 

See the Ammonium Perchlorate section. It has been documented in a russian journal if you know anyone who can get their hands on it.

 

I think the way for the amateur for ammonium Perk. is via Calcium Perchlorate. It is relatively easy to make Ca Perk. (I presume). Then without taking the Ca perk out of solution add ammonium Sulphate and you get insoluble Ca Sulphate + Ammonium Perk.

Ammonium Sulphate is cheap and easy to get. Ca Chloride is cheap and easy to get.

 

Job done??


Edited by eb666, 16 January 2021 - 10:49 PM.


#9 eb666

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Posted 22 January 2021 - 12:38 PM

 

What you need is attached. It is in Japanese unfortunately.

 

EB

Attached Files


Edited by eb666, 22 January 2021 - 05:05 PM.


#10 eb666

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Posted 26 January 2021 - 06:53 PM

It turns out the document is not of much use. It does tell you that Ammonium Perk. will ppt. out but exact amouts/solubilies are not very obvious (if they can be acertained at all).

I am not up to speed on those Janecke projections.

 

Figure 2 that is attahced here is the one that I thought give the exact required info. but it turns out it is mislabled :(

 

EB

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