Sciencemadness Discussion Board

HCl + ?? = NH3 + ??

simmerman - 9-10-2013 at 00:12

Hello,

I need to find a compound that frees ammonia in gas form when reacted with dry HCl. I've been searching but couldn't find any. Could anyone please help me?

Fantasma4500 - 9-10-2013 at 00:43

frees ammonia when reacted with HCl??
this sounds quite hard as acid vapours will react with the freshly formed NH3, if its even possible to do, and then make NH4Cl
i know that KNO3 + NaOH + Al = NH3
the hydrogen is coupled with the nitrogen from the KNO3, somehow.. quite interesting experiment.. however also ammonia salts reacted with a carbonate or hydroxide will form (NH4)2CO3 (decomposes at 70*C IIRC into NH3 and CO2) and with hydroxide NH4OH which naturally decomposes from water (NH3*H2O > NH3 + H2O)

what are you planning anyways?

deltaH - 9-10-2013 at 00:51

HCl + NaNH2 => NH3 + NaCl

NaNH2 = sodium amide.

[Edited on 9-10-2013 by deltaH]

bismuthate - 9-10-2013 at 02:55

The ammonia would be mostly impure just mix NaOH with an ammonium salt and it will make ammonia.

bismuthate - 9-10-2013 at 03:10

sorry. if you want to make it in the gas phase the first thing you need to worry about is your apparatus.
I recomend the method suggested by deltaH.

woelen - 9-10-2013 at 03:28

@bismuthate: Please read more carefully what the OP wants. This is not a general question about making ammonia gas, this is a (most likely theoretical) quest for a very special situation in which addition of HCl gas to a certain chemical gives NH3. DeltaH gives a perfect answer to this question. No more explanation is needed.

Btw, in practice, I found a similar thing the other way around. Adding NH3 to a chemical can give HCl. If you add aqueous NH3 to TCCA, then you get N2 and HCl (material becomes strongly acidic) and other products, which in turn leads to formation of Cl2.

deltaH - 9-10-2013 at 03:37

Quote:
Btw, in practice, I found a similar thing the other way around. Adding NH3 to a chemical can give HCl. If you add aqueous NH3 to TCCA, then you get N2 and HCl (material becomes strongly acidic) and other products, which in turn leads to formation of Cl2.
Interesting! I've always wanted to try a few things with TCCA, never had the pleasure of fiddling with it. I have however experimented extensively with its cousins melamine and cyanuric acid!



[Edited on 9-10-2013 by deltaH]

bismuthate - 9-10-2013 at 04:08

I belive magnesium nitride reacts with acids (and water) to make ammonia.

simmerman - 9-10-2013 at 04:33

Thanks all for your answers.

In my (theoric) reaction, I got HCl as byproduct (which I need to neutralize), and as I need to react the product with ammonia, it will be nice to get it produced rather than gassing it from an external aparatus.

Sodium amide proposed by deltaH seems to fit me, however it is a nasty chemical that I would like to avoid. Ayone knows any other option?

WGTR - 9-10-2013 at 10:17

Supposedly the "First commercial process using ionic liquids" was developed by BASF for the purpose of scavenging HCl from a reaction mixture. http://www.basf.com/group/corporate/en/innovations/publicati... . 1-methylimidazole is reacted with HCL to form 1-methylimidazolium chloride, which separates as a separate liquid (at over 75°C) phase in non-polar solvents. The 1-methylimidazole can be reclaimed by reacting the chloride salt with a base.

I realize that this doesn't produce ammonia, but maybe it will be of use to you.


[Edited on 9-10-2013 by WGTR]

bismuthate - 9-10-2013 at 11:27

magesium nitride will make ammonia on contact with HCl. it is safer than sodium amide because instead of making caustic NaOH on contact with water it makes rather harmless MgOH. I know that I already posted this, but I feel that this is safer.

deltaH - 9-10-2013 at 12:18

What about ammonium carbamate, its a really cheap salt made as an intermediate to urea and fairly safe (smells strongly of ammonia though), but the down side is that it would produce ammonia and carbon dioxide, though maybe the CO2 is not a problem in the context of your needs?

The reaction would be:

NH4CO2NH2 + HCl => NH4Cl + NH3 + CO2

simmerman - 9-10-2013 at 12:25

Great ideas guys, CO2 is not a problem. Thank you all!

deltaH - 9-10-2013 at 12:42

Pleasure, my consulting fee is $1000... just kidding... come again :D

deltaH - 9-10-2013 at 12:43

@bismuthate, you only get $100 'cause I need the money more :o lol

bismuthate - 9-10-2013 at 12:49

;)Hey I though we agreed that i get 25%! nice idea ammonium bicarbonate is safe and easy to find.

deltaH - 9-10-2013 at 13:16

ammonium bicarbonate wouldn't work though, that would just release carbon dioxide with no ammonia:

NH4HCO3 + HCl => NH4Cl + CO2 + H2O

ammonium carbamate is not the same thing, the carbamate ion has the looks like this: [O-CO-NH2]-

ok ok, I agree to 25% of $100 :P

bismuthate - 9-10-2013 at 13:28

sorry i messed up there however the heat of the reaction woul most likely decompose the bicarbonate. This would release ammonia I believe so there is a nonchemical way to do this. (sorry I misread)

deltaH - 9-10-2013 at 13:42

No problems, I figured as much, I just wanted to make sure op wouldn't use bicarbonate instead of carbamate.