Sciencemadness Discussion Board - What to do with all this ammonium sulphate?

What to do with all this ammonium sulphate?

mycotheologist - 8-4-2012 at 05:59

I was having a gander around the hardware shop and got a spontaneous urge to buy 3kg of ammonium sulphate (or sulphate of ammonia as they call it). Its been lying around in my lab for months but I have some time off college at the moment and want to use it to further my hands on, practical chemistry knowledge. So I want to play around with this (NH₄)₂SO₄ since I have plenty of it.

First thing that comes to mind is adding a base. If I add NaOH, it will convert the ammonium ion back into free ammonium and I will end up with a solution of Na₂SO₄ and NH₄OH, if I'm not mistaken. How much free NH₃ will escape I wonder? Could I somehow use this as a method to generate NH₃ gas? For example if I dissolve anything in a solvent that cannot be deprotonated by NH₃, then the ammonia gas would remain a gas and escape the solution (especially if it was hot). Is ammonia strong enough to deprotonate ethanol? Another idea that pops into my head is somehow using the fact that NH₃ to perform a metathesis reaction that, in the case of a non volatile cation, would yield a mixture of products. Also I'm wondering what electrolysis would do to this salt.

Anyhow, I'm not trying to make any specific compound, I'm just looking for suggestions on useful things I can do with all this (NH₄)₂SO₄. I can buy this stuff in large quantities relatively cheaply so it would be cool if I could use it to make various useful reagents.

[Edited on 8-4-2012 by mycotheologist]

Adas - 8-4-2012 at 09:08

By long-time electrolysis you will get H2SO4, because ammonia easily escapes from the solution, while H2SO4 is a high-boiling liquid.

If you add NaOH powder and mix them well it will make ammonia gas.

woelen - 8-4-2012 at 09:18

By mixing solid NaOH (use slight excess of NaOH) and solid ammonium sulfate you can make gaseous NH3. The reaction can be started by adding a few drops of water. Once it is going it will generate its own water and soon you will be producing quite some NH3 gas. This gas you can lead through more dilute ammonia (e.g. household ammonia) for making concentrated ammonia.

I do not agree with Adas about making H2SO4 by means of electrolysis. How do you think ammonia escapes from the liquid?

Another interesting experiment is to make much purer ammonium sulfate. The stuff from hardware stores is impure and gives turbid and somewhat brownish solutions (at least where I live, this is impure stuff). You can dissolve as much as possible in warm water and filter through coffee filters. The clear solution then is allowed to cool down and evaporate. You'll obtain nice colorless crystals of much purer ammonium sulfate.

Yet another interesting experiment is making double salts with this. With nickel sulfate you can make ammonium nickel sulfate and with ferrous sulfate you can make Mohr's salt.

mycotheologist - 8-4-2012 at 16:16

Very interesting. So it is a viable method of producing NH3 gas. I find the H2SO4 theory interesting too. woelen: I see your point that the freed ammonia produced would instantly be converted into highly soluble NH3OH, which in turn would react with the H2SO4 but what if you were to use a solvent in which the H2SO4 cannot ionise? I can already see a flaw in my logic though, a solvent that does not solvate cations won't conduct electricity. Also I'm not sure if the acid needs to be ionised in order for a strong base like NH3 to react with it. First time I hear of Morh's salt, I'll look into that. Thanks.

meaniac - 8-4-2012 at 19:04

Mohrs salt:
Ferrous ammonium sulphate. Crystallizes beautifully and resists oxidation to the (rather ugly) brown ferrous salt.
Look up ferrous sulphate preparation to get some clues on keeping your initial supply of ferrous in its nice green ferrous state.

Making ammonia can a bit exciting if you don't have the means to control the gas as its made (fume hood, appropriate glassware etc).

Keep us posted.

[Edited on 9-4-2012 by meaniac]

reckless explosive - 8-4-2012 at 19:05

what if you heated the solution to force the ammonia gas out of the solution as it was formed youd need a decent current so it could boil the solution by itself so wouldnt just have to monitor the fluid level and fill it as water leaves because even if its run for days i dont see how electrolysis would get it to sulphuric acids boiling point but thats just my thought on that

mycotheologist - 9-4-2012 at 05:48

Quote: Originally posted by meaniac

I made some ferrous sulphate accidentally one day and was very impressed by its appearance. Looked like semi transparent, turquoise beads. I don't know if it was the Fe(II)SO4 or contaminants but it reeked of something awful so I disposed of it as fast as possible. Probably contaminants as I read that ferrous sulphate is sometimes used as an odour absorber. I love making visually appealing crystals so I'm gonna make some Mohrs salt, thanks.

Quote: Originally posted by meaniac

Mohrs salt:
Making ammonia can a bit exciting if you don't have the means to control the gas as its made (fume hood, appropriate glassware etc).

Keep us posted.

Yeah I wouldn't generate large amounts of it without an adequate setup for channeling it into solution. The same kind of setup used to produce hydrochloric acid from NaCl and 98% H2SO4 would work though, I believe. I've never actually encountered NH3, I hear it reeks.

Quote: Originally posted by reckless explosive

what if you heated the solution to force the ammonia gas out of the solution as it was formed youd need a decent current so it could boil the solution by itself so wouldnt just have to monitor the fluid level and fill it as water leaves because even if its run for days i dont see how electrolysis would get it to sulphuric acids boiling point but thats just my thought on that

Problem is that ammonia gas reacts with water to form ammonium hydroxide. The hotter the solution, the more it will react. Good thinking though, I'm sure we can come up with a way around this problem if we put enough thought into it. I just completely side tracked this thread by writing a load of proposed solutions so I'll start a new thread for this.

[Edited on 9-4-2012 by mycotheologist]

MrHomeScientist - 9-4-2012 at 08:24

Ammonium hydroxide doesn't really exist in any significant amount. Such solutions are the vast majority just ammonia gas dissolved in water - the wiki states that "In a 1M ammonia solution, about 0.42% of the ammonia is converted to ammonium." Ammonia gas is very highly soluble in water, and it really only ionizes to a minor degree.
Personally I prefer to avoid using the term ammonium hydroxide when discussing it, and in calculations I always use NH<sub>3</sub> only.

[Edit] Also forgot to mention that heating the solution drives off the ammonia gas, as gases are less soluble in hot solution. Try titrating some ammonia cold, then heat some up for a few minutes and titrate that portion, and you should see that you've lost quite a bit of the gas. Do that outside of course, it's nasty stuff!

On another note, I've tried making concentrated ammonia solution by reacting saturated ammonium nitrate and potassium hydroxide solutions, but met little success. Ammonia is just so incredibly soluble, not much made it out of the starting solutions. Mixing the solids and initiating gas production with a few drops of water is an excellent idea.

[Edited on 4-9-2012 by MrHomeScientist]

mycotheologist - 9-4-2012 at 11:10

UPDATE: I mixed some potassium hydroxide flakes with some ammonium sulphate and mixed it up a bit. I was under the impression that a tiny amount of water would trigger a chain reaction based on something someone said in this thread. That didn't happen at all so I boiled the kettle and added a bit of boiling water to the mixture and then she got going. The whole thing fizzed up, made a loud sizzling sound and gave off white vapour. I got a small whiff of the gas at one point and it was like nothing I had ever smelled before. I don't know what NH3 smells like, I heard that it smells like urine but this stuff did not resemble urine odour at all. I kept adding small increments of water (and backing away each time since it gave off quite a bit of gas) until the reaction was complete. The major product left in the beaker is potassium sulphate which should have very low volatility (and thus no odour) but when I washed the beaker out I got this smell that was so strong it almost burned so I backed away. What could this smell be I wonder. It reminds me of the sensation of breathing a bit of HCl gas the way it gives you a bit of a fright that prevents you from inhaling any more. Could it be ammonia?

watson.fawkes - 9-4-2012 at 12:17

Quote: Originally posted by mycotheologist

I mixed some potassium hydroxide flakes with some ammonium sulphate and mixed it up a bit.

Did you weigh your reagents, so that you know which of them is in molar excess?

barley81 - 9-4-2012 at 12:25

That's ammonia all right. Ammonia doesn't smell like urine very much. It really does burn. If you put your hand above an open bottle of the concentrated solution, you can feel your skin tingle and start to become numb. Be careful with it. It'll sting your eyes and nose very badly.

mycotheologist - 9-4-2012 at 13:49

I setup a gas bubbler and it seems to work pretty well with ammonium sulphate. Here it is in action:
https://www.youtube.com/watch?v=NJ_JnW4Qa8I
sorry for the bad video quality. My friend was too scared to go in and record it himself (probably wise of him lol) so I had to use it myself and didn't realise it had 2 cameras so I was holding it backwards and couldn't see what I was filming. You can still kinda see whats going on, as soon as I dropped a few mils of warm water into the RB flask, the contents of the flask started foaming and fizzing and the water in the receiving beaker started to rise and bubble. I didn't smell a bit of ammonia so it seems to work very well. I think the bubbles that escape are air because the receiving beaker only bubbled each time I opened the addition funnel.

Quote: Originally posted by watson.fawkes

Quote: Originally posted by mycotheologist

I mixed some potassium hydroxide flakes with some ammonium sulphate and mixed it up a bit.

Did you weigh your reagents, so that you know which of them is in molar excess?

No, I just eyeballed the amounts. I just remembered someone suggesting to add an excess of hydroxide but I can't remember the reason behind it. Why the excess?

Quote: Originally posted by barley81

That's ammonia all right. Ammonia doesn't smell like urine very much. It really does burn. If you put your hand above an open bottle of the concentrated solution, you can feel your skin tingle and start to become numb. Be careful with it. It'll sting your eyes and nose very badly.

Ah right, so thats what NH3 smells like. Maybe the people I heard describe it were mistaking another gas for ammonia because I get the impression that if you inhale enough to be able to smell it, you're close to inhaling enough to cause harm so the bodies defensive reflexes kick in. At least thats what happened with me. I got a whiff of it twice and both times I jumped back for safety. Gave me a strange suffocating feeling, I've had that sensation before from inhaling a bit too much HCl. I think I know what happened now, I couldn't smell any NH3 initially because it was dissolved in cold water and it got released when I used hot water to wash the beaker out. Lesson learned.

[Edited on 9-4-2012 by mycotheologist]

barley81 - 9-4-2012 at 13:59

Check out <a href="http://www.sciencemadness.org/talk/viewthread.php?tid=16061">this thread</a>. It may be of use.

mycotheologist - 10-4-2012 at 11:01

Quote: Originally posted by MrHomeScientist

On another note, I've tried making concentrated ammonia solution by reacting saturated ammonium nitrate and potassium hydroxide solutions, but met little success. Ammonia is just so incredibly soluble, not much made it out of the starting solutions. Mixing the solids and initiating gas production with a few drops of water is an excellent idea.

My attempt seemed to be very successful yesterday, especially considering it was the first time I tried it. I added a fair bit of ammonium sulphate and potassium hydroxide to the flask then poured about a mL of boiling water and in a matter of seconds, the water receiving flask started rising. The reaction was so vigorous I got worried for a minute. I ended up adding way too much water because I had no stir bar in there and I didn't want to shake the flask since it was all clamped in place. I can safely say this is an excellent method of producing concentrated ammonia solutions.

AndersHoveland - 10-4-2012 at 21:58

There was a thread somewhere on this forum that discussed the possibility of reacting chlorine gas with a solution of ammonium sulfate to make sulfuric acid. The reaction, if there is one, is apparently very slow and reluctant. Ideally it should be kept boiling, and I would expect it to take at least an hour. Caution also needs to be used, because dangerously explosive nitrogen trichloride could form and separate out as oily droplets! One source mentioned that (NH4)2SO4 has an ideal pH range for the formation of NCl3, better than the NH4Cl. So one would probably want to add a little H2SO4 initially just to keep the pH low enough so that NCl3 formation is not favorable. http://www.sciencemadness.org/talk/viewthread.php?tid=17235

[Edited on 11-4-2012 by AndersHoveland]

Fluorite - 17-11-2020 at 12:05

You can heat ammonium sulfate with copper oxide this should make ammonium bisulfate in situ and ammonia gas therefore bisulfates react with copper oxide to make copper sulfate I tried this using sodium bisulfate to make copper sulfate and separated this by a simple crystallization overall you can make ammonia gas and copper sulfate! Electrolyse CuSO4 to make sulfuric acid and copper metal, you can heat copper in air to make more copper oxide! So from ammonium sulfate you can make ammonia solution and sulfuric acid

copper is the catalyst

karlos³ - 17-11-2020 at 12:38

Was precipitation of enzymes already noted?

And Fluorite, you're at the necroposting again?

MidLifeChemist - 17-11-2020 at 13:11

Quote: Originally posted by karlos³

Was precipitation of enzymes already noted?

And Fluorite, you're at the necroposting again?

Yep, definitely more necroposting by Fluorite

[Edited on 11/17/2020 by MidLifeChemist]

Fluorite - 17-11-2020 at 14:47

Hey! My idea is perfect :3

aromaticfanatic - 26-11-2020 at 15:26

If you are feeling up to a bit of a project you can produce dry ammonia gas at a constant rate (or store it in a pressurized tank, not recommended and you need to know your shit before you do this) and run it over a metallic catalyst (copper apparently works for this) and allow NO and NO2 to form. Bubble said gas into water or hydrogen peroxide and you would be making nitric acid.

It is faster than making nitric acid from air but also slower than just distilling some. The upside is that you won't have to buy any nitrates. More labor intensive as a result.

Fluorite - 26-11-2020 at 17:55

aromaticfanatic oh can copper catalyse the oxidation f ammonia? Without platinum?

aromaticfanatic - 26-11-2020 at 21:35

Quote: Originally posted by Fluorite

aromaticfanatic oh can copper catalyse the oxidation f ammonia? Without platinum?

Ammonia is converted to nitric acid in 2 stages. It is oxidized by heating with oxygen in the presence of a catalyst such as platinum with 10% rhodium, platinum metal on fused silica wool, copper or nickel[3], to form nitric oxide (nitrogen(II) oxide) and water (as steam). This reaction is strongly exothermic, making it a useful heat source once initiated:[4]

https://en.wikipedia.org/wiki/Ostwald_process

It is Wikipedia after all and there might be some info missing but it seems as if many metals will work.

Sulaiman - 26-11-2020 at 22:44

Quote: Originally posted by mycotheologist

Ah right, so thats what NH3 smells like.

Opening a bottle of concentrated hydrochloric acid when ammonia is in the air will produce white ammonium chloride 'smoke'
carefully blow over the mouth of the acid bottle to see the extent of your ammonia cloud.

Bedlasky - 27-11-2020 at 04:09

mycotheologist: You can make some ammonium alums crystals. Ammonium chrome alum have nice dark purple colour. Ammonium ferric sulfate have lovely violet colour and it grow very fast. But you must protect it, because on the air it become rusty due to loss of water. I have one in mineral oil, but maybe nail polish is good enough, I'll once try it.

You can also make ammonium persulfate by electrolysis of solution of ammonium sulfate/sulfuric acid in 1:1 molar ratio.

Quote: Originally posted by meaniac

Mohrs salt:
Ferrous ammonium sulphate. Crystallizes beautifully and resists oxidation to the (rather ugly) brown ferrous salt.
Look up ferrous sulphate preparation to get some clues on keeping your initial supply of ferrous in its nice green ferrous state.

Making ammonia can a bit exciting if you don't have the means to control the gas as its made (fume hood, appropriate glassware etc).

Keep us posted.

[Edited on 9-4-2012 by meaniac]

Yes, ammonium ferrous sulfate is somewhat more resistant to aerial oxidation, but still oxygen oxidize it. I have some ammonium ferrous sulfate and when I dissolve it in water and add KSCN, I obtain red solution. Crystal of this salt should be protected somehow, because with time it will degrade. Nail polish isn't enough for ferrous salts, I saw FeSO4 crystal preserve in epoxy resin, mineral oil probably also do the job.

aromaticfanatic - 27-11-2020 at 10:04

Quote: Originally posted by Bedlasky

mycotheologist: You can make some ammonium alums crystals. Ammonium chrome alum have nice dark purple colour. Ammonium ferric sulfate have lovely violet colour and it grow very fast. But you must protect it, because on the air it become rusty due to loss of water. I have one in mineral oil, but maybe nail polish is good enough, I'll once try it.

You can also make ammonium persulfate by electrolysis of solution of ammonium sulfate/sulfuric acid in 1:1 molar ratio.

Quote: Originally posted by meaniac

This question probably belongs in the energetics section but isn't the tetraamine copper salt of persulfate an explosive? Just asking because I vaguely remember it from a discussion I've had prior.

woelen - 27-11-2020 at 11:50

Tetraamminecopper peroxodisulfate indeed is somewhat energetic, but it also is unstable. If you store it, then after a few days it has decomposed to some basic copper salt, which has lost all its energetic properties. Not really interesting to make. A better thing is making tetraamminecopper sulfate monohydrate. This can be made from a concentrated copper sulfate solution, to which an excess amount of concentrated ammonia is added, so that a very dark blue (nearly black) solution is obtained. To this, you have to add some ethanol in order to reduce the solubility. After some time, you get really nice dark blue crystals of tetraamminecopper sulfate monohydrate. In a closed vial, these can be kept indefinitely.

zed - 4-12-2020 at 14:02

I've precipitated the material with methanol, which is cheap and available in the U.S..

The Tetraaminecopper Sulfate, is beautiful and apparently non-energetic.

Not so, the Nitrate, which I have seen detonated, in YouTube videos.

Now, the original post, was a long time ago. That Ammonium Sulfate has probably passed on.

So, the question is: What to do, with Ammonium Sulfate, folks have now?

Ummmm. Well, possibly if you Microwave it under vacuum, you can vaporize and remove the Ammonia.

Eventually leaving you with Concentrated H2SO4, which isn't very volatile.

Now, I don't need to do that. I can buy concentrated H2SO4 at my neighborhood, Home improvement center, or Hardware store. Cheap too.

Some of you however, are in countries where H2SO4, is harder to acquire.

This technique also works for producing Phosphoric Acid from Ammonium Phosphate, or dehydrating Phosphoric Acid, until it approximates Poly Phosphoric Acid.

woelen - 31-3-2021 at 00:59

I don't think that strongly heating ammonium sulfate produces H2SO4.

First, on heating, it loses ammonia. I have tried that myself and it definitely gives off ammonia. What remains behind becomes acidic. It could be considered impure NH4HSO4 (ammonium bisulfate, mixed with ammonium sulfate).

I suspect that on stronger heating, there will be complete decomposition by internal oxidation/reduction. The ammonium ion then reduces all sulfate to SO2 and H2O, itself being converted to N2. I think that on strong heating of ammonium sulfate you get a mix of NH3, H2O, N2 and maybe a little H2SO4 or NH4HSO4, which is reformed from the gas mix. No way to obtain pure clean H2SO4.

clearly_not_atara - 31-3-2021 at 06:46

It is my general understanding that heating ammonium sulfate leads first to the bisulfate, then to the pyrosulfate (250-300 C):
http://www.sciencemadness.org/talk/viewthread.php?tid=4689

Pyrosulfates decompose around ~400 C to SO3; NH4Br decomposes at 450 C, and HBr is similar to H2S2O7 in Hammett strength, so I expect the sulfate anion to decompose before losing NH3. The result is most likely redox decomp. I imagine the products are quite noxious, so if you're trying to make the pyrosulfate, heating should be careful.

I would also imagine that ammonium pyrosulfate is probably good for something, but I'm not sure what. Maybe sulfamate?