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mycotheologist
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What to do with all this ammonium sulphate?
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]
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Adas
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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.
Rest In Pieces!
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woelen
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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.
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mycotheologist
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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.
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meaniac
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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]
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reckless explosive
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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 
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mycotheologist
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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.
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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.
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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
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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]
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MrHomeScientist
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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]
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mycotheologist
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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?
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watson.fawkes
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Did you weigh
your reagents, so that you know which of them is in molar excess?
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barley81
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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.
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mycotheologist
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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.
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.
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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]
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barley81
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Check out <a href="http://www.sciencemadness.org/talk/viewthread.php?tid=16061">this thread</a>. It may be of use.
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mycotheologist
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| 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.
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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.
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AndersHoveland
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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]
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Fluorite
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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
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karlos³
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Was precipitation of enzymes already noted?
And Fluorite, you're at the necroposting again? 
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MidLifeChemist
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Yep, definitely more necroposting by Fluorite
[Edited on 11/17/2020 by MidLifeChemist]
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Fluorite
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Hey! My idea is perfect :3
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aromaticfanatic
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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.
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Fluorite
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aromaticfanatic oh can copper catalyse the oxidation f ammonia? Without platinum?
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aromaticfanatic
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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.
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Sulaiman
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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.
CAUTION : Hobby Chemist, not Professional or even Amateur
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Bedlasky
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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.
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aromaticfanatic
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| 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 | 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. |
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.
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