a123x
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Sodium sulfide production
I'm trying to come up with a practical way to make sodium sulfide with easily obtainable chemicals. I'm thinking something like reacting an
insoluble sulfide such as iron sulfide(since I can just buy some at a mineral shop) with dilute sulfuric or hydrochloric acid. The reaction should
evolve toxic hydrogen sulfide but considering iron sulfide is insoluble and I'll be using dilute acids I wouldn't expect it to be very rapid
at all. Anyway this is done in a stoppered flask with a tube running into another stoppered flask filled with ammonium hydroxide solution to bubble
the H2S through it. Another tube comes out from this flask(from above the solution) and runs into another solution of ammonia. I figure that since the
H2S evolution should be slow and an excess of ammonia solution all the H2S will be converted to ammonium sulfide. The solution is boiled to remove
remaining ammonium hydroxide and then reacted with NaOH giving Na2S and more ammonia to just boil off. I would just bubble H2S directly into NaOH
solution but I want an excess of base to ensure full reaction with the H2S and at the end it is easier to remove ammonium hydroxide excess than NaOH
excess. Does my reasoning here have any flaws in it?
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Marvin
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How about,
Dissolving S in NaOH solution and seperating the sulphide?
Sodium hydroxide or carbonate, sulphur, carbon and heating to red heat to produce just sulphide and carbon.
Reducing sodium sulphate with carbon at a slightly higher heat?
Reducing CaSO4 with C might require a temperature not easily managable.
H2S apart from being rather toxic and unpleasent, above a certain concentration we cant smell it anymore.
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a123x
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I thought that dissolving S in NaOH tends to not properly work for making picramic acid, the intended use of the sodium sulfide. Then again
that's using the solution directly, I hadn't really considered evaporating off the water to get the pure sulfide. I've found that my
method won't work anyway because ammonium sulfide decomposes into ammonia and H2S from heating at lowish temperatures so I wouldn't be able
to remove the excess ammonium hydroxide. I'd suppose I could just use NaOH solution to bubble the H2S into. I'm not particularly worried
about H2S toxicity since it should be produced very slowly so that all of it should react with NaOH(aq) and even if it doesn't it shouldn't
build up so long as done outside.
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kryss
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Your best bet is to bubble it directly into NaOH - you may also find some polysulphide being formed.Although if you can get elemental sulphue id go
with that route.Any excess h2s u can remove by bubbling through peroxide solution - or bleach.
Na2S isnt very stable however and its very soluble in water - you'll find your solution loses H2S as you concentrate it ie a smelly process
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White Yeti
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Here is what I would do:
I would bubble excess hydrogen sulphide gas through a saturated solution of sodium carbonate. To make the H2S I would react stoichiometric amounts of
aluminium and sulphur powders to form aluminium sulphide and react the subsequent solid with water.
This process, as laid out above seems like it would work like a charm, but I must warn you. The hazards associated with H2S cannot be stressed enough.
I messed around with H2S before and losing your sense of smell is not fun. If you attempt this, use all the safety equipment required.
"Ja, Kalzium, das ist alles!" -Otto Loewi
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blogfast25
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http://en.wikipedia.org/wiki/Sodium_sulfide#Production
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LHcheM
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Why don't you just generate the H2S from the mineral and acids and bubble it through a solution of NaOH?@@
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White Yeti
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Quote: Originally posted by LHcheM  | | Why don't you just generate the H2S from the mineral and acids and bubble it through a solution of NaOH?@@ |
Because H2S is a really nasty gas that you wouldn't want to mess with.
"Ja, Kalzium, das ist alles!" -Otto Loewi
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Amos
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I'm looking to produce sodium sulfide in order to precipitate insoluble sulfides for pigment production/waste disposal. How does the addition of
powdered sulfur to molten NaOH sound?
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gdflp
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I don't even think the NaOH needs to be molten, just dissolve excess sulfur in a hot solution of concentrated sodium hydroxide, cool, and filter out
the insoluble sulfur, and sodium thiosulfate.
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Amos
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| Quote: Originally posted by gdflp | | I don't even think the NaOH needs to be molten, just dissolve excess sulfur in a hot solution of concentrated sodium hydroxide, cool, and filter out
the insoluble sulfur, and sodium thiosulfate. |
The idea was to just minimize as much formation of H2S as possible by limiting water. But then I found this patent which suggests water is necessary for a clean product.
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Oscilllator
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| Quote: Originally posted by gdflp | | I don't even think the NaOH needs to be molten, just dissolve excess sulfur in a hot solution of concentrated sodium hydroxide, cool, and filter out
the insoluble sulfur, and sodium thiosulfate. |
I've tried this (I even made a thread about it somewhere) and it doesn't work like that. The NaOH does react with the sulfur just fine, but it forms
lots of red polymeric gunk. This gunk is near on impossible to separate out, so I advise that anyone trying to make sodium sulfide (or thiosulfate for
that matter) avoids aqueous reactions of sodium hydroxide with sulfur for this reason
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Amos
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I'll have no shortage of either reagent once my sodium hydroxide refill arrives, so I'll play around with the methods and report back.
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subsecret
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I've had the same experience as Oscillator. To purify it, you could react it with H2SO4 to produce H2S, and this could be bubbled
into a sodium hydroxide solution to get sodium sulfide. Your yield will be lower unless you use a fritted gas dispersion tube.
[Edited on 2-1-2015 by Awesomeness]
Fear is what you get when caution wasn't enough.
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Metacelsus
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My preferred method of making hydrogen sulfide is reacting sulfur with aluminum powder to form aluminum sulfide, and then reacting the aluminum
sulfide with water or dilute acid. I'm not afraid to work with hydrogen sulfide gas in a closed system in a well-ventilated area (outdoors).
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Amos
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How readily does the hydrogen sulfide react with sodium hydroxide? I'd prefer not to have my neighborhood evacuated because everyone thinks they smell
a gas leak.
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