woelen
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Acetone plus sulphur plus NaOH
It is known fairly well that sulphur dissolves slightly in acetone. Not very much, but the effect is noticeable.
A funny reaction occurs, when also NaOH (or KOH) is added and some water. This leads to formation of a 2-layer system (salting out effect, acetone
cannot be completely mixed with water in the presence of dissolved NaOH). The sulphur in this solution leads to formation of a brown/green compound
with a very bad smell. For me, the formation of this brown/green compound is a riddle. It only is formed if ale three of NaOH, sulphur and acetone are
present as well as a little water. Any idea what this compound can be?
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AndersHoveland
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Probably quite a variety of different compounds. All three of these chemicals can react with any other. I guess the question is which reaction pathway
would be fastest. The order of addition of the 3 reactants probably makes a significant difference also.
I suspect some acetone sulfonate may be forming, with conjugated bonding, at least in its tautomeric form.
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mayko
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I ran across the same thing; not sure what exactly is going on, but here's some discussion about it:
http://www.sciencemadness.org/talk/viewthread.php?tid=23236#...
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SteveJones
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It could be that your forming a thiol; it's well known that one can form thiols by the addition of an organolithium or Grignard reagents (most
commonly) to solid sulphur. After work up one obtains the protonated thiol.
The pKa of acetone is around 20 or so of the top of my head, the pKa of primary alcohols is around 16 or so, for thiols it will be even lower because
sulphur is better able to stabilise a negative charge due to it's larger size and access to d-orbitals.
It might not be entirely unreasonable to guess that the hydroxide deprotonates a small quantity of acetone to generate the enolate, which then attacks
the sulphur to give the thiol, which would more than likely be accounting for the awful smell you're getting
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AndersHoveland
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Several elements react and disproportionate in the presence of aqueous base, including sulfur.
You can boil gardening-type sulfur with cement lime (calcium hydroxide) to form calcium thiosulfate and polysulfides:
5 Ca(OH)2 + 10 S --> CaS2O3 + 5 H2O + 4 CaS2
I wrote "CaS2" in the equation, but higher polysulfides are also formed, for example CaS3, CaS4, etc.
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madscientist
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How weird, I had just looked for the original thread on this, but it was apparently a casualty of a database error. I did this back in 2002, I think
it was the third thread on the forum, and quite appropriately it was a tale of how I stunk up my entire neighborhood with that discovery. It got hot
fast, turned dark, and began boiling, releasing the most intense, overpowering stench I have ever encountered. My guess is the sulfur is oxidizing the
enolate, affording thiols derived from acetone, while the aldol chemistry throws a tar party.
I have no idea what I was trying to do, it seems so random now.
http://pipeline.corante.com/archives/2009/06/11/things_i_won...
I really doubt it's producing thioacetone, but it's vaguely relevant, and amusing.
| Quote: | | "Recently we found ourselves with an odour problem beyond our worst expectations. During early experiments, a stopper jumped from a bottle of
residues, and, although replaced at once, resulted in an immediate complaint of nausea and sickness from colleagues working in a building two hundred
yards away. Two of our chemists who had done no more than investigate the cracking of minute amounts of trithioacetone found themselves the object of
hostile stares in a restaurant and suffered the humiliation of having a waitress spray the area around them with a deodorant. The odours defied the
expected effects of dilution since workers in the laboratory did not find the odours intolerable ... and genuinely denied responsibility since they
were working in closed systems. To convince them otherwise, they were dispersed with other observers around the laboratory, at distances up to a
quarter of a mile, and one drop of either acetone gem-dithiol or the mother liquors from crude trithioacetone crystallisations were placed on a watch
glass in a fume cupboard. The odour was detected downwind in seconds." |
I weep at the sight of flaming acetic anhydride.
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Eddygp
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I have remembered today about having read something about dissolving sulfur in acetone and adding NaOH, so I searched it and here it was. I am
actually a bit interested in this reaction and, if the stench isn't too stench-y, I might do it once I have a slight idea about what it forms. I think
that it might form some sort of complex substituting one of the hydrogens in acetone and complexing with a sodium cation, giving this product AND
water too. What do you think?
Sorry for un-earthing this thread.
there may be bugs in gfind
[ˌɛdidʒiˈpiː] IPA pronunciation for my Username |
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Adas
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Quote: Originally posted by Eddygp  | I have remembered today about having read something about dissolving sulfur in acetone and adding NaOH, so I searched it and here it was. I am
actually a bit interested in this reaction and, if the stench isn't too stench-y, I might do it once I have a slight idea about what it forms. I think
that it might form some sort of complex substituting one of the hydrogens in acetone and complexing with a sodium cation, giving this product AND
water too. What do you think?
Sorry for un-earthing this thread. |
The odor is very faint, not even close to what woelen described. I even find it a little pleasant. Go ahead and try it! 
Rest In Pieces!
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DraconicAcid
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| Quote: Originally posted by Adas | | Quote: Originally posted by Eddygp | I have remembered today about having read something about dissolving sulfur in acetone and adding NaOH, so I searched it and here it was. I am
actually a bit interested in this reaction and, if the stench isn't too stench-y, I might do it once I have a slight idea about what it forms. I think
that it might form some sort of complex substituting one of the hydrogens in acetone and complexing with a sodium cation, giving this product AND
water too. What do you think?
Sorry for un-earthing this thread. |
The odor is very faint, not even close to what woelen described. I even find it a little pleasant. Go ahead and try it! |
I've been told that before. Heck, I think I've even *told* people that before- few were foolish enough to believe me.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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woelen
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The stench is not as bad as madscientist describes, but I find the smell unpleasant. It is quite strong to me, but in order to smell it I have to blow
some of the vapor towards my nose by waving with my hands above the flask, containing the acetone, NaOH and water. You should not stick your nose in
the flask!
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franklyn
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Perhaps this may help. Mercaptan is the older name for Thiol.
These compounds are known for their irrepressible odor.
Mercaptans & Derivative Chemistry
www.arkema-inc.com/literature/pdf/368.pdf
.
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Zyklon-A
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I found this reaction by mistake on woelen's site and used it to clean an old test tube that was caked with molten sulfur (thanks BTW
woelen, dissolved the sulfur like a charm!)
Anyway, I didn't smell anything bad as far as I remember (it was several weeks ago), anyone have ideas as to why?
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Mildronate
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1 step maybe aldol condensation and product react with sulfur?
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Σldritch
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I have been looking for the answer to this on and of for some years now and i think i finally found it!
https://books.google.se/books?id=Mtth5g59dEIC&pg=PA523&a...
Page 518
Because i can not copy it, please excuse the at least ten inevitable spelling errors:
"If alkali metal polysulfides are added to a polar media like acetone, dimethylformamide, dimethylsulfoxide or alkali halide melts, the resulting
solutions are colored. The color is due to the presence of polysulfides(1-) SSn-: the yellow green
disulfide(1-), S2- (which corresponds to O2-): the blue trisulfide(1-),
S3- (which corresponds to the ozonide, O3-); and the red tetrasulfide(1-),
S4-."
[Edited on 11-1-2018 by Σldritch]
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Σldritch
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For some reason i could not write further than that in a single post (why?) so here is the rest:
The stability of these anions decreases in the order: S3- > S2- > S4- .
And it goes on... Really intresting read!
It should be pretty obvious what is happening in this reaction now. Maybe im the only one that still cares about this but i thought i might as well
post it.
[Edited on 11-1-2018 by Σldritch]
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Texium
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Thread Moved
11-1-2018 at 15:29 |
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