Ionic Chemist
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Production of vinyl acetate...simple question
Is it possible to produce vinyl acetate by heating acetaldehyde with glacial acetic acid and a moderate quantity (more than a typically catalytic
amount) of concentrated sulfuric acid?
I am wondering as acetaldehyde, which is in its keto form, can undergo acid-catalyzed enolizaation to form, vinyl alcohol.
[ Wikipedia article http://en.wikipedia.org/wiki/Keto-enol_tautomerization ].
So seeing this I am also wondering if the enol can then be esterified in situ with ethanoic acid to yield vinyl acetate.
Does anyone know of any type of process/method that is able to do so?
Thank You......
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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ScienceSquirrel
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Probably not, the acetaldehyde will polymerise to brown gunk.
Viable reactions are here;
http://en.wikipedia.org/wiki/Vinyl_acetate#Preparation
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Nicodem
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There are examples of ketones being O-acetylated with moderate to good yields in acetic anhydride and a couple of mol% of a sulfonic acid (like
tosylic acid). I have never seen, or do not remember seeing, any example of such an acetylation done on an aldehyde, quite likely due to the
instability of the aldehydes (but feel free to check the literature - there might be examples). While I would not immediately discard the possibility
that such a method works on some aldehydes, perhaps even on acetaldehyde, I would immediately concur with ScienceSquirrel in regard to your proposal.
BTW, I suggest you to avoid using the "ethanoic acid" name. It makes you appear clueless even though it is obvious you do not want to appear as such.
Only non-chemists call acetic acid that way.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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ScienceSquirrel
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I think that the competing aldol reaction will just happen too fast.
Maybe if you could preform the enolate by reacting butyl lithium with THF and then O acetylate with acetyl chloride.
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Ionic Chemist
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Well then that won't work....
Just had to try that acid-acetaldehyde reaction to see what would happen. ScienceSquirrel was indeed correct in the assertion that the acetaldehyde
would polymerize into brown gunk. I didn't expect that it would work but I still wanted to see what would happen.
So then that route won't work so... change of target compound (still on the topic though of alkenyl esters however). The most important thing for the
reaction I am trying to perform is that I need a way to produce an alkenyl ester so I have changed the target compound to hex-1-en-1-yl acetate.
I have access to 1-hexene already but factoring in the 'polymerization-condensation' reaction with the acetaldehyde beforehand I guess oxidizing it to
hexanal would be pointless and a futile effort in attempt to produce the target compound. I am wondering then the result of first halogenating the
hexene, maybe reacting with chlorine to form 1,2-dichlorohexane, then reacting the dihaloalkane with potassium hydroxide to yield an alkyne, 1-hexyne?
[ Wikipedia article http://en.wikipedia.org/wiki/Elimination_reaction ]
Then also keeping in mind the production of vinyl acetate as ScienceSquirrel stated before, especially the gas phase addition of acetylene to acetic
acid, I would think that if acetylene is substituted with 1-hexyne in that process then that could yield hex-1-en-1-yl acetate. Is this a feasible
reaction scheme?
Thank You......
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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ScienceSquirrel
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I think that the bromination would work well and the elimination with something like sodium amide in liquid ammonia would be a success as well.
The problem would come with the addition of acetic acid.
This is a known reaction catalysed with mercury II sulphate but it proceeds with Markovnikov orientation so it would produce the 2-Hexenyl acetate.
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Dr.Bob
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If you want hex-1-en-1-yl acetate, the simplest way I can imagine is to take hexanone, deprotonate, then react with acetyl chloride or acetic
anhydride. I have one it with TMSCl before and that works great. You may get some reaction of the ene, but you should be able to separate any, and
with the right base, I would think it would be minimized.
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ScienceSquirrel
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Quote: Originally posted by Dr.Bob  | | If you want hex-1-en-1-yl acetate, the simplest way I can imagine is to take hexanone, deprotonate, then react with acetyl chloride or acetic
anhydride. I have one it with TMSCl before and that works great. You may get some reaction of the ene, but you should be able to separate any, and
with the right base, I would think it would be minimized. |
I suggested something similar upthread.
Getting O acetylation versus C acetylation may be possible with good solvent and counter ion choice.
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Ionic Chemist
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Why couldnt I live somewhere else?!
Please keep in mind that I really don't have access to a very wide range of chemicals unless I make them myself or in fact find a commercial product
that contains a chemical I think would be useful for a future date. So if you wouldn't mind with that I'm trying to find the most accessible chemicals
I can or if anything where to find new ones, it's not so easy to get access to chemicals in Jamaica especially when you don't live near to the
shipping ports in Kingston.
Well good news is that I finally made some sulfur chlorides (dichloride and monochloride mixed) and I should be able to synthesize some acetyl
chloride for use  ... or maybe I'll synthesize some benzotrichloride and then
make some acetyl chloride using that.
But on the other hand, a few other chemicals are a bit out of my reach for the moment so I'll need more assistance in figuring out a proper procedure
using chemicals I can either make or extract.
Thank You......
"Discoveries are not made by idly sitting around and hoping something interesting might happen; they are made
by getting out there and doing something to push the results and odds in your favour." "Chemistry always works... just not always in the way you
want."
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blogfast25
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| Quote: Originally posted by Nicodem | | BTW, I suggest you to avoid using the "ethanoic acid" name. It makes you appear clueless even though it is obvious you do not want to appear as such.
Only non-chemists call acetic acid that way. |
Hmmm... a bit harsh, isn't it? So we have one guy using IUPAC nomenclature and he 'appears clueless'? I think you could argue he's pretty clued up!
 Although it would have been more convincing had he applied that to acetaldehyde
too...
As regards non-chemists using the term ethanoic acid, I'd love to meet one!
[Edited on 11-5-2013 by blogfast25]
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