Visiblur
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Synthesis of Octyl Acetate
I am looking to do an esterification to obtain Octyl Acetate. I understand the basics of it, Octane and Acetic acid is refluxed with conc. Sulphuric
acid as a catalyst. What I'm wondering is about amounts. Do I just use an arbitrary amount of both and add a few drops of Sulphuric acid?
If any of you have a paper, some instructions or just know the answer, it would be greatly apreciated
[Edited on 4-4-2018 by Visiblur]
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Deathunter88
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If you are after Octyl Acetate for the smell (it's supposed to smell like oranges) then don't both. I have tried this reaction several times, each
time I have ended up with a dark brown oily liquid that smells so bad I vomited a few times cleaning up the glassware.
Usually, when doing an esterification you want either the acid or the alcohol in excess. I tried both, and never got a good result. The product has a
boiling point too close to the reactants, and I could never separate out a good product.
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Boffis
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You can't esterify octane. You need an octanol and there are numerous isomers; n-octanol is octan-1-ol but octan-2-ol is also pretty readily available
and there are also the 3 and 4-ol alcohols not to mention the various methylheptanol type isomers etc. Which on are you trying to make (or which one
smells of oranges).
You may be better to use acetic anhydride or acetyl chloride. I advise you to check out one of the practical organic chemistry books available online
such as Vogel's Textbook of Practical Organic Chemistry before launching into it. Also if you are going to use acetic acid make sure its glacial ie
>99% d use a large excess of acid because you can extract the excess acid with water /sodium bicarbonate
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Dr.Bob
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I seem to remember that one of the octanol isomers is what mosquitoes smell in mammal sweat to attract them, so it may be useful as a way to attract
them.
I agree that I might use say 1 mol equivalents of octanol to 1.2 to 2.0 mol equivalents of acetic acid, then add some sulfuric acid, maybe a ml or so,
and reflux for a day or two. The rate of making esters of alcohols goes in order of the size/sterics of the alcohol, so methanol is fast, ethanol is
slower (by a good bit), then other primary alcohols are about the same, even slower, and then secondary ones are real pain with simple Fisher
esterification reactions.
Not sure of the bp of octyl acetate, but if it is lower than either starting material, that would let you just distill it off as it forms, thus
driving the reaction forward. Try googling the materials for their BPs.
[Edited on 4-4-2018 by Dr.Bob]
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DavidJR
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Quote: Originally posted by Dr.Bob  | I seem to remember that one of the octanol isomers is what mosquitoes smell in mammal sweat to attract them, so it may be useful as a way to attract
them.
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This stuff? https://en.wikipedia.org/wiki/1-Octen-3-ol
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