rrkss
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Cellulose Acetate w/o AcOAc
I'm going to attempt a synthesis of Cellulose Acetate over this weekend but don't have any Acetic Anhydride which is how I esterified cellulose in the
past. Anybody know if glacial acetic acid + sulfuric acid catylist and heat will be enough to esterify the cotton and give me the cellulose
tri-acetate?
On paper the reaction looks like it will work but reality could be quite different.
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fractional
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I have no experience with Cellulose Acetate with GAA but I have synthesised Acetanilide using GAA. Also here the standard acetylating reagent is
normally Acetic Anhydride. This gave a fairly good yield (about 65%) by using GAA in two-fold excess, and by refluxing the reaction mixture (aniline +
GAA) using an air-condensor in such a way as to hold back/condense the acetic acid, but allowing the product water to distill off. With other words
the temperature at the top of the air-condensor was kept at 100...105 degC for the duration of the reaction, until no more water came over.
Aniline serves also as a catalyst in this reaction. For the cellulose you will need the sulfuric acid to catalyse the reaction.
I could imagine that also other ways of removing the product water would do the trick (e.g. using molecular sieves or azeotropic distillation with
toluene).
[Edited on 12-2-2010 by fractional]
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rrkss
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Sounds interesting. I'm gonna try the reaction in a simple erlenmeyer flask in a hot water bath to control temperature. I'll report what happens.
Don't plan on doing any distillation or anything to remove water just want to see if the reaction is possible.
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entropy51
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Adding some anhydrous NaOAc to the aniline and AcOH seems to improve the yield of acetanilide made as fractional describes. Just a thought.
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