Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: lukas.stib on March 26, 2020, 06:34:44 AM
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Hello chemists,
I was synthesized octyl formate by weighing 35 g of 85% formic acid and 100 g of octan,1-ol (but I used 55 g of formic acid). I have been refluxing for more than 3 hours, and there is no "fruity" odor of the ester, just the unpleasant odor of octan-1-ol and formic acid. Is the reason that with higher alcohol, esterification is difficult or impossible? I was synthesized many formates, and the pleasant smell of the esters was felt after a few minutes without heating, but octan-1-ol is a problem. Is it lacking a catalyst? I have always produced formates without catalyst (H2SO4), because formic acid is strong, and H2SO4 decomposes it into CO and H2O.
I want to do the same reactions with decan-1-ol later, and also mix acetic acid with these alcohols, and I guess I can't do it ...
Thank you all for your advice and answers.
Lukáš S.
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There is no miscibility of HCO2H 85% with octanol.
Try the esterification in toluene (bp = 111oC, water azeotrope = 84oC).
Do the same for acetic acid with long fatty alcohols but in this case, add a catalytic amount of H2SO4.
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How dry is your setup, or are you removing water in any way?
Has this exact procedure, but with shorter chain alcohols worked for you previously?
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For pgk:
So the normal way I have bad luck on the octyl formate ... I do not have toluene.
Do I understand that without toluene I have bad luck?
For wildfyr:
My compounds are dry, and I don´t remove the water. With alcohols with shorter chain is happy work and was working good by my procedure.
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I understand good that with long chain alcohols, esterification does not simply work as with alc. short chains?
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Yes and no!
There is no reaction if the reactants are not miscible each other. So and in general, small alcohols react with small acids and long alcohols with long acids. Otherwise, a miscibility-helping solvent must be added.
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For example, toluene! So next time: take toluene, and esterifycation the reactants and catalyst in toluene. Thank you for the explanation, I do understand.