Random - 17-10-2010 at 00:12
I don't have any sulfuric acid and I would like to make esters. I read somewhere that lewis acids can do it instead of sulfuric acid. Would iron(iii)
chloride form ester with benzoic acid in brandy (40-70% alcohol) to form ethyl benzoate?
DDTea - 17-10-2010 at 00:46
In principle, FeCl<sub>3</sub> should work as a catalyst. The purpose of the lewis acid in Fischer esterification is to stabilize the
carboxylic acid as an oxonium ion. FeCl<sub>3</sub> should form a complex with the said oxonium ion, stabilizing the charge on the oxygen
atom and activating the acid for nucleophilic attack by the alcohol.
As far as doing the reaction in brandy, it may have too much water for Fischer esterification to be feasible since the equilibrium is unfavorable
enough as it is.
entropy51 - 17-10-2010 at 10:10
Sodium bisulfate, sold as "pH Down" for swimming pools, will work as a catalyst for some esterifications. Here is one example. There are others.
12AX7 - 17-10-2010 at 11:25
Also, FeCl3 hydrate is not a lewis acid, it's already "reacted" with water. You have to use anhydrous material. If nothing else, you'll need to
distill your brandy up to near absolute (98%) to get that to work.
Tim
DJF90 - 17-10-2010 at 11:36
Fe (III) sulfate.xH20 works excellently for catalysing the esterification of aliphatic acids and di-acids. Toluene and a dean stark apparatus are
necessary though. Theres a nice paper on it, yields all look over 90% IIRC.
Random - 26-12-2010 at 16:34
I have some potassium metabisulfite and in reaction with water should make so2 and potassium bisulfite which should oxidize into khso4. Could I use
that to make ester from brandy and benzoic acid? I read in king's chemistry survival guide the preparation that uses 30% sulfuric acid, ethanol
(possible vodka) and only 9% vinegar to make ethyl acetate.