Ester co-production

A process for the simultaneous co-production of ethyl acetate and n-butyl acetate, in a reaction of a mixture of ethanol and n-butanol with acetic acid in the liquid phase in the presence of an acidic catalyst, said process comprising the steps of:

• i. feeding the reactants comprising ethanol, n-butanol and acetic acid to the base of a reaction Column A which contains the acidic esterification catalyst and maintaining the reactants at elevated temperature to form a product comprising ethyl acetate and n-butyl acetate which rises up the Column A,
• ii. feeding the overheads from Column A comprising the mixture of ethyl acetate and n-butyl acetate, optionally after a decantation step, to about the upper half of a distillation Column C operated under elevated temperature whereby:
• a. a light ends fraction is separated from the reaction products and recovered as overheads therefrom,
• b. a stream comprising predominantly ethyl acetate and n-butyl acetate is withdrawn from the base thereof and fed to the upper half of a purification Column E,
• c. a side-stream comprising the reactant alcohols, water and some of the esters is withdrawn from the upper half of Column C fed to a decanter wherefrom, following decantation, the oil phase is returned to the Column C feed and the aqueous phase fed to Column D,
• iii. fractionating the stream comprising a mixture of ethyl acetate and n-butyl acetate in Column E so as to recover:
• a. substantially pure ethyl acetate overhead,
• b. substantially pure n-butyl acetate from the base of Column E and
• c. a liquid waste stream at a point intermediate between the withdrawal points for (iii) (a) and (iii) (b) above and comprising the unwanted impurities including the unwanted carbonyl compounds which stream is discharged, and
• iv. fractionating the side-stream comprising a mixture of the esters and alcohols fed to Column D so as to remove a mixture comprising predominantly ethanol and n-butanol along with small amounts of water, ethyl acetate and n-butyl acetate overhead, and water from the base of Column D.