Dehydration of acetic acid by azeotropic distillation in the production of an aromatic acid

摘要

Disclosed is a process for the separation of water from a liquid phase medium containing an aliphatic carboxylic acid using azeotropic distillation in the presence of an entrainer. The entrainer, water, and organics are subsequently separated, wherein the entrainer is recycled back to the azeotropic distillation column and organics recycled back to the oxidation reactor.

主权项

1. A process for the azeotropic distillation of a solvent for an oxidation reaction, wherein the solvent comprises an aliphatic carboxylic acid and water, the process comprising:
(a) conducting the azeotropic distillation in the presence of an entrainer to produce (i) a liquid phase component comprising said aliphatic acid having a reduced water content relative to the water content in the solvent feedstock and (ii) a vapor phase component comprising the entrainer, organics and water; (b) condensing the vapor phase component to form a liquid condensate; (c) separating the entrainer and organics from the liquid condensate to form a liquid organic phase; (d) returning a first portion of the liquid organic phase to the top of the azeotropic distillation as a reflux; (e) forming a purge stream from a second portion of the liquid organic phase from step (d); (f) contacting the purge stream from step (e) with a clean aqueous stream, to produce (i) a recovered aqueous stream comprising water and entrainer and (ii) an organic stream comprising organics and entrainer; (g) providing the recovered aqueous stream from step (f) comprising recovered entrainer to a recovery column to recover the entrainer; and (h) recycling the organics stream from step (f) to the oxidation reactor or purging it from the process.