Process for the preparation of ethyl acetate

• Main Authors: COLIN RATHMELL, STEPHEN WILLIAM COLLEY, MICHAEL WILLIAM MARSHALL TUCK, CHRISTOPHER RICHARD FAWCETT
• Format: Patent
• Language: English
• Published: 27.06.2001
• Edition: 7
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; CHEMISTRY; GENERAL METHODS OF ORGANIC CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

Ethanol is dehydrogenated in the presence of hydrogen over a dehydrogenation catalyst, for example, a copper on silica catalyst. The liquefiable products present in the resulting intermediate reaction product mixture are selectively hydrogenated over a suitable catalyst, such as 5% ruthenium on carbon, so as selectively to hydrogenate reactive carbonyl-containing by-products to the corresponding alcohols. Butan-2-one and n-butyraldehyde, which would otherwise cause difficulties in purification of the ethyl acetate product, due to the proximity of their boiling points to that of ethyl acetate, are thereby hydrogenated to 2-butanol and n-butanol respectively. A two stage distillation procedure is then used to purify the selectively hydrogenated product. The first distillation zone is typically operated at less than about 4 bar (4 x 105 Pa) absolute, while the second distillation zone is typically operated at a pressure of from about 4 bar (4 x 105 Pa) absolute to about 25 bar (2.5 x 106 Pa). A first distillate of ethyl acetate, ethanol and water produced in the first distillation zone is redistilled in the second distillation zone, thereby producing a bottom product comprising, typically, from about 99.8 mol % to about 99.95 mol % ethyl acetate and an overhead second distillate, which has a different composition from that produced in the first distillation zone and which is returned to the first distillation zone, preferably at a point above the feed point for the liquefiable products of the selectively hydrogenated reaction product mixture.