Process for the preparation of ethanol from methanol

Abstract

Ethanol is produced economically by a gas phase carbonylation of methanol with carbon monoxide followed by a hydrogenation. Specifically, the inventive process comprises: (a) carbonylating methanol in a gas phase with carbon monoxide in a carbonylation reactor, said carbon monoxide being optionally in admixture of hydrogen, in the presence of a rhodium catalyst comprised of a rhodium compound and a second metallic component selected from the group consisting of an alkali metal, an alkaline earth metal, a transition metal and a mixture thereof, and supported on an inert material, and a halide co-catalyst under mild carbonylation conditions and a high GHSV(Gas Hourly Space Velocity) of methanol to produce a mixture of acetic acid and methyl acetate; (b) separating from the production mixture in a distillation column the acetic acid as a high boiling fraction thereof, and a mixture of the methyl acetate and the co-catalyst as a low boiling fraction thereof; (c) further separating said methyl acetate and the co-catalyst from the low boiling fraction and recycling the separated co-catalyst to the carbonylation reactor; (d) hydrogenating the separated methyl acetate with hydrogen gas in a hydrogenation reactor in the presence of a copper-containing hydrogenation catalyst to produce ethanol at a high yield.

Dependencies are inferred from the claim text.