Chemisorption of ethyl acetate during hydrogenation of acetic acid to ethanol

Abstract

A hydrogenation catalyst and process using the catalyst for converting a mixture comprising acetic acid and ethyl acetate to ethanol at a first temperature, and the catalyst desorbs ethyl acetate, in the absence of hydrogen, at a second temperature that is greater than the first temperature. The catalyst has a suitable chemisorption of ethyl acetate at the first temperature in the absence of hydrogen. In one embodiment, the first temperature ranges from 125° C. to 350° C. and the second temperature ranges from 300° C. to 600° C. The catalyst comprises one or more active metals or oxide thereof on a support that comprises tungsten or an oxide thereof. The one or more active metals are selected from the group consisting of cobalt, copper, gold, iron, nickel, palladium, platinum, iridium, osmium, rhenium, rhodium, ruthenium, tin, zinc, lanthanum, cerium, manganese, chromium, vanadium, and molybdenum.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a catalyst that chemisorbs ethyl acetate at the reaction temperature for hydrogenating acetic acid and / or ethyl acetate to ethanol. A catalyst that adsorbs ethyl acetate with suitable strength is useful for producing ethanol without net production of ethyl acetate when a mixed stream of acetic acid and ethyl acetate is used as a feedstock.BACKGROUND OF THE INVENTION[0002]Ethanol for industrial use is conventionally produced from petrochemical feed stocks, such as oil, natural gas, or coal, from feed stock intermediates, such as syngas, or from starchy materials or cellulose materials, such as corn or sugar cane. Conventional methods for producing ethanol from petrochemical feed stocks, as well as from cellulose materials, include the acid-catalyzed hydration of ethylene, methanol homologation, direct alcohol synthesis, and Fischer-Tropsch synthesis. Instability in petrochemical feed stock prices contributes to fluctuations...

AI Technical Summary

Benefits of technology

[0051]One advantage of catalysts of the present invention is the stability or activity of the catalyst for producing ethanol. Accordingly, it can be appreciated that the catalysts of the present invention are fully capable of being used in commercial scale industrial applications for hydrogenation of acetic acid and ethyl acetate, particularly in the production of ethanol. In particular, it is possible to achieve such a degree of stability such that catalyst activity will have a rate of productivity decline that is less than 6% per 100 hours of catalyst usage, e.g., less than 3% per 100 hours or less than 1.5% per 100 hours. Preferably, the rate of productivity decline is determined once the catalyst has achieved steady-state conditions.

Problems solved by technology

In addition, fermentation of starchy or cellulose materials competes with food sources and places restraints on the amount of ethanol that can be produced for industrial use.

Existing processes suffer from a variety of issues impeding commercial viability including: (i) catalysts without requisite selectivity to ethanol; (ii) catalysts which are possibly prohibitively expensive and / or nonselective for the formation of ethanol and that produce undesirable by-products; (iii) required operating temperatures and pressures which are excessive; and / or (iv) insufficient catalyst life.

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