Title of Paper:Synthesis of Acetic Acid on Pd-H4SiW12O40-Based Catalysts by Direct Oxidation of Ethylene

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Date of Publication:2002-01-01

Journal:Journal of Natural Gas Chemistry

Included Journals:Scopus

Volume:11

Issue:1-2

Page Number:51-56

ISSN No.:10039953

Abstract:Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, acetic acid was predominantly produced via an intermediate of acetaldehyde. The active sites for acetic acid formation existed mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 had higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and the acetic acid could be greatly increased by adding a suitable amount of dichloroethane (C2H4Cl2/C2H4 mole ratio = 0.03:1) to the reactants. On all catalysts containing SiW12, a small amount of ethanol was detected, which was almost unchanged by the catalyst composition.