Amoco Corporation

Standard Oil Company (Indiana)

Donald E Thomka

Neal R Nowicki

Hobe Schroeder

A method is disclosed for the liquid-phase oxidation of pseudocumene in the presence of an oxidation catalyst comprising cobalt, manganese, and bromine components wherein the metal catalyst are recycled to the oxidation reactor in the form of their oxalates.

Batch or semicontinuous pseudocumene oxidation and catalyst recovery and

The oxidation of butane vapor with air produces an impure maleic anhydride which when fractionated to first remove materials boiling lower than maleic anhydride and then a maleic anhydride product, leads to a maleic anhydride product fraction which when held at 140.degree. C. for 90 minutes discolors and is not a commercially acceptable product. Such discoloration can be substantially reduced by maintaining the impure maleic anhydride at a temperature from 60.degree. up to 200.degree. C. in the presence of small amounts of either hydrogen peroxide and/or sulfuric acid.

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Romeoville, IL, United States of America

Donald E Thomka