PURPOSE: To recover a catalyst without affecting the activity thereof, by bringing trimethylphenol into contact with oxygen in the presence of a copper halogen complex catalyst, separating an organic phase after completing the reaction, and extracting the catalyst from the organic phase with water while keeping the pH within a specific range.
CONSTITUTION: 2,3,6-Trimethylphenol is brought into contact with oxygen (or a gas containing oxygen) in a heterogeneous system of water and a 5W10C aliphatic alcohol in the presence of a catalyst consisting of a copper halogen complex expressed by the formula (M is alkali metal or ammonium; X is halogen; l is an integer 1W3; m and p are 1 or 2; n is an integer 3W8) or the above-mentioned complex and an alkali metal halide to give 2,3,5-trimethylbenzoquione. In the process, the aqueous phase containing the catalyst and the organic phase are subjected to phase separation after the reaction, and the catalyst is extracted from the organic phase with water while keeping the organic phase at 1.5W2.5 pH. Water in the extract solution is then evaporated to recover the catalyst. Preferably, a hydrohalogenic acid, particularly hydrochloric acid is used for keeping the pH within the above-mentioned range.
YUI TOMOYUKI
HAGIWARA ISAO
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