| 摘要 |
<p>PROBLEM TO BE SOLVED: To simply and inexpensively restore the activity of a catalyst, in a method for producing glycolic acid by catalytically oxidizing oxygen- containing gas in the presence of a catalyst, by subjecting the catalyst lowered in activity by long-time use to catalytic oxidation reaction treatment under specific oxygen partial pressure. SOLUTION: In a method for producing glycolic acid by the catalytic oxidation of ethylene glycol using a solid metal catalyst, oxygen partial pressure is temporarily made higher than a usual glycolic acid producing reaction condition by 0.5kg/cm<2> or higher to restore the lowered activity of the catalyst to the activity almost equal to that of the new catalyst. There is no special limit with respect to this catalyst but a catalyst produced by making about 0.5-10wt.% of one or more kinds of a platinum group element selected from among platinum, palladium and rhodium supported with a carrier such as activated carbon, silica or alumina is generally used. Further, if necessary, a catalyst wherein an element such as vanadium, chromium, molybdenum or manganese is allowed to coexist as a cocatalyst component is used.</p> |
