To produce a novel palladium-rhenium catalyst having rhenium extremely uniformly distributed and carried on a coal, coconut or peat type activated carbon as a carrier and having a good hydrogenation capability for dicarboxylic acids and very high selectivity to lactones even if hydrogenation pressure is extremely lowered.
In this catalyst having palladium and rhenium carried thereon for hydrogenating dicarboxylic acids, the catalyst is characterized in that the proportions of intensity ratios of 2 or more between the rhenium intensity at reversal measuring points obtained by analysis at the X-ray microprobe line along the line of the longest particle size of the cross-section giving the largest sectional area of the catalyst particle and the average value of the rhenium intensity at all measuring points are 20% or more based on the number of the total measuring points, and further the carrier is the coal, coconut or peat type activated carbon.
ISHIHARA TAKESHI
KOBAYASHI KENJI
ICHIKI TATSUMI
