CHARACTERISTICS OF CARBON-SUPPORTED PALLADIUM CATALYSTS FOR LIQUID-PHASE HYDROGENATION OF NITROAROMATICS

Effects of the properties of support and the preparation condition on the characteristics of carbon-supported palladium catalysts were investigated. The characteristics included dispersion and distribution of metal and the catalytic activity on the liquid-phase hydrogenation of dinitrotoluene. Oxidation of carbon support appeared to increase the number of surface oxygen groups and to enhance dispersion of palladium. However, the catalytic activity did not improve in proportion to the dispersion. In carbon-metal salt slurry, nuclei formation and growth by ion exchange and/or reduction was considered to be the most important step in determining the final state of the catalysts prepared by the alkali hydrolysis method. The catalytic activity was found to be strongly dependent on metal location throughout the mesopore structure especially in the case of catalysts supported on highly porous activated carbon.