SELECTIVE HYDROGENATION OF 3,4-DIMETHOXYBENZOPHENONE IN LIQUID PHASE OVER PD/C CATALYST IN A SLURRY REACTOR

Selective hydrogenation of benzophenone to benzhydrol is industrially relevant. In the current work, selective hydrogenation of 3,4-dimethoxybenzophenone (3,4-DMBP) to 3,4-dimethoxybenzhydrol (3,4-DMBH) was investigated over 5% w/w Pd/C and 5% w/w Pt/C as catalysts in a slurry reactor. The effects of hydrogen partial pressure (0.2-1MPa), catalyst loading (2.0x10(-4) to 8.0x10(-4)g/cm(3)), initial concentration of 3,4-dimethoxybenzophenone (5.0x10(-6) to 1.5x10(-4)mol/cm(3)) and temperature (40-70 degrees C) on rate of reaction and selectivity were studied. Effect of solvent such as methanol, ethanol, 2-propanol and tetrahydrofuran (THF) was also investigated. 5% w/w Pd/C was the better catalyst with THF as the best solvent, which gave 100 % conversion and 80 % selectivity in 1h for 0.5MPa hydrogen pressure at 60 degrees C. The Langmuir-Hinshelwood-Hougen-Watson model was fitted. The intrinsic kinetics and mechanism of hydrogenation were established.