Selective Hydrogenation Of Dimethyl Terephthalate And 3,5-dinitro-4-chlorobenzoic Acid Isobutyl Ester

In the first part, Ru-based heterogeneous catalysts were prepared and used to catalyze the selective hydrogenation of dimethyl terephthalate (DMT) for preparing dimethyl 1,4-cyclohexanedicarboxylate (DMCD). First, the effects of supports, preparation methods, treating conditions, were investigated for the selective hydrogenation of DMT. Results showed that, Ru/TiO2 prepared from a simple reduction in H2 flow at 500? after the incipient wetness impregnation performed the highest activity on this reaction. Furthermore, various reaction conditions such as solvent, temperature, and hydrogenion pressure were studied. Then, a conversion higher at 97.9% was reached within 60 minutes under the conditions of 0.26 mol/L substrate in isopropyl alcohol solution,387 mol ratio of substrate to Ru,6 MPa and 120?, but the selectivity to DMCD was 93.8%. The selectivity can be improved to 99% by simply reducing the reaction temperature to 80?. Meanwhile, Ru/TiO2 can also catalyze the selective hydrogenation of dimethyl phthalate (DMP) and dimethyl isophthalate(DMIP) with both the yields near 100%.In the second part, Pt/C was applied to catalyze the selective hydrogenation of 3,5-dinitro-4-chlorobenzoic acid isobutyl ester to 3,5-diamino-4-chlorobenzoic acid isobutyl ester. Through investigating the influence of preparation methods and reduction conditions on the catalytic activity, a simple but effective way was established to obtain the high performance Pt/C from reduction in sodium formate aqueous solution. The concentration and amount of sodium formate could affect the performance of Pt/C to a certain extent. Finally, a selectivity of 91% at 100% conversion within 20 minutes was achieved on this Pt/C catalyst under the conditions of 0.33 mol/L substrate in methanol solution,2580 mol ratio of substrate to Pt,1 MPa and 90?.