3,4-Dichlorotoluene Ammoxidation to 3,4-Dichlorobenzonitrile over VPO/SiO_2 Catalyst

摘要

Ammoxidation of 3,4|dichlorotoluene(DCT) to prepare 3,4|dichlorobenzonitrile (DCBN) over silica supported vanadium phosphorus oxide catalysts has been studied. On the VPO/SiO 2 catalyst, the influence of the reaction temperature, the molar ratio of air/DCT, the molar ratio of NH 3 /DCT in the feed gas and the space velocity ( v s) on the conversion, yield and selectivity was observed. The most appropriate reaction condition is: reaction T =673 K, n (DCT)∶ n (NH 3 )∶ n (air)=1∶7∶30 and v s=250 h -1 . At this optimum reaction condition, the conversion of DCT is 97.8%; the molar yield of DCBN is 67.4%. It was found that the addition of element phosphorus can improve the yield of DCBN compared with VO/SiO 2 catalyst.