Influence of V/P Ratio on the Catalytic Performance of VPO/SiO_2 Catalysts for Ammoxidation of Chloro-Substituted Toluenes  

作　　者：DONG Yanling XU Longlong ZHANG Zhenguo LIU Wenhui LI Xiongjian ZHONG Yalan HUANG Chi 

机构地区：[1]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology [2]Tianhua Chemical Branch,Xi'an Sunward Aeromat Co.,Ltd. [3]Sanjiang Chemical Factory of CSSG [4]College of Chemistry and Molecular Sciences,Wuhan University

出　　处：《Wuhan University Journal of Natural Sciences》2019年第1期23-29,共7页武汉大学学报（自然科学英文版）

基　　金：Supported by the National Natural Science Foundation of China(51572201)

摘　　要：A series of vanadium phosphate oxide(VPO) catalysts supported on silica(VPO/Si O2) with various mole ratios of V/P(nV:nP=1:0.8-1:3) were prepared through impregnation method. The catalytic activity was evaluated by ammoxidation reactions of several kinds of chloro-substituted toluenes(CT) in a fixed-bed reactor. The catalyst presented the best performance when nV:nP is 1:1.6. The prepared catalysts were characterized by N2 adsorption, hydrogen temperature programmed reduction(TPR) and ammonia temperature programmed desorption(TPD) and etc. The results reveal that P can decrease the bonding energy of V=O and increase the mobility of lattice oxygen which was beneficial for the improvement of the catalysts, while too much P can greatly decrease the average oxidation number of V which leads to deactivation of the catalysts. The surface acidity of the VPO/Si O2 catalysts is affected by nV:nP and the catalyst had the highest surface acidity when nV:nP is 1:1.6. The selectivity of catalysts is proportional to the surface acidity when nV:nP is lower than 1:3.0.A series of vanadium phosphate oxide(VPO) catalysts supported on silica(VPO/Si O2) with various mole ratios of V/P(nV:nP=1:0.8-1:3) were prepared through impregnation method. The catalytic activity was evaluated by ammoxidation reactions of several kinds of chloro-substituted toluenes(CT) in a fixed-bed reactor. The catalyst presented the best performance when nV:nP is 1:1.6. The prepared catalysts were characterized by N2 adsorption, hydrogen temperature programmed reduction(TPR) and ammonia temperature programmed desorption(TPD) and etc. The results reveal that P can decrease the bonding energy of V=O and increase the mobility of lattice oxygen which was beneficial for the improvement of the catalysts, while too much P can greatly decrease the average oxidation number of V which leads to deactivation of the catalysts. The surface acidity of the VPO/Si O2 catalysts is affected by nV:nP and the catalyst had the highest surface acidity when nV:nP is 1:1.6. The selectivity of catalysts is proportional to the surface acidity when nV:nP is lower than 1:3.0.

关 键 词：AMMOXIDATION VPO/SiO2 catalyst SUBSTITUTED toluenes SUBSTITUTED BENZONITRILES 

分 类 号：O625.67[理学—有机化学]