磷酸盐改性对TS-1分子筛及其丙烯液相环氧化性能的影响  

Effect of Phosphates Modification on TS-1 Zeolite and its Catalytic Performance in Epoxidation of Propylene and Hydrogen Peroxide

作　　者：张超[1] 王刚[1] 李越[1] 吴国星 冯兆池[2] 郭洪臣[1] Zhang Chao;Wang Gang;Li Yue;Wu Guo-xing;Feng Zhao-chi;Guo Hong-chen(Department of Catalytic Chemistry and Engineering&State Key Laboratory of Fine Chemicals,Dalian University of Technology,Liaoning Dalian 116024,China;State Key Laboratory of Catalysis,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Liaoning Dalian 116023,China)

机构地区：[1]大连理工大学催化化学与工程系,精细化工国家重点实验室,辽宁大连116024 [2]中国科学院大连化学物理研究所,催化国家重点实验室,辽宁大连116023

出　　处：《分子催化》2021年第1期1-12,I0001,共13页Journal of Molecular Catalysis(China)

摘　　要：丙烯和过氧化氢在钛硅沸石TS-1上的液相环氧化反应是合成环氧丙烷HPPO新工艺的核心.首先比较了3种酸性磷酸盐溶液(磷酸二氢铵、磷酸二氢钾和磷酸二氢钠)和两种碱性磷酸盐溶液(磷酸氢二钠和磷酸三钠)浸渍改性对TS-1沸石及其环氧化性能的影响,发现酸性磷酸盐溶液改性可以明显提高TS-1的过氧化氢转化率和环氧丙烷选择性,但碱性磷酸盐溶液改性则会降低TS-1沸石的催化性能.在此基础上,重点对酸性磷酸盐溶液改性的TS-1沸石催化剂进行了不同表征.结果显示,酸性磷酸盐溶液改性之所以能促进TS-1沸石的催化性能,主要与磷酸根物种与四配位和六配位钛物种的相互作用有关.这种相互作用比较弱,水洗可以破坏这种相互作用,导致磷酸根流失.但是这种弱相互作用却足以钝化六配位钛物种,同时调节四配位钛活性中心的微环境.Liquid-phase epoxidation of propylene and hydrogen peroxide over titanium silicalite-1(TS-1) is the basis of the new HPPO technology for propylene oxide synthesis. A comparative study was conducted to gain insight into the effects of impregnation modification of acidic phosphate solutions(ammonium dihydrogen phosphate, monopotassium phosphate and monosodium phosphate) and alkaline phosphate solutions(sodium hydrogen phosphate and sodium phosphate) on TS-1 zeolite and its catalytic performance in the epoxidation. Results show that impregnation modification with the acidic phosphate solutions can notably increase both hydrogen peroxide conversion and selectivity of propylene oxide of TS-1, However, impregnation modification with the alkaline phosphate solutions can obviously deteriorate the catalytic performance of TS-1. Therefore, only the acidic phosphate modified TS-1 catalysts were focused insample characterizations. Results indicate that the reason why the TS-1 catalysts modified with the acidic phosphates exhibit improved catalytic performances mainly lies in the interactions of phosphate anion species with tetra-coordinated titanium and hexa-coordinated species. Said interactions should be weak since it would be unbound by water rinse and the phosphate anion species would be washed away. Even so, the interactions seem enough to passivate the hexa-coordinated titanium species and to modify the local environment of the tetra-coordinated titanium active sites.

关 键 词：磷酸盐改性 TS-1沸石 丙烯液相环氧化 四配位钛物种 六配位钛物种 

分 类 号：O643.32[理学—物理化学]