【作者】 金鑫；

【导师】 吴鹏； 徐浩；

【作者基本信息】 华东师范大学 ， 物理化学， 2021， 硕士

【摘要】 气相贝克曼重排催化反应是实现己内酰胺清洁生产的重要途径。已有研究证明TS-1钛硅分子筛在气相贝克曼重排反应中的催化活性要优于目前工业中常使用的催化剂S-1全硅分子筛。本文以研发TS-1高效催化剂及其催化气相贝克曼重排反应过程为目的,开展了TS-1的化学改性及其活性评价研究,包括以下两部分内容。第一部分探究了TS-1催化气相贝克曼重排反应的活性中心。对比相似硅钛比不同种的钛硅分子筛在气相贝克曼重排反应中的催化性能,研究证实MFI结构的TS-1具有最佳的催化性能。通过调控TS-1分子筛的钛含量,发现贝克曼重排反应的催化活性随着钛含量的增加而提升。通过对TS-1进行钠离子交换,证实了TS-1分子筛中与“open”Ti位点相邻的硅羟基是催化活性中心,同时否定了Lewis酸是催化气相贝克曼重排反应的活性中心。此外,外表面硅羟基、巢式羟基等羟基组也是反应的催化中心。第二部分围绕TS-1分子筛化学改性条件的探究,在催化气相贝克曼重排反应活性评价体系中筛选了最佳的后处理温度、TPAOH浓度和铵盐助剂的添加三方面的改性条件。研究发现1 Si O₂:0.03 TPAOH:0.03（NH₄）₂CO₃:18 H₂O在443K条件下后处理24 h是最佳的改性条件。此外,研究证明TS-1分子筛内多级孔结构的引入能有效提高反应的催化活性,并利用改性的材料筛选出气相贝克曼重排反应最佳的催化反应条件,同时考察了催化剂的再生性能。更多还原

【Abstract】 Gas-phase Beckmann rearrangement（BR）of cyclohexanone oxime（CHO）is a key solution for the clean production of caprolactam（CPL）.The literature has reported that the catalytic activity of TS-1 titanosilicate in the gas-phase Beckman rearrangement reaction is better than that of Silicalite-1（S-1）zeolite.In this paper,with purpose to develop highly effective TS-1 catalyst for the gas-phase BR reaction,chemical modification of TS-1 and its activity evaluation in the BR reaction have been carried out,which is composed of following two parts.First,the gas-phase Beckmann rearrangement（BR）of cyclohexanone oxime to caprolactam has been studied over various titanosilicates with different topologies.Superior to Ti-MWW,Ti-Beta and Ti-MOR,TS-1 showed the best catalytic performance.The effecting factors of Ti content,reaction parameters and regeneration test on the BR reaction over TS-1 have also been investigated.The hydroxyl groups,generated form adjacent to the“open”Ti sites,were proved to be the active centers for catalyzing BR reaction form CHO to CPL,whereas the Lewis acid sites directly related to tetrahedral Ti were not the true active ones.Other silanols including external silanols,hydrogen-bonded silanols and hydrogen-bonded silanol nests were also considered to be the active centers of BR reaction.Secondary,the chemical modifications have been optimized for the exploration of more effective TS-1 for the Beckamnn rearrangement reaction.The results demonstrated that the composition of 1 Si O₂:0.03 TPAOH:0.03（NH₄）₂CO₃:18 H₂O and hydrothermal treatment at 443 K for 24 h were the best modification conditions.In addition,hierarchically porous TS-1 was synthesized successfully by post-treatment to investigate the effect of diffusion properties on catalytic performance.Moreover,the modified materials were used to screen out the catalytic reaction conditions for the gas-phase Beckman rearrangement.The regeneration of the catalyst was also investigated in gas-pahse Beckmann rearrangement.更多还原