甲苯侧链烷基化制苯乙烯催化剂碱中心的作用机制及乙苯生成路径研究

项目名称： 甲苯侧链烷基化制苯乙烯催化剂碱中心的作用机制及乙苯生成路径研究

项目编号： No.21506202

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 徐力

作者单位： 中国科学院大连化学物理研究所

项目金额： 21万元

中文摘要： 苯乙烯作为重要的化工原料，在我国长期面临着产能不足的问题。由于传统的乙苯脱氢生产苯乙烯技术存在工艺流程长、副反应多及能耗大等缺陷，通过甲苯侧链烷基化反应一步合成苯乙烯的方法受到越来越多的关注。尽管如此，目前所考察的催化剂活性均较低，碱中心的作用成为其研究的重点。此外，还普遍存在产物中苯乙烯/乙苯比偏低等问题。本项目拟通过研究碱金属改性的X分子筛的催化活性随Si/Al比、碱金属种类及离子交换度的变化，建立碱中心的数量和强度与活性的关系；通过原位红外与在线质谱相结合的手段研究反应过程中催化剂表面的吸附物种，考察乙苯副产物的生成路径。基于该实验路线，期望能够明确碱中心的影响趋势和乙苯的生成方式。然后通过改进反应条件、改变烷基化试剂控制乙苯的生成，同时通过调变碱中心开发新型催化剂，从而得到较高的反应物转化率和苯乙烯选择性。

中文关键词： 甲苯；侧链烷基化；苯乙烯；原位红外；碱中心

英文摘要： As an important industrial chemical, styrene in productivity is not able to meet the demand of our country during a long-term period. It is known that the traditional method of styrene production is dehydrogenation of ethylbenzene. Due to the issues of long technological process, too many side reactions and high energy consumption, one-pot synthesis of styrene by side-chain alkylation of toluene have been paid more attention in recent years. However, the investigated catalysts generally showed low catalytic activity. The key problem to the development of relative catalyst is to clarify the role of base sites. Moreover, the styrene/ethylbenzene ratio of the reaction products is relatively lower. Herein, we plan to investigate the catalytic behavior of alkali metals modified X zeolite catalysts vary with the Si/Al ratio, the kind of alkali metal and the ion exchange degree. Based on the studies, we are aimed to correlate the catalytic activity and the base content. The adsorbed species on the catalyst surface during the side-chain alkylation process are going to be studied by in-situ FT-IR coupled with on-line MS methods for the reveal of generation path of ethylbenzene by-products. The research on this project is hopeful to identify the influence trend of base sites and generated process of ethylbenzene. Then high reactants conversion and styrene selectivity is required to obtain by improving the reaction conditions, optimizing the alkylation reagent for the control of styrene generation, and simultaneously adjust the base sites for the development of novel catalysts.

英文关键词： toluene;side-chain alkylation ;styrene;in-situ FT-IR;base sites