甲苯侧链甲醛烷基化制苯乙烯酸碱双功能磁核催化剂的构建及反应机理研究

甲苯侧链甲醇烷基化制苯乙烯曾被认为具有很好的工业化前景，但甲苯转化率和苯乙烯收率都太低，一直未能实现工业化。我们通过对反应机理和热力学特性对比研究，发现甲苯转化率和苯乙烯收率难以提高的主要因素是在高温、气-固反应条件下甲醇极易分解所致。基于此，我们开发了一种甲苯侧链甲醛烷基化一步制苯乙烯的新工艺，即以具有酸碱中心和二维层板结构的复合氧化物（LDO）作为催化活性组分，构建了酸碱双功能LDO@SiO2@Fe3O4磁性催化剂，以甲醛为烷基化剂，在液-固、较低反应温度条件下，实现了甲苯侧链甲醛烷基化一步制苯乙烯的高甲苯转化率和苯乙烯收率。申请项目将深入研究催化剂结构与性能关系、反应机理、反应动力学、磁性分离和稳定性，形成具有自主知识产权的磁性催化剂制备新技术和甲苯侧链甲醛烷基化制苯乙烯的反应-磁性分离一体化新工艺。项目实施对深刻认识LDO酸碱活性位和二维层板结构的协同催化作用本质有重要的科学意义。

The side-chain alkylation of toluene with methanol to styrene was considered to have good industrialization prospects. Because of the lower conversion of the toluene and yield of the styrene, until now this catalytic reaction has not carried out the industrialization. Based on intensive investigated the mechanism and the thermodynamic of this catalytic reaction, we found that in the reaction the methanol is extremely easily decomposed under the gas-solid reactor and the higher reaction temperature conditions. This is the key factor of the lower conversion of the toluene and yield of the styrene. In this project a novel catalytic process for the side-chain alkylation of toluene with formaldehyde one-step to styrene was proposed. This is that, firstly, the layered double oxide (LDO) shell had both acid and base sites as the catalytic component and the SiO2@Fe3O4 as the magnetic core, the acid-base bifunctional LDO@SiO2@Fe3O4 magnetic catalysts had been constructed. Secondly, the side-chain alkylation of toluene with formaldehyde to styrene had been carried out under the lower reaction temperature and the liquid-solid reactor. Especially, both the conversion of toluene and the yield of styrene were very high. At the same time, the performance of the acid-base bifunctional LDO@SiO2@Fe3O4 magnetic catalysts for the side-chain alkylation of toluene with formaldehyde to styrene in the liquid-solid catalytic reactor will be evaluated. The relationship of the catalytic activity and the structure of the catalyst, the catalytic reaction mechanism, and reaction kinetics will be adequately investigated. Actualized this project, the new technology of preparation the acid-base bifunctional LDO@SiO2@Fe3O4 magnetic catalysts and the novel catalysis process of the the side-chain alkylation of toluene with formaldehyde to styrene will be formed. This project has an important scientific significance to understand the role of the acid-base bifunctional LDO@SiO2@Fe3O4 magnetic catalysts for the side-chain alkylation of toluene with formaldehyde to styrene and the reaction mechanism of the LDO synergistic catalyzing the side-chain of toluene and the alkylation of formaldehyde. There is a bright future application for the side-chain alkylation of toluene with formaldehyde to styrene catalysis process.