FTIR研究聚丙烯负载型催化剂的制备过程

FTIR Study on the Preparation of Supported Catalyst for Propylene Polymerization

采用红外光谱跟踪分析用于丙烯聚合的ＭｇＣｌ２负载型催化剂的制备过程，阐明了制备过程中的主要化学变化．认为载体ＭｇＣｌ２含水对催化剂负载过程及钛含量有极大的影响；ＭｇＣｌ２的溶解是一经过中间过渡态的醇化过程；邻苯二甲酸酐不仅会与部分醇反应生成酯，而且还与水反应生成酸，起了除水的作用；其中酯在ＴｉＣｌ４负载中作为内酯，酸容易与－Ｍｇ—（ＯＲ）作用生成Ｍｇ（ＯＨ）２或Ｍｇ（ＯＨ）Ｃｌ；在负载过程中，ＴｉＣｌ４倾向于在ＭｇＣｌ２表面的结构缺陷处与ＭｇＣｌ２发生“结构锚定”．用红外光谱跟踪分析的结论。

FTIR spectrometry was used to monitor the preparation of the MgCl2supported catalyst for propylene polymerization. It is found that water, introduced by the support\{ MgCl2,\} has great effect on the catalyst preparation and the titanium content. FTIR analysis also shows that the dissolution of MgCl2 is an alcoholization reaction through a transition state. Anhydrous phthalate reacts with both alcohol and water and produces ester and acid, respectively, which results in the elimination of water. The acid reacts easily with MgOR to form Mg(OH)2 or Mg(OH)Cl; while the ester acts as an internal ester produced in the TiCl4supporting system, in which TiCl4 is inclined to anchor MgCl2 on the surface by structural defects. The results from FTIR are confirmed by the results of XPS and the activity and titanium content of catalysts prepared with MgCl2 containing different water amounts.