MgCl_2-SiO_2复合载体Ti系催化剂的制备及其催化乙烯/1-己烯共聚

Preparation and Characterization of TiCl_4/MgCl_2-SiO_2 Di-Support Catalyst System for Copolymerization of Ethylene with 1-Hexene

在SiO2载体中引入分子状态的MgCl2后再负载TiCl4,制备了高活性的用于乙烯与1-己烯淤浆共聚的双载体Ziegler-Natta催化剂TiCl4/SiO2-MgCl2。催化剂的最佳制备条件:n(TiCl4)∶n(MgCl2)=10,滴加TiCl4温度为-25℃,n(C2H5OH)∶n(MgCl2)=2.4,m(SiO2)∶m(MgCl2)=1。用激光粒度分析仪、SEM和WAXD等手段对催化剂的粒径分布、颗粒形态和结晶情况进行表征的结果显示,催化剂的粒径在20～45μm之间,较均匀;且颗粒形态呈球形。当催化剂中Ti的质量分数为5.1%时,该催化剂可高效催化乙烯与1-己烯进行淤浆共聚,催化效率达1.59kg/g,乙烯-1-己烯共聚物的数均相对分子质量为3.1×104g/mol,相对分子质量分布为16.3,呈宽分布。

A novel di-support Ziegler-Natta catalyst TiCl4/SiO2-MgCl2 with high activity was prepared and used in copolymerization of ethylene with 1-hexene. The optimum catalyst preparation conditions were： n （TiCl4） ： n （MgCl2） 10, adding TiCl4 temperature - 25℃, n （ C2H5OH） ： n（MgCl2） 2.4 and m （SiO2 ） ： m （MgCl2 ） 1. The particle shape, size distribution and crystalline morphology of the catalyst were determined by means of laser granulometer, SEM and WAXD. The results showed that the catalyst particles were spherical with the 20 -45 um particle diameter. When mass fraction of Ti in the catalyst was 5.1%, the catalyst could effectively catalyze the copolymerization. The catalytic efficiency was 1. 59 kg/g, number-average relative molecular mass of the obtained ethylene-1-hexene copolymer was 3.1 ×10 4 g/mol and its relative molecular mass distribution was 16.3.