MgCl_2负载(dbm)_2Ti(OPh)_2催化乙烯聚合

烯烃聚合的新型非茂催化剂由于合成相对简便并具有一些新特点,近年来开始受到人们的关注1,2].ＩＶＢ族金属的β二酮络合物与烷基铝或烷氧基铝形成的催化体系对烯烃聚合也显现出一定的聚合活性.在一定压力下,β二酮锆/ＭＡＯ均相催化乙烯聚合时具有较高聚合活性3].β二酮钛催化剂对于丙烯无规聚合和苯乙烯间规聚合均有较好结果4～6].本文将报道用ＭｇＣｌ2负载的二苯氧基二(二苯甲酰甲烷)钛络合物((ｄｂｍ)2Ｔｉ(ＯＰｈ)2),以甲基铝氧烷(ＭＡＯ)为助催化剂,常压催化乙烯聚合的结果.1　原料ＭｇＣｌ2为抚顺301厂产品.ＭＡＯ(1.4ｍｏｌ/Ｌ甲…

ETHYLENE POLYMERIZATION WITH MgCl_2-SUPPORTED (dbm)_2Ti(OPh)_2

A diphenoxybis(β diketonato)titanium complex, (dbm) 2Ti(OPh) 2, was synthesized and the corresponding MgCl 2\|supported catalyst was prepared by impregnation method. The polymerization activity was drastically improved by using MgCl 2\|supported (dbm) 2Ti(OPh) 2 activated by aluminoxane (MAO) for ethylene polymerization (1.5×10 5 g/molTi with the heterogeneous catalyst and 1.3×10\+3 g/molTi with the homogeneous one). When the molar ratio of Al to Ti increased from 50 to 1000, the crystallinity and molecular weight of polyethylene were decreased rapidly. Also, the molecular weight of polyethylene was decreased from 5.1×10 5 to 2.8×10\+5 by increasing the molar content of titanium of the supported catalyst from 0.5×10 -5 to 3.42 ×10 -5 . After 60 min of the reaction, the molecular weight was at 5.0×10 5 or so. It is revealed that the MgCl 2\|supported β diketonato titanium complex is influenced by the polymerization conditions markedly.