烷基铝预还原铬钒双中心催化剂的制备及其催化乙烯聚合

摘要

Novel chromium/vanadium(Cr/V)bimetallic catalyst for ethylene polymerization was developed on the basis of Phillips inorganic Cr catalyst. Triethyl aluminum(TEAL)and triisobutyl aluminium(i-Bu3Al) were used as pre-reducers/cocatalysts respectively to observe the polymerization behavior of the novel catalyst and the microstructures of products. The results show that the amount of cocatalysts slump in polymerization when the main catalysts were pre-reduced by TEAL andi-Bu3Al respectively. When using the same cocatalyst, the activities of the pre-reduced catalysts are close,and the products prepared by these catalysts show similar molecular weight and molecular weight distribution,which indicate that the TEAL andi-Bu3Al perform approximately in pre-reduction effect. The copolymers obtained from the pre-reduced catalysts show higher 1-hexene incorporation than that of before,which reduces the amount of1-hexene.%在Phillips无机铬系催化剂基础上开发了新型铬钒双中心聚乙烯催化剂,分别选用三乙基铝(TEAL)和三异丁基铝(i-Bu3Al)作为助催化剂以及预还原剂对该双中心催化剂的乙烯聚合活性及产品结构性能进行了研究.结果表明:以TEAL与i-Bu3Al分别作为预还原剂得到的两种催化剂在聚合过程中助催化剂的用量极大降低;使用相同助催化剂时,上述两种催化剂聚合活性的高低和变化趋势基本一致,得到的产品相对分子质量及其分布基本相同,说明TEAL和i-Bu3Al的预还原效果相近;采用预还原催化剂制备的共聚产物的1-己烯插入率显著提高,降低了1-己烯的用量.