乙烯气相聚合高效催化剂的组成和聚合反应

Studies on Highly Active Catalysts for the Gas Phase Polymerization of Ethylene

研究了２种类型的乙烯气相聚合高活性催花剂．用ＳｉＯ２，ＭｇＣｌ２作复合载体，负载ＴｉＣｌ４制得的ＳＭ型催化剂，载体中含ｗ（Ｔｉ）为２％～３％，ｗ（Ｔｉ３＋）为３５％～５９％，比表面积１０５～１２０ｍ２／ｇ，催化活性每小时每克催化剂Ｔｉ催化得５．０～５．７ｋｇ产物ＰＥ（ｋｇ·ｇ－１·ｈ－１），聚合动力学曲线为衰减型．用镁粉、卤代烷、四氯化钛为主要组分制备的ＭＧ－２型催化剂，载体中ｗ（Ｔｉ）为６％～７％，ｗ（Ｔｉ３＋）为５５％～６９％，比表面积７０～８５ｍ２／ｇ，催化活性１．８～２．０ｋｇ·ｇ－１·ｈ－１，聚合动力学曲线为平稳型．对ＳＭ型催化剂扫描电镜及图象分析得到颗粒平均粒径（ｄ），颗粒长短轴比（ｄｌ／ｄｓ）及颗粒大小粒径比（ｄｍａｘ／ｄｍｉｎ）分别为３１μｍ，１．４０２，４．１，ＭＧ－２型催化剂为３３μｍ，１．５２４，７．０，相应聚合产物颗粒的ｄ，ｄｌ／ｄｓ，ｄｍａｘ／ｄｍｉｎ，ＳＭ型催化剂为２４７μｍ，１．２９５，４．６，ＭＧ－２型催化剂为２６３μｍ，１．５４０，９．０．显示出ＳＭ催化剂更优良的聚合性能．

Two kinds of highly active catalysts composed of TiCl 4 SiO 2 MgCl 2 AlR 3(SM) and Mg RX TiCl 4 AlR 3(MG 2) for the gas phase polymerization of ethylene were studied The mass friction of Ti,the surface area of catalysts and catalytic activity in SM and MG 2 are 2%～3%,6%～7% by mass, 105～120,70～85 m 2/g,the mass of PE catalyzed by 1 g of Ti in one hour is 5 0～5 7,1 8～2 0 kg,respectively.Kinetic curve of ethylene polymerization with SM is decadent and that with MG 2 is steady.The influence of catalytic properties on gas phase polymerization of ethylene were discussed.The morphology of catalyst particles of SM and MG 2 is studied by SEM and image analysis The average value of particle diameter( ) ,the ratio between major axis and minor axis of the particle( d l /d s) and the ratio between big and little particle diameter( d max / d min ) of the SM MG 2 catalyst are 31 μm, 33 μm,1 402,1 524 and 4 1,7 0, respectively. The corresponding values ,d l /d s ,d max / d min of polymerization product for SM and MG 2 catalyst are 247 μm,263 μm,1 295,1 540 and 4 6,9 0, respectively The results indicate that the quality of SM catalyst is good