摘要
以S iO2为载体,将Z ieg ler-Natta(Z-N)催化剂和非茂催化剂的活性组分负载在同一载体上,制得S iO2负载型Z-N/非茂双金属催化剂;研究了双金属催化剂催化乙烯聚合的动力学规律,考察Zr的负载量、n(T i)∶n(Zr)对双金属催化剂催化活性和聚乙烯产物的影响。实验结果表明,双金属催化体系中同时存在两类性质不同的活性中心,两类活性中心之间存在着协同效应;控制Zr的负载量和n(T i)∶n(Zr),可在保持较高催化活性的同时,得到宽相对分子质量分布和高熔流比的聚乙烯;采用Zr的质量分数为2.08%、n(T i)∶n(Zr)=4.45的双金属催化剂,在氢分压为0.2M Pa、总压为0.8M Pa、聚合温度为70℃、n(A l)∶n(T i+Zr)=200的条件下催化乙烯聚合时,其催化活性(每摩尔T i和Zr每小时产生的聚乙烯的质量)为4.30×105g/(m ol.h),聚乙烯的相对分子质量分布可达17.22,熔流比可达89.93。
The bimetallic catalyst was prepared by supporting Ziegler -Natta and non -metallocene active components on SiO2 carder with a special method. Ethylene polymerization kinetics on bimetallic catalyst was studied, which indicated that two different kinds of active sites existed on the catalyst. The two kinds of sites had a cooperative effect in ethylene polymerization. By controlling Zr content and n （Ti） ： n （Zr）of catalyst, relative molecular mass distribution of polyethylene could be effectively broadened and bimetallic catalyst had high catalytic activity. Under following polymerization conditions：70 ℃, hydrogen pressure 0.2 MPa, total pressure 0.8 MPa,mass fraction of Zr in bimetallic catalyst 2. 08% and n （Ti） ： n （Zr） = 4. 45, catalyst activity （polyethylene mass produced per mole Ti and Zr per hour）was 4.30 × 10^5 g/（ mol · h）and polyethylene with relative molecular mass distribution 17.22 and melting flow ratio 89.93 could be obtained.
出处
《石油化工》
EI
CAS
CSCD
北大核心
2005年第11期1050-1054,共5页
Petrochemical Technology
