负载二亚胺镍催化剂的乙烯气相聚合性能  

Gas-phase polymerization of ethylene with supported diimine nickel catalysts

作　　者：李岩[1] 高榕[1] 刘东兵[1] 周俊领[1] 

机构地区：[1]中国石化北京化工研究院,北京100013

出　　处：《石油化工》2016年第6期685-690,共6页Petrochemical Technology

摘　　要：合成了3种α-二亚胺镍金属配合物C30H28Br2NiN2，C36H40Br2NiN2，C28H40Sr2NiN2，并负载于MgCl2／SiO2复合载体上得到负载催化剂，分别记为Cat-a，Cat-b，Cat-c.利用1HNMR，ICP，SEM，GPC，BET等方法对配合物及催化剂的结构进行了表征，并将催化剂用于乙烯气相聚合，考察了催化剂的乙烯气相聚合性能。表征结果显示，当负载方法相同时，不同配合物对催化剂的表面性能及颗粒形态影响不大。实验结果表明，在相同聚合条件下，催化剂的乙烯气相聚合活性的高低顺序为：Cat—b〉Cat—a〉Cat—c。Cat—a所得聚乙烯的相对分子质量较低，Mw／Mm较宽；Cat—c所得聚乙烯的相对分子质量最高，相对分子质量分布最窄；负载二亚胺镍金属催化剂在气相聚合中不需引入共聚单体即可制得具有一定支化度的支化聚乙烯。Cat—a和cat-b所得聚乙烯的颗粒形态较好，基本呈球形。α-Diimine nickel complexes, namely C30H28Br2NiN2, C36H40Br2NiN2 and C2sH40Br2NiN2, were synthesized and supported on composite MgCl/SiO2 support separately. The supported catalysts were named as Cat-a, Cat-b and Cat-c, respectively. The structures of the nickel complexes and catalysts were characterized by means of 1H NMR, ICP, SEM, GPC and BET. The performances of the catalysts in the gas phase polymerization of ethylene were studied. The results showed that the effects of the nickel complexes on the surface properties and morphology of the catalysts were little when the similar immobilization method was used. Under the similar polymerization conditions, the sequence of the catalyst activities was Cat-b〉Cat-a〉Cat-c. The polyethylene products prepared with Cat-a has lower relative molecular mass and broader Mw/Mn. The polyethylene products prepared with Cat-c has higher relative molecular mass and the narrowest Mw/Mn. Branched polyethylene can be synthesized with the diimine nickel complex catalysts without comonomer. The polyethylene products prepared with Cat-a and Cat-b showed better spherical morphology.

关 键 词：二亚胺镍 聚乙烯催化剂 乙烯气相聚合 支化聚乙烯 

分 类 号：TQ426.8[化学工程]