文献类型：期刊文献

英文题名：Experimental and theoretical studies on ethylene polymerization using SiO2-supported silyl chromate type catalysts prepared by a green method

作者：Li, Xiaofang[1]; Cheng, Ruihua[1]; Luo, Jun[1]; Dong, Qi[1]; He, Xuelian[1]; Li, Liuzhong[2]; Yu, Yongling[2]; Da, Jianwen[2]; Liu, Boping[1]

机构：[1] State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, China; [2] Research Institute of Qilu Branch Co., SINOPEC, Zibo 255400, Shandong, China

年份：2010

卷号：330

期号：1-2

起止页码：56

外文期刊名：Journal of Molecular Catalysis A: Chemical

收录：EI(收录号：20103913258240)

语种：英文

外文关键词：Catalyst activity - Ethylene - Silica - Chromates - Polymerization - Catalyst supports - Chlorine compounds - Chromium

摘要：SiO2-supported silyl chromate catalyst (UCC S-2 catalyst) is an important catalyst for the commercial production of polyethylene. Cann first reported a possible green synthesis route for the preparation of S-2 catalyst through transformation from Phillips catalyst by addition of triphenylsilanol (TPS) to avoid the use of toxic bis(triphenylsilyl) chromate (BC). In this work, this green synthesis route was further investigated by the combination of experimental and theoretical methods. The obtained catalyst was named as PS catalyst based on the incomplete conversion of Phillips catalyst to S-2 catalyst. Polymerization activity of PS1.5 catalyst was higher than that of S-2 catalyst with either TEA or MAO as cocatalyst. The existence of the simultaneously formed hydroxyl group and its coordination to the reduced Cr site was favorable to the PS catalyst, and this might attribute to the higher polymerization activity of PS catalyst than that of S-2 catalyst. A further modification of PS catalyst by a series of alkyl chlorosilane compounds showed that the role of the electron-withdrawing group only limited at a certain distance away from Cr active site. This preliminary study provided a solid basis for a further innovation of PS catalysts and final substitution of S-2 catalyst in commercial processes. ? 2010 Elsevier B.V. All rights reserved.