Immobilization of Ziegler–Natta Catalyst for Ethylene Polymerization on Macropores SiO2 with an Open-Framework Structure

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• 作者：Bing Xue ; Lei Hui ; Huaqin Yang ; Yulai Zhao ; Linxi Hou ; Wei Li
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：56
• 期：1
• 页码：135-142
• 全文大小：484K
• ISSN：1520-5045

文摘

A macroporous SiO₂ (Macro-SiO₂), which has uniformed macropores, an open-framework structure, and thin walls, was synthesized to support Ziegler–Natta catalysts. The immobilization behaviors of the Ziegler–Natta catalysts inside the Macro-SiO₂ were investigated. Notable agglomerations of δ-MgCl₂/titanium complex were observed because of the unconstrained environment of the Macro-SiO₂. A highly superficial Ti content and a heterogeneously chemical structure of Ti active sites were thus achieved inside the Macro-SiO₂. The ethylene polymerization results revealed that the Macro-SiO₂/MgCl₂/TiCl₄ exhibited much higher catalytic activity (i.e., 12.1 × 10⁶ g PE·(mol Ti·h)⁻¹ or 17.8 × kg PE·(g cat·h)⁻¹) than that of the traditional 955-SiO₂ supported catalyst (i.e., 2.0 × 10⁶ g PE·(mol Ti·h)⁻¹ or 2.7 × kg PE·(g cat·h)⁻¹). Finally, the fragmentation behavior of Macro-SiO₂/MgCl₂/TiCl₄ was investigated during the polymerization. This unconstrained environment of Macro-SiO₂ afforded fewer resistances to the diffusion of reactants and also the polymer growth.