MgCl2路6CH3OH: A Simple Molecular Adduct and Its Influence As a Porous Support for Olefin Polymerization

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• 作者：Edwin S. Gnanakumar ; Ravikumar R. Gowda ; Shrikant Kunjir ; T. G. Ajithkumar ; P. R. Rajamohanan ; Debashis Chakraborty ; Chinnakonda S. Gopinath
• 刊名：ACS Catalysis
• 出版年：2013
• 出版时间：March 1, 2013
• 年：2013
• 卷：3
• 期：3
• 页码：303-311
• 全文大小：467K
• 年卷期：v.3,no.3(March 1, 2013)
• ISSN：2155-5435

文摘

A single phase molecular adduct, MgCl₂路6CH₃OH has been synthesized using MgCl₂ and the simplest alcohol, methanol. Structural, spectroscopic, and morphological studies have been carried out for a better understanding of the single phase MgCl₂路6CH₃OH adduct. ¹³C CPMAS solid state NMR studies show all six methanol molecules are magnetically equivalent and present in a single environment around the Mg²⁺ center. Raman spectral analysis of the characteristic peak at 708 cm^鈥? substantiates octahedral coordination of six CH₃OH molecules around Mg²⁺. Solid state ¹³C NMR measurements, made after heat treatment at different temperatures, have been utilized to understand the variations in CH₃OH stoichiometry and coordination around Mg²⁺ with temperature. A titanated active catalyst, TiCl₄ on MgCl₂路6CH₃OH, has also been synthesized and subjected to detailed characterizations. The active catalyst shows high surface area (102 m²/g) and mesoporosity. The titanated catalyst has been screened for ethylene polymerization reactions using different cocatalysts (R₃Al; R= 鈭扖H₃, 鈭扖H₂CH₃, and 鈭扖H₂CH(CH₃)₂). A total of 7.25 kg of polyethylene per gram of catalyst has been obtained with Me₃Al cocatalyst, which is six times higher in activity compared with commercial Me₃Al/TiCl₄/ MgCl₂路6EtOH-supported catalyst. Although porosity influences the catalytic activity, other factors also seem to contribute to the total catalytic activity.

Keywords:

molecular adduct; heterogeneous catalysis; Ziegler鈭扤atta catalyst; olefin polymerization; MgCl₂