Synthesis of novel electron donors and their application to propylene polymerization

Abstract

A series of electron donors, including 1,1-cyclopentanecarboxylic acid diethyl ester (CPCADEE), 1,1-cyclopentanedimethanol acetic diester (CPDMAD), 1,1-biethoxymethyl pentane (BEMP), 2,2-diethyl diethylmalonate (DEDEM)and 2,2-diethyl-1,3-propanediol acetic diester (DEPDADE), were synthesized by diethyl malonate (DEM). The purities and structures of the above products were characterized by gas chromatography (GC) and gas chromatography-mass spectrometer (GC-MS), respectively. Furthermore, the possible optimal three-dimensional structures of these donors were simulated by means of Gaussian 03 and Chem 3D. Then these electron donors were coordinated with tetrachloro titanium (TiCl₄) and chloride magnesium (MgCl₂) to obtain the catalysts for the polymerization of propylene. The catalytic activities and properties of polypropylene are greatly improved by adding external donor(ED) when CPCADEE or DEPDADE is used as internal donor(ID). However, when BEMP was used as ID, the highest catalytic activity is obtained without adding ED, which can reduce production costs and simplify catalytic synthesis. The experiments indicate that BEMP has the shortest distance of oxygen atoms and the highest electronegativity.

Keywords

electron donor / structural simulation / propylene polymerization / 1,1-biethoxymethyl pentane

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