The Preparation Research Of Magnesium Ethoxide-Based Polypropylene Catalyst

In this paper, from the preparation of Mg(OEt)2, the preparation of catalyst and catalytic propylene polymerization this three aspects of using Mg(OEt)2as precursor for prepare polypropylene catalysts was studied, and got some valuable conclusions:Using magnesium powder and ethanol as raw material synthesis Mg(OEt)2, the influence of magnesium powder particle size、material ratio、charging process and reaction temperature was studied.Using the optimal Mg(OEt)2as precursor synthesis catalyst, studied the influence of the initial reaction temperature and heating rate、internal electronic donor join conditions and chose the better conditions.Using the optimal catalyst to catalytic propylene polymerization, the influence of Al/Ti(mol/mol)、Al/Si(mol/mol)、polymerization temperature、polymerization time and hydrogenation quantity was studied, and the better polymerization conditions was:Al/Ti (mol/mol) was3400, Al/Si(mol/mol) was6.0, polymerization temperature was70℃, hydrogenation quantity was0.2MPa.The catalyst under the low polymerization temperature or short polymerization time also could show high activity、low trigger temperature and short induction time. The catalyst could suit the requirements of the gas phase polymerization process. The catalyst under70℃catalytic propylene bulk polymerization, the activity reached48kgPP/(gcat-h), polypropylene isotacticity reached98.9%, polypropylene bulk density was0.41gPP/cm3. All the data were exceed the present requirements of Mg(OEt)2-based polypropylene catalyst. The shape of optimal Mg(OEt)2precursor、catalysts and polypropylene were spherical or ellipsoid, the catalyst had favourable "copy" phenomenon.