Olefin polymerization method

Abstract

The invention relates to an olefin polymerization method. The method comprises steps as follows: a hexane solution of triethyl aluminum, a hexane solution of cyclohexyldimethoxymethylsilane and a catalyst are sequentially added to a high-pressure reactor under the protection of nitrogen, the high-pressure reactor is closed, 1.5-8.0 L of hydrogen and liquid olefin are added, the components are heated to 60-80 DEG C to react for 1-2 h, cooled, subjected to pressure release, discharged and dried, and polymers are obtained. According to the olefin polymerization method, a supporter and the catalyst are improved, so that when the catalyst prepared from the supporter is used for polymerization of olefin, especially, polymerization of propylene, activity and hydrogen regulation sensitivity of the catalyst can be improved, particle morphology of obtained polymers is good, bulk density of the polymers can be reduced, and no special-shaped materials are produced basically.

Description

technical field [0001] The invention belongs to the field of organic chemical synthesis, in particular to an olefin polymerization method. Background technique [0002] In the polymerization of olefins, catalysts are often required for catalysis. At present, Ziegler-Natta catalysts for olefin polymerization are basically prepared by loading titanium halides on supports. The carrier commonly used in the preparation of Ziegler-Natta catalysts is magnesium chloride alcoholate, and its overall performance is superior to catalysts prepared by other carriers. The preparation of carrier magnesium chloride alcoholate generally adopts methods such as spray drying, spray cooling, high-pressure extrusion, high-speed stirring, emulsification molding, and high-gravity rotating bed. However, in the process of catalyzing the polymerization of olefins, the catalyst prepared by the carrier obtained by this method is prone to breakage of polymer particles, resulting in excessive fine powder...

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Problems solved by technology

However, the composite spherical carrier is easy to stick during the preparation process, and it is difficult to form spherical particles with suitable particle size.

[0003] In the prior art, the methods for preparing catalysts for olefin polymerization mainly include: ① first prepare the carrier by reacting the magnesium halide alcoholate with ethylene oxide compounds, and then directly add the magnesium halide alcoholate to the In the reactor of ethylene oxide compounds, the catalyst carrier prepared by this method has the disadvantages of unstable preparation process, easy carrier adhesion, and poor carrier molding effect.

② Use epoxide and tributyl phosphate compounds to dissolve magnesium chloride to form a uniform solution, and then use titanium tetrachloride to precipitate the carrier and carry out titanium loading. The reaction products are very complicated, and the by-products produced are difficult to handle. In the process of titanium oxide precipitation, some precipitation aids are also used, which makes the reaction by-products more complicated.

However, the preparation of the carrier needs to prepare the corresponding magnesium halide adduct first, and then contact the alkylene oxide compound to obtain it. The steps are cumbersome and the reaction controllability is poor.

④ It is also reported that alkoxymagnesium carrier is used to support titanium metal compound for catalyst preparation. The alkoxymagnesium carrier is prepared by reacting metal magnesium and ethanol, but there are disadvantages such as low bulk density of the obtained polymer.

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