A kind of catalytic system for preparing wide distribution polyolefin and its application

Abstract

The invention relates to a catalytic system for preparation of wide-distribution polyolefin, and application of the catalytic system. The catalytic system comprises a solid catalyst component (A), a cocatalyst (B) and a first external electron donor (ED1), wherein the component (A) is a magnesium halide loaded Ti solid component and contains a composite internal electron donor (ID); the first external electron donor (ED1) is selected from one or more of compounds as shown in a general formula (1), (the formula is as shown in the description); and the R1 is selected from C1-C6 alkyl, C3-C8 naphthenic base, C6-C14 aryl or C6-C14 ceteroary, R2 is selected the formulas as shown in the description, and R3 is selected from OR1, R2, C1-C6 alkyl and C3-C8 naphthenic base. When being applied to olefin polymerization, the catalytic system has various advantages: catalytic activity and hydrogen sensitivity are high; and the polymerization product is high in isotactic index, wide in molecular weight distribution and high in weight-average molecular weight.

Description

technical field [0001] The invention relates to a catalytic system for olefin polymerization, in particular to a catalytic system for preparing wide-distributed polyolefin and its application, and belongs to the field of catalysts. Background technique [0002] Ziegler-Natta catalyst systems for olefin polymerization are known in the art as catalyst systems for olefin polymerization. Generally, the catalytic system includes a main catalyst, an internal electron donor, a co-catalyst and an external electron donor. [0003] Among them, the main catalyst generally adopts transition metal halides, oxyhalides, acetylacetonate compounds, etc., and the commonly used transition metal compounds are titanium and vanadium. The co-catalyst generally adopts metal-organic compounds containing elements of group IA-IIIA of the periodic system, mainly aluminum alkyls or halides of aluminum alkyls. [0004] Second, internal electron donors are indispensable as components in catalytic system...

AI Technical Summary

Problems solved by technology

Each of these internal electron donors has certain defects in practical industrial applications: as the catalytic activity of catalysts using aromatic diester compounds is low, the relative molecular mass distribution of the resulting polymer is moderate; the catalysts of glycol ester compounds The sensitivity to hydrogen adjustment is not as good as that of catalysts using diether compounds, and the relative molecular mass distribution of the obtained polymers is generally not as good as the evaluation results of catalysts using 2,3-dihydrocarbyl succinate compounds; although catalysts using diether compounds High catalytic activity and good hydrogen tuning sensitivity, but the relative molecular mass distribution of the obtained polymer is narrow; although the relative molecular mass distribution of 2,3-dihydrocarbyl succinate compounds is wide, there are internal electron donor compounds The synthesis process is difficult in industrial application; use the C with ω-cyano group 2 ~C 5 Monobasic acid ester compounds are catalysts for internal electron donors, except for C containing ω-cyano 2 In addition to monobasic acid ester compounds, there are also ω-cyano C 3 ~C 5 Difficulties in the synthesis of monobasic acid ester compounds, and compared with the catalysts of aromatic diester compounds, the C of ω-cyano 2 ~C 5 Monobasic acid ester compounds are less active catalysts for internal electron donors, and the obtained polymers are also poor in isotacticity

[0005] Because of the importance of the role played by the internal electron donor in the catalyst and the above-mentioned internal electron donors have their own shortcomings in practical applications, so in the prior art, people usually use the method of adding more catalysts during the preparation of the catalyst. The method of an internal electron donor compound improves the overall performance of the catalyst to meet the requirements of the polyolefin industrial production on the catalyst, but there are also various problems that need to be improved

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