Novel [ONN] tridentate fourth subgroup metal complex as well as preparation method and application thereof

Abstract

The invention provides a novel [ONN] tridentate fourth subgroup metal complex and a preparation method and application thereof. The novel [ONN] tridentate fourth subgroup metal complex has a structureas shown in formula I which is described in the specification. According to the complex, multiple groups are grafted to carbon adjacent to intermediate nitrogen, the steric effect and the electricaleffect of a metal center are changed, a better modification effect can be achieved on a metal active center, and the polymerization performance of a catalyst on ethylene is improved. Due to the existence of nitrogen covalent bonds in the complex, the stability is greatly enhanced. The catalyst is very high in activity of catalyzing ethylene homopolymerization, and ultrahigh molecular weight polyethylene can be obtained. The complex is used as a catalyst to catalyze copolymerization of ethylene, norbornene, 1-hexene and 1-octene, the activity is high, and the co-monomer insertion rate in the polymer is also very high. The maximum molecular weight of polyethylene obtained by catalyzing ethylene homopolymerization by the complex is 163.4 * 10 < 4 > g/mol; the maximum molecular weight of a polymer obtained by catalyzing copolymerization of ethylene and norbornene is 75.7 * 10 < 4 > g/mol.

Description

technical field [0001] The invention belongs to the technical field of olefin polymerization catalysts, and in particular relates to a novel [ONN] tridentate fourth subgroup metal complex and its preparation method and application. Background technique [0002] Polyolefin products have become the most widely used synthetic resin materials in production and life due to their abundant raw materials, low price, easy production and processing, good mechanical properties, and superior performance. The development level of the polyolefin industry It directly represents the development level of a country's petrochemical industry and is an important part of the national economy and national defense strategy. [0003] Olefin polymerization catalyst directly determines the internal structure and morphology of polyolefin products. It is the core technology in the development of polyolefin industry. Its development generally goes through three stages: a). Ziegler-Natta catalyst, this ty...

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Problems solved by technology

[0004] The patent applied by Tang Yong in 2001 (publication number CN 1332182 A), the patent applied by Hua Wei in 2011 (CN102850391 A), the ligand of this type of metal complex They are all salicylaldimine compounds. Although salicylaldehyde compounds are cheap and easy to obtain, the synthesis process of amine compounds is relatively complicated, which increases the application cost. At the same time, the imine bonds in this type of metal complexes are unstable. In the process of olefin polymerization, it is easy to be reduced by alkylaluminum, resulting in a multi-active center system in the catalytic system, unstable catalyst properties and short catalytic life, and poor quality of polymer products; although the patent (CN108440694 A) applied by Muying in 2018 tried to change This classic salicylaldimine structure has been changed, but its skeleton still contains unsaturated imine bonds. During the catalytic polymerization reaction, there is still the problem of double bonds being reduced to cause multiple active centers. The stability of the catalyst is poor, and this type of catalyst catalyzes ethylene and The polymerization activity of the copolymerization of ethylene and α-olefin is very low

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