Composition used for rare earth catalyst, rare earth catalyst and its application

Abstract

The invention provides a composition used for a rare earth catalyst. The composition contains alkyl aluminum and / or alkyl aluminum hydride, a rare earth compound and conjugated diene. The rare earth compound is a compound having a general formula as MR3.nL, wherein M is a rare earth metal, R is halogen, L is an electron-donating ligand, and the value of n is 1-3. Also, the alkyl aluminum and / or alkyl aluminum hydride, the rare earth compound and the conjugated diene are in a molar ratio of 0.05-1.5:0.01-0.05:1. The invention provides a rare earth catalyst, which is obtained by enabling the composition provided in the invention to contact an inert organic solvent mutually under the protection of an inert gas. Specifically, the contact condition enables the conjugated diene in the composition to polymerize so as to obtain a conjugated diene polymer with a polymerization degree of not less than 150. The invention also provides application of the catalyst in the polymerization of conjugated diene. The rare earth catalyst provided in the invention has good stability, and is in favor of synthesizing polymer products with stable quality and uniformity when it is used for conjugated diene polymerization.

Description

technical field [0001] The invention relates to a rare earth catalyst composition, a rare earth catalyst and the application of the rare earth catalyst in the polymerization of conjugated dienes. Background technique [0002] Neodymium chloride / alkyl aluminum rare earth catalyst is the earliest neodymium rare earth catalyst used in the polymerization of conjugated dienes. NdCl is used in "Rare Earth Catalytic Synthetic Rubber Collection" 3 -C 2 h 5 OH-Al(C 2 h 5 ) 3 The catalyst is used to polymerize butadiene or isoprene to obtain cis-polybutadiene or cis-polyisoprene. However, due to the heterogeneous phase state of the catalyst, there are multiple active centers with different lifetimes, and the stability is very poor, which makes the catalytic process and polymerization process difficult to control. High, low content of cis 1,4-structure, and possible problems such as bimodal distribution of molecular weight and wide distribution, difficulty in controlling molecul...

AI Technical Summary

Problems solved by technology

However, due to the heterogeneous phase state of the catalyst, there are multiple active centers with different lifetimes, and the stability is very poor, which makes the catalytic process and polymerization process difficult to control. High, low cis 1,4-structure content, and the possibility of bimodal distribution of molecular weight and wide distribution, difficult to control molecular weight and molecular weight distribution, etc.

[0003] By adding an electron donor to the neodymium chloride catalyst system, the solubility of neodymium chloride can be increased, which is beneficial to the catalyst activity and the polymerization process, but it still cannot effectively solve the poor stability of the above-mentioned rare earth catalysts, which leads to the catalytic process and polymerization process. The process is not easy to control, the synthesized diolefin polymer has high gel content, low cis 1,4-structure content, and may have problems such as bimodal and wide distribution of molecular weight, difficult to control molecular weight and molecular weight distribution, etc.

[0004] Therefore, the neodymium chloride / alkylaluminum heterogeneous catalyst is considered unfavorable for industrial production

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