| 简介 |
FIELD : chemistry.
SUBSTANCE : invention relates to a "preformed" type catalytic system for stereospecific cis-1, 4-polymerization of conjugated dienes, a process for its preparation, a method for the synthesis of diene elastomers, a method for activating a catalytic system, a catalytic system and the use of compounds corresponding to formula (I). The catalytic system is based on conjugated diene monomers for pre-formation, salts of rare earth metals of acids selected from organophosphorus acid, carboxylic acid and a mixture thereof, alkylating agents consisting of alkylaluminum compounds of formula AlR3 Or HAlR2, where R is alkyl and H is a hydrogen atom, donors of halogen atoms representing alkylaluminum halides and compounds of formula (I) in which the groups from R1 to R6, which are identical or different, are selected from hydrogen atoms, linear or branched saturated or unsaturated aliphatic, cycloaliphatic or aromatic alkyls, with the proviso that at least one of the groups from R1 to R6 do not represent the hydrogen atom. Molar ratio of formula (I) compounds and salts of rare-earth element is in the interval from 5 to 1000. The production process comprises the following steps : in a first step, a suspension or solution or gel of a rare earth metal salt is prepared in a solvent containing, if appropriate, a compound of formula (I); if the solvent does not contain a compound of formula (I), a compound corresponding to formula (I) is added; then, in a second step, a monomer of conjugated dienes is added to the mixture obtained in the previous step; In a third step, the alkylating agent is added to the mixture obtained in the previous step to produce the alkylated salt, and in the fourth stage, the donor of the halogen atoms is added to the alkylated salt obtained in the previous step.
EFFECT : improvement of catalytic activity.
18 cl, 6 tbl, 17 ex |
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