Polybutadiene and process for producing same

Claim 1

A process for the production of polybutadiene consisting of 2-40% of the 1,2-cis structure, 60-98% of the cis-1,4-structure and not more than 1.5% of the trans-1,4-structure which comprises the two successive steps of: first, polymerizing for a period of time ranging between a period of ten minutes and 10 hours, 1,3-butadiene in an inert organic solvent in the presence of a cis-1,4-polymerization catalyst consisting essentially of a. a cobalt component selected from the group consisting of (a 1 ) a cobalt compound and (a 2 ) a material formed by electrochemically depositing metallic cobalt on metallic zinc, and b. a halogen-containing organoaluminum compound represented by the formula wherein R is an alkyl or cycloalkyl group having 1 to 6 carbon atoms or a phenyl group, X is a halogen atom and n is a positive number in the range of 1.5 to 2.0 thereby forming cis-1,4-polybutadiene, and secondly, without deactivating the remaining cis-1,4-polymerization catalyst and with the addition or no addition of 1,3-butadiene and/or an inert organic solvent to the polymerization system, effecting the 1,2-polymerization of 1,3-butadiene, (A) in the case where the following component (a') is not the same as component (a) of the cis-1,4-polymerization catalyst employed, by adding thereto, without deactivating the remaining cis-1,4-polymerization catalyst, a 1,2-polymerization catalyst comprising a'. a cobalt component selected from the group consisting of (a' 1 ) a cobalt compound and (a' 2 ) a material formed by electrochemically depositing metallic cobalt on metallic zinc, b'. an organoaluminum compound represented by the formula AlR.sub.3 ( 2) wherein R represents the group defined hereinbefore, and c'. carbon disulfide, when the component (a') is not the same as the component (a) of the cis-1,4-polymerization catalyst employed, or, B. in the case where the component (a') is the same as the component (a) of the cis-1,4-polymerization catalyst employed, by adding to the polymerization system, without deactivating the remaining cis-1,4-polymerization catalyst, either (B1) all the components of said 1,2-polymerization catalyst or (B2) the components of said 1,2-polymerization catalyst except component (a') when the component (a') is the same as the component (a) of said cis-1,4-polymerization catalyst employed, the aforesaid 1,2-polymerization being conducted for a period of time varying between ten minutes and ten hours, thereby forming the desired polybutadiene product, in which said cobalt compound of (a 1 ) and (a' 1 ) is a member selected from the group consisting of i. a cobalt salt of a carboxylic acid having 6 to 10 carbon atoms, ii. a cobalt complex of a β-diketone represented by the formula: ##EQU3## wherein each of R 1 and R 4 is an alkyl group having 1 to 3 carbon atoms and each of R 2 and R 3 is a hydrogen atom or an alkyl group having 1 to 3 atoms, iii. a cobalt complex of a β-keto acid ester represented by the formula ##EQU4## wherein R 1 , R 2 , R 3 and R 4 are as defined in preceding formula (3), and (iv) a cobalt halide complex prepared from a cobalt halide represented by the formula CoXn wherein X is a halogen atom and n is 2 or 3 and a ligand capable of forming a complex in coordination with the cobalt halide, selected from the group consisting of tertiary amines, alcohols, tertiary phosphines, ketones and N,N-dialkylamides, said cis-1,4-polymerization catalyst containing 0.002 to 50 millimoles of the cobalt compound (a 1 ) and 0.2 to 200 millimoles of the halogen-containing organoaluminum compound (b), per each mole of 1,3-butadiene, and the molar ratio (Al/Co) of the halogen-containing organoaluminum compound (b) to the cobalt compound (a 1 ) being 5 to 500, or containing 0.025 to 5 g of the material (a 2 ) formed by electrochemically depositing metallic cobalt on metallic zinc per 100 g of 1,3-butadiene and 0.1 to 5 times the weight of the material (a 2 ), of the halogen-containing organoaluminum compound (b), and said 1,2-polymerization catalyst containing 0.001 to 10 millimoles of the cobalt compound (a' 1 ), 0.1 to 100 millimoles of the organoaluminum compound (b') and 0.001 to 20 millimoles of carbon disulfide (c'), per each mole of 1,3-butadiene, and the molar ratio (Al/Co) of the organoaluminum compound (b') to the cobalt compound (a' 1 ) being 5 to 500, or containing 0.05 to 10 g of the material (a' 2 ) formed by electrochemically depositing metallic cobalt on metallic zinc per 100 g of 1,3-butadiene, 0.1 to 5 times the weight of the material (a' 2 ), of the organoaluminum compound (b') and 0.001 to 20 millimoles of carbon disulfide (c') per mole of 1,3-butadiene.