Process for cis-1,4-poly-butadiene production with reduced gel formation

摘要

A process for producing high cis-1,4-polybutadienes wherein there is reduced gel formation is provided which process comprises: polymerizing 1,3-butadiene in a polymerization medium comprising an inert hydrocarbon solvent and water at a temperature of from about -30°C to about 60°C in the presence of a catalyst system which is a mixture of (1) a substantially anhydrous divalent cobalt salt, (2) diethyl aluminum chloride or ethyl aluminum sesquichloride and (3) an organo aluminum compound of the formula R₃Al wherein R is an alkyl group having from 8 to 12 carbon atoms and, optionally triethylaluminum, the molar ratio of chloride in the diethyl aluminum chloride plus (3) being from about 0.7:1 to about 1 and the molar ratio of chloride in the ethyl aluminum sesquichloride plus (3) being from about 0.7:1 to about 1.4:1 and the ratio of the mols of the divalent cobalt salt to the total mols of diethyl aluminum chloride or ethyl aluminum sesquichloride plus (3) being from about 1:15 to about 1:30, the water being employed at a level of from about 0.1 to about 0.8 millimol for every millimol of diethyl aluminum chloride or ethyl aluminum sesquichloride used, to the desired conversion.