| abstract |
Abstract of the Disclosure A catalyst consisting of: A) A rare earth carboxylates corresponding to the following general formula B) an aluminium alkyl AIR43 and/or R2 AlH, C) a Lewis acid, wherein M represents a trivalent rare earth element having an atomic number of from 57 to 71 R1, R2, and R3, which may be the same or different, represent an alkyl group having from 1 to 10 carbon atoms, the sum of all the carbon atoms in the substituents R1, R2 and R3 being from 6 to 20, and R4 represents an alkyl group having from 1 to 10 carbon atoms, can be used for polymerizing butadiene in solution. It is prepared by mixing the components A, B and C in an inert organic solvent at a temperature in the range of from -30°C to 80°C. |