Process for the polymerization of vinyl monomers in the presence of metal alcoholates

Vinyl monomers are polymerized in the presence of a compound of formula Mn(OR1)xRy, where M is a metal of valency n of Groups I, II or III of the Periodic Table, R and R1 are the same or different straight-chain or branched alkyl radicals, x is 1, 2 or 3, and y is n-x. Polymerization is effected at - 100 DEG to + 100 DEG C., with or without solvents such as saturated aliphatic hydrocarbons containing 4-12 carbon atoms, ethers, or chloroform. Examples specify polymerization of vinyl chloride and fluoride, and acrylonitrile, using as catalyst, Al(C2H5)2(OC4H9), Al(C2H5)(OC4H9)2, Al(OC4 H9)3, Al(C2H5)2(OC2H5), Mg(C4H9)(OC3H7), or LiOBu, alone, or in n-heptane or ether. The product is a polymer of high linearity having a specific viscosity of 0.9-2 and syndiotactic index of 1.9-2.2.