Support, catalyst and process for polymerizing olefins

A process for the polymerization of one or more alpha olefins under conditions characteristic of Ziegler polymerization which process comprises employing as a polymerization catalyst a composition resulting from the addition of a reducing agent to a mixture of a support suspended in an inert liquid hydrocarbon and a transition metal compound of Groups 4b, 5b, 6b, 7b, or 8 of Mendeleev's Periodic Table under conditions so as to provide a catalytically active solid product and in such proportions that the magnesium:transition metal atomic ratio is from about 0.1:1 to about 30:1 followed by washing the resultant solid catalyst product with an inert liquid hydrocarbon wherein said support comprises the reaction product of (1) a mixture of an organomagnesium compound represented by the formula MgR.sub.2 and a silcon halide represented by the formula R'.sub.4-n SiX.sub.n, said mixture being in a non-polar solvent, with (2) an alcohol represented by the formula R"OH;

• wherein the organomagnesium compound is or can be rendered hydrocarbon soluble and wherein each R, R' and R" is independently a hydrocarbyl group having from 1 to about 20 carbon atoms, X is C1, Br or I, n has a value of from 1 to 4 and wherein the molar ratio of R"OH:MgR.sub.2 is at least 2:1 and the molar ratio of R"OH:R'.sub.4-n SiX.sub.n is sufficient so as to provide at least one X group per OH group.