Transition metal compositions

Claim 2

A transition metal composition, useful as an initiator for the polymerization of olefins, which is the product obtained by mixing together under dry and oxygen-free conditions a transition metal complex of the general formula R.sub.m MX.sub.p with a substantially inert inorganic matrix material having a plurality of --OH groups attached to the surface of the matrix material, the hydrogen atoms of the --OH groups being capable of acting as proton sources, said matrix material being free from adsorbed water, wherein M is a transition metal of Groups IVA to VIA of the Periodic Table of the Elements, R is a hydrocarbon group or --CH 2 Y where Y is --Z (R 1 ) 3 where Z is silicon, germanium, tin or lead and R 1 is hydrogen or hydrocarbon, X is a halogen and m and p are integers, m having a value from 2 to the highest valency of the metal M and p having a value from 0 to 2 less than the valency of the metal M, except when M is a metal of Group VIA when p is 0.

Claim 3

A composition as claimed in claim 1 in which at least one of the hydrocarbon groups R is π-allyl or π-methylallyl.

Claim 4

A composition as claimed in claim 2 in which the transition metal complex is selected from the group consisting of tetrakis(π-allyl) zirconium and hafnium, tris(π-allyl) chromium, tetrakis(π-methallyl) zirconium and hafnium, tris(π-methylallyl) chromium and zirconium tris(π-allyl) bromide.

Claim 5

A composition as claimed in claim 1 in which at least one R has the formula --CH 2 Y' sigma-bonded to the metal M, where Y' is a mono- or di-cyclic aryl group composed of hydrogen and carbon, cycloalkenyl, halogen or the group Z(R 1 ) 3 where Z represents silicon, germanium, tin or lead, and R 1 is hydrocarbon or hydrogen.

Claim 6

A composition as claimed in claim 4 in which --CH 2 Y is selected from the group consisting of benzyl, 1-methylene-1-naphthyl, p-methyl benzyl and trimethylsilymethylene.

Claim 7

A composition as claimed in claim 5 in which the transition metal complex is selected from the group consisting of zirconium and titanium tetra(benzyl), tris(benzyl)zirconium chloride, zirconium tetrakis(p-methyl benzyl), zirconium and titanium tetrakis(1-methylene-1-naphthyl) and zirconium tetrakis(trimethylalkylmethylene).

Claim 8

A composition as claimed in claim 1 in which the inert matrix material is selected from the group consisting of silica, alumina and mixtures thereof.

Claim 9

A process for the preparation of a composition as claimed in claim 1, which comprises mixing together under dry and oxygen-free conditions a transition metal complex of the general formula R.sub.m MX.sub.p with a substantially inert inorganic matrix material having a plurality of --OH groups attached to the surface of the matrix material, the hydrogen atoms of the --OH groups being capable of acting as proton sources, said matrix material being free from adsorbed water, wherein M is a transition metal of Groups IVA to VIA of the Periodic Table of the Elements, R is a hydrocarbon group or --CH 2 Y where Y is --Z (R 1 ) 3 where Z is silicon, germanium, tin or lead and R 1 is hydrogen or hydrocarbon, X is a halogen and m and p are integers, m having a value from 2 to the highest valency of the metal M and p having a value from 0 to 2 less than the valency of the metal M, except when M is a metal of Group VIA when p is 0, the proportions of transition metal complex and inert matrix material being chosen so that each reactable hydrocarbon group is reacted with a hydroxylic group of the matrix material.

Claim 10

A process as claimed in claim 8 in which the matrix material is freed from adsorbed water, suspended in an inert liquid and titrated with a solution of the transition metal complex in an inert solvent until all the reactable hydroxylic groups of the matrix material have been reacted.

Claim 11

A process as claimed in claim 8 in which, firstly, an excess of a transition metal complex or a Grignard reagent is added to one portion of a matrix material previously freed from adsorbed water and the number of molecules of hydrocarbon evolved measured and, secondly, sufficient of an appropriate transition metal complex is added to a second portion of the same matrix material to liberate an equivalent amount of hydrocarbon.

Claim 12

A composition as claimed in claim 1 wherein the matrix material is silica, alumina or mixture thereof and the transition metal complex is selected from the group consisting of tetrakis(π-allyl) zirconium and hafnium, tris (π-allyl) chromium, tetrakis (π-methallyl) zirconium and hafnium, tris(π -methylallyl) chromium, zirconium tris(π-allyl) bromide, zirconium and titanium tetra(benzyl), tris(benzyl)zirconium chloride, zirconium tetrakis(p-methyl benzyl), zirconium and titanium tetrakis(1-methylene-1-naphthyl) and zirconium tetrakis (trimethylalkylmethylene).