Polymerization process using chromium on a support treated with titanium polymer

Claim 2

A process comprising: combining an inorganic support with a titanium polymer, said support having a chromium compound combined therewith either before, during or after said titanium polymer and said support are combined; activating the resulting support-titanium-chromium composition in an oxygen-containing atmosphere at a temperature within the range of 500°-1000° C., said titanium polymer being present in an amount sufficient to give 2 to 30 weight percent titanium based on the weight of the thus activated composition to produce a catalyst; contacting at least one mono-1-olefin having 2 to 8 carbon atoms per molecule in a reaction zone under polymerization conditions with said catalyst; and recovering a polymer.

Claim 3

A method according to claim 1 wherein said at least one mono-1-olefin is selected from among ethylene, propylene, 1-butene, 1-hexene and 1-octene.

Claim 4

A method according to claim 2 wherein said at least one mono-1-olefin is predominantly ethylene.

Claim 5

A method according to claim 1 wherein said polymerization is carried out under slurry conditions.

Claim 6

A method according to claim 4 wherein said polymerization is carried out at a temperature within the range of 60° to 110° C.

Claim 7

A method according to claim 1 wherein said support is a silica-containing material and wherein said chromium compound is present in an amount sufficient to give chromium in an amount within the range of 0.1 to 5 weight percent based on the weight of said thus activated composition.

Claim 8

A method according to claim 1 wherein said support is a silica-containing material and wherein said titanium is present in an amount within the range of 6 to 25 weight percent.

Claim 9

A method according to claim 1 wherein said support is a silica-containing material and wherein said titanium polymer is combined with said silica-containing material by impregnating said silica-containing material with a solution of said titanium polymer dissolved in an organic solvent, said titanium polymer being a dimer of the formula TiO 2 (Oi-C 3 H 7 ) 6 .

Claim 10

A method according to claim 1 wherein said support is a silica-containing material and wherein said titanium polymer is prepared from a titanium tetraalkoxide having 2 to 10 carbon atoms per alkoxide group employing a suitable quantity of water or diol to vary the chain length of the polymer from 2 to about 50 titanium atoms per molecule.

Claim 11

A method according to claim 1 wherein said support is a silica-containing material and wherein said silica-titanium-chromium composition is subjected to a reduction step prior to activation, said activation being done in the presence of air.

Claim 12

A method according to claim 1 wherein said support is a silica-containing material and wherein said silica-containing material is a large pore silica prepared by removing water from a hydrogel stage thereof by means of azeotropic distillation or washing with a water miscible volatile organic compound.

Claim 13

A method according to claim 1 wherein said support is a silica-containing material and wherein said activating is carried out at a temperatue within the range of 590° to 800° C.

Claim 14

A method according to claim 12 wherein said titanium polymer comprises a dimer produced by combining titanium tetraisopropoxide with water and isopropanol, said titanium polymer is combined with said silica-containing material by impregnating said silica-containing material with a solution of said titanium polymer in isopropanol, said solution being used in an amount sufficient to give 6 to 25 weight percent titanium based on the weight of the final activated composition, said chromium compound is present in an amount sufficient to give chromium in an amount within the range of 0.1 to 5 weight percent based on the weight of said final activated composition, said activating is carried out at a temperature of 600° to 800° C. in air, and wherein prior to said activating the silica-titanium-chromium composition is subjected to a reduction step in an ambient comprising carbon monoxide at a temperature within the range of 700° to 925° C.