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Titanium impregnated silica-chromium catalysts
| Details |
Inventors: McDaniel, Max P.;
Assignee: Phillips Petroleum Company (Bartlesville, OK)
Primary Examiner: Levin; Stanford M.
Assistant Examiner:
Attorney, Agent or Firm:
In accordance with one embodiment of this invention, a silica hydrogel is prepared and dried in the presence of a pore preserving agent after which a titanium compound is anhydrously incorporated therewith. In accordance with the second embodiment of this invention, a silica hydrogel or a silica xerogel is impregnated with an aqueous organic acid solution of a substituted or unsubstituted titanium acetylacetonate. The invention allows the use of conventional drying to produce a silica exhibiting characteristics associated with azeotrope dried titanium-silica for use as a support for chromium catalysts. The resulting catalysts are broadly applicable in the polymerization of olefins and are of particular utility in the slurry polymerization of olefins, particularly predominantly ethylene monomer. |
|
DETAILED DESCRIPTION I claim: 1.
A polymerization process compsiring contacting at least one mono-1-olefin having 2 to 8 carbon atoms per molecule with a catalyst produced by: (a) forming a silica hydrogel containing a pore preserving agent selected from (1) organic silicon compounds having the structure R.
sub.
n SiA.
sub.
4-n wherein n is an integer of 2 or 3, and wherein each R is a saturated or unsaturated hydrocarbon group wherein each R can be the same or different and wherein A is selected from the group consisting of hydroxy radicals, halides and alkoxy radicals in which the alkyl group therein contains from 1 to about 10 carbon atoms, (2) water soluble inorganic acids which are sufficiently ionized to produce a pH of 0 to 3.
5, (3) organic acids having an acid strength equal to or greater than that of acetic acid, and (4) anionic, cationic or non-ionic surfactants; (b) drying said hydrogel by means of air oven drying, spray drying, tray drying, vacuum oven drying or drying under a heat lamp to form a xerogel; (c) anhydrously incorporating a titanium compound into said xerogel; (d) wherein chromium is introduced by either coprecipitating same with said silica hydrogel, by combining a water-soluble chromium compound with said hydrogel, or adding anhydrous solution of a chromium compound soluble in non-aqueous solvents to said xerogel; and (e) after said drying of (b) and after said chromium of (d) is introduced, activating the resulting dried, chromium-containing composition by means of an activation procedure which comprises treatment at an elevated temperature in an atmosphere containing oxygen.
2.
A method according to claim 1 wherein said olefin is selected from ethylene, propylene, 1-butene, and 1-hexene.
3.
A method according to claim 2 wherein said olefin is predominantly ethylene.
4.
A method according to claim 3 wherein said polymerization is carried out at a temperature within the range of 66.
degree.
to 110.
degree.
C.
5.
A process according to claim 1 wherein said chromium in the form of a compound soluble in nonaqueous solvents is anhydrously impregnated onto said xerogel
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Molecular Biology 
