Claims
- 1. A catalyst precursor for reaction with a titanium halide to form a catalyst for the production of a stereospecific alpha olefin polymer comprising a silica support treated to reduce surface hydroxyl or silanol group content reacted with a magnesium compound selected from the group consisting of hydrocarbyloxy magnesium, hydrocarbyloxy magnesium halides, and mixtures thereof, further reacted with at least one titanium compound having the structural formula Ti(OR).sub.n X.sub.m where R is aryl, alkyl, alkaryl or mixtures thereof; X is halogen; n is an integer of 1 to 4; and m is 0 or an integer of 1 to 3 with the provision that the sum of n and m is 4, and thereafter reacted with a titanium halide with the proviso that the titanium halide is not the same as said titanium compound having the formula Ti(OR).sub.n X.sub.m.
- 2. The catalyst precursor of claim 1 wherein the magnesium compound is an alkoxy magnesium halide.
- 3. The catalyst precursor of claim 2 wherein the titanium compound is a halogen free titanium alkoxide.
- 4. A catalytic precursor according to claim 3 wherein the silica support is contacted with a silicon halide, boron halide, aluminum halide, alkyl silicon halide or mixtures thereof, prior to interreaction with said titanium compound.
- 5. A catalytic precursor according to claim 1 wherein the silica support is calcined in an inert atmosphere or treated with a monofunctional organic silicon compound to provide said reduced SiOH content.
- 6. A catalytic precursor according to claim 5, wherein said monofunctional organic silicon compound is a hexaalkyl disilazane.
- 7. A catalytic precursor according to claim 1 wherein the silica has a surface area in the range of between about 80 and about 300 m.sup.2 /g, a median particle size of about 20 to 200 microns and a pore volume of between about 0.6 to about 3.0 cc/g.
- 8. A catalytic precursor according to claim 7 wherein the silica is pure silica, silica containing minor amounts of one or more of alumina, titania, zirconia, magnesia or mixtures thereof.
- 9. A catalytic precursor according to claim 3 wherein said titanium ester is tetracresyl titanate, titanium tetrastearate, titanium tetrabutoxide, titanium tetranonolate, tetra-2-ethylhexyltitanate, tetraisobutyltitanate, tetra-n- propyltitanate, tetraisopropyl titanate or mixtures oligomers or isomers thereof.
- 10. A supported catalyst for the polymerization of olefins to stereospecific polymers obtainable by reacting a modified silica support having a selective distribution of reactive hydroxyl groups with a magnesium compound reactive with said surface hydroxyl groups, optionally reacting the thus obtained product with a silicon halide, alkyl silicon halide, boron halide or aluminum halide, further reacting the so-produced first material with a tetra- substituted organo halogen-free titanium compound wherein the organic moiety sterically hinders accessability of said organo titanium compound to the reactive sites on the modified silica support and thereafter reacting the so-produced second material with a titanium halide.
Parent Case Info
This is a continuation of Ser. No. 435,495 filed Jul. 11, 1989, now abandoned, which is a continuation-in-part of Ser. No. 99,190 filed Sept. 21, 1987, now abandoned.
US Referenced Citations (21)
Foreign Referenced Citations (5)
Number |
Date |
Country |
0206172 |
Dec 1986 |
EPX |
0244678 |
Nov 1987 |
EPX |
58-162607 |
Sep 1983 |
JPX |
62-124105 |
Jun 1987 |
JPX |
2184448 |
Jun 1987 |
GBX |
Non-Patent Literature Citations (2)
Entry |
Ser. No. 498,308 Buehler (pending) Mar. 23, 1990. |
Ser. No. 569,688 Buehler et al. (pending) Aug. 20, 1990. |
Continuations (1)
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Number |
Date |
Country |
Parent |
435495 |
Jul 1989 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
99190 |
Sep 1987 |
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