Claims
- 1. A catalyst for the preparation of high molecular weight polysiloxanes by polymerization/rearrangement of polysiloxanes of lower molecular weight, comprising
- a porous, inorganic mineral particulate support having an average pore diameter in excess of 20 .ANG. and a pore volume ranging from 0.2 to 2 ml/g, said porous support being grafted with less than 15 mg/m.sup.2 of a film of polymeric material comprising pendant sulfonic or phosphonic acid functions, and said polymeric material being characterized by an ion exchange capacity of less than 2 milliequivalents per gram.
- 2. The catalyst as defined by claim 1, said particulate support having a particle size ranging from 4 mm to 5 mm, an average pore diameter ranging from 20 to 3,000 .ANG., and a pore volume ranging from 0.2 to 1.5 ml/g.
- 3. The catalyst as defined by claim 2, said particulate support having a specific surface area ranging from 5 to 500 m.sup.2 /g.
- 4. The catalyst as defined by claim 3, said particulate support having an average pore diameter ranging from 20 to 2,500 .ANG., a specific surface area ranging from 50 to 150 m.sup.2 /g, and a pore volume ranging from 0.2 to 1 ml/g.
- 5. The catalyst as defined by claim 2, said polymeric material being characterized by an ion exchange capacity of less than 1 milliequivalent of H.sup.+ per gram.
- 6. The catalyst as defined by claim 1, said porous, inorganic mineral particulate support comprising a metal oxide.
- 7. The catalyst as defined by claim 1, said porous, inorganic mineral particulate support comprising a titanium oxide.
- 8. The catalyst as defined by claim 1, said porous, inorganic mineral particulate support comprising an alumina.
- 9. The catalyst as defined by claim 1, said porous, inorganic mineral particulate support comprising a silica.
- 10. The catalyst as defined by claim 1, said porous, inorganic mineral particulate support comprising an agglomerated silica.
- 11. The catalyst as defined by claim 1, said polymeric material being crosslinked.
- 12. The catalyst as defined by claim 11, said polymeric material being a synthetic polymer, copolymer or polycondensate.
- 13. The catalyst as defined by claim 12, said porous support being coated with from 0.3 to 8 mg/m.sup.2 of said film of polymeric material.
- 14. The catalyst as defined by claim 1, said polymeric material comprising pendant sulfonic acid functions.
Priority Claims (1)
Number |
Date |
Country |
Kind |
81 09571 |
May 1981 |
FRX |
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Parent Case Info
This application is a division of application Ser. No. 377,589, filed May 12, 1982, and now U.S. Pat. No. 4,426,508.
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
312855 |
Aug 1971 |
SUX |
Divisions (1)
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Number |
Date |
Country |
Parent |
377589 |
May 1982 |
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