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US 7,678,871 B2Granted
Preparation of cyclic oligosiloxane
AssigneeShin-Etsu Chemical Co., Ltd.
InventorKouichi Shinbo
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Abstract
Cyclic oligosiloxane is prepared through disproportionation reaction of organopolysiloxane in the presence of a catalyst. Cyclic oligosiloxane of high purity can be produced in high yields by using a catalyst having formula (4): wherein M is Al, Ti, Zr, Sn or Zn, p is the valence of M, and R4 is a monovalent hydrocarbon group or the like.
Claims7
A method for preparing a cyclic oligosiloxane, comprising reacting an organopolysiloxane having formula (1):
- wherein each R1 is independently a substituted or unsubstituted monovalent hydrocarbon group, each R2 is independently a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 20 to 10,000, in the presence of a catalyst, the cyclic oligosiloxane prepared having formula (3):
- wherein each R2 is independently a substituted or unsubstituted monovalent hydrocarbon group, and k is an integer of 3 to 8, wherein
- said catalyst has the formula (4):
- wherein each R4 is independently a substituted or unsubstituted monovalent hydrocarbon group or a group of the formula (5):
- wherein each R5 is independently a substituted or unsubstituted monovalent hydrocarbon group and h is an integer of 0 to 100,
- whereby the cyclic oligosilxane is produced without forming impurities having a silicon-alkoxide bond.
3 more elements
Dependencies are inferred from the claim text.