Siloxane bischloroformates
AssigneeGeneral Electric Company
InventorsJames Manio Silva, David Michel Dardaris, Gary Charles Davis
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Abstract
Siloxane bischloroformates are prepared in a continuous process by phosgenating siloxane bisphenols in a flow reactor using a substantial excess of phosgene and sodium hydroxide. While very high levels (>95%) of conversion of the siloxane bisphenol to the corresponding siloxane bischloroformate are achieved using a flow reactor according to the method of the invention, only more modest conversion (˜90%) of the siloxane bisphenol to the corresponding siloxane bischloroformate is attained when analogous batch processes are employed. The process holds promise for use in the manufacture of silicone-containing copolycarbonates which requires high purity siloxane bischloroformate intermediates.
Claims15
A continuous method for the preparation of bischloroformates of siloxane bisphenols, said method comprising introducing into a flow reactor at least one siloxane bisphenol, at least one alkali metal hydroxide or alkaline earth metal hydroxide, and phosgene, said phosgene being introduced at a rate such that the ratio of phosgene to siloxane bisphenol OH groups is in a range between about 2.5 and about 6 moles of phosgene per mole of siloxane bisphenol OH group, said alkali metal hydroxide or alkaline earth metal hydroxide being introduced as an aqueous solution, said aqueous solution having a concentration of at least about 5 percent by weight metal hydroxide, said metal hydroxide being introduced at a rate such that the molar ratio of metal hydroxide to phosgene is in a range between about 3.5 and about 6.
A continuous method for the preparation of eugenol siloxane bischloroformate VIII
- wherein p is an integer from 1 to about 100, said method comprising introducing into a flow reactor a solution of eugenol siloxane bisphenol II
- wherein p is an integer between 1 and about 100, said solution comprising methylene chloride, an aqueous solution of sodium hydroxide, and phosgene, said phosgene being introduced at a rate such that the ratio of phosgene to eugenol siloxane bisphenol OH groups is in a range between about 2.5 and about 6 moles of phosgene per mole of eugenol siloxane bisphenol OH group, said aqueous solution of sodium hydroxide having a concentration of at least about 5 percent by weight sodium hydroxide, said aqueous solution of sodium hydroxide being introduced at a rate such that the molar ratio of metal hydroxide to phosgene is in a range between about 3.5 and about 6.
Dependencies are inferred from the claim text.