Process for preparing cyclic polysiloxanes from linear polysilox

Details Process for preparing cyclic polysiloxanes from linear polysilox Process for preparing cyclic polysiloxanes from linear polysilox

1995-04-20

1996-02-13

Shaver, Paul F.

Organic compounds -- part of the class 532-570 series

Organic compounds

Silicon containing

556461, C07F 708

Patent

active

054912490

ABSTRACT:
Cyclic polysiloxanes are produced by continuously passing a feed comprising linear polysiloxanes through a reactor containing a solid acidic catalyst at a pressure greater than one atmosphere under an inert atmosphere to produce a mixture comprising volatile cyclic polysiloxanes, nonvolatile reaction products, and unreacted linear polysiloxanes. The volatile products can then be recovered, and the nonvolatile reaction products and unreacted linear polysiloxanes can be added to the linear polysiloxane feed to form a recycle stream that is passed back through the reactor. Recycling increases the yield of the desired cyclic species.

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J. V. Crivello, et al., "Synthesis of Cyclic Siloxanes by the Thermal Depolymerization of Linear Poly(siloxanes)", Chemistry of Materials, 1989, vol. 1, pp. 445-451.

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