Benzoin-bonded organopolysiloxanes and method for the preparation thereof

Claim 1

A benzoin-bonded organopolysiloxane represented by the general formula (Q).sub.a (R.sup.1).sub.3-a Si--O--Si(Q)(R.sup.2)--O].sub.m [Si(R.sup.2).sub.2 O].sub.n Si(Q).sub.a (R.sup.1).sub.3-a, Where Q is a benzoin group represented by the general formula ##STR27## Ph is a phenyl group, R is a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, R 1 is a monovalent hydrocarbon group having from 1 to 6 carbon atoms, R 2 is a substituted or unsubstituted monovalent hydrocarbon group, a is a number of 0, 1 or 2, m is 0 or a positive integer with the proviso that a and m are not simultaneously equal to zero, and n is zero or a positive integer.

Claim 10

A method for the preparation of a benzoin-bonded organopolysiloxane represented by the general formula (Q).sub.a (R.sup.1).sub.3-a Si--O--Si(Q)(R.sup.2)--O].sub.m [Si(R.sup.2).sub.2 --O].sub.n Si(Q).sub.a (R.sup.1)3-a where Q is a benzoin group represented by the general formula ##STR30## Ph is a phenyl group, R is a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, R 1 is a monovalent hydrocarbon group having from 1 to 6 carbon atoms, R 2 is a substituted or unsubstituted monovalent hydrocarbon group, a is a number of 0, 1 or 2, m is 0 or a positive integer with the proviso that a and m are not simultaneously equal to zero, and n is zero or a positive integer, which comprises reacting an organopolysiloxane having at least one functional group represented by the general formula (X).sub.a (R.sup.1).sub.3-a Si--O--Si(X)(R.sup.1)--O].sub.m [Si(R.sup.2).sub.2 --O].sub.n Si(X).sub.a (R.sup.1)3-a where X is a functional group selected from the class consisting of halogen atoms, a hydrogen atom, a hydroxy group and alkoxy groups, and R 1 , R 2 , a, m and n each have the same meaning as defined above, with a benzoin compound represented by the general formula ##STR31## where Ph and R each have the same meaning as defined above.

Claim 11

A method for the preparation of a benzoin-bonded organopolysiloxane represented by the general formula (Q).sub.a (R.sup.1).sub.3-a Si--O--Si(Q)(R.sup.2)--O].sub.m [Si(R.sup.2).sub.2 --O].sub.n Si(Q).sub.a (R.sup.1)3-a where Q is a benzoin group represented by the general formula ##STR30## Ph is a phenyl group, R is a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, R 1 is a monovalent hydrocarbon group having from 1 to 6 carbon atoms, R 2 is a substituted or unsubstituted monovalent hydrocarbon group, a is a number of 0, 1 or 2, m is 0 or a positive integer with the proviso that a and m are not simultaneously equal to zero, and n is zero or a positive integer, which comprises reacting an organopolysiloxane having at least one functional group represented by the general formula (X).sub.a (R.sup.1).sub.3-a Si--O--Si(X)(R.sup.1)--O].sub.m [Si(R.sup.2).sub.2 --O].sub.n Si(X).sub.a (R.sup.1)3-a where X is a functional group selected from the class consisting of halogen atoms, a hydrogen atom, a hydroxy group and alkoxy groups, and R 1 , R 2 , a, m and n each have the same meaning as defined above, with a benzoin compound represented by the general formula ##STR31## where Ph and R each have the same meaning as defined above.