Preparation of organopolysiloxanes

Claim 2

A process for preparing an organopolysiloxane, which comprises polymerizing an organosilicon compound having the general formula HO--(SiR.sub.2 O).sub.m --H in which R is selected from the class consisting of an unsubstituted monovalent hydrocarbon radical and a substituted monovalent hydrocarbon radical and m represents a positive integer up to 1000, in the presence of a phosphoronitrile chloride and a hydroxyaryl compound in which one or two hydroxy groups are bonded to an aryl radical.

Claim 3

The process of claim 1, wherein an organosilicon compound is also present having the general formula R.sub.3 Si--(OSiR.sub.2).sub.m --R in which R is selected from the class consisting of an unsubstituted monovalent hydrocarbon radical and a substituted monovalent hydrocarbon radical and m represents a positive integer up to 1000.

Claim 4

The process of claim 1 wherein at least 50 mole percent of the radicals represented by R in the organosilicon compound are methyl radicals and any remaining radicals represented by R are vinyl or phenyl radicals.

Claim 5

The process of claim 1 wherein the phosphoronitrile chloride was obtained from the reaction of phosphorus pentachloride and ammonium chloride in a molar ratio of about 2:1.

Claim 6

The process of claim 1, wherein the phosphoronitrile chloride is represented by the formula Cl.sub.3 PNPCl.sub.2 NPCl.sub.3 . PCl.sub.6

Claim 7

The process of claim 1, wherein the phosphoronitrile chloride is present in an amount of from 0.00l to 0.1 percent by weight, based on the weight of the organosilicon compound.

Claim 8

The process of claim 1 wherein the phosphoronitrile chloride is dissolved in an inert solvent.

Claim 9

The process of claim 1 wherein the hydroxyaryl compound is selected from the class consisting of (a) a phenol of the general formula ##STR5## in which q represents 1 or 2, n represents 0 or an integer of up to 5, with the provision that n cannot be 5 when q is 2, and R 1 represents a radical selected from the group consisting of a methyl radical, a methoxy radical, a tert-butyl radical, a tert-butoxy radical, a 1,1,3,3-tetramethylbutyl radical, a 1,1,3,3-tetramethylbutoxy radical and a radical of the general formula ##STR6## in which p represents 0 or 1, n is the same as above, R 2 represents a radical selected from the group consisting of an oxygen atom, a methylene radical, an isopropylene radical and a sulfonyl radical, and R 3 represents a radical selected from the class consisting of a methyl radical, a methoxy radical, a tert-butyl radical, a tert-butoxy radical, a 1,1,3,3-tetramethylbutyl radical, and a 1,1,3,3-tetramethylbutoxy radical; b. a naphthol of the general formula ##STR7## in which q represents 1 or 2, r represents 0 or an integer up to 7, with the provision that r cannot be 7 when q is 2, and R 1 is the same as above; and c. a bis-phenol of the general formula ##STR8## in which s is 0 or an integer up to 4, and R 1 and R 2 are the same as above.

Claim 10

The process of claim 1 wherein the hydroxyaryl compound is selected from the class consisting of a phenol, 4-tertbutylphenol, 4-phenyl-phenol, 3-tert-butyl-4-hydroxyanisole, 4-hydroxyanisole, 2-tert-butylphenol, 2,4-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, 2,6-di-tert-butyl-4-methylphenol, catechol, hydroquinone, resorcinol, toluhydroquinone, trimethylhydroquinone, 2,6-di-tert-butylhydroquinone, alpha-naphthol, beta-naphthol, 1,4-naphthohydroquinone, 2,2-bis-(4-hydroxyphenyl)-propane, bis-(4-hydroxyphenyl)-sulphone, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol) or 4,4'-methylene-bis-(2,6-di-tert-butylphenol).

Claim 11

The process of claim 1 wherein the hydroxyaryl compound is present in an amount of from 0.001 to 10 mole percent based on the organosilicon compound or siloxane units therein.

Claim 12

The process of claim 1 wherein the hydroxyaryl compound is dissolved in an inert polar solvent.

Claim 13

The process of claim 1 wherein it is carried out at a temperature of from 0 to 200° C.

Claim 14

The process of claim 1 wherein the resultant organopolysiloxane has a viscosity of from 10 3 to 5 × 10 7 cP at 25° C.

Claim 15

The process of claim 1 wherein an amine is added to terminate the polymerization.

Claim 16

The process of claim 14 where the amine is a tertiary amine, and said amine is present in an amount of from 1 to 1.5 moles per mole of the phosphoronitrile chloride.

Claim 17

The process of claim 14 wherein the amine is ammonia or a compound of the formula YHNC(CH.sub.3).sub.e (CH.sub.2 X).sub.3-e in which each X is selected from the class consisting of a radical of the formula --OCH 3' --N(CH 3 ) 2' --C(CH 3 ) 3' --C(CH 3 ) 2 NHY and --OC(CH 3 ) 3 and a hydrogen atom, each Y denotes a hydrogen atom or a trimethylsilyl radical, e represents 0, 1, 2 or 3, said amine is present in an amount of from 1 to 5 moles per mole of phosphoronitrile chloride based on PNCl 2 .