Patent GB-897973-A (GB)
Title: Peroxy-organosiloxanes
IPC: C08L83/04
Filed: 1960-03-18
Abstract: The invention comprises organopolysiloxanes having at least one siloxane unit per molecule of the general formula <FORM:0897973/IV (a)/1> or of the general formula <FORM:0897973/IV (a)/2> in which Y is H, an aliphatic hydrocarbon or halohydrocarbon radical, a cycloaliphatic hydrocarbon or halohydrocarbon radical, an aralkyl or haloaralkyl radical or an acyl radical of the formula R11C = O in which R11 is a hydrocarbon or halohydrocarbon radical, m is 1 or 2, Me is a methyl radical, C is a tertiary carbon atom, R is a hydrocarbon radical of 1 to 11 C atoms, R1 is a monovalent hydrocarbon or halohydrocarbon radical of less than 7 C atoms and n is 0, 1 or 2, any remaining siloxane units in the siloxane being of the general formula ZaSiO 4-a/2, in which Z is a monovalent hydrocarbon or halohydrocarbon radical, a is 1, 2 or 3 and has an average value of at least 1 in the polymer.  The peroxides can be made by reacting (a) the corresponding siloxane alcohols with H2SO4 to form the sulphate and then reacting the sulphate either with hydroperoxides (where Y is a saturated hydrocarbon or halohydrocarbon) or with H2O2 (where Y is H), or (b) the corresponding organosilicon hydroperoxides with an acyl chloride (where Y is an acyl group) in the presence of a hydrogen halide acceptor, e.g. pyridine; or (c) the K salts of the siloxane hydroperoxide with a halogenated olefin (where Y is an unsaturated hydrocarbon or halohydrocarbon).  Another general method involves the selective oxidation of siloxanes of the formula <FORM:0897973/IV (a)/3> by passing oxygen through the siloxane at 80 DEG  to 105 DEG C.  In Example (1) <FORM:0897973/IV (a)/4> was reacted with <FORM:0897973/IV (a)/5> in the presence of chloroplatinic acid to give the corresponding siloxane alcohol which was reacted with H2SO4, to give the sulphate and then with t-butylhydroperoxide to give a liquid peroxy siloxane of the formula <FORM:0897973/IV (a)/6> In other examples similar reactions gave (2) a mixture or <FORM:0897973/IV (a)/7> and <FORM:0897973/IV (a)/8> (3) first the siloxane alcohol <FORM:0897973/IV (a)/9> and then the peroxide <FORM:0897973/IV (a)/100> (4) first the alcohol <FORM:0897973/IV (a)/111> and then the peroxide <FORM:0897973/IV (a)/122> (6) <FORM:0897973/IV (a)/133> (7) <FORM:0897973/IV (a)/144> <FORM:0897973/IV (a)/155> <FORM:0897973/IV (a)/166> <FORM:0897973/IV (a)/178> and a copolymer of <FORM:0897973/IV (a)/189> diethylsiloxane, monopropylsiloxane, cyclohexylsiloxane and a ,a ,a -trifluorotolylmethylsiloxane units; and (9) <FORM:0897973/IV (a)/190> (5) Oxygen was passed over the surface of a heated (85 DEG C.) aqueous emulsion of <FORM:0897973/IV (a)/201> to give <FORM:0897973/IV (a)/212> (8) the method (c) above yielded <FORM:0897973/IV (a)/223> (10) the hydroperoxide <FORM:0897973/IV (a)/234> was reacted with different acyl halides to yield:- <FORM:0897973/IV (a)/245> and <FORM:0897973/IV (a)/256> (11, 12, 13) The peroxy-siloxanes of Examples 1, 2 and 4 were each milled with a vinyldimethylsilyl-terminated dimethylsiloxane gum and trimethylsiloxy surface-modified silica xerogel and heat cured.  (14) A dimethylpolysiloxane gum, a liquid dimethylpolysiloxane, a 3,3,3-trifluoropropylmethylpolysiloxane gum and an ethylmethylpolysiloxane gum were each milled with fume silica and cured with the peroxysiloxanes of Example 1.  (15) A dimethylpolysiloxane was vulcanized with each of the peroxysiloxanes of Examples 5 to 10.  Uses: As catalysts for polymerizing olefins, vulcanizing silicone rubbers, curing silicone resins, and as intermediates in making organo-functional organosilicon compounds.