SELECTIVE HYDROSILYLATION CONDITIONS
A method to form an asymmetric silicone copolymer, comprises effecting a monoselective hydrosilylation reaction between a dihydridosiloxane and a first aliphatically unsaturated compound in the presence of a precious metal hydrosilylation catalyst to form a reaction product comprising substantial monohydridosiloxane; and hydrosilylating the monohydridosiloxane with another different aliphatic unsaturated compound to form an asymmetric silicone copolymer.
1 . A method to make an asymmetric organosiloxane comprising in a first step, reacting a dihydridosiloxane under a selective hydrosilylation condition, with an hydrocarbon or heterocarbon compound containing a terminal carbon to carbon double bond to form a monohydridosiloxane, and in a second step, hydrosilylating the monohydridosiloxane with a second and different hydrocarbon or heterocarbon compound containing a terminal carbon to carbon double bond and in the presence of the same or different hydrosilylation catalyst under hydrosilylation conditions to form an asymmetrically substituted organosiloxane, wherein the asymmetric organosiloxane product contains at least one polyalkylene oxide group.
2 .- 41 . (canceled)
42 . A method to make an asymmetric siloxane, comprising in a first step, reacting a silicone having the formula M H D x M′ H where M H is R 1 R 2 HSiO 1/2 , M′ H is R 4 R 5 HSiO 1/2 and x is an integer 0≦x≦10 under selective hydrosilylation conditions [in the presence of a rhodium catalyst,] with an olefinic compound containing one or more terminal carbon to carbon double bonds to form a monohydridosiloxane; nowhere each of R 1 , R 2 , R 4 and R 5 is independently the same or different and each is a hydrocarbon radical, an alkoxy radical or alkenyloxy radical; and in a second step, hydrosilylating the monohydridosiloxane with a polyalkylene oxide of 2 to 10 carbon atoms and different from the first olefinic compound and having one or more alkylene oxide groups containing one or more terminal carbon to carbon double bonds to form an asymmetric siloxane.
43 .- 81 . (canceled)
82 . The method of claim 1 , wherein reacting the dihydridosiloxane comprises selectively hydrosilylating the dihydridosiloxane at a single hydride position to produce a substantial monohydridosiloxane product.
83 . The method of claim 1 , wherein the selective hydrosilylation condition comprises a combination of a reactant molar ratio and catalyst that results in selective hydrosilylation substantially at a single hydride position of the dihydridosiloxane.
84 . The method of claim 1 , wherein the selective hydrosilylation condition comprises a molar ratio of the dihydridosiloxane to hydrocarbon or heterocarbon compound containing the terminal carbon to carbon double bond and a catalyst that result in selective hydrosilylation substantially at a single hydride position of the dihydridosiloxane.
85 . The method of claim 1 , wherein the selective hydrosilylation condition comprises a molar ratio of the dihydridosiloxane to hydrocarbon or heterocarbon compound containing the terminal carbon to carbon double bond and the presence of a precious metal catalyst comprising a complex of rhodium, ruthenium, palladium, osmium, iridium or platinum.
86 . The method of claim 1 , wherein the selective hydrosilylation condition comprises the presence of a precious metal catalyst.
87 . The method of claim 1 , wherein the selective hydrosilylation condition comprises the presence of a precious metal catalyst comprising tris(dibutylsulfide) rhodium chloride.
88 . The method of claim 1 , wherein the selective hydrosilylation condition comprises the presence of a tris(triphenylphosphine) rhodium chloride catalyst.
89 . The method of claim 1 , wherein the selective hydrosilylation condition comprises a platinum catalyst selected from the formula (PtCl 2 Olefin) and the formula H(PtCl 3 Olefin).
90 . The method of claim 1 , wherein the selective hydrosilylation condition comprises a catalyst that is a complex of chloroplatinic acid with up to 2 moles per gram of platinum of a member selected from the class consisting of alcohols, ethers, aldehydes and mixtures.
91 . The method of claim 1 , wherein the selective hydrosilylation condition comprises the presence of a complex of Rh(III) or Rh(I).
92 . The method of claim 1 , wherein the selective hydrosilylation condition comprises the presence of a trichlorotris (dibutyl sulfide) rhodium (III) catalyst.
93 . The method of claim 44 , wherein the selective hydrosilylation condition comprises the presence of a platinum Karstedt's complex.
94 . The method of claim 1 , comprising employing from 1000 ppm to 0.5 ppm of a catalyst for either step range.
95 . The method of claim 1 , comprising employing from 10 ppm to 3 ppm of a catalyst for either step range.
96 . The method of claim 1 , wherein a molar ratio of the dihydridosiloxane compound to the compound containing a terminal carbon to carbon double bond in the first step hydrosilylation is 4:1 to 1.1:1.
97 . The method of claim 1 , wherein a molar ratio of the dihydridosiloxane compound to the compound containing a terminal carbon to carbon double bond in the first step hydrosilylation 1.3:1 to 1:1.
98 . The method of claim 1 , wherein a molar ratio of the dihydridosiloxane compound to the compound containing a terminal carbon to carbon double bond in the first step hydrosilylation is about 1:1.
99 . The method of claim 1 , wherein the first step reaction or the second step hydrosilylation is conducted at a temperature in a range of 0 to 120° C.
100 . The method of claim 1 , wherein the first step reaction is conducted at a temperature in a range of 20 to 80° C. and the second step hydrosilylation is conducted at a temperature of 80 to 100° C.
101 . The asymmetric organosiloxane product of the method of claim 1.