Selective hydrosilylation method and product
View Patent ↗An asymmetric siloxane is made by 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 precious metal hydrosilylation catalyst, with a first olefinic compound and in a second step, a monohydridosiloxane produced in the first step is reacted under hydrosilylating conditions with another olefinic compound different from the first olefinic compound.
1. A method to make an asymmetrically substituted organosiloxane containing at least one polyalkylene oxide group comprising:
(a) in a first step, reacting a dihydridosiloxane having the chemical Formula (1),
M H D x M′H (1)
in the presence of a tris(dibutylsulfide)rhodium trichloride hydrosilylation catalyst under selective hydrosilylation conditions with an unsaturated hydrocarbon comprising a vinyl silane to form a monohydridosiloxane wherein: each occurrence of M H is independently selected from the species R 1 R 2 HSiO 1/2 ; each occurrence of M′ H is independently selected from the species R 4 R 5 HSiO 1/2 ; each occurrence of D is independently selected from the species (R) 2 SiO; each occurrence of the subscript x is independently an integer from about 0 to about 10; each occurrence of R, R 1 , R 2 , R 4 and R 5 is independently selected from the group consisting of a hydrocarbon of from 1 to about 50 carbon atoms and a heterocarbon of from about 1 to 100 carbon atoms containing at least one oxygen or at least one silicon atom that has replaced a carbon atom; and
(b) in a second step, hydrosilylating the monohydridosiloxane with a different unsaturated hydrocarbon containing from about 2 to about 100 carbon atoms and one or more terminal carbon to carbon double bonds or with a different unsaturated heterocarbon containing from about 3 to about 100 carbon atoms, one or more terminal carbon to carbon double bonds and at least one oxygen or at least one silicon atom that has replaced a carbon atom in the presence of the same or different precious metal hydrosilylation catalyst to form an asymmetric siloxane and with the proviso that at least one heterocarbon containing one or more terminal carbon to carbon double bond is a polyalkylene oxide compound with one or more terminal carbon to carbon double bonds.
2. The method of claim 1 , wherein at least one of R 1 , R 2 , R 4 and R 5 is independently a same or different C 1 to C 12 alkyl radical selected from the group consisting of methyl, ethyl, propyl, butyl, isopentyl, n-hexyl and decyl.
3. The method of claim 1 , wherein the polyalkylene oxide is a polyether defined by the general formula:
CH 2 ═CH(R 13 )(R 12 ) d O(C 2 H 4 O) a (C 3 H 6 O) b (C 4 H 8 O) c R 16
where R 13 is H or methyl; R 12 is a divalent alkyl radical of 1 to 6 carbons where the subscript d may be 0 or 1; and R 16 is H, a monofunctional hydrocarbon radical of 1 to 6 carbons, or acetyl and where the subscripts a, b and c are zero or positive and satisfy the following relationships; 2 is less than or equal to a+b+c, which total less than or equal to 20 with a greater than or equal to 2.
4. The method of claim 1 , wherein the polyalkylene oxide is a polyether comprising a random or blocked configuration selected from the group consisting of -(oxyethylene) a (oxypropylene) b -, -(oxybutylene) c (oxyethylene) a - and -(oxypropylene) b (oxyethylene) a (oxybutylene) c -.
5. The method of claim 1 , wherein the polyalkylene oxide is a polyether comprising a member selected from the group consisting of CH 2 ═CHCH 2 O(CH 2 CH 2 O) 8 H; CH 2 ═CHCH 2 O(CH 2 CH 2 O) 8 CH 3 ; CH 2 ═CHCH 2 O(CH 2 CH 2 O) 4 CH 2 CH(CH 3 )O 5 H; CH 2 ═CHO(CH 2 CH 2 O) 5 (CH 2 CH(CH 3 )O) 5 H; CH 2 ═C(CH 3 )CH 2 O(CH 2 CH 2 O) 4 (CH 2 CH(CH 3 )O) 5 C(═O)CH 3 ; and CH 2 ═CHCH 2 O(CH 2 CH 2 O) 5 (CH 2 CH(CH 3 )O) 2 (CH 2 CH(CH 2 CH 3 )O) 2 H.
6. The method of claim 1 , wherein x=0 (M H M′ H ).
7. A method to make an asymmetric organosiloxane comprising in a first step, reacting a molar excess up to less than 4:1 of a dihydridosiloxane under hydrosilylation conditions in the presence of a rhodium hydrosilylation catalyst, with a vinyl silane 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.
8. The method of claim 7 , wherein the alkylene oxide is a methyl capped allylpolyethyleneglycol.
9. The method of claim 7 , wherein the alkylene oxide comprises a polyether defined by the general formula:
CH 2 =CH(R 13 )(R 12 ) d O(C 2 H 4 O) a (C 3 H 6 O) b (C 4 H 8 O) c R 16
where R 13 is H or methyl; R 12 is a divalent alkyl radical of 1 to 6 carbons where the subscript d may be 0 or 1; and R 16 is H, a monofunctional hydrocarbon radical of 1 to 6 carbons, or acetyl and where the subscripts a, b and c are zero or positive and satisfy the following relationships: 2 is less than or equal to a+b+c, which total less than or equal to 20 with a greater than or equal to 2.
10. The method of claim 7 , wherein the alkylene oxide comprises a polyether comprising a random or blocked configuration selected from the group consisting of -(oxyethylene) 1 (oxypropylene) b -, -(oxybutylene) c (oxyethylene) a - and -(oxypropylene) b (oxyethylene) a (oxybutylene) c -.
11. The method of claim 7 , wherein the alkylene oxide comprises a polyether comprising a member selected from the group consisting of CH 2 ═CHCH 2 O(CH 2 CH 2 O) 8 H; CH 2 ═CHCH 2 O(CH 2 CH 2 O) 8 CH 3 ; CH 2 ═CHCH 2 O(CH 2 CH 2 O) 4 (CH 2 CH(CH 3 )O) 5 H; CH 2 ═CHO(CH 2 CH 2 O) 5 (CH 2 CH(CH 3 )O) 5 H; CH 2 ═C(CH 3 )CH 2 O(CH 2 CH 2 O) 4 (CH 2 CH(CH 3 )O) 5 C(═O)CH 3 ; and CH 2 ═CHCH 2 O(CH 2 CH 2 O) 5 (CH 2 CH(CH 3 )O) 2 (CH 2 CH(CH 2 CH 3 )O) 2 H.
12. The method of claim 7 , comprising reacting the dihydridosiloxane with a vinylsilane selected from the group consisting of trimethylvinylsilane, triethylvinylsilane, dimethyl-tert-butoxyvinylsilane, dimethylisopropoxyvinylsilane, tris-(trimethylsiloxy)vinylsilane, methyl-bis-(tert-butoxy)vinylsilane and tris-(tert-butoxy)vinylsilane.
13. The method of claim 7 , wherein the rhodium catalyst is a complex of Rh(III) or Rh(I).
14. The method of claim 7 , wherein the rhodium catalyst is trichlorotris(dibutyl sulfide)rhodium (III).
15. The method of claim 7 , wherein the rhodium catalyst is tris(triphenylphosphine)rhodium chloride.
16. The method of claim 7 , comprising isolating the monohydridosiloxane reaction product of the first step.
17. The method of claim 7 , comprising reacting a molar excess of dihydridosiloxane to hydrocarbon or heterocarbon compound containing a terminal carbon to carbon double bond vinyl silane of 1.3:1 to greater than 1:1.
18. The method of claim 7 , comprising isolating the monohydridosiloxane of the first step and then conducting the second step on the isolated monohydridosiloxane.