PROCESS FOR PREPARING SILOXANES FROM HYDRIDOSILICON COMPOUNDS

Abstract

A process for preparing siloxanes wherein (a) at least one hydridosilicon compound selected from (a1) compounds of general formula (I), and/or from (a2) compounds of general formula (I), and (b) at least one carbonyl compound selected from (b1) compounds of the general formula (II), and/or (b2) compounds of general formula (II), and (c) at least one cationic compound of general formula (III) are brought into contact and reacted with one another.

Claims

1-10. (canceled)

11. A process for preparing siloxanes, wherein (a) at least one hydridosilicon compound selected from (a1) compounds of general formula (I)
R.sup.1R.sup.2R.sup.3SiH(I), in which the radicals R.sup.1, R.sup.2 and R.sup.3 are each independently selected from the group consisting of (i) hydrogen, (ii) halogen, (iii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbon radical, and (iv) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbonoxy radical, wherein two of the radicals R.sup.1, R.sup.2 and R.sup.3 may also form with each other a monocyclic or polycyclic, unsubstituted or substituted C.sub.2-C.sub.20-hydrocarbon radical, wherein substituted means in each case that the hydrocarbon or hydrocarbonoxy radical each independently has at least one of the following substitutions: a hydrogen atom may be replaced by halogen, CH(O), OR.sup.z, SR.sup.z, NR.sup.z.sub.2, and PR.sup.z.sub.2, a CH.sub.2 group may be replaced by O, S or NR, a CH.sub.2 group not directly bonded to Si may be replaced by a C(O) moiety, a CH.sub.3 group may be replaced by a CH(O) moiety, and a carbon atom may be replaced by a Si atom, wherein R is each independently selected from the group consisting of C.sub.1-C.sub.6-alkyl radical and C.sub.6-C.sub.14-aryl radical; and/or (a2) compounds of general formula (I)
(SiO.sub.4/2).sub.a(R.sup.xSiO.sub.3/2).sub.b(HSiO.sub.3/2).sub.b(R.sup.x.sub.2SiO.sub.2/2).sub.c(R.sup.xHSiO.sub.2/2).sub.c(H.sub.2SiO.sub.2/2).sub.c(R.sup.x.sub.3SiO.sub.1/2).sub.d(HR.sup.x.sub.2SiO.sub.1/2).sub.d(H.sub.2R.sup.xSiO.sub.1/2).sub.d(H.sub.3SiO.sub.1/2).sub.d(I), in which the radicals R.sup.x are each independently selected from the group consisting of (i) halogen, (ii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbon radical, and (iii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbonoxy radical, wherein substituted means in each case that the hydrocarbon or hydrocarbonoxy radical each independently has at least one of the following substitutions: a hydrogen atom may be replaced by halogen or CH(O), a CH.sub.2 group may be replaced by O or NR.sup.z, where W is in each case independently selected from the group consisting of C.sub.1-C.sub.6-alkyl radical and C.sub.6-C.sub.14-aryl radical, a CH.sub.2 group not directly bonded to Si may be replaced by a C(O) moiety, and a CH.sub.3 group may be replaced by a CH(O) moiety; and wherein the indices a, b, b, c, c, c, d, d, d, d indicate the number of the respective siloxane unit in the compound and is each independently an integer in the range of 0 to 100 000, with the proviso that the sum of a, b, b, c, c, c, d, d, d, d together has at least the value 2 and at least one of the indices b, c, c, d, d or d is not equal to 0; and (b) at least one carbonyl compound selected from (b1) compounds of general formula (II)
R.sup.yC(O)R.sup.z(II), wherein R.sup.y is selected from the group consisting of (i) hydrogen, (ii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbon radical, and (iii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbonoxy radical; and where R.sup.z is selected from the group consisting of (i) hydrogen and (ii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbon radical; and/or (b2) compounds of general formula (II)
(SiO.sub.4/2).sub.a(R.sup.xSiO.sub.3/2).sub.b(R.sup.aSiO.sub.3/2).sub.b(R.sup.aSiO.sub.3/2).sub.b(R.sup.x.sub.2SiO.sub.2/2).sub.c(R.sup.xR.sup.aSiO.sub.2/2).sub.c(R.sup.a.sub.2SiO.sub.2/2).sub.c(R.sup.x.sub.3SiO.sub.1/2).sub.d(R.sup.aR.sup.x.sub.2Si O.sub.1/2).sub.d(R.sup.a.sub.2R.sup.xSiO.sub.1/2).sub.d(R.sup.a.sub.3SiO.sub.1/2).sub.d(II), where the radicals R.sup.a are each independently a substituted C.sub.2-C.sub.20-hydrocarbon radical, wherein substituted means that the hydrocarbon radical each independently has at least one of the following substitutions: a CH.sub.2 group not directly bonded to Si may be replaced by a C(O) or OC(O) moiety, a hydrogen atom may be replaced by a CH(O) moiety, and a CH.sub.3 group may be replaced by a CH(O) moiety, the hydrocarbon radical may optionally have the following further substitutions: a hydrogen atom may be replaced by halogen, a CH.sub.2 group may be replaced by O or NR.sup.z, where R.sup.z is in each case independently selected from the group consisting of C.sub.1-C.sub.6-alkyl radical and C.sub.6-C.sub.14-aryl radical; and wherein the radicals R.sup.x are each independently selected from the group consisting of (i) halogen, (ii) hydrogen, (iii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbon radical, and (iv) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbonoxy radical, where substituted means in each case that the hydrocarbon or hydrocarbonoxy radical each independently has at least one of the following substitutions: a hydrogen atom can be replaced by halogen, a CH.sub.2 group may be replaced by O or NR.sup.z, where R.sup.z is in each case independently selected from the group consisting of C.sub.1-C.sub.6-alkyl radical and C.sub.6-C.sub.14-aryl radical; and wherein the indices a, b, b, c, c, c, d, d, d, d indicate the number of the respective siloxane unit in the compound and is each independently an integer in the range of 0 to 100 000, with the proviso that the sum of a, b, b, c, c, c, d, d, d, d together has at least the value 2 and at least one of the indices b, c, c, d, d or d is not equal to 0; and (c) at least one cationic compound of general formula (III)
([M(II)Cp].sup.+).sub.aX.sup.a(III), where M is selected from the group consisting of silicon, and germanium, and Cp is a -bonded cyclopentadienyl radical of general formula (IIIa) ##STR00002## where the radicals R.sup.y are each independently selected from the group consisting of (i) triorganosilyl radical of formula SiR.sup.b.sub.3, where the radicals R b are each independently C.sub.1-C.sub.20-hydrocarbon radical, (ii) hydrogen, (iii) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbon radical, and (iv) unsubstituted or substituted C.sub.1-C.sub.20-hydrocarbonoxy radical, wherein two radicals R.sup.y may also in each case form with each other a monocyclic or polycyclic C.sub.2-C.sub.20-hydrocarbon radical, and where substituted means in each case that in the hydrocarbon or hydrocarbonoxy radical at least one carbon atom may also be replaced by one Si atom, X.sup.a is an a valent anion and a can take the values 1, 2 or 3; are brought into contact and reacted.

12. The process as claimed in claim 11, wherein in formula (I) the radicals R.sup.1, R.sup.2 and R.sup.3 are each independently selected from the group consisting of (i) hydrogen, (ii) chlorine, (iii) unsubstituted or substituted C.sub.1-C.sub.12-hydrocarbon radical, and (iv) unsubstituted or substituted C.sub.1-C.sub.12-hydrocarbonoxy radical; and wherein in formula (I) the radicals R.sup.x are each independently selected from the group consisting of (i) chlorine, (ii) C.sub.1-C.sub.6-alkyl radical, (iii) phenyl, and (iv) C.sub.1-C.sub.6-alkoxy radical, and the indices a, b, b, c, c, c, d, d, d, d are each independently selected from an integer in the range of 0 to 1000.

13. The process as claimed in claim 12, wherein in formula (I) the radicals R.sup.1, R.sup.2 and R.sup.3 are each independently selected from the group consisting of (i) hydrogen, (ii) chlorine, (iii) C.sub.1-C.sub.6-alkyl radical, (iv) phenyl, and (v) C.sub.1-C.sub.6-alkoxy radical; and where in formula (I) the radicals R.sup.x are each independently selected from the group consisting of chlorine, methyl, methoxy, ethyl, ethoxy, n-propyl, n-propoxy and phenyl, and the indices a, b, b, c, c, c, d, d, d, d are each independently selected from an integer in the range of 0 to 1000.

14. The process as claimed in claim 13, wherein in formula (I) the radicals R, le and R.sup.3 and in formula (I) the radicals R.sup.x are each independently selected from the group consisting of hydrogen, chlorine, methyl, methoxy, ethyl, ethoxy, n-propyl, n-propoxy and phenyl, and wherein the indices a, b, b, c, c, c, d, d, d, d are each independently selected from an integer in the range of 0 to 1000.

15. The process as claimed in claim 11, wherein in formula (II) the radicals R.sup.y are selected from the group consisting of (i) hydrogen, (ii) unsubstituted or substituted C.sub.1-C.sub.8-hydrocarbon radical, (iii) unsubstituted or substituted C.sub.1-C.sub.8-hydrocarbonoxy radical, and wherein the radicals R.sup.z are selected from the group consisting of (i) hydrogen and (ii) unsubstituted C.sub.1-C.sub.8-hydrocarbon radical; and where in formula (II) the radicals R.sup.a are selected from the group consisting of substituted C.sub.1-C.sub.8-hydrocarbon radicals, and where the radicals R.sup.x are selected from (i) unsubstituted C.sub.1-C.sub.8-hydrocarbon radical and (ii) unsubstituted C.sub.1-C.sub.8-hydrocarbonoxy radical.

16. The process as claimed in claim 15, wherein in formula (II) the radicals R.sup.y are selected from the group consisting of (i) hydrogen, (ii) C.sub.1-C.sub.8-alkyl radical and (iii) C.sub.1-C.sub.8-alkoxy radical, and where the radicals R.sup.z are selected from the group consisting of (i) hydrogen, (ii) C.sub.1-C.sub.8-alkyl radical and (iii) phenyl radical; and where in formula (II) the radicals R.sup.a are selected from the group consisting of substituted C.sub.1-C.sub.8-hydrocarbon radicals, and where the radicals R.sup.x are selected from unsubstituted C.sub.1-C.sub.8-hydrocarbon radicals.

17. The process as claimed in claim 11, wherein in formula (IIIa) the radicals R.sup.y are each independently selected from the group consisting of (i) C.sub.1-C.sub.3-alkyl radical, (ii) hydrogen and (iii) triorganosilyl radical of formula SiR.sup.b.sub.3, where the radicals R b are each independently C.sub.1-C.sub.20-alkyl radicals.

18. The process as claimed in claim 11, wherein in formula (III) the anions X.sup. are selected from the group consisting of the compounds of the formulae [B(R.sup.a).sub.4].sup. and [Al(R.sup.a).sub.4].sup., where the radicals R.sup.a are each independently selected from aromatic C.sub.6-C.sub.14-hydrocarbon radicals, in which at least one hydrogen atom has been each independently substituted by a radical selected from the group consisting of (i) fluorine, (ii) perfluorinated C.sub.1-C.sub.6-alkyl radical, and (iii) triorganosilyl radical of the formula SiR.sup.b.sub.3, where the radicals R b are each independently C.sub.1-C.sub.20-alkyl radicals.

19. The process as claimed in claim 18, wherein in formula (III) the anions X.sup. are selected from the group consisting of the compounds of formula [B(R.sup.a).sub.4].sup., where the radicals R.sup.a are each independently selected from aromatic C.sub.6-C.sub.14-hydrocarbon radicals, in which all hydrogen atoms have been each independently substituted by a radical selected from the group consisting of (i) fluorine and (ii) triorganosilyl radical of formula SiR.sup.b.sub.3, where the radicals R b are each independently C.sub.1-C.sub.20-alkyl radicals.

20. The process as claimed in claim 11, wherein the cationic compound of formula (III) is selected from the group consisting of Cp*M+B(C.sub.6F.sub.5).sub.4.sup.; Cp*M.sup.+B[C.sub.6F.sub.4(4-TBS)].sub.4.sup., where TBS=SiMe.sub.2tert-butyl; Cp*M.sup.+B(2-NaphF).sub.4.sup., where 2-NaphF=perfluorinated 2-naphthyl radical; and Cp*M.sup.+B[(C.sub.6F.sub.5).sub.3(2-NaphF)].sup., where 2-NaphF=perfluorinated 2-naphthyl radical, where M is selected from the group consisting of silicon and germanium, where Cp* is pentamethylcyclopentadienyl.

Description

EXAMPLES

Example 1: Reaction of Triethylsilane with Hexanal

[0095] Under an argon atmosphere, a solution of 1.3 mg of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. (1.5 mol, 0.059 mol %) in 940 mg of dichloromethane was initially charged and then 30.2 mg (2.60 mmol) of triethylsilane and 259 mg (2.59 mmol) of hexanal were added. The reaction was exothermic and was complete after 0.5 h.

[0096] The yield of hexaethyldisiloxane was 99% (GC analysis) of the theoretical value.

Example 2: Reaction of Triethylsilane with Hexanal

[0097] 299 mg (2.57 mmol) of triethylsilane and 257 mg (2.57 mmol) of hexanal were mixed. To this mixture were added slowly dropwise 2.8 mg (3.2 mol, 0.12 mol % based on hexanal) of Cp*Ge+B(C.sub.6F.sub.5).sub.4.sup. as a solution in 780 mg of dichloromethane. After one hour at 50 C. the reaction was complete.

[0098] The yield of hexaethyldisiloxane was 98% (GC analysis) of the theoretical value.

[0099] .sup.1H-NMR (CD.sub.2Cl.sub.2): =0.54 (m, 6 CH.sub.2), 0.95 ppm (6 CH.sub.3)

Example 3: Reaction of Triethylsilane with Ethyl Methyl Ketone

[0100] Under an argon atmosphere, a solution of 1.1 mg of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. (1.3 mol, 0.05 mol % based on triethylsilane) in 853 mg of dichloromethane was initially charged, then 301 mg (2.59 mmol) of triethylsilane and 188 mg (2.60 mmol) of ethyl methyl ketone were added. The reaction was strongly exothermic and was complete after 0.5 h.

[0101] The yield of hexaethyldisiloxane was 81% (GC analysis) of the theoretical value.

Example 4: Reaction of Triethylsilane with Ethyl Methyl Ketone

[0102] Under an argon atmosphere, a solution of 3.5 mg of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. (4.15 mol, 0.05 mol % based on triethylsilane) in 15 g of dichloromethane was initially charged and then 1011 mg (8.70 mmol) of triethylsilane were added. To the solution, cooled to 74 C., were added 629 mg (8.72 mmol) of ethyl methyl ketone. The reaction solution was then slowly brought to room temperature. After 1.5 h at room temperature, 76% hexaethyldisiloxane was formed (GC analysis), starting from the theoretical value.

Example 5: Reaction of Dimethylchlorosilane with Ethyl Methyl Ketone

[0103] Under argon, 0.5 mg of Cp*Ge+B(C.sub.6F.sub.5).sub.4.sup. (0.56 mol, 0.021 mol % based on 2-butanone) was dissolved in 660 mg of dichloromethane. To this solution was added a mixture of 252 mg (2.66 mmol) of dimethylchlorosilane and 195 mg (2.70 mmol) of ethyl methyl ketone. An exothermic reaction was observed. After 24 hours at room temperature, 1,3-dichloro-1,1,3,3-tetramethyldisiloxane had formed (GC analysis), starting from the theoretical value.

Example 6: Reaction of Pentamethyldisiloxane with Hexanal

[0104] Under an argon atmosphere, a solution of 3.2 mg of Cp*Ge+B(C.sub.6F.sub.6).sub.4.sup. (3.6 mol, 0.05 mol % based on pentamethyldisiloxane) in 15.6 g of dichloromethane and 1.00 g (6.77 mmol) of pentamethyldisiloxane was initially charged. To the solution, cooled to +2 C., were added 676 mg (6.75 mmol) of hexanal. The reaction solution was slowly brought to room temperature and then stirred at room temperature for 18 h.

[0105] The yield of decamethyltetrasiloxane was 56% (GC analysis) of the theoretical value.

Example 7: Reaction of Triethylsilane with Acetophenone

[0106] Under an argon atmosphere, a solution of 1.2 mg of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. (1.4 mol, 0.055 mol % based on triethylsilane) in 860 mg of dichloromethane was initially charged and then 312 mg (2.59 mmol) of triethylsilane and 312 mg (2.60 mmol) of acetophenone were added. The reaction solution was heated to 70 C. for 15 minutes.

[0107] The yield of hexaethyldisiloxane was 98% (GC analysis) of the theoretical value.

Example 8: Reaction of Triethylsilane with Acetophenone (1:1)

[0108] Under argon, a mixture of 301 mg (2.59 mmol) of triethylsilane, 313 mg (2.61 mg) of acetophenone and 340 mg of CD.sub.2Cl.sub.2 was prepared. This mixture was slowly added dropwise to a solution of 2.3 mg (2.6 mol, 0.10 mol % based on acetophenone) of Cp*Ge+B(C.sub.6F.sub.5).sub.4.sup. in 713 mg of dichloromethane. After 24 hours at 50 C., all of the triethylsilane had reacted.

[0109] The yield of hexaethyldisiloxane was 98% (GC analysis) of the theoretical value.

Example 9: Reaction of Triethylsilane with Acetophenone (2:1)

[0110] Under argon, a mixture of 399 mg (3.43 mmol) of triethylsilane, 210 mg (1.75 mg) of acetophenone and 370 mg of CD.sub.2Cl.sub.2 was prepared. This mixture was slowly added dropwise to a solution of 3.1 mg (3.5 mol, 0.20 mol % based on acetophenone) of Cp*Ge+B(C.sub.6F.sub.5).sub.4.sup. in 380 mg of dichloromethane. After 23 hours at 50 C., the reaction was complete.

[0111] The yield of hexaethyldisiloxane was 99% (GC analysis) of the theoretical value.

Example 10: Reaction of Triethylsilane with Ethyl Acetate

[0112] 304 mg (2.61 mmol) of triethylsilane and 116 mg (1.32 mmol) of ethyl acetate were mixed. To this mixture was added a solution of 1.2 mg (1.4 mol, 0.11 mol % based on ethyl acetate) of Cp*Ge+B(C.sub.6F.sub.5).sub.4.sup. in 346 mg of dichloromethane. The reaction mixture was heated at 70 C. for 16 hours. Triethylsilane had reacted completely.

[0113] The yield of hexaethyldisiloxane was 43% (GC analysis) of the theoretical value.

Example 11: Reaction of Triethylsilane with Ethyl Acetate

[0114] 302 mg (2.60 mmol) of triethylsilane and 117 mg (1.33 mmol) of ethyl acetate were mixed. To this mixture was added a solution of 1.1 mg (1.3 mol, 0.098 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 346 mg of dichloromethane. The reaction mixture was heated at 70 C. for 16 hours. Triethylsilane had reacted completely.

[0115] The yield of hexaethyldisiloxane was 50% (GC analysis) of the theoretical value.

Example 12: Reaction of Triethylsilane with Ethyl Propionate

[0116] 300 mg (2.58 mmol) of triethylsilane and 130 mg (1.27 mmol) of ethyl propionate were mixed. To this mixture was added a solution of 1.2 mg (1.4 mol, 0.11 mol %) of Cp*Ge+B(C.sub.6F.sub.5).sub.4.sup. in 360 mg of dichloromethane. The reaction mixture was heated at 70 C. for 16 hours. Triethylsilane had reacted completely.

[0117] The yield of hexaethyldisiloxane was 56% (GC analysis) of the theoretical value.

Example 13: Reaction of 1,1,3,3-Tetramethyldisiloxane with Hexanal (Synthesis of a Linear Siloxane Polymer)

[0118] 1.00 g (7.46 mmol) of 1,1,3,3-tetramethyldisiloxane, 1.49 g (14.9 mmol) of hexanal and 6.5 g of dichloromethane were mixed and a solution of 1.7 mg (2.02 mol, 0.03 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 1 g of dichloromethane was added with stirring at 10 C.

[0119] The solution was warmed to 40 C. and then again returned to ambient temperature (25 C.). After a total reaction time of 2 hours, SiH was no longer detectable by NMR spectroscopy. .sup.29Si-NMR (CD.sub.2Cl.sub.2): =6.78 (SiH chain end),19.8 (HSiOSiMe.sub.2O), 21.8 (SiMe.sub.2O chain link), calculated average chain length: 42 silicone units.

Example 14: Reaction of 1,1,3,3-Tetramethyldisiloxane and Diethylsilane with Hexanal (Synthesis of a Linear Siloxane Copolymer)

[0120] 0.50 g (3.74 mmol) of 1,1,3,3-tetramethyldisiloxane, 0.329 mg (3.73 mmol) of diethylsilane, 1.49 g (14.9 mmol) of hexanal and 6.5 g of dichloromethane were mixed and a solution of 1.6 mg (1.90 mol, 0.025 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 1.1 g of dichloromethane was added with stirring at 25 C. After a total reaction time of ca. 2 days, SiH was no longer detectable by .sup.1H-NMR spectroscopy. The reaction solution was evaporated under reduced pressure. GPC measurement: M.sub.n=3830, M.sub.w=12 316, D=3.2.

Example 15: Reaction of 1,1,3,3-Tetramethyldisiloxane and Diphenylsilane with Hexanal (Synthesis of a Siloxane Copolymer)

[0121] 0.50 g (3.74 mmol) of 1,1,3,3-tetramethyldisiloxane, 0.687 mg (3.73 mmol) of diphenylsilane, 1.49 g (14.9 mmol) of hexanal and 4.7 g of dichloromethane were mixed and a solution of 1.4 mg (1.90 mol, 0.022 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 1.1 g of dichloromethane was added with stirring at 20 C. The solution was heated to a bath temperature of 60 C. for 22 hours, after which time the reaction was complete (no SiH signals detectable in the .sup.1H-NMR spectrum). The reaction solution was evaporated under reduced pressure. GPC measurement: M.sub.n=3375, M.sub.w=7755, D=2.3.

Example 16: Reaction of 1,1,3,3-Tetramethyldisiloxane and 1,4-Bis(Dimethylsilyl)Benzene with Hexanal (Synthesis of a Siloxane Copolymer)

[0122] 0.52 g (3.74 mmol) of 1,1,3,3-tetramethyldisiloxane, 0.728 mg (3.74 mmol) of 1,4-bis(dimethylsilyl)benzene, 1.49 g (14.9 mmol) of hexanal and 3.1 g of dichloromethane were mixed and a solution of 1.5 mg (1.78 mol, 0.024 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 1.1 g of dichloromethane was added with stirring at 25 C. The solution was warmed to 40 C. and then again returned to ambient temperature (25 C.).

[0123] After a total reaction time of 22 hours, the reaction was complete (no SiH signals detectable in the .sup.1H-NMR spectrum). The reaction solution was evaporated under reduced pressure. GPC measurement: M.sub.n=2581, M.sub.w=7819, D=3.0.

Example 17: Reaction of 1,1,3,3-Tetramethyldisiloxane and Diphenylsilane with Hexanal (Synthesis of a Siloxane Copolymer)

[0124] 0.50 g (3.74 mmol) of 1,1,3,3-tetramethyldisiloxane, 0.687 mg (3.73 mmol) of diphenylsilane, 1.49 g (14.9 mmol) of hexanal and 4.7 g of dichloromethane were mixed and a solution of 1.4 mg (1.90 mol, 0.022 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 1.1 g of dichloromethane was added with stirring at 20 C. The solution was heated to a bath temperature of 60 C. for 22 hours, after which time the reaction was complete (no SiH signals detectable in the .sup.1H-NMR spectrum). The reaction solution was evaporated under reduced pressure. GPC measurement: M.sub.n=3375, M.sub.w=7755, D=2.3.

Example 18: Reaction of 1,1,3,3-Tetramethyldisiloxane and 1,4-Bis(Dimethylsilyl)Benzene with Hexanal (Synthesis of a Siloxane Copolymer)

[0125] 0.52 g (3.74 mmol) of 1,1,3,3-tetramethyldisiloxane, 0.728 mg (3.74 mmol) of 1,4-bis(dimethylsilyl)benzene, 1.49 g (14.9 mmol) of hexanal and 3.1 g of dichloromethane were mixed and a solution of 1.5 mg (1.78 mol, 0.024 mol %) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. in 1.1 g of dichloromethane was added with stirring at 25 C. The solution was warmed to 40 C. and then again returned to ambient temperature (25 C.). After a total reaction time of 22 hours, the reaction was complete (no SiH signals detectable in the .sup.1H-NMR spectrum). The reaction solution was evaporated under reduced pressure. GPC measurement: M.sub.n=2581, M.sub.w=7819, D=3.0.

Example 19: Reaction of 1,4-Bis(Dimethylsilyl)Benzene with Hexanal (Synthesis of a Copolymer)

[0126] A solution of 3.50 g (18.0 mmol) of 1,4-bis(dimethylsilyl)benzene and 3.62 mg (36.1 mmol) of hexanal was initially charged under an argon atmosphere in 4.5 g of dichloromethane. To this mixture were slowly added dropwise 3.3 mg (3.9 mol, 0.02 mol % based on 1,4-bis(dimethylsilyl)benzene) of Cp*Si+B(C.sub.6F.sub.5).sub.4.sup. as a solution in 1.1 g of dichloromethane. After 2 hours at 50 C., 1,4-bis(dimethylsilyl)benzene was almost completely consumed. The polymer HSiMe.sub.2-[(1,4-phenyl)-SiMe.sub.2OSiMe.sub.2].sub.n(1,4-phenyl)-SiMe.sub.2H was formed. The chain length was determined by determining the SiH end groups in the .sup.1H-NMR spectrum at =4.44 ppm, n=220.

[0127] NMR data of the polymer formed:

[0128] .sup.1H-NMR (CD.sub.2Cl.sub.2): =0.37 (s, SiMe.sub.2), 7.58 (s, phenyl);

[0129] .sup.29Si-NMR (CD.sub.2Cl.sub.2): =1.12 ppm (SiO-phenyl chain link).