PROCESS FOR PREPARING SILOXANES

Abstract

A process for preparing siloxanes, wherein at least one alkoxy-organosilicon compound selected from compounds of the general formula (I) and/or from compounds of the general formula (II) is/are reacted in the presence of a cationic silicon and/or germanium compound at a temperature of −40 to 250° C.

Claims

1-15. (canceled)

16. A process for preparing siloxanes, comprising: providing at least one alkoxy-organosilicon compound which is selected from compounds of the general formula (I)
R.sup.1R.sup.2R.sup.3Si—OR.sup.x  (I), wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group comprising halogen, unsubstituted or substituted C.sub.1-C.sub.20 hydrocarbon radical and unsubstituted or substituted C.sub.1-C.sub.20 hydrocarbonoxy radical, and wherein two of the radicals R.sup.1, R.sup.2 and R.sup.3 may together form a monocyclic or polycyclic, unsubstituted or substituted C.sub.2-C.sub.20 hydrocarbon radical, where substituted in each case means that the hydrocarbon radical or hydrocarbonoxy radical independently has at least one of the following replacements: wherein replacement of a hydrogen atom is done by halogen, —CH(═O), —C≡N, —OR.sup.z, —SR.sup.z, —NR.sup.z.sub.2, and —PR.sup.z.sub.2, wherein replacement of a CH.sub.2 group is done by —O—, —S— or —NR.sup.z—, wherein replacement of a CH.sub.2 group not bonded directly to Si is done by —C(═O)—, wherein replacement of a CH.sub.3 group is done by —CH(═O), and wherein replacement of a C atom is done by an Si atom, wherein R.sup.z is in each case independently selected from the group comprising C.sub.1-C.sub.6 alkyl radical and C.sub.6-C.sub.14 aryl radical, where R.sup.x is a C.sub.1-C.sub.20 hydrocarbon radical, and/or wherein the at least one alkoxy-organosilicon compound is selected from compounds of the general formula (II)
(SiO.sub.4/2).sub.a(R.sup.ySiO.sub.3/2).sub.b[(R.sup.xO)SiO.sub.3/2].sub.b′(R.sup.y.sub.2SiO.sub.2/2).sub.c[(R.sup.xO)R.sup.ySiO.sub.2/2].sub.c′[(R.sup.xO).sub.2SiO.sub.2/2].sub.c″(R.sup.y.sub.3SiO.sub.1/2).sub.d[(R.sup.xO)R.sup.y.sub.2SiO.sub.1/2].sub.d′[(R.sup.xO).sub.2R.sup.ySiO.sub.1/2].sub.d″[(R.sup.xO).sub.3SiO.sub.1/2].sub.d′″  (II), wherein R.sup.y is as defined for R.sup.1, R.sup.2 or R.sup.3, and wherein the indices a, b, b′, c, c′, c″, d, d′, d″, d′″ indicate the number of the respective siloxane unit and independently represent an integer from 0 to 100 000, with the proviso that the sum total of all indices has a value of at least 2 and at least one of the indices b′, c′, c″, d′, d″ or d′″ is not equal to 0; and reacting the at least one alkoxy-organosilicon compound in the presence of at least one cationic silicon and/or germanium compound at a temperature of −40° C. to 250° C.

17. The process of claim 16, wherein the reaction takes place at a temperature of 0° C. to 200° C., preferably 10° C. to 100° C.

18. The process of claim 16, wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group comprising unsubstituted or substituted C.sub.1-C.sub.12 hydrocarbon radical and unsubstituted or substituted C.sub.1-C.sub.12 hydrocarbonoxy radical.

19. The process of claim 16, wherein R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group comprising methyl, ethyl, vinyl, phenyl, methoxy and ethoxy.

20. The process of claim 16, wherein R.sup.x is independently selected from the group comprising unsubstituted or substituted C.sub.1-C.sub.12 hydrocarbon radical, vinyl and phenyl.

21. The process of claim 16, wherein the indices a, b, b′, c, c′, c″, d, d′, d″, d′″ are independently selected from an integer in the range of 0 to 1000.

22. The process of claim 16, wherein the reaction is performed in the presence of at least one carbonyl compound.

23. The process of claim 22, wherein the carbonyl compound is selected from compounds of the general formula (III)
R.sup.d—(X).sub.n—CO—(X).sub.n—R.sup.d  (III), wherein R.sup.d is independently hydrogen or an unsubstituted or substituted C.sub.1-C.sub.40 hydrocarbon radical, wherein the two radicals R.sup.d may be joined to one another and form a ring, wherein X is independently oxygen, —N(H)— or —N(R.sup.d)—, and wherein independently n=0 or 1.

24. The process of claim 23, wherein n=0 and R.sup.d is independently hydrogen or a C.sub.1-C.sub.12 hydrocarbon radical.

25. The process of claim 22, wherein the carbonyl compound is used in a proportion by weight of 0.01% to 500%, preferably 0.1% to 100%, particularly preferably 1% to 50%, based on the compound of the general formula (I) or (II).

26. The process of claim 16, wherein the cationic silicon and/or germanium compound is selected from the group comprising cationic silicon(II), silicon(IV), germanium(II) and germanium(IV) compounds.

27. The process of claim 16, wherein the cationic silicon and/or germanium compound is selected from compounds of the general formula (IV)
([M(II)Cp].sup.+).sub.aX.sup.a-  (IV), wherein X.sup.a- is an a-valent anion, where a=1, 2 or 3, wherein M is Ge(II) or Si(II), wherein Cp is π-bonded cyclopentadienyl radical of the general formula (IVa) ##STR00003## wherein R.sup.v is independently selected from the group of hydrogen, unsubstituted or substituted C.sub.1-C.sub.20 hydrocarbon radical, unsubstituted or substituted C.sub.1-C.sub.20 hydrocarbonoxy radical and triorganosilyl radical of the formula —SiR.sup.b.sub.3, wherein R.sup.b is independently selected from the group of C.sub.1-C.sub.20 hydrocarbon radical and C.sub.1-C.sub.20 hydrocarbonoxy radical, wherein two radicals R.sup.v may also be joined to one another so that bi- or polycyclic rings are formed; and/or wherein the cationic silicon and/or germanium compound is selected from compounds of the general formula (V) ##STR00004## wherein X.sup.a- is an a-valent anion, where a=1, 2 or 3, wherein Z is independently silicon(IV) or germanium(IV), and wherein Y is a divalent C.sub.2-C.sub.50 hydrocarbon radical and where R.sup.w is independently hydrogen or a C.sub.1-C.sub.50 hydrocarbon radical.

28. The process of claim 27, wherein a=1 in formulae (IV) and/or (V).

29. The process as claimed in claim 28, wherein X.sup.− is independently selected from the group comprising [B(SiCl.sub.3).sub.4].sup.−, compounds of the formula [B(R.sup.a).sub.4].sup.− and compounds of the formula [Al(OR.sup.c).sub.4].sup.−, and wherein R.sup.c is independently a fluorinated, aliphatic C.sub.3-C.sub.12 hydrocarbon radical.

30. The process of claim 27, wherein the cationic silicon and/or germanium compound is selected from the group comprising silicon(II) and germanium(II) compounds of formula (IV), wherein R.sup.v is independently selected from the group comprising methyl radical, hydrogen and trimethylsilyl radical, and wherein X.sup.a-, where a=1, is selected from the group comprising [B(SiCl.sub.3).sub.4].sup.−, [B(C.sub.6F.sub.5).sub.4].sup.−, {B[C.sub.6F.sub.4(4-TBS)].sub.4}.sup.−, where TBS=SiMe.sub.2tert-butyl, and [B(2-Naph.sup.F).sub.4].sup.−, where 2-Naph.sup.F=perfluorinated 2-naphthyl radical.

31. The process of claim 26, wherein the cationic silicon and/or germanium compound is selected from the group comprising silicon(IV) and germanium(IV) compounds of the general formula (V), where R.sup.w is independently selected from the group comprising C.sub.1-C.sub.6 alkyl radical and phenyl radical, where Y is a 1,8-naphthalenediyl radical, and where X.sup.− is selected from the group comprising [B(C.sub.6F.sub.5).sub.4].sup.− and [B(SiCl.sub.3).sub.4].sup.−.

Description

EXAMPLES

Example 1

[0092] 201 mg of trimethylethoxysilane (formula (I) where R.sup.1═R.sup.2═R.sup.3=Me, R.sup.x=Et) was dissolved in 405 mg of dichloromethane, admixed with 8.9 mg of catalyst of formula (V) where Z=Si, Y=1,8-naphthalenediyl, R.sup.w=Ph and Me, where Ph:Me=1:1, and X=B(C.sub.6F.sub.5).sub.4 and heated to 70° C. for 18 h. This formed 90 mol % each of hexamethyldisiloxane and diethyl ether based on trimethylethoxysilane used.

Example 2

[0093] 200 mg of dimethyldiethoxysilane (formula (I) where R.sup.1═R.sup.2=Me, R.sup.3═OEt, R.sup.x=Et) was dissolved in 412 mg of dichloromethane, admixed with 7.1 mg of catalyst of formula (V) where Z=Si, Y=1,8-naphthalenediyl, R.sup.w=Ph and Me, where Ph:Me=1:1, and X═B(C.sub.6F.sub.5).sub.4 and heated to 70° C. for 18 h. This formed the oligomers EtO—(SiMe.sub.2-O).sub.n—SiMe.sub.2-OEt, where n=1 to 10, and diethyl ether. The conversion was 85%.

Example 3

[0094] 205 mg of methyltriethoxysilane (formula (I) where R.sup.1=Me, R.sup.2═R.sup.3=OEt, R.sup.x=Et) was dissolved in 417 mg of dichloromethane, admixed with 5.2 mg of catalyst of formula (V) where Z═Si, Y=1,8-naphthalenediyl, R.sup.w=Ph and Me, where Ph:Me=1:1, and X═B(C.sub.6F.sub.5).sub.4 and heated to 70° C. for 24 h. This formed oligomeric siloxanes and diethyl ether. The conversion was 85%.

Example 4

[0095] The experiment according to Example 1 was repeated using 8.0 mg of the catalyst of formula (V) where Z═Si, Y=1,8-naphthalenediyl, R.sup.w=Me, and X═B(C.sub.6F.sub.5).sub.4. The reaction time at 70° C. was 2 days. This formed 95% each of hexamethyldisiloxane and diethyl ether.

Example 5

[0096] The experiment according to Example 2 was repeated using 6.2 mg of the catalyst of formula (V) where Z═Si, Y=1,8-naphthalenediyl, R.sup.w=Me and X═B(C.sub.6F.sub.5).sub.4. The reaction time at 70° C. was 2 days. This formed the oligomers EtO—(SiMe.sub.2-O).sub.n—SiMe.sub.2-OEt, where n=1 to 10, and diethyl ether. The conversion was 70%.

Example 6

[0097] The experiment according to Example 3 was repeated using 5.2 mg of the catalyst of formula (V) where Z═Si, Y=1,8-naphthalenediyl, R.sup.w=Me and X═B(C.sub.6F.sub.5).sub.4. The reaction time at 70° C. was 2 days. This formed oligomeric siloxanes and diethyl ether. The conversion was 45%.

Example 7

[0098] 154 mg of methyltrimethoxysilane (formula (I) where R.sup.1=Me, R.sup.2═R.sup.3═OMe, R.sup.x=Me) was admixed with 1.0 mg of Cp*Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV)) in 100 mg of dichloromethane and left to stand for 24 h. After this time, 1% of 1,1,3,3-tetramethoxydimethyldisiloxane had formed. 4 mg of methyl ethyl ketone (formula (III)) was then added, and the solution was again left to stand for 24 h. After this time, 14% of 1,1,3,3-tetramethoxydimethyldisiloxane and 2% of pentamethoxy-1,3,5-trimethyltrisiloxane had formed.

Example 8

[0099] 134 mg of dimethoxydimethylsilane (formula (I) where R.sup.1═R.sup.2=Me, R.sup.3═OMe, R.sup.x=Me) was admixed with 1.0 mg of Cp*Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV)) in 100 mg of dichloromethane and left to stand for 24 h. After this time, 2.5% of 1,3-dimethoxytetramethyldisiloxane had formed. 5 mg of methyl ethyl ketone (formula (III)) was then added and the solution was again left to stand for 24 h. After this time, 16% of 1,5-dimethoxytetramethyldisiloxane and 5% of 1,7-dimethoxyhexamethyltrisiloxane had formed.

Example 9

[0100] 136 mg of trimethylethoxysilane (formula (I) where R.sup.1═R.sup.2═R.sup.3=Me, R.sup.x=Et) was admixed with 1.1 mg of Cp*Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV)) in 100 mg of dichloromethane and left to stand for 24 h. After this time, 2.5% of 1,3-dimethoxytetramethyldisiloxane had formed. 5.5 mg of methyl ethyl ketone was then added, and the solution was again left to stand for 24 h. After this time, 11% of hexamethyldisiloxane had formed.

Example 10: Crosslinking of MSE 100 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Acetaldehyde (Evidence of Dimethyl Ether Formation)

[0101] 341 mg of MSE 100 is mixed with a solution of 0.18 mg of Cp*Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (0.053% by weight based on MSE 100) in 70 μl of dichloromethane in an NMR tube with shaking. The sample is cooled to 2° C. and 21 mg of acetaldehyde (formula (III)), which has also been cooled to 2° C., is added. The NMR tube is sealed and left to stand for 3 h at 23° C. Dilution is performed with CD.sub.2Cl.sub.2 and the sample is analyzed by NMR spectroscopy. The signal at δ□□□3.2 ppm indicates the formation of dimethyl ether. MSE 100 is a siloxane that is formed from MeSi(OMe).sub.3 by hydrolytic condensation and comprises 31% by weight of methoxy groups.

Example 11: Crosslinking of MSE 100 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Acetaldehyde

[0102] 231 mg of acetaldehyde (formula (III)) and 2506 mg of MSE 100 are mixed in a SpeedMixer. 1.3 mg of Cp*Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (0.052% by weight based on MSE 100) dissolved in 200 μl of dichloromethane is added to this mixture and the latter is mixed for approx. 2 min in the SpeedMixer, with the mixture having cured completely.

Example 12: Crosslinking of MSE 100 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.−

[0103] The experiment according to Example 10 is repeated without the addition of acetaldehyde. The sample is still liquid after the mixing and has cured after 24 h at 23° C.

Example 13: Crosslinking of MSE 100 with Cp(SiMe.SUB.3.).SUB.3.Ge.SUP.+.B(SiCl.SUB.3.).SUB.4..SUP.− and Acetone

[0104] 2520 mg of MSE 100 and 127 mg of acetone (formula (III), 5% by weight based on MSE 100) are mixed in a SpeedMixer. 1.2 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(SiCl.sub.3).sub.4.sup.− (formula (IV), 0.048% by weight based on MSE 100) dissolved in 180 μl of dichloromethane is added to this mixture and the latter is mixed again for approx. 2 min in the SpeedMixer. After 5 h at 23° C. the mixture has cured and is colorless.

Example 14: Crosslinking of MSE 100 with Cp(SiMe.SUB.3.).SUB.3.Ge.SUP.+.B(SiCl.SUB.3.).SUB.4..SUP.− and Acetone

[0105] 2565 mg of MSE 100 and 130 mg of acetone (formula (III), 5% by weight based on MSE 100) are mixed in a SpeedMixer. 0.27 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(SiCl.sub.3).sub.4.sup.− (formula (IV), 0.011% by weight based on MSE 100), without added solvent, is then added to this mixture and the latter is mixed again for approx. 2 min in the SpeedMixer. After 5 h at 23° C. the mixture has cured and is colorless.

Example 15: Crosslinking of MSE 100 with Cp(SiMe.SUB.3.).SUB.3.Ge.SUP.+.B(SiCl.SUB.3.).SUB.4..SUP.− and Methyl Ethyl Ketone

[0106] 2531 mg of MSE 100 and 125 mg of methyl ethyl ketone (formula (III), 5% by weight based on MSE 100) are mixed in a SpeedMixer. 1.1 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(SiCl.sub.3).sub.4.sup.− (formula (IV), 0.043% by weight based on MSE 100) dissolved in 190111 of dichloromethane is then added to this mixture and the latter is mixed again for approx. 2 min in the SpeedMixer. After 5 h at 23° C. the mixture has cured and is colorless.

Example 16: Crosslinking of MSE 100 with Cp(SiMe.SUB.3.).SUB.3.Ge.SUP.+.B(SiCl.SUB.3.).SUB.4..SUP.− and Methyl Ethyl Ketone

[0107] 2560 mg of MSE 100 and 126 mg of methyl ethyl ketone (formula (III), 5% by weight based on MSE 100) are mixed in a SpeedMixer. 0.29 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(SiCl.sub.3).sub.4.sup.− (formula (IV), 0.011% by weight based on MSE 100), without added solvent, is then added to this mixture and the latter is mixed again for approx. 2 min in the SpeedMixer. After 5 h at 23° C. the mixture has cured and is colorless.

Example 17: Crosslinking of MSE 100 with Cp(SiMe.SUB.3.).SUB.3.Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Methyl Ethyl Ketone

[0108] 2602 mg of MSE 100 and 129 mg of methyl ethyl ketone (formula (III), 5% by weight based on MSE 100) are mixed in a SpeedMixer. 1.4 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV), 0.054% by weight based on MSE 100), without added solvent, is then added to this mixture and the latter is mixed again for approx. 2 min in the SpeedMixer. After approx. 4 h at 23° C. the mixture has cured and is colorless.

Example 18: Crosslinking of MSE 100 with Cp(SiMe.SUB.3.).SUB.3.Ge.SUP.+.B(SiCl.SUB.3.).SUB.4..SUP.− and Acetaldehyde Diethyl Acetal

[0109] 2529 mg of MSE 100 and 134 mg of acetaldehyde diethyl acetal (5% by weight based on MSE 100) are mixed in a SpeedMixer. 1.1 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(SiCl.sub.3).sub.4.sup.− (formula (IV), 0.043% by weight based on MSE 100), without added solvent, is then added to this mixture and the latter is mixed again for approx. 2 min in the SpeedMixer. After approx. 4 h at 23° C. the mixture has cured and is colorless.

Example 19: Crosslinking of MSE 100 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Paraldehyde

[0110] 2536 mg of MSE 100 and 129 mg of paraldehyde (5% by weight based on MSE 100) are mixed in a SpeedMixer. 1.2 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV), 0.047% by weight based on MSE 100), without added solvent, is then added to this mixture and the latter is mixed for approx. 2 min in the SpeedMixer. The mixture has cured after approx. 4 h at 23° C.

Example 20: Crosslinking of MSE 100 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Paraldehyde

[0111] The experiment in Example 19 is repeated. After the mixing, the sample is heated to 50° C. and has cured after approx. 1 h at this temperature.

Example 21: Crosslinking of MSE 100 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Dimethyl Carbonate (DMC)

[0112] 2563 mg of MSE 100 and 130 mg of DMC (formula (III), 5% by weight based on MSE 100) are mixed in a SpeedMixer. 0.5 mg of Cp*Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV), 0.02% by weight based on MSE 100), without added solvent, is then added to this mixture and the latter is mixed for approx. 2 min in the SpeedMixer. The mixture has cured after approx. 7 h at 23° C.

Example 22: Crosslinking of Silres IC 368 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Acetaldehyde

[0113] 2533 mg of Silres IC 368 and 242 mg of acetaldehyde (formula (III), 10% by weight based on Silres IC 368) are mixed in a SpeedMixer. 1.2 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV), 0.05% by weight based on Silres IC 368) in 200 μl of dichloromethane is then added to this mixture and the latter is mixed for approx. 2 min in the SpeedMixer. The mixture has cured after approx. 24 h at 23° C. Silres IC 368 is a hydrolytic condensate of PhSi(OMe).sub.3 and MeSi(OMe).sub.3 in the ratio 62:38 that comprises 14% by weight of methoxy groups.

Example 23: Crosslinking of Silres IC 368 with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Paraldehyde

[0114] 2528 mg of Silres IC 368 and 131 mg of paraldehyde (5% by weight based on Silres IC 368) are mixed in a SpeedMixer. 1.2 mg of Cp(SiMe.sub.3).sub.3Ge.sup.+B(C.sub.6F.sub.5).sub.4.sup.− (formula (IV), 0.047% by weight based on Silres IC 368) in 200 μl of dichloromethane is then added to this mixture and the latter is mixed for approx. 2 min in the SpeedMixer. The mixture has cured after approx. 24 h at 23° C.

Example 24: Crosslinking of TRASIL with Cp*Ge.SUP.+.B(C.SUB.6.F.SUB.5.).SUB.4..SUP.− and Methyl Ethyl Ketone

[0115] Example 23 is repeated using TRASIL instead of Silres IC 368. The mixture has cured after approx. 24 h at 23° C. TRASIL is a hydrolytic condensate of MeSi(OEt).sub.3 with a molar ratio of EtO:Me=0.7:1.