Halogenated Tetrasilyl Boranates

Abstract

The invention relates to halogenated tetrasilylboranates of the general formula

M.sup.z+[B(SiR.sub.mX.sub.n).sub.4.sup.−].sub.z  (I),

where the radicals and indices have the meanings indicated in claim 1, with the proviso that m+n=3,
processes for the production thereof and also the use.

Claims

1-8. (canceled)

9. A halogenated tetrasilylboranate, comprising: wherein the halogenated tetrasilylboranate has the general formula
M.sup.z+[B(SiR.sub.mX.sub.n).sub.4.sup.−].sub.z  (I), wherein M.sup.z+ is an inorganic or organic cation; wherein z is 1 or 2, preferably 1; wherein R is identical or different on each occurrence and is a hydrogen atom or hydrocarbon radical having from 1 to 3 carbon atoms; wherein X is identical or different on each occurrence and is a halogen atom; wherein m is 0, 1 or 2; wherein n is 1, 2 or 3; and wherein m+n=3.

10. The halogenated tetrasilylboranate of claim 9, wherein M.sup.z+ is H.sup.+ or Ph.sub.3C.sup.+.

11. The halogenated tetrasilylboranate of claim 9, wherein X is F or Cl.

12. The halogenated tetrasilylboranate of claim 9, wherein it is H.sup.+B(SiCl.sub.3).sub.4.sup.−, H.sup.+B(SiHCl.sub.2)(SiCl.sub.3).sub.3.sup.− or Ph.sub.3C.sup.+B(SiCl.sub.3).sub.4.sup.−.

13. A process for producing a tetrasilylboranates, comprising: reacting boron trihalides with at least two different halosilanes bearing Si-bonded hydrogen, and wherein the boranate obtained in this way is reacted with a proton acceptor (B) in an optionally performed further step.

14. The process of claim 13, wherein boron trihalides BX.sub.3 are reacted with silanes (S1) of the formula HSiR.sub.mX.sub.n and silanes (S2) of the formula H.sub.2SiR.sub.m′X.sub.n′; wherein the radicals R in each case can be identical or different and is a hydrogen atom or hydrocarbon radical having from 1 to 3 carbon atoms; wherein X in each case can be identical or different and is a halogen atom; wherein m is 0, 1 or 2; wherein n is 1, 2 or 3; wherein m′ is 0 or 1; wherein n′ is 1 or 2; wherein m+n=3; and wherein m′+n′=2.

15. A process for converting compounds (H) bearing Si-bonded hydrogen into the corresponding compounds bearing Si-bonded halogen atoms by a reaction with halogenated hydrocarbons (K) in the presence of compounds of the general formula (I) wherein X is Cl and M.sup.z+ is H.sup.+ as catalyst.

16. The process of claim 15, wherein the molar ratio of Si—H groups in the organosilicon compounds (H) to C—Cl groups in the compounds (K) is at least 100:1 and not more than 1:10.sup.6.

Description

EXAMPLE 1

Synthesis and Characterization of H.SUP.+.B(SiCl.SUB.3.).SUB.4

[0062] 50 g of trichlorosilane and 2 g of dichlorosilane are placed under a nitrogen atmosphere at 0° C. in a steel autoclave. 20 mg of boron trichloride are introduced while stirring. The autoclave is closed and allowed to stand for 20 hours at 70° C. with pressure regulation at a gauge pressure of about 2 bar. The reaction mixture is devolatilized at atmospheric pressure at a liquid-phase temperature of up to about 30° C. The autoclave is then closed again and operated under a nitrogen atmosphere with pressure regulation at a gauge pressure of 1 bar for 100 hours at 55° C.

[0063] Finally, evaporation of the resulting reaction solution gives 40 mg of a crystalline residue of H.sup.+B(SiCl.sub.3).sub.4.sup.−, which is characterized as follows: melting point 187° C.; .sup.29Si-NMR(CD.sub.2Cl.sub.2, 99.4 MHz): □□□=19.8 ppm (q, .sup.1J.sub.Si,B=89.0 Hz), .sup.11B-NMR (CD.sub.2Cl.sub.2, 160 MHz): □□=−26.84 ppm.

EXAMPLE 2

Synthesis of H.SUP.+.B(SiCl.SUB.3.).SUB.4

[0064] A mixture of 100 g of trichlorosilane with 5 g of dichlorosilane and 55 mg of boron trichloride is allowed to stand at 70° C. while stirring and under a nitrogen atmosphere in a steel autoclave with pressure regulation at a gauge pressure of 2 bar for 24 hours. Subsequent devolatilization at about 30° C. is followed by renewed reaction in the closed steel autoclave at a gauge pressure of 1 bar and 55° C. for 120 hours. Evaporation of the reaction solution gives 140 mg of H+B(SiCl.sub.3).sub.4.sup.−.

EXAMPLE 3

Production of Ph.SUB.3.C.SUP.+.B(SiCl.SUB.3.).SUB.4..SUP.−

[0065] Under argon, 101 mg (0.18 mmol) of H.sup.+B(SiCl.sub.3).sub.4.sup.− are dissolved in 3.36 g of d.sub.6-benzene and, while stirring, a solution of 46.8 mg (0.18 mmol) of triphenylmethanol in 823 mg of d.sub.6-benzene is added dropwise. The reaction solution acquires a dark-yellow color and the product precipitates as orange-colored solid which settles at the bottom. The supernatant solution is decanted off and the solid (product) is washed with a little d.sub.6-benzene and dried at room temperature under reduced pressure. The yield is 180 mg (90%).

[0066] .sup.1H-NMR (CD.sub.2Cl.sub.2, 500 MHz): □□□=7.70 (mc, 6 aromat. H), 7.93 (mc, 6 aromat. H), 8.31 (mc, 3 aromat. H); .sup.13C-NMR (CD.sub.2Cl.sub.2, 126 MHz): □□=130.7, 139.9, 142.8, 143.7 ppm; .sup.29Si-NMR(CD.sub.2Cl.sub.2, 99.4 MHz): □□□=21.58 ppm (q, .sup.1J.sub.Si,B=89.0 Hz), .sup.11B-NMR (CD.sub.2Cl.sub.2, 160 MHz): □=−30.74 ppm.

EXAMPLE 4

Production of methyltrichlorosilane

[0067] A solution of 102 mg (0.90 mmol) of methyldichlorosilane in 770 mg of dichloromethane is admixed while shaking with a solution of 0.29 mg (0.53 μmol, 0.059 mol %) of H.sup.+B(SiCl.sub.3).sub.4.sup.− in 43 mg of dichloromethane. The reaction mixture is allowed to stand at 23° C. in the closed vessel and the formation of methyltrichlorosilane is examined by NMR spectroscopy: 13 mol % (45 min), 42 mol % (3 hours), 99 mol % conversion (20 hours). Chloromethane and methane are additionally formed.

[0068] .sup.1H-NMR (CD.sub.2Cl.sub.2, 500 MHz): δ=1.17 (s, CH.sub.3); .sup.29Si-NMR (CD.sub.2Cl.sub.2, 500 MHz): δ=12.72 ppm.

EXAMPLE 5

Production of methyltrichlorosilane

[0069] A solution of 102 mg (0.90 mmol) of methyldichlorosilane in 800 mg of d6-benzene is admixed while shaking with a solution of 0.44 mg (0.81 μmol, 0.09 mol %) of H.sup.+B(SiCl.sub.3).sub.4.sup.− in 49 mg of d6-benzene. Chloromethane is passed into the solution and the amount thereof is determined by .sup.1H-NMR spectroscopy: 67 mg (1.3 mmol). The reaction mixture is allowed to stand in the closed vessel at 23° C.; methyltrichlorosilane and methane are formed. Conversion into methyltrichlorosilane: 2 mol % (40 minutes), 10 mol % (1.6 hours), 39 mol % conversion (4.6 hours), 52 mol % conversion (30 hours), 100 mol % conversion (3 days).

[0070] .sup.1H-NMR (d6-benzene, 500 MHz): δ=1.17 (s, CH.sub.3); .sup.29Si-NMR (CD.sub.2Cl.sub.2, 500 MHz): δ=12.72 ppm.

[0071] .sup.1H-NMR (d6-benzene, 500 MHz) of the product methane: δ=0.22.

EXAMPLE 6

Production of dimethyldichlorosilane

[0072] A solution of 0.50 mg (0.91 μmol) of H.sup.+B(SiCl.sub.3).sub.4.sup.− in 620 mg of dichloromethane is admixed while shaking with a mixture of 155 mg (2.02 mmol) of allyl chloride and 130 mg (1.38 mmol) of dimethylchlorosilane. The mixture heats up briefly to 37° C. and then cools down to room temperature again. GC analysis indicates complete conversion and 80% by weight of dimethyldichlorosilane. In addition, propene is formed.

EXAMPLE 7

Production of chloropentamethyldisiloxane

[0073] 3.5 mg (6.6 μmol) of H.sup.+B(SiCl.sub.3).sub.4.sup.−, 152 mg (1.99 mmol) of allyl chloride and 196 mg (1.32 mmol) of pentamethyldisiloxane are mixed. GC analysis after a reaction time of 20 hours indicates 62% by weight of chloropentamethyldisiloxane. In addition, propene is formed.

EXAMPLE 8

Production of di-tert-butyldichlorosilane

[0074] 154 mg (2.01 mmol) of allyl chloride and 234 mg (1.32 mmol) of di-tert-butylchlorosilane are mixed and admixed with a solution of 3.6 mg (6.5 mmol) of H.sup.+B(SiCl.sub.3).sub.4.sup.− in 300 mg of dichloromethane. An exothermic reaction with formation of propene takes place, leading to formation of di-tert-butyldichlorosilane.

[0075] Yield (GC): 83% by weight.

[0076] .sup.1H-NMR (CD.sub.2Cl.sub.2, 500 MHz): δ=1.22 (s, tert-butyl).