Method for the dehydrogenation and methylation of silanes with methyl chloride

Abstract

A process for dehydrogenating and methylating silanes. The process includes providing methyl chloride that is reacted with a silane selected from the group consisting of SiH.sub.4, H.sub.2SiMe.sub.2, H.sub.2SiMeCl, H.sub.3SiMe, H.sub.3SiCl and HSiMe.sub.2Cl, in the presence of at least one ammonium and/or phosphonium salt at a temperature in the range of 70-350° C.

Claims

1-7. (canceled)

8. A process for dehydrogenating and methylating silanes, comprising: providing methyl chloride that is reacted with a silane selected from the group consisting of SiH.sub.4, H.sub.2SiMe.sub.2, H.sub.2SiMeCl, H.sub.3SiMe, H.sub.3SiCl and HSiMe.sub.2Cl, in the presence of at least one ammonium and/or phosphonium salt at a temperature in the range of 70-350° C.

9. The process as claimed in claim 8, wherein the temperature is in a range of 100-350° C.

10. The process of claim 8, wherein the molar ratio of silane to methyl chloride is in a range of 1:1 to 1:10.

11. The process of claim 8, wherein the molar ratio of catalyst to silane is in a range of 0.01:1 to 0.2:1.

12. The process of claim 8, wherein the ammonium and/or phosphonium salt is selected from the group consisting of quaternary ammonium halides [R.sub.4N]X, quaternary phosphonium halides [R.sub.4P]X and tertiary ammonium halides [R.sub.3NH]X, wherein in each case: X=Cl, Br or I, and R=independently selected from the group consisting of (i) C.sub.1-C.sub.12-alkyl group, (ii) C.sub.6-C.sub.14-aryl group substituted by C.sub.1-C.sub.6-alkyl, and (iii) phenyl group.

13. The process of claim 12, wherein the ammonium and/or phosphonium salt is selected from the group consisting of [n-Bu.sub.4N]Cl, [Et.sub.4N]Cl, [Ph.sub.4P]Cl and [n-Bu.sub.4P]Cl.

14. The process of claim 8, wherein the process is conducted continuously or batchwise.

Description

EXAMPLES

[0021] GC measurements were carried out using an Agilent 6890N (WLD detector; columns: HP5 from Agilent: length: 30 m/diameter: 0.32 mm/film thickness: 0.25 μm; RTX-200 from Restek: length: 60 m/diameter: 0.32 mm/film thickness: 1 μm). Retention times were compared with the commercially available substances; all chemicals were used as purchased. MS measurements were carried out using a ThermoStar™ GSD 320 T2 with iridium cathode.

Example 1

Reactions of SiH.SUB.4 .with MeCl

[0022] An autoclave was charged with SiH.sub.4 (9 g; 0.50 mol), [n-Bu.sub.4F]Cl (2.1 g; 7 mmol) and MeCl (64.0 g; 1.27 mol). The autoclave was heated to 150° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 30 bar. The pressure was reduced to 10 bar by decompression and then the autoclave was once again heated to 150° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 15 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 60% by weight of HSiMeCl.sub.2, 14% by weight of MeSiCl.sub.3, 10% by weight of H.sub.2SiMeCl, 8% by weight of Me.sub.2SiCl.sub.2, 4% by weight of MeCl and 4% by weight of other chlorine-, methyl- or/and methylene-substituted silanes. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.

Example 2

Reactions of SiH.SUB.4 .with MeCl

[0023] An autoclave was charged with SiH.sub.4 (9 g; 0.34 mol), [n-Bu.sub.4P]Cl (2.2 g; 7 mmol) and MeCl (48.0 g; 0.95 mol). The autoclave was heated to 145° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 25 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 89% by weight of MeSiCl.sub.3, 9% by weight of MeCl and 2% by weight of Me.sub.2SiCl.sub.2; in addition, small amounts of HSiMeCl.sub.2 were detectable. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.

Example 3

Reactions of SiH.SUB.4 .with MeCl

[0024] An autoclave was charged with SiH.sub.4 (7 g; 0.34 mol), [Ph4F]Cl (2.1 g; 6 mmol) and MeCl (25.0 g; 0.50 mol). The autoclave was heated to 300° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 25 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 56% by weight of MeSiCl.sub.3, 2% by weight of MeCl and 42% by weight of Me.sub.2SiCl.sub.2; in addition, small amounts of HSiMeCl.sub.2 were detectable. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.

Example 4

Reactions of a mixture of SiH.SUB.4 .and SiCl.SUB.4 .with MeCl

[0025] An autoclave was charged with SiH.sub.4 (9 g; 0.34 mol), [n-Bu.sub.4P]Cl (2.2 g; 0.7 mmol), MeCl (70.0 g; 1.38 mol) and SiCl.sub.4 (50.0 g; 0.29 mol). The autoclave was heated to 190° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 50 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 48% by weight of SiCl.sub.4, 47% by weight of MeSiCl3, 3% by weight of MeCl and 2% by weight of Me.sub.2SiCl.sub.2; in addition, small amounts of HSiMeCl.sub.2 and SiCl.sub.4 were detectable. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.

Example 5

Reactions of HSiCl.SUB.2.Me with MeCl

[0026] An autoclave was charged with HSiCl.sub.2Me (85 g; 0.75 mol), [n-Bu.sub.4P]Cl (2.1 g; 7 mmol) and MeCl (50.0 g; 0.99 mol). The autoclave was heated to 130° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 5 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 56% by weight of HSiCl.sub.2Me, 31% by weight of MeSiCl.sub.3, 7% by weight of Me.sub.2SiCl.sub.2, 5% by weight of MeCl and 1% by weight of other chlorine-, methyl- or/and methylene-substituted silanes. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.

Example 6

Reactions of HSiCl.SUB.2.Me with MeCl

[0027] An autoclave was charged with HSiCl.sub.2Me (85 g; 0.75 mol), [n-Bu.sub.4P]Cl (2.5 g; 8 mmol) and MeCl (51.0 g; 1.01 mol). The autoclave was heated to 176° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 20 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 16% by weight of HSiCl.sub.2Me, 41% by weight of MeSiCl.sub.3, 33% by weight of Me.sub.2SiCl.sub.2, 9% by weight of MeCl and 1% by weight of other chlorine-, methyl- or/and methylene-substituted silanes. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.

Example 7

Reactions of HSiClMe.SUB.2 .with MeCl

[0028] An autoclave was charged with HSiCl.sub.2Me (85 g; 0.75 mol), [n-Bu.sub.4P]Cl (2.5 g; 8 mmol) and MeCl (48.0 g; 0.95 mol). The autoclave was heated to 176° C. for 13 hours. After cooling, the pressure in the autoclave remained at approx. 30 bar. The autoclave was decompressed and the gas space was purged with argon. The liquid product mixture consisted to an extent of 16% by weight of HSiClMe.sub.2, 67% by weight of Me.sub.2SiCl.sub.2, 7% by weight of Me.sub.3SiCl, 9% by weight of MeCl and 1% by weight of other chlorine-, methyl- or/and methylene-substituted silanes. It was possible to unambiguously identify the gas formed in the reaction as hydrogen by means of mass spectrometry.