EP4622978A1

EP4622978A1 - Process for the production of hydridosilanes

Info

Publication number: EP4622978A1
Application number: EP23805608.9A
Authority: EP
Inventors: Roland Wagner; Felix NEUMEYER; Christian WENSKE; Thorsten FELDER; Justine TAXACHER; Norbert Auner
Original assignee: Momentive Performance Materials GmbH
Current assignee: Momentive Performance Materials GmbH
Priority date: 2022-11-22
Filing date: 2023-11-15
Publication date: 2025-10-01
Also published as: CN120476124A; WO2024110270A1; JP2025538298A; KR20250120303A

Abstract

A process for the production of one or more silane compounds having at least one Si-H bond (A), comprising a step of subjecting one or more compounds having at least one Si-X bond (B), wherein X is a halogen atom, to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids.

Description

Process for the Production of Hydridosilanes

TECHNICAL FIELD

The present invention relates to the production of hydridosilanes using a metal hydride as reductant in a heterocyclic ionic liquid serving both as solvent and redistribution promoter, in particular to a process for the production of organohydridosilanes and organohydridohalosilanes, especially to the production of dimethylchlorosilane from dimethyldichlorosilane using CaH2 as the reductant, and to compositions comprising hydridohalosilanes, metal halides and one or more heterocyclic ionic liquids.

BACKGROUND OF THE INVENTION

The partial or complete reduction of halosilanes, in particular of chlorosilanes, to their hydrogenated analogues is an important transformation yielding key intermediates in the field of both organic and inorganic silicon chemistry.

Especially organohydrido- and organohydridochlorosilanes are versatile reagents due to their ability of addition to multiple bonds by means of hydrosilylation reactions.

In particular, hydridochlorosilanes are valuable building blocks in synthetic silicon chemistry due to their bifunctional substitution, which allows either the Si-CI moiety or the Si-H moiety of such a silane to be subjected to selective transformations, while the other moiety remains unaffected and may be further functionalized in a subsequent step.

For example, Me2SiHCI is a key intermediate for the synthesis of a broad variety of functional silicones by means of hydrosilylation. Me2SiHCI is a component naturally occurring in the chlorosilane mixture received by the Rochow process. However, the portion of Me2SiHCI occurring as a side-product in the Rochow process is too low to satisfy a demand which increases because of the ongoing development of a broad portfolio of highly specialized functional silicones.

There is a need for a straight forward and efficient one step process which gives access to organohydridosilanes, for example Me2SiHCI using unconstraint and affordable raw materials.

The following concepts were proposed and are partially used for the synthesis of simultaneously Si-CI and Si-H bonds containing silanes by reduction:

1 . Reduction of Si-CI bonds to Si-H bonds using H2

H2 is a low-priced reducing agent, however, the reduction of Si-CI to Si-H was found to be depending on very specific catalytic reaction sites in combination with drastic conditions. US 5716590 discloses that Ni-silicide in combination with H2 at elevated temperatures gives access to SiH silanes starting from SiCI silanes ((). US 4059608 discloses the hydrogenolytic cleavage of Si-Si bonds yielding SiH silanes in the presence of dispersed Ni in HMPT in combination with H2.

2. Reductions of Si-CI using metal hydrides

JP H03 24091 discloses a process employing LiH in combination with LiCI/KCI salt mixtures for the reduction of chlorosilanes at high temperatures above 350 °C. LiH, however, is a very expensive metal hydride, and the process’ energy consumption is high.

In EP 0301678, a Sn-based system is disclosed. Sn-based systems, however, are expensive, toxic and/or difficult to handle.

In EP0878476 a process using MgH2/AICh combinations in inert solvents activated by milling, and in US 5455367 a process using MgH2 in ether activated by ultrasound were disclosed. AlC is a volatile compound and therefore hard to separate from the target products. Milling and ultrasound require non-standard equipment and thus increase the complexity of the reaction.

G. Simon et al., J. Organomet. Chem., 1^st January 1981 , p. 279-286 discloses that Me2SiCh can be reduced to Me2SiHCI by CaH2 at temperatures as high as 300 °C in very low yields only.

US 11008349 proposes a system consisting of LiH, ether solvent and PR4CI as redistribution catalysts. LiH forms Me2SiH2 out of Me2SiCh. Me2SiH2 is then redistributed with Me2SiCh in the presence of PR4CI yielding Me2SiHCI. Therefore an excess of Me2SiCh is important for the formation of the target product Me2SiHCI from the intermediate Me2SiH2. Further, the patent discloses in a general manner the use of quaternary ammonium compounds NR4CI instead of PR4CI as a redistribution catalyst.

Further, EP3915995 A1 and WO2019/060487 A1 disclose methods for the production of compounds having at least one Si-H bond using LiH in the presence of n-Bu4PCI. The reactions are thus performed in the absence of any heterocyclic ionic liquid.

EP1717241 A1 discloses a redistribution reaction of MeSiCh and SiH2Ch in the presence of 1-butyl-3-methylimidazolium chloride. Thus, the process does not comprise a reduction reaction of chlorosilanes by metal hydrides followed by a redistribution reaction between chlorosilanes and the hydridosilanes formed, but is directed at a redistribution reaction in which an organochlorosilane is brought to reaction with a hydridochlorosilane having no organyl residue. SUMMARY OF THE INVENTION

The present invention described in detail hereafter relates to a process for the production of one or more silane compounds having at least one Si-H bond (A), comprising a step of subjecting one or more compounds having at least one Si-X bond (B), wherein X is a halogen atom, to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

The process according to the invention is a process for the production of one or more silane compounds having at least one Si-H bond (A), which comprises a step of subjecting one or more compounds having at least one Si-X bond (B), wherein X is a halogen atom, to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids.

The term “one or more compounds having at least one Si-X bond (B)” as defined herein comprises any compound containing at least one Si-X bond (B), wherein X is a halogen, i.e. a fluoro, chloro, bromo or iodo group, preferably chloro, and mixtures of two or more such compounds, which serve as starting materials in the process of the invention.

Accordingly, the starting material(s) may be selected from monosilanes, disilanes, oligo- or polysilanes and carbodisilanes having at least one Si-X bond, wherein monosilanes, di-, oligo- and polysilanes are preferred compounds (B), mono- and disilanes are more preferred compounds (B), and monosilanes are generally the most preferred compounds (B) in the process according to the invention.

The process of the invention may be applied to any type of silane compounds (B) including silanes having at least one Si-X bond (B) with substituents exclusively selected from halogen atoms and hydrogen atoms, but preferably the process of the invention is applied to organosilanes, i.e. compounds (B) having at least one Si-R bond, wherein R is an organyl group. The term “organyl group” as defined herein refers to any organic group having one free valence at a carbon atom, and accordingly the organyl groups R are bonded to the Si atoms of the silanes via a carbon atom.

According to an embodiment of the invention, the organyl groups R comprise optionally substituted, but preferably unsubstituted groups, which are independently selected from the groups consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, even more preferably selected from alkyl, cycloalkyl, alkenyl and aryl groups, even further preferably selected from methyl, ethyl, vinyl and phenyl, and most preferably R is a methyl group.

As defined herein, the term “alkyl groups” comprises unbranched n-alkyl groups, branched alkyl groups and cycloalkyl groups. According to an embodiment of the invention, alkyl groups having 1 to 22 carbon atoms are preferred, alkyl groups having 1 to 12 carbon atoms are more preferred, and alkyl groups having 1 to 8 carbon atoms are even further preferred, in particular methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, cyclopentyl, sec-pentyl, iso-pentyl, neo-pentyl, n-hexyl, cyclohexyl, n-heptyl and n-octyl groups.

As defined herein, the term “aryl group” comprises all groups derived from monoyclic and polycyclic aromatic hydrocarbons by removal of a hydrogen atom from a ring carbon atom.

According to an embodiment of the invention, aryl groups having 6-22 carbon atoms are preferred, in particular phenyl groups.

As defined herein, the term “alkenyl group” comprises unbranched, branched and cyclic hydrocarbyl residues having one or more carbon-carbon double bonds. According to an embodiment of the invention, alkenyl groups having 1 to 22 carbon atoms are preferred, alkenyl groups having 1 to 12 carbon atoms are more preferred, and alkenyl groups having 1 to 8 carbon atoms are even further preferred, in particular vinyl and allyl groups.

The one or more halogen atoms X bonded to the Si atom or atoms of the silane compounds (B) are selected from fluorine atoms, chlorine atoms, bromine atoms and iodine atoms, preferably chlorine, wherein the silane compounds B may contain two or more different types of halogen atoms, but preferably the silane compounds B contain one type of halogen atom bonded to the Si atom or atoms. While the silanes (B) containing all types of halogen atoms cited above can be submitted to the process of the invention, in an embodiment of the invention it is preferred that the halogen atom X is selected from iodine atoms, bromine atoms and chlorine atoms, more preferably from bromine atoms and chlorine atoms, and most preferably all halogen atoms X of a silane compound (B) are selected from chlorine atoms.

Further, according to an embodiment of the invention, it is preferred that the silane compounds (B) are exclusively substituted by halogen substituents or organic substituents and halogen substituents, i.e. the compounds (B) are preferably perhalogenated silanes and in particular perhalogenated organosilanes. More preferably, the compounds (B) are perchlorinated silanes and in particular perchlorinated organosilanes, even more preferably selected from tetrachlorosilane and the organochloromonosilanes RSiC , R2SiCh, RsSiCI, wherein R is an organyl group. Even more preferably, the compound (B) is selected from MeSiC and Me2SiCh, most preferably the compound (B) is Me2SiCh. The silane compounds having at least one Si-X (B) bond can be monosilanes, disilanes, polysilanes and carbodisilanes. As defined herein, the term polysilanes covers all types of silanes having three or more silicon atoms bonded to each other in a linear manner, i.e. forming for example a- Si-Si-Si- moiety in the case of a trisilane.

Monosilanes:

The monosilanes having at least one Si-X bond (B) serving as starting materials can be either monosilanes bearing only substituents selected from one or more halogen atoms X, preferably chlorine atoms, and optionally hydrogen atoms, or monosilanes bearing substituents selected from one or more halogen atoms, preferably chlorine atoms, one or more organyl substituents R and optionally hydrogen atoms. The organyl groups R can be the same or different in an organomonosilane bearing two or more groups R. The one or more organyl groups R are optionally substituted, but preferably unsubstituted groups, which are independently selected from the groups consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, even more preferably selected from alkyl, cycloalkyl, alkenyl and aryl groups, even further preferred selected from methyl, ethyl, vinyl and phenyl, and most preferably R is a methyl group.

Preferred monosilanes bearing only halogen atoms and hydrogen atoms are SiCk, SiBr4, Si , HSiCh, HSiBrs and HSih, wherein SiCk and HSiCh are most preferred.

In an embodiment, preferably the monosilanes having at least one Si-X bond (B) are organomonosilanes, i.e. they have one or more substituents R, further preferably R is an unsubstituted alkyl group or phenyl group.

According to an embodiment of the invention, it is preferred that the organomonosilanes (B) have the general formula RaSiHbXc, wherein X is a halogen atom, preferably chlorine,

R is an organyl group, a = 1 to 3, b = 0 to 2, c = 1 to 3, and a + b + c = 4.

While the process according to the invention is also suitable for the reduction of organohalomonosilanes of the general formula RsSiX, in particular RsSiCI, in an embodiment the process is preferably applied to organodihalomonosilanes and organotrihalomonosilanes of the general formulas R2SiX2 and RSiXs, in particular R2SiCh and RSiC . Therein, R is an organyl group and X is a halogen atom as defined before, and R is preferably selected from the group consisting of unsubstituted C1-C12 alkyl groups, unsubstituted C1-C12 alkenyl groups and C6-C12 aryl groups, more preferably from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, cyclopentyl, cyclohexyl, norbornyl, isopropyl, isobutyl, tert-isobutyl, isoamyl, vinyl, allyl, phenyl and naphthyl groups, most preferably from methyl, vinyl and phenyl groups.

Therein, the organodihalo- and organotrihalosilanes as described above may be fully hydrogenated by replacement of all Si-X bonds by Si-H bonds in the reaction with the metal hydride, but preferably the corresponding organohydridohalosilanes of the general formula R2SiHX, RSiH2X and RSiHX2, more preferably of the general formula R2SiHCI, RSiH2CI and RSiHCh are obtained in the process according to the invention.

In an embodiment, the most preferred monosilanes (B) are Me2SiCl2 and MeSiC , and the most preferred products (A) of the process according to the embodiment of the invention based on the monosilane starting materials (B) as described are Me2SiHCI, MeSiHCh and MeSiH2CI.

Disilanes:

The disilanes having at least one Si-X bond (B) serving as starting materials can be either disilanes bearing only substituents selected from one or more halogen atoms X, preferably chlorine atoms, and optionally hydrogen atoms, or disilanes bearing substituents selected from one or more halogen atoms, preferably chlorine atoms, one or more organyl substituents R, and optionally hydrogen atoms. The organyl groups R can be the same or different in an organodisilane bearing two or more groups R. The one or more organyl groups R are optionally substituted, but preferably unsubstituted groups, which are selected from the groups consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, even more preferably selected from alkyl, cycloalkyl, alkenyl and aryl groups, even further preferred selected from methyl, ethyl, vinyl and phenyl, and most preferably R is a methyl group.

Preferred disilanes bearing only halogen atoms and hydrogen atoms are Si2Cle, Si2Bre and Si₂l₆, wherein Si2Cle is most preferred.

Preferably, the disilanes having at least one Si-X bond (B) are organodisilanes, i.e. they have one or more substituents R, further preferably R is an unsubstituted alkyl group or phenyl group.

According to an embodiment of the invention it is preferred that the organodisilanes (B) have the general formula R_eSi2HfX_g wherein R is an organyl group as defined above, andX is a halogen atom, preferably chlorine, e = 1 to 5, f = 0 to 4, g = 1 to 5 and e + f + g = 6.

The disilanes of the general empirical formula

ReSi2HfX_g can also be depicted by the structural formula:

R' R'

R' - Si — Si — R'

R' R' wherein the substituents R‘ are independently selected from organyl groups R as defined above, hydrogen atoms and halogen atoms X, preferably chlorine, wherein the number of organic substituents e = 1 to 5, the number of hydrogen atoms f = 0 to 4 and the number of halogen atoms g = 1 to 5, and the total of e + f + g = 6.

As defined herein, the term “empirical formula” intends to mean that the formulae do not represent the structural formulae, but just sum up the chemical groups or atoms present in the molecule. For example, the empirical formula R2Si2Ck may comprise the structural formulae:

According to an embodiment of the invention, it is preferred that the organodisilanes (B) bear only organyl substituents R and halogen substituents X, more preferably the organodisilanes are selected from the group of disilanes having the formulas R2Si2X4, RsSi2X3 and R4Si2X2, even more preferably R2Si2Ck, R3Si2C and R4Si2Ch, wherein R is as defined above. Further preferably, therein R is selected from alkyl, aryl and alkenyl groups, even more preferably from phenyl, vinyl, ethyl and methyl groups.

While in the process according to the invention all halogen atoms of the disilane compounds (B) may be replaced by hydrogen atoms, in an embodiment it is preferred that the organohalodisilanes are only partially hydrogenated, thus yielding organohydridohalodisilanes (A), in particular organohydridochlorodisilanes (A). Concurrently with the hydrogenation, preferably partial hydrogenation, effected in the process by a reaction of the silane starting materials (B) with the metal hydrides (C) and redistribution reactions promoted by the heterocyclic ionic liquids, the organohalodisilanes (B) and the products (A) obtained by partial or full hydrogenation of the starting material (B) can undergo cleavage reactions in the process according to the invention. In the cleavage reaction of disilanes, the Si-Si bond of the compounds is cleaved, resulting in the formation of monosilanes.

The rate of the cleavage reaction depends on the substitution pattern of the compounds (B), for example on the number and type of organyl residues R present in the disilane compound, and the reaction conditions, in particular the type of the heterocyclic ionic liquid, the reaction temperature and the reaction time.

By cleavage of the disilane compounds (B) and their hydrogenated analogues, monosilanes having at least one Si-H bond (A) can be obtained from disilanes (B) in the process according to an embodiment of the invention, preferably organohydridohalomonosilanes are obtained, even more preferably organohydridochloromonosilanes of the formulas RSiHCh, RSiH2CI and R2SiHCI, most preferably MeSiHCh, MeSiH2CI and Me2SiHCI.

Particularly preferred organodisilanes (B) are Me2Si2Cl4, Me3Si2C and Me4Si2Cl2, and the preferred products obtained therefrom in the process according to the embodiment of the invention are Me2SiHCI, MeSiHCh, MeSiH2CI, and MesSiH.

Polysilanes:

The polysilanes having at least one Si-X bond (B) serving as starting materials can be either polysilanes bearing only substituents selected from one or more halogen atoms X, preferably chlorine atoms, and optionally hydrogen atoms, or polysilanes bearing substituents selected from one or more halogen atoms, preferably chlorine atoms, one or more organyl substituents R and optionally hydrogen atoms. The organyl groups R can be the same or different in an organopolysilane bearing two or more groups R. The organyl groups R are optionally substituted, but preferably unsubstituted groups, which are selected from the groups consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, even more preferably selected from alkyl, cycloalkyl, alkenyl and aryl groups, even further preferred selected from methyl, ethyl, vinyl and phenyl, and most preferably R is a methyl group.

According to an embodiment of the invention, the polysilanes are preferably selected from the group of oligosilanes that have a linear or branched silane skeleton, wherein q = 3 to 7 and the silicon atoms are bonded to each other by single bonds, and the compounds have the general empirical formula RpSiqHrXs, wherein

R is an organyl group,

X is a halogen atom, preferably a chlorine atom, q = 3-7 p = 0 to (2q + 1) r = 0 to (2q + 1) s = 1 to (2q + 2) r + s = (2q + 2) - p.

Preferred polysilanes bearing no organic residues are SisCh, Si4Cl , SisCli2, SieClu and SiyCh 6-

It is preferred that the polysilanes according to an embodiment of the invention have one or more substituents R, further preferably R is an unsubstituted alkyl group or phenyl group.

According to an embodiment of the invention, it is preferred that these organopolysilanes (B) bear only organyl substituents R and halogen substituents X, more preferably the organopolysilanes are selected from the group of organopolysilanes with R = alkyl, aryl and alkenyl groups, even more preferably from the group of organopolysilanes with R = phenyl, vinyl and methyl groups, and most preferably the substituents are selected from methyl and chloro groups.

While in the process according to the invention all halogen atoms of the polysilane compounds (B) may be replaced by hydrogen atoms, in an embodiment it is preferred that the organohalopolysilanes are only partially hydrogenated, thus yielding organohydridohalopolysilanes, in particular organohydridochloropolysilanes.

In analogy to the description of the cleavage reaction of the disilanes above, the organohalopolysilanes (B) and the products obtained therefrom by hydrogenation and redistribution can be cleaved in the process according to an embodiment of the invention by cleavage of one or more Si-Si bonds, thus yielding silanes with a lower number of silicon atoms, in particular organomonosilanes, more preferably organohydridohalomonosilanes, even more preferably organohydridochloromonosilanes of the formulas RSiHCh, RSiH2CI and R2SiHCI, most preferably MeSiHCh, MeSiH2CI and Me2SiHCI.

In the process according to an embodiment of the invention, the preferred products obtained from organohalopolysilanes, which are typically available as complex mixtures, e.g. as sideproducts in the Direct Process for the production of Me2SiCl2, are R2SiHCI, RSiHCh, RSiH2CI, RsSiH, wherein R is an organyl group, preferably an alkyl group. Most preferably, the products are Me2SiHCI, MeSiHCh, MeSiH2CI, and MesSiH. Carbodisilanes:

The carbodisilanes having at least one Si-X bond (B) serving as starting materials in the process according to the invention have the general empirical formula

Rm(Si[CH₂]z Si)H_nX₀ wherein R is an organyl group as defined above, m = 0 to 5, n = 0 to 5, o = 1 to 6, z = 1 or 2, and m + n + o = 6.

The organyl group R can be the same or different in a carbodisilane bearing two or more groups R.

The organyl group R is optionally substituted, but preferably an unsubstituted group, which is selected from the groups consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, even more preferably selected from alkyl, cycloalkyl, alkenyl and aryl groups, even further preferred selected from methyl, ethyl, vinyl and phenyl, and most preferably R is a methyl group. While preferred carbodisilanes bearing only halogen residues are C (SiCH2Si)Cl3 or C SiCH2CH2SiCl3, wherein the latter can be obtained from the reaction C SiH + CH2=CHSiCl3, it is generally preferred that the carbodisilanes silanes according to an embodiment of the invention have one or more substituents R, further preferably R is an unsubstituted alkyl group or phenyl group.

According to an embodiment of the invention, it is preferred that these carbodisilanes (B) bear only organyl substituents R and halogen substituents X, more preferably the carbodisilanes are selected from the group of carbodisilanes with R = alkyl, aryl and alkenyl groups, even more preferably from the group of carbodisilanes with R = phenyl, vinyl, ethyl and methyl groups, and most preferably the substituents are selected from methyl and chloro groups.

Examples of specifically preferred carbodisilanes are Me2CISiCH2CH2SiCl3, MeCI₂SiCH₂CH₂SiCl3, Cl3SiCH₂CH₂SiCl3, Me₂CISiCH2CH2SiMe₂CI, and Me₂CISiCH2CH2SiMeCI₂.

While in the process according to the invention all halogen atoms of the carbodisilane compounds (B) may be replaced by hydrogen atoms, in an embodiment it is preferred that the carbodisilanes are only partially hydrogenated, thus yielding organohydridohalocarbodisilanes, in particular organohydridochlorocarbodisilanes.

According to an embodiment of the invention, organocarbodisilanes may also serve as starting materials (B) for the production of organomonosilanes, preferably organohydridohalomonosilanes, even more preferably organohydridochloromonosilanes of the formulas RSiHCh, RSiH2CI and R2SiHCI, most preferably MeSiHCh, MeSiH2CI and Me2SiHCI. In contrast to the cleavage of disilanes and carbodisilanes, the cleavage reaction of the carbodisilanes described above resulting in the formation of monosilanes requires the cleavage one or more Si-C bonds.

From the above classes of silane compounds which have one or more Si-X bonds (B) and which can thus serve as starting material in the process according to the invention, in an embodiment it is preferred that one or more of the following silanes is subjected to the process:

- Monosilanes, which are selected from the formulas:

MeSiC , Me2SiCh and MesSiCI;

- Disilanes, which are selected from the formulas:

ChMeSi-SiMeCh, Cl2MeSi-SiMe2CI, ChMeSi-SiMes, CIMe2Si-SiMe2CI, Me3Si-SiMe2CI;

- Oligosilanes, which are selected from the formulas:

CIMe2Si-SiMe2-SiMe2CI, CIMe2Si-SiMe2-SiMe2-SiMe2CI, (CIMe2Si)3SiMe, (ChMeSi^SiMeCI, (CI₂MeSi)₃SiMe, (CI₂MeSi)₂SiMe-SiCIMe-SiCI₂Me, [(CI₂MeSi)₂SiMe]₂,

[(CI₂MeSi)₂SiMe]₂SiCIMe, (CI₂MeSi)₂SiMe-SiMe₂CI;

- Carbodisilanes, which are selected from the formulas:

CI₂MeSi-CH₂-SiMeCI₂, CIMe₂Si-CH₂-SiMeCI₂, CIMe₂Si-CH₂-SiMe₂CI, Me₃Si-CH₂-SiMeCl2 and Me₃Si-CH2-SiMe₂CI, Me₂CISiCH₂CH₂SiCl3, MeCI₂SiCH₂CH₂SiCl3, Cl3SiCH₂CH₂SiCl3, Me₂CISiCH2CH2SiMe₂CI, Me₂CISiCH2CH₂SiMeCl2.

As defined herein, the term “one or more silane compounds having at least one Si-H bond (A)” comprises any compound containing at least one Si-H bond. Such compound (A) or mixtures of several of such compounds (A) are the desired products obtained in the process of the invention by submitting the starting material compounds (B) to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids.

The type of compounds (A) obtained in the process according to the invention is mainly determined by the choice of starting materials, i.e. of the one or more compounds (B) submitted to the process, and further the type of compounds formed and/or the distribution of several compounds (A) obtained may be controlled by the specific reaction conditions applied. In the process according to the invention, the starting material silane compounds (B) are subjected to reaction with one or more metal hydrides (C) in order to obtain one or more silane compounds (A) having at least one Si-H bond. Therein, at least one Si-X bond of one or more compounds (B) is replaced by a Si-H bond, resulting in the formation of one or more hydrogenated products.

As defined herein, the term “subjecting to a reaction with” is understood as any way of bringing the compound (B) and the metal hydride (C) into contact in the presence of one or more heterocyclic ionic liquids that a reaction of one or more silane compounds (B) and one or more metal hydride (C) takes place.

The metal hydrides (C) serve as hydride donors and are converted to the analogous metal halogenides, while at least one Si-X bond of one or more compounds (B) is replaced by a Si- H bond in the course of the hydrogenation reaction.

As defined herein, the term “metal hydride (C)” refers to any hydride donor containing at least one metal atom or metal ion, including complex metal hydrides, organometallic reagents and binary metal hydrides. The term “complex metal hydrides” refers to metal salts wherein contain hydride anions, e.g. as hydridometalate anions, for example UAIH4 or NaBH4. Typically, complex metal hydrides contain more than one type of metal or metalloid. As defined herein, the term “metalloid” comprises the elements boron, silicon, germanium, arsenic, antimony, tellurium, carbon, aluminum, selenium, polonium, and astatine.

The term “organometallic hydride reagent” refers to compounds that contain bonds between carbon atoms and metal atoms, and which are capable of donating at least one hydride anion used in a reaction of silane compounds (B), resulting in the replacement of at least one Si-X bond by a Si-H bond. Binary metal hydrides as defined herein are metal hydrides consisting of cations of one specific metal and hydride ions exclusively.

In an embodiment of the invention, the metal hydrides are preferably selected from binary metal hydrides or complex metal hydrides, more preferably selected from alkali metal hydrides, earth alkaline metal hydrides and complex metal hydrides comprising alkaline metal or alkaline earth metal cations, even more preferably selected from the group of lithium hydride, sodium hydride, potassium hydride, magnesium hydride, calcium hydride, even more preferably from magnesium hydride, sodium hydride or calcium hydride, most preferably the metal hydride is calcium hydride.

The molar ratio of hydride ions of the one or more metal hydrides in relation to halogen atoms of the one or more compounds (B) allows to control the extent of replacement of Si-X bonds in the starting material compounds (B) and thus determines which product silane compound or compounds (A) are primarily formed in the process of the invention. The addition of an equimolar amount or excess of hydride ions in the metal hydride (C) over the Si-X bonds in the compound (B), i.e. a molar ratio of hydride ions to Si-X bonds of equal 1 or more than 1 , is expected to result in the full hydrogenation of the halosilanes unless hydride anions are consumed otherwise in the reaction mixture. The addition of a substoichiometric amount of hydride ions, i.e. in a molar ratio of less than 1 , results in the partial hydrogenation of the starting material (B) in case the one or more compounds have more than one Si-X bond, and to incomplete conversion in case the starting material (B) has only a single Si-X bond.

The reaction of the process resulting in the replacement of one or more Si-X bonds of the compounds (B) by Si-H bonds is performed in the presence of one or more heterocyclic ionic liquids. As defined herein, a heterocyclic ionic liquid is a salt comprising a heterocyclic anion and/or cation which is liquid under the conditions of the process according to the invention. Usually, the salt or ionic liquid has a melting point of below about 150°C, preferable below about 140°C, more preferable below about 120°C, still more preferable below about 100°C, and most preferable below about 50°C. The melting points are measured at normal pressure with a digital apparatus, such as of Electrothermal.

The selection of the ionic liquid or ionic liquids is made on the basis of parameters such as melting point, polarity, compatibility with the Si compound to be hydrogenated, commercial availability, ease of purification and recyclability.

Without wishing to be bound to any theory, it is assumed that the presence of one or more heterocyclic ionic liquids promotes and accelerates the reaction of the one or more compounds (B) and the metal hydride or metal hydrides (C), inter alia by removing the metal halogenide formed on the surface of the metal hydride particles in the hydrogenation reaction. This renders the application of other means of activation such as milling, sonication or the addition of other activating agents, redundant, thus significantly facilitating the hydrogenation process. Further, the presence of the heterocyclic ionic liquids allows to control the ratio of the different silane product compounds (A) formed by hydrogenation by promoting redistribution reactions between the different hydrogenated species of silane compounds formed, as well as between the different hydrogenated species of silane compounds formed and the starting material silane compounds (B).

According to an embodiment of the invention, the heterocyclic structure of the ionic liquid is not restricted in any way except for the restriction that a cyclic structure containing one or more heteroatoms needs to be present in the ionic liquid, i.e. at least one atom different from a carbon atom and a hydrogen atom, is necessarily included as a ring member, wherein the cyclic structure may be aromatic or non-aromatic. A ring structure consisting of carbon atoms exclusively having one or more heteroatom substituents is not considered a heterocycle according to the invention. The heteroatoms are typically selected from oxygen atoms (O), sulfur atoms (S), phosphorus atoms (P), and nitrogen atoms (N), wherein P-heterocycles and N-heterocycles are generally preferred.

While there is no restriction to the ring size of the heterocyclic structure, the number of heteroatoms present in the heterocyclic ring and the type of heteroatoms, it is preferred that the heterocyclic structures are 5- or 6- membered rings containing one or two heteroatoms, wherein the heteroatoms are preferably selected from N atoms and P atoms. These structures can be either aromatic or non-aromatic.

According to an embodiment of the invention, the heterocyclic ionic liquid is preferably selected from the group consisting of N-heterocyclic ionic liquids and P-heterocyclic ionic liquids.

As defined herein, N-heterocyclic ionic liquids and P-heterocyclic ionic liquids are heterocyclic ionic liquids as defined above, wherein the heterocycle of the ionic liquid compound is a P- heterocycle, i.e. a cyclic structure containing one or more P-atoms as ring members, or an N- heterocycle, i.e. a cyclic structure containing one or more N-atoms as ring members.

The P-heterocycle or the N-heterocycle, respectively, can be present in the cation, the anion or both the cation and the anion of the ionic liquid, but preferably a P-heterocycle or an N- heterocycle is comprised by the cation of the ionic liquid.

According to an embodiment of the invention, N-heterocyclic ionic liquids are preferred and can be selected from aromatic N-heterocyclic ionic liquids or non-aromatic N-heterocyclic ionic liquids. Examples of aromatic N-heterocyclic ionic liquids according to the embodiment of the invention are ionic liquids selected from imidazolium salts, pyridinium salts, pyrrolium salts and triazolium salts.

The general structure of 1 ,3-substituted imidazolium salts is wherein R¹ and R² are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSCh (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of N-substituted pyridinium compounds is wherein R³ is an organyl residue, preferably a C1-C12 alkyl residue, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSOs (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of an N,N-disubstituted pyrrolium salt is wherein R⁴ and R⁵ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSCh (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of an 1 ,3-substituted 1 ,2,3-triazolium salt is wherein R⁶ and R⁷, are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSOs (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate;

As defined herein, each or the ring carbon atoms of the structures shown above may independently also bear a further substituent instead of a hydrogen substituent, wherein the substituents are preferably selected from halogen substituents and alkyl groups, more preferably from C1-C12 alkyl groups. Specific examples of imidazolium salts comprise 1-ethyl-3-methylimidazolium chloride, 1- butyl-3-methylimidazolium chloride and1-hexyl-3-methylimidazolium chloride, specific examples of pyridinium salts comprise N-butyl pyridinium chloride, N-hexyl pyridinium chloride and N-octyl pyridinium chloride, specific examples of pyrrolium salts comprise N,N-dimethyl pyrrolium chloride, N-methyl-N-ethyl pyrrolium chloride, N-methyl-N-butyl pyrrolium chloride and N-methyl-N-hexyl pyrrolium chloride, and specific examples of triazolium salts are N-butyl- N’-methyl-C-methyl triazolium chloride and N-butyl-N’-methyl-C-butyl triazolium chloride.

Examples of non-aromatic N-heterocyclic ionic liquids according to the embodiment of the invention are ionic liquids selected from morpholinium salts, piperidinium salts, pyrrolidinium salts, and piperazinium salts.

The general structure of N, N-substituted morpholinium salts is

^R\ / - \

Z' N + O z \ _ / wherein R⁸ and R⁹ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSCh (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of N, N-substituted piperidinium compounds is wherein R¹⁰ and R¹¹ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSOs (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of N, N-substituted pyrrolidinium salts is wherein R¹² and R¹³ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSOs (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of piperazinium mono salts is wherein R¹⁴, R¹⁵ and R¹⁶ are organyl residues, preferably C1-C12 alkyl residues and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSCh (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate; the general structure of piperazinium di salts is wherein R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSOs (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate. As defined herein, each of the ring carbon atoms of the structures shown above may independently also bear a further substituent instead of a hydrogen substituent, wherein the substituents are preferably selected from halogen substituents and alkyl groups, more preferably from C1-C12 alkyl groups.

Specific examples of morpholinium salts comprise N,N-dimethyl-morpholinium chloride, N- methyl-N-ethyl-morpholinium chloride, N-methyl-N-butyl-morpholinium chloride, and N-methyl- N-hexyl-morpholinium chloride, specific examples of piperidinium salts comprise N,N- dimethyl-piperidinium chloride, N-methyl-N-ethyl-piperidinium chloride, N-methyl-N-butyl- piperidinium chloride and N-methyl-N-hexyl-piperidinium chloride, specific examples of pyrrolidinium salts comprise N,N-dimethyl-pyrrolidinium chloride, N-methyl-N-ethyl- pyrrolidinium chloride, N-methyl-N-butyl-pyrrolidinium chloride and N-methyl-N-hexyl- pyrrolidinium chloride, specific examples of piperazinium mono salts comprise N,N,N’- trimethyl-piperazinium chloride, N,N’-dimethyl-N-ethyl-piperazinium chloride, N,N’-dimethyl-N- butyl-piperazinium chloride, and N,N’-dimethyl-N-hexyl-piperazinium chloride, specific examples of piperazinium di salts comprise N,N,N’,N’-tetramethyl-piperazinium dichloride, N,N’-dimethyl-N,N’-diethyl-piperazinium dichloride, N,N’-dimethyl-N,N’-dibutyl-piperazinium dichloride, and N,N’-dimethyl-N,N’-dihexyl-piperazinium chloride.

According to an embodiment of the invention, the P-heterocyclic ionic liquids can be selected from aromatic P-heterocyclic ionic liquids and non-aromatic P-heterocyclic ionic liquids. Examples of aromatic P-heterocyclic ionic liquids according to the embodiment of the invention are ionic liquids are phospholium salts (containing five-membered rings with one P heteroatom) and phosphininium salts (containing six-membered rings with one P heteroatom), which are exemplified by the specific structures below:

Examples of non-aromatic P-heterocyclic ionic liquids according to the embodiment are ionic liquids selected from phospholanium salts (containing a saturated five-membered ring with one P heteroatom) and phosphinanium salts (containing a saturated six-membered ring with one P heteroatom). The general structure of phospholanium salts is wherein R¹⁸ and R¹⁹ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSCh (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate;

The general structure of phosphinanium salts is wherein R²⁰ and R²¹ are organyl residues, preferably C1-C12 alkyl residues, and Z can be any type of anion, preferably an anion selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSOs (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate or methylsulfonate.

According to the embodiment of the invention, the structures displayed above may also independently bear further substituents, preferably halogen substituents and alkyl substituents, on the carbon ring atoms.

Specific examples of phospholanium salts comprise P, P-dimethyl-phospholanium chloride and P-methyl-P-butyl-phospholanium chloride (five membered ring), specific examples of phosphinanium salts comprise P,P-dimethyl-phosphinanium chloride (six membered ring) and P-methyl-P-butyl-phosphinanium chloride (six membered ring).

It is preferred according to an embodiment of the invention that the cation of the ionic liquid comprises a heterocyclic structure. The anions of the ionic liquid compounds can be selected from any kind of organic and inorganic anion or anions, wherein monovalent cations are preferred.

Examples of anions of the ionic liquid compounds are F; Cl; Br, I; AICU", heptachlorodialuminate (AI2CI7 ), hexafluoroantimonate, hexafluoroarsenate, fluorosulphonate, hexafluorophosphate (PFe’), tetrafluoroborate (BF4'), bis- perfluoroalkylsulfonyl amides (in particular methyl, butyl and nonyl, most particular bis(trifluormethylsulfonyl)imide (NTf2', TFSI)), and perfluoroalkyl sulfonates (in particular trifluoromethanesulfonate), tetrachloroborate, dicyanamide anion (DCA-), acetate, trifluoroacetate, methanesulfonate, tetrafluoroborate, hexafluorophosphate, lactate, citrate, sulfate, phosphate, methyl sulfate, ethyl sulfate, hydrogen sulfate, carbonate and methylcarbonate.

Preferably the anion is selected from chloride, bromide, acetate, trifluoroacetate, OTf (trifluormethanesulfonate), MeSCh (methanesulfonate), TFSI (bis(trifluormethylsulfonyl)imide), tetrafluoroborate, or hexafluorophosphate, more preferred from chloride, tetrafluoroborate (BF4), hexafluorophosphate (PFe), bis-trifluoromethanesulfonimide (NTf2), and trifluoromethanesulfonate (OTf).

In order to obtain a high proportion of a specific partially hydrogenated halosilane, a substoichiometric amount of hydride ions is provided by the addition of a metal hydride. In parallel and/or following the reduction reaction, the product mixture is formed by an equilibration process involving redistribution reaction of compounds (A) formed in the process and starting materials (B) present in the reaction mixture.

As defined herein, the term “redistribution reaction” describes the redistribution of hydrogen and halogen substituents, preferably of hydrogen and chlorine substituents, bound to silicon atoms of one or more silane compounds by exchange of these substituents. The exchange can be monitored in particular by ²⁹Si NMR, by GC and/or GC/MS. Preferably, by the redistribution reaction of silanes bearing mostly or only chlorine substituents besides organyl substituents at the silicon atoms and silanes bearing only or mostly hydrogen substituents besides organyl substituents at the silicon atoms, organohydridohalosilanes bearing both hydrogen and halogen substituents, preferably hydrogen and chlorine substituents, at the silicon atoms are obtained.

The redistribution reaction of silanes as defined herein includes in particular the comproportionation of two different organosilanes, in particular of one having only halogen as additional substituents, and one having only hydrogen as additional substituents) with the formation of one specific halohydridoorganosilane, such as e.g.

Me₂SiCI₂ + Me₂SiH₂ = 2 Me₂SiHCI

2 MeSiC + MeSiH₃ = 3 MeSiHCh.

The redistribution reactions may be considered to be the opposite to the undesired disproportionation wherein for example a chlorohydridomethylsilane reacts with itself to form two different methylsilanes (one having only chlorine as additional substituents, and one having only hydrogen as additional substituents): 2 Me₂SiHCI = Me₂SiCI₂ + Me₂SiH₂

3 MeSiHCI₂ => 2 MeSiC + MeSiH₃.

The redistribution reactions are catalyzed or promoted by the one or more heterocyclic ionic liquids. While the presence of further different redistribution catalysts is within the scope of the process of the invention, it is preferred in an embodiment that there is no further redistribution catalyst added besides the heterocyclic ionic liquid.

As defined above, the starting materials of the process according to the invention are the silane compounds having at least one Si-X bond (B), which include monosilanes, disilanes, carbodisilanes and polysilanes, wherein the silane compounds may either also contain organyl substituents or not. While the term “organyl” is herein defined to refer to any organic substituent group, regardless of functional type, which is bonded to a silicon atom of the compound (B) via a carbon atom thereof, in an embodiment of the invention the organyl group preferably is an substituted or unsubstituted, more preferably unsubstituted group, which is selected from the group consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, and cycloaralkynyl groups, even more preferably alkyl, cycloalkyl, alkenyl and aryl groups, even further preferrably methyl, ethyl, vinyl and phenyl groups, and most preferably R is a methyl group (herein also abbreviated as Me).

According to the embodiment of the invention, it is preferred that the process results in the formation of one or more halohydridoorganomonosilanes, in particular the chlorohydridoorganomonosilanes R₂SiHCI, RSiH₂CI and RSiHCI₂.

Such compounds are highly attractive and valuable due to their bifunctional nature, which renders them useful reagents in synthesis. The most preferred silane compounds having at least one Si-H bond (A) obtained in the process according to the embodiment of the invention are Me₂SiHCI, MeSiH₂CI and MeSiHCI₂.

The aforementioned bifunctional halohydridoorganomonosilane compounds can be obtained in general by submitting monosilanes (B) as described above to the process of the invention, but in an embodiment the process is also suitable to obtain organohydridohalomonosilanes by submitting the corresponding disilanes, polysilanes and carbodisilanes (B) as described above.

This requires that a cleavage reaction takes place in the process according to the embodiment of the invention.

The term “cleavage reaction” is used above to describe the transformation by which disilanes (B), polysilanes (B) and carbodisilanes (B) as described above are reacted to produce monosilanes (A). In the case of disilanes and polysilanes, the term “cleavage reaction” further indicates that according to the present invention, the cleavage of the aforementioned substrates is effected by breaking the bond connecting the silicon atoms of these disilanes and polysilanes or of the fully or partly hydrogenated derivatives thereof. In the case of carbodisilanes, the term “cleavage reaction” indicates that the cleavage reaction is effected by breaking one or both Si-C bonds between the silyl groups and the methylene group or ethylene group linking the silyl groups in the carbodisilanes. In order to promote cleavage reactions as described above, further cleavage promoters or cleavage catalysts may be added to the reaction mixture of the process according to an embodiment of the invention.

Such cleavage promoters or catalysts are preferably selected from the group consisting of: a quaternary Group 15 onium compound R4QX, wherein each R is independently a hydrogen or an organyl group, Q is nitrogen, phosphorus, arsenic, antimony or bismuth, and X is a halide selected from the group consisting of F, Cl, Br and I, a heterocyclic amine, a heterocyclic ammonium halide, a mixture of R3P and RX, wherein R is as defined above, and X is as defined above, alkali metal halide, an alkaline earth metal halide, an alkali metal hydride, alkaline earth metal hydride or mixtures thereof.

According to an embodiment of the invention, however, it is preferred that no further cleavage catalyst or cleavage promoter is added in addition to the heterocyclic ionic liquid applied in the process according to the invention.

In general, the type of compounds having at least one Si-H bond (A) is determined by the silane starting material (B) and the amount of metal hydride brought to reaction with the silane starting material (B). Further, in case cleavage of di- and polysilanes is involved, the type of mono silanes (A) obtained is primarily determined by the substitution pattern of the di- and polysilanes and the amount of metal hydride used.

In a most preferred embodiment of the invention, Me2SiCl2 is subjected to a reaction with CaH2 in the presence of one or more heterocyclic ionic liquids at a temperature of about 0 °C to about 150 °C, thus yielding Me2SiHCI, wherein the heterocyclic ionic liquid is preferably selected from an N-heterocyclic aromatic quaternary ammonium ionic liquid, more preferably from an ionic liquid selected from imidazolium salts, even more preferably from a 1 -substituted imidazolium salt, even further preferably selected from the 1-alkyl-3-methylimidazolium chlorides, most preferably from ethyl MIMCI, butyl MIMCI and hexyl MIMCI. In an embodiment according to the invention, each X is independently selected from a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom, more preferably every X in the compound (B) is a chlorine atom.

Si-CI bonds, Si-Br bonds and Si-1 bonds can be easily replaced in the process according to the embodiments of the invention by contacting the silane compounds having one or more Si-X bonds (B) with a metal hydride in the presence of a heterocyclic ionic liquid. Preferably, at least one X of a silane compound (B) represents a chlorine atom, and more preferably all substituents X in the silane compound (B) are chlorine atoms.

In an embodiment according to the invention, the compound having at least one Si-H bond (A) is an organomonosilane compound, preferably an organohydridochloromonosilane.

The target compounds according to this embodiment are monosilanes bearing one or more organyl groups R and one or more hydrido substituent.

Both organohydridomonosilanes having the formulas RsSiH, R2SiH2 and RsSiH, and organohydridohalosilanes having the formulas RSiX2H, RSiXH2 and R2SiXH are produced according to this embodiment of the invention. Therein, the substituent R is independently selected from organyl groups, preferably from C1-C12 alkyl groups or phenyl groups, more preferably from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl, cyclohexyl or phenyl groups, most preferably from methyl and phenyl groups.

According to the embodiment, X is independently selected from F, Cl, Br or I substituents, preferably every X represents a Cl atom.

It is preferred according to the embodiment that the compounds having at least one Si-H bond (A) are organohydridochloromonosilanes, i.e. organomonosilanes bearing one or more hydrogen atoms and one or more chlorine atoms as substituents. Accordingly, preferred target compounds (A) have the general formulas RSiH2CI, RSiHCh and R2SiHCI, wherein R is independently selected from organyl groups, preferably from C1-C12 alkyl groups or phenyl groups, more preferably from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl, cyclohexyl or phenyl groups, most preferably from methyl and phenyl groups. In the case of the silane compounds (A) of the formula R2SiHCI, it is preferred that both R represent the same substituent, most preferably methyl groups. Organohydridochloromonosilanes bearing one or more organyl groups R, one or more hydrido substituents and one or more chloro substituents are valuable building blocks in synthetic silicon chemistry due to their bifunctional substitution. The most preferred target compounds (A) according to the embodiment are MeSiH2CI, MeSiHCh and Me₂SiHCI. In an embodiment according to the invention, the compound having at least one Si-X bond (B) is an organosilane compound, preferably an organoperchlorosilane, more preferably an organoperchloromonosilane compound. The starting materials (B) according to the embodiment thus comprise monosilanes, disilanes, polysilanes and carbodisilanes having one or more groups R and at least one halo group X bonded to one or several Si atoms of the compound. In the process according to the embodiment, any type of organosilane having one or more Si-X bonds including organohydridohalosilanes (B) can be further hydrogenated by contacting the silane compounds (B) with metal hydride.

According to the embodiment, the groups R of a silane compound (B) are independently selected from optionally substituted, preferably unsubstituted, alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl, cycloaralkynyl, more preferably selected from alkyl, cycloalkyl, alkenyl and aryl groups, even further preferred selected from methyl, vinyl and phenyl, and most preferably R is a methyl group. Preferably, the compound having at least one Si-X bond (B) is an organoperchlorosilane, i.e. all substituents of the silane compound (B) different from an organyl group are chloro substituents. Preferred monosilanes according to the embodiment have the general formulas RSiC , R₂SiCI₂ and R₃SiCI, preferred disilanes have the general formulas RChSi-Si-RCh, R2CISi-SiRCl2 and R2CISi-SiR2CI, preferred polysilanes have the general formulas CIR2Si-SiR2-SiR2CI, CIR2Si-SiR2-SiR2-SiR2CI, (CIR₂Si)₃SiR, (CI₂RSi)₂SiRCI, (CI₂RSi)₃SiR, (CI₂RSi)₂SiR-SiCIR-SiCI₂R, [(CI₂RSi)₂SiR]₂, [(CI₂RSi)₂SiR]₂SiCIR, (CI₂RSi)₂SiR- SiR₂CI, and preferred carbodisilanes have the general formulas CI₂RSi-CH₂-SiRCI₂, CIR₂Si- CH₂-SiRCI₂, CIR₂Si-CH₂-SiR₂CI, R₃Si-CH₂-SiRCI₂ R₃Si-CH₂-SiR₂CI, R₂CISiCH₂CH₂SiCI₃, RCI₂SiCH₂CH₂SiCI₃, CI₃SiCH₂CH₂SiCI₃, R₂CISiCH₂CH₂SiR₂CI, and R₂CISiCH₂CH₂SiRCI₂.

Preferred examples of compounds having at least one Si-X bond (B) according to the embodiment of the invention are MeSiC , Me₂SiCI₂, Me₃SiCI, CI₂MeSi-SiMeCI₂, CI₂MeSi- SiMe₂CI, CI₂MeSi-SiMe₃, CIMe₂Si-SiMe₂CI, Me₃Si-SiMe₂CI, CIMe₂Si-SiMe₂-SiMe₂CI, CIMe₂Si- SiMe₂-SiMe₂-SiMe₂CI, (CIMe₂Si)₃SiMe, (CI₂MeSi)₂SiMeCI, (CI₂MeSi)₃SiMe, (CI₂MeSi)₂SiMe- SiCIMe-SiCI₂Me, [(CI₂MeSi)₂SiMe]₂, [(CI₂MeSi)₂SiMe]₂SiCIMe, (CI₂MeSi)₂SiMe-SiMe₂CI, CI₂MeSi-CH₂-SiMeCI₂, CIMe₂Si-CH₂-SiMeCI₂, CIMe₂Si-CH₂-SiMe₂CI, Me₃Si-CH₂-SiMeCI₂, Me₃Si-CH₂-SiMe₂CI, Me₂CISiCH₂CH₂SiCI₃, MeCI₂SiCH₂CH₂SiCI₃, CI₃SiCH₂CH₂SiCI₃, Me₂CISiCH₂CH₂SiMe₂CI, and Me₂CISiCH₂CH₂SiMeCI₂.

More preferably, the compound (B) is an organoperchloromonosilane compound, most preferably the compound (B) is selected from Me₂SiCI₂ and MeCI₃, in particular Me₂SiCI₂.

In an embodiment according to the invention, the product (A) is selected from monosilanes of the general formula (I) RxSiHyCIz (I), wherein R is an organyl group, x = 0 to 3, preferably 0, 1 , 2 and 3, y = 1 to 4, preferably 1 to 2, most preferred 1 z = 0 to 3, preferably 0, 1 , 2 and 3, and x + y + z = 4.

The monosilanes (A) of the embodiment can be chlorosilanes which do not bear any organyl group R, i.e. x = 0 in the general formula (I). Preferred halomonosilanes according to the embodiment are SiCk, SiBr4, Sik, HSiCh, HSiBrs and HSih, wherein SiCk and HSiCh are most preferred. It is more preferred that the monosilanes (A) are organomonosilanes wherein x is 1 to 3, even more preferably 1 or 2, and y is preferably 1 or 2. Preferred organomonosilanes according to the embodiment are R2SiHCI, RSiH2CI and RSiHCh. Preferably, the organyl group R is selected from methyl, ethyl, phenyl and vinyl. The most preferred monosilane products (A) are Me₂SiHCI, MeSiHCh and MeSiH₂CI.

In an embodiment according to the invention, the product (A) is selected from monosilanes of the general formula (I)

RxSiHyCIz (I), wherein R is an organyl group, x = 1 to 3, preferably 1 to 2, y = 1 to 3, preferably 1 to 2, z = 0 to 2, preferably 1 to 2, and x + y + z = 4.

Preferred organomonosilanes according to the embodiment are R2SiHCI, RSiH2CI and RSiHCh. Preferably, the organyl group R is selected from methyl, ethyl, phenyl and vinyl. The most preferred monosilane products (A) are Me2SiHCI, MeSiHCh and MeSiH2CI.

In an embodiment according to the invention, the compound having at least one Si-X bond (B) is selected from organochloromonosilanes of the general formula (II) RaSiHbCIc (II) wherein R is as defined above, a = 1 to 3, b = 0 to 2, c = 1 to 3, and a + b + c = 4.

It is preferred that a = 1 or 2, and that b = 0, i.e. that the starting material is a monosilane bearing one or two organyl groups and chlorine substituents only. It is further preferred that the organyl group R is selected from methyl, ethyl, phenyl and vinyl. The most preferred monosilane starting materials (B) are Me2SiCl2, and MeSiCh.

In an embodiment according to the invention, the organyl groups R are independently selected from alkyl groups, cycloalkyl groups or phenyl groups, preferably R represents a methyl group. Preferably, all groups R in an organosilane containing one or more Si-X bonds (B) or an organosilane containing one or more Si-H bonds (A) are selected from the same type of group selected from alkyl groups, cycloalkyl groups or phenyl groups, more preferably from C1-C12 alkyl groups, C3-C8 cycloalkyl groups and phenyl groups, and most preferably from methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl and phenyl groups. Most preferably, any R is a methyl group, and accordingly the most preferred organosilanes (B) according to the embodiment are Me2SiCh and MeSiCh, and correspondingly the most preferred organosilanes (A) according to the embodiment are Me2SiHCI, MeSiHCh and MeSiH2CI.

In an embodiment according to the invention, the compound (A) is selected from Me2SiHCI, MeSiH2CI, MeSiHCh, Me2SiHCI, HSiCh and MesSiH, preferably the compound (A) is Me₂SiHCI.

Methylhydridomonosilanes, in particular methylhydridomonosilanes, are particularly valuable reagents and thus there is a high interest in providing such compounds in a sustainable and cost- and resource-efficient manner. It is preferred according to this embodiment to provide the methylhydridomonosilanes (A) MeSiH2CI, MeSiHCh, HSiCh, and MesSiH by subjecting the analogous methylchloromonosilanes MeSiCh, Me2SiCh and MesSiCI, respectively, to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids, preferably using CaH2 as metal hydride, and further preferably using a heterocyclic ionic liquid selected from the group of N containing aromatic quaternary ammonium compounds.

In an embodiment according to the invention, the compound (B) is selected from Me2SiCh, MeSiCh, SiCk and MesSiCI, preferably the compound (B) is Me2SiCh. The compounds (B) according to this embodiment can be fully hydrogenated by reacting the silanes with an excess of hydride ions from the metal hydrides (C) in the presence of a heterocyclic ionic liquid without any additional means or agents of activation, resulting in the production of the silane products (A) MeSiHs, Me2SiH2 and MesSiH. Preferably, the compounds (B) according to the embodiment are brought to reaction with a substoichiometric amount of hydride ions from the metal hydrides (C), resulting in the partial replacement of the Si-X bonds of the starting material. The most preferred products therein are Me2SiHCI, MeSiHCh and MeSiH2CI. The presence of heterocyclic ionic liquids allows to perform such reaction in the absence of further activating means or agents, and further reduces the amount of starting materials (B) and the perhydrogenated analogues thereof MeSiHs, Me2SiH2 and MesSiH, respectively, in favor of the desired organohydridochlorosilanes by equilibration via redistribution of chlorine and hydrogen atoms.

In an embodiment according to the invention, the metal hydride (C) is selected from alkaline metal hydrides, alkaline earth metal hydrides or complex metal hydrides comprising alkaline metal or alkaline earth metal cations, preferably the metal hydride (C) is selected from LiH, NaH, KH, MgH2, CaH2 and UAIH4, most preferably the metal hydride (C) is CaH2. Preferably, the metal hydrides (C) according to the embodiment of the invention are selected from binary metal hydrides, more preferably selected from alkali metal hydrides and alkaline earth metal hydrides, even more preferably selected from the group of lithium hydride, sodium hydride, potassium hydride, magnesium hydride, calcium hydride, even more preferably from calcium hydride and magnesium hydride, most preferably the metal hydride (C) is calcium hydride. While the reaction of silane compounds having one or more Si-X bonds with metal hydrides often requires activation by activation means such as sonication, milling or the addition of activating agents, the compounds (B) can be readily transformed to the desired products (A) by contacting the metal hydrides with the silanes (B) in the presence of heterocyclic ionic liquids. This enables to perform the reaction of the process with relatively low cost hydrides NaH, KH, MgH2 and CaH2, in particular with CaH2. As the form of the metal hydride (C) is not restricted, it is preferred according to the embodiment to add the metal hydride as a micronized powder or as a slurry of such powder to the reaction mixture. The heterocyclic ionic liquid promotes the reaction by removal of a passivating layer of metal oxides and in particular of metal halides formed in the reaction with the halosilanes from the surface of the metal hydride particles.

In a further embodiment according to the invention, the process is carried out in the absence of any metal hydride reagent (C) other than CaH2. As already mentioned before, it is preferred to use calcium hydride as metal hydride (C), because this hydride is readily available at low cost. In the presence of a heterocyclic ionic liquid, no further metal hydride reagent (C) is required, which further improves the cost efficiency of the process for the production of one or more silane compounds having at least one Si-H bond (A).

In an embodiment according to the invention, the molar ratio of hydride ions of the one or more metal hydrides in relation to halogen atoms, preferably chlorine atoms, of the one or more compounds (B) in the reaction mixture is in the range of about 0.01 to about 300, more preferably about 0.1 to about 10, even more preferably about 0.4 to about 6, and most preferably about 0.7 to about 3.

As described before, the amount of the metal hydride (C) delivering hydride ions to be added in relation to the halogen atoms is determined by whether full replacement of all Si-X bonds by Si-H bonds is desired, and whether there is further consumption of the hydride ions, e.g. by reactions of further compounds not falling under the definition of the silane compounds (B) in the reaction mixture.

In an embodiment according to the invention, the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic ionic liquids and P-heterocyclic ionic liquids.

According to the invention, N-heterocyclic ionic liquids and P-heterocyclic ionic liquids are heterocyclic ionic liquids as defined before, wherein the heterocycle of the ionic liquid compound is a P-heterocycle, i.e. a cyclic structure containing a P-atom as ring member, or an N-heterocycle, i.e. a cyclic structure containing an N-atom as ring member. The P- heterocycle or the N-heterocycle, respectively, can be present in the cation, the anion or both the cation and the anion of the ionic liquid, but preferably the cation of the ionic liquid comprises a P-heterocycle or an N-heterocycle.

In an embodiment according to the invention, the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic ionic liquids and P-heterocyclic aromatic ionic liquids.

The compounds of the N- or P-heterocyclic ionic liquids, respectively, according to this embodiment comprise one or more aromatic moieties. Preferably, the aromatic structure of the N- or P-heterocyclic compounds is the heterocyclic structure. Examples of N-heterocyclic aromatic ionic liquids according to the embodiment are ionic liquids selected from imidazolium salts, pyridinium salts and triazolium salts, examples of P-heterocyclic aromatic ionic liquids according to the embodiment are ionic liquids selected from phospholium salts and phosphininium salts.

In an embodiment according to the invention, the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic quaternary ammonium ionic liquids and P-heterocyclic phosphonium ionic liquids.

The compounds of the N- or P-heterocyclic ionic liquids, respectively, according to this embodiment comprise one or more quaternary ammonium groups or phosphonium groups, respectively. Typically, the quaternary structure of the N- or P-heterocyclic compounds is located in the heterocyclic structure, i.e. it is a quaternary N- or P-atom being part of the ring structure. N-heterocyclic quaternary ammonium ionic liquids may, for example, be selected from pyridinium salts, imidazolium salts, 1 ,2,3-triazolium salts, imidazolinium salts and pyrrolium salts, morpholinium salts, piperidinium salts, piperazinium salts and pyrrolidinium salts.

Preferred P-heterocyclic ionic liquids compounds according to this embodiment are phospholanium salts of the general structure wherein R¹⁸ and R¹⁹ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R¹⁸ is selected from methyl or butyl and R¹⁹ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R¹⁸ is selected from methyl or butyl and R¹⁹ is selected from methyl, ethyl or butyl, most preferably R¹⁸ and R¹⁹ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the P,P-substituted phospholanium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C or 4-C ring atom, more preferably a methyl, ethyl or butyl residue.

Specifically preferred P,P-substituted phospholanium compounds are 1 ,1 -dimethylphospholanium chloride, 1-ethyl-1-methyl-phospholanium chloride, 1-butyl-1-methyl- phospholanium chloride, 1-hexyl-1-methyl-phospholanium chloride, 1 -octyl- 1-methyl- phospholanium chloride, 1-butyl-1-ethyl-phospholanium chloride, 1 ,1-dibutyl-phospholanium chloride, 1-hexyl-1-butyl-phospholanium chloride and 1 -octyl- 1 -butyl- phospholanium chloride. Another type of preferred P-heterocyclic ionic liquids compounds according to this embodiment are phosphinanium salts of the general structure wherein R²⁰ and R²¹ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R²⁰ is selected from methyl or butyl and R²¹ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R²⁰ is selected from methyl or butyl and R²¹ is selected from methyl, ethyl or butyl, most preferably R²⁰ and R²¹ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the P,P-substituted phosphinanium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C or 4-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred P,P-substituted phosphinanium compounds are 1 ,1 -dimethyl- phosphinanium chloride, 1- ethyl-1-methyl-phosphinanium chloride, 1-butyl-1 -methyl- phosphinanium chloride, 1-hexyl-1- methyl-phosphinanium chloride, 1 -octyl- 1 -methyl- phosphinanium chloride, 1 -butyl-1 -ethyl- phosphinanium chloride, 1 ,1-dibutyl-phosphinanium chloride, 1-hexyl-1-butyl-phosphinanium chloride and 1-octyl-1-butyl-phosphinanium chloride.

In an embodiment according to the invention, the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic quaternary ammonium ionic liquids and P- heterocyclic aromatic quaternary phosphonium ionic liquids.

In an embodiment according to the invention, the heterocyclic ionic liquid is selected from the group of aromatic heterocyclic quaternary ammonium salts comprising pyridinium salts, imidazolium salts, 1 ,2,3-triazolium salts, imidazolinium salts, pyrrolium salts, the group of nonaromatic heterocyclic quaternary ammonium salts comprising morpholinium salts, piperidinium salts, piperazinium salts and pyrrolidinium salts, and the group of aromatic heterocyclic quaternary phosphonium salts comprising phosphininium salts. Preferably, the counter anion in an aromatic heterocyclic quaternary ammonium salt-based ionic liquid, a non-aromatic heterocyclic quaternary ammonium salt-based ionic liquid or an aromatic heterocyclic quaternary phosphonium salt-based ionic liquid as cited above is selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably from chloride, bromide and tetrafluoroborate. According to the embodiment, preferred 1 ,2,3-triazolium salts are 1 ,3-substituted 1 ,2,3- triazolium salts of the general structure wherein R⁶ and R⁷ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R⁶ is selected from methyl or butyl and R⁷ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R⁶ is selected from methyl or butyl and R⁷ is selected from methyl, ethyl or butyl, most preferably R⁶ and R⁷ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the 1 ,3-substituted 1 ,2,3-triazolium salt can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 4-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred 1 ,3- substituted 1 ,2,3-triazolium compounds are 1-methyl-3-methyl-1 ,2,3-triazolium chloride, 1- ethyl-3-methyl-1 ,2,3-triazolium chloride, 1-butyl-3-methyl-1 ,2,3-triazolium chloride, 1-hexyl-3- methyl-1 ,2,3-triazolium chloride, 1-octyl-3-methyl-1 ,2,3-triazolium chloride, 1 -butyl-3-ethyl- 1 ,2,3-triazolium chloride, 1-butyl-3-butyl-1 ,2,3-triazolium chloride, 1-hexyl-3-butyl-1 ,2,3- triazolium chloride, and 1-octyl-3-butyl-1 ,2,3-triazolium chloride. Specifically preferred 1 ,3- substituted 1 ,2,3-triazolium compounds bearing a further substituent at a ring C-atom are 1- methyl-3-methyl-4-methyl-1 ,2,3-triazolium chloride, 1-ethyl-3-methyl-4-methyl-1 ,2,3-triazolium chloride, 1-butyl-3-methyl-4-methyl-1 ,2,3-triazolium chloride, 1-butyl-3-ethyl-4-methyl-1 ,2,3- triazolium chloride, 1-butyl-3-butyl-4-methyl-1 ,2,3-triazolium chloride, 1-methyl-3-methyl-4- butyl-1 ,2,3-triazolium chloride, 1-ethyl-3-methyl-4-butyl-1 ,2,3-triazolium chloride, 1-butyl-3- methyl-4-Bu-triazolium chloride, 1-butyl-3-ethyl-4-butyl-1 ,2,3-triazolium chloride, 1-butyl-3- butyl-4-butyl- 1 ,2,3-triazolium chloride.

According to the embodiment, preferred pyrrolium salts are N,N-alkyl pyrrolium salts of the general structure wherein R⁴ and R⁵ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R⁴ is selected from methyl or butyl and R⁵ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R⁴ is selected from methyl or butyl and R⁵ is selected from methyl, ethyl or butyl, most preferably R⁴ and R⁵ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the N,N-substituted pyrrolium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C or 3-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred N,N-substituted pyrrolium compounds are 1 ,1-dimethyl-pyrrolium chloride, 1-ethyl-1-methyl-pyrrolium chloride, 1-butyl-1-methyl-pyrrolium chloride, 1-hexyl-1-methyl-pyrrolium chloride, 1 -octyl- 1 -methylpyrrolium chloride, 1-butyl-1-ethyl-pyrrolium chloride, 1 , 1 -dibutyl-pyrrolium chloride, 1-hexyl- 1-butyl-pyrrolium chloride and 1-octyl-1-butyl-pyrrolium chloride. Specifically preferred N,N- substituted pyrrolium compounds bearing a further substituent at the 2-C ring atom are 1 ,1 ,2- trimethyl-pyrrolium chloride, 1-ethyl-1 ,2-dimethyl-pyrrolium chloride, 1 -butyl-1 ,2-dimethyl- pyrrolium chloride, 1-hexyl-1 ,2-dimethyl-pyrrolium chloride, 1-octyl-1 ,2-dimethyl-pyrrolium chloride, 1 -butyl-1 -ethyl-2-methyl-pyrrolium chloride, 1 ,1-dibutyl-2-methyl-pyrrolium chloride, 1-hexyl-1-butyl-2-methyl-pyrrolium chloride, and 1-octyl-1-butyl-2-methyl-pyrrolium chloride,

1.1-dimethyl-2-butyl-pyrrolium chloride, 1-ethyl-1-methyl-2-butyl-pyrrolium chloride, 1 ,2- dibutyl-1-methyl-pyrrolium chloride, 1-hexyl-1-methyl-2-butyl-pyrrolium chloride, 1-octyl-1- methyl-2-butyl-pyrrolium chloride, 1 ,2-dibutyl-1 -ethyl-pyrrolium chloride, 1 , 1 ,2-tributyl- pyrrolium chloride, 1-hexyl-1 ,2-dibutyl-pyrrolium chloride, and 1-octyl-1 ,2-dibutyl-pyrrolium chloride. Specifically preferred N,N-substituted pyrrolium compounds bearing a further substituent at the 3-C ring atom are 1 ,1 ,3-trimethyl-pyrrolium chloride, 1 -ethyl-1 ,3-dimethyl- pyrrolium chloride, 1 -butyl-1 , 3-dimethyl-pyrrolium chloride, 1-hexyl-1 ,3-dimethyl-pyrrolium chloride, 1-octyl-1 , 3-dimethyl-pyrrolium chloride, 1 -butyl-1 -ethyl-3-methyl-pyrrolium chloride,

1.1-dibutyl-3-methyl-pyrrolium chloride, 1-hexyl-1-butyl-3-methyl-pyrrolium chloride, and 1- octyl-1-butyl-3-methyl-pyrrolium chloride, 1 ,1-dimethyl-3-butyl-pyrrolium chloride, 1 -ethyl-1 - methyl-3-butyl-pyrrolium chloride, 1 ,3-dibutyl-1-methyl-pyrrolium chloride, 1-hexyl-1-methyl-3- butyl-pyrrolium chloride, 1-octyl-1-methyl-3-butyl-pyrrolium chloride, 1 ,3-di butyl-1 -ethyl- pyrrolium chloride, 1 , 1 ,3-tributyl-pyrrolium chloride, 1-hexyl-1 ,3-dibutyl-pyrrolium chloride, and 1-octyl-1 ,3-dibutyl-pyrrolium chloride.

Preferred N,N-morpholinium salts according to the embodiment are N,N-alkyl morpholinium salts of the general structure wherein R⁸ and R⁹ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R⁸ is selected from methyl or butyl and R⁹ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R⁸ is selected from methyl or butyl and R⁹ is selected from methyl, ethyl or butyl, most preferably R⁸ and R⁹ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the N,N-substituted morpholinium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C or 3-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred N,N- substituted morpholinium compounds are 1 ,1-dimethyl-morpholinium chloride, 1-ethyl-1- methyl-morpholinium chloride, 1-butyl-1-methyl-morpholinium chloride, 1-hexyl-1-methyl- morpholinium chloride, 1 -octyl- 1 -methyl- morpholinium chloride, 1-butyl-1-ethyl-morpholinium chloride, 1 ,1-dibutyl-morpholinium chloride, 1-hexyl-1-butyl-morpholinium chloride and 1-octyl- 1-butyl-morpholinium chloride.

Preferred N,N-piperidinium salts according to the embodiment are N,N-alkyl piperidinium salts of the general structure wherein R¹⁰ and R¹¹ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R¹⁰ is selected from methyl or butyl and R¹¹ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R¹⁰ is selected from methyl or butyl and R¹¹ is selected from methyl, ethyl or butyl, most preferably R¹⁰ and R¹¹ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion.

Optionally, the N,N-substituted piperidinium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C or 4-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred N,N-substituted piperidinium compounds are 1 ,1-dimethyl-piperidinium chloride, 1-ethyl-1-methyl-piperidinium chloride, 1 -butyl-1 - methyl- piperidinium chloride, 1-hexyl-1-methyl-piperidinium chloride, 1 -octyl- 1-methyl- piperidinium chloride, 1 -butyl-1 -ethyl-piperidinium chloride, 1 , 1 -dibutyl-piperidinium chloride, 1-hexyl-1-butyl-piperidinium chloride and 1-octyl-1-butyl-piperidinium chloride.

Preferred N,N-pyrrolidinium salts according to the embodiment are N,N-alkyl pyrrolidinium salts of the general structure wherein R¹² and R¹³ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R¹² is selected from methyl or butyl and R¹³ is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R¹² is selected from methyl or butyl and R¹³ is selected from methyl, ethyl or butyl, most preferably R¹² and R¹³ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the N,N-substituted pyrrolidinium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C or 4-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred N,N-substituted pyrrolidinium compounds are 1 ,1-dimethyl-pyrrolidinium chloride, 1-ethyl-1- methyl-pyrrolidinium chloride, 1 -butyl-1 -methyl- pyrrolidinium chloride, 1-hexyl-1-methyl- pyrrolidinium chloride, 1-octyl-1-methyl-pyrrolidinium chloride, 1 -butyl-1 -ethyl-pyrrolidinium chloride, 1 , 1 -dibutyl-pyrrolidinium chloride, 1-hexyl-1-butyl-pyrrolidinium chloride and 1-octyl- 1-butyl-pyrrolidinium chloride.

Preferred piperazinium mono salts according to the embodiment are N,N,N’-alkyl piperazinium mono salts of the general structure wherein R¹⁴, R¹⁵ and R¹⁶ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R¹⁵ is selected from methyl or butyl, and R¹⁴ and R¹⁶ are selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R¹⁵ is selected from methyl or butyl and R¹⁴ and R¹⁶ are selected from methyl, ethyl or butyl, most preferably R¹⁴, R¹⁵ and R¹⁶ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the N,N,N’- substituted piperazinium mono salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C, 5-C or 6-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred N,N,N’-substituted piperazinium mono salt compounds are 1 ,1 ,4-trimethyl-piperazinium chloride, 1-ethyl-1 ,4-dimethyl-piperazinium chloride, 1-butyl- 1 ,4-dimethyl-piperazinium chloride, 1-hexyl-1 ,4-dimethyl-piperazinium chloride, 1-octyl-1 ,4- dimethyl-piperazinium chloride, 1-butyl-1-ethyl-4-methyl-piperazinium chloride, 1 , 1 -dibutyl-4- methyl-piperazinium chloride, 1-hexyl-1-butyl-4-methyl-piperazinium chloride, and 1-octyl-1- butyl-4-methyl-piperazinium chloride, 1 ,1-dimethyl-4-butyl-piperazinium chloride, 1-ethyl-1- methyl-4-butyl-piperazinium chloride, 1 ,4-dibutyl-1-methyl-piperazinium chloride, 1-hexyl-1- methyl-4-butyl-piperazinium chloride, 1-octyl-1-methyl-4-butyl-piperazinium chloride, 1 ,4- dibutyl-1-ethyl-piperazinium chloride, 1 ,1 ,4-tributyl-piperazinium chloride, 1 -hexyl-1 ,4-dibutyl- piperazinium chloride, and 1-octyl-1 ,4-dibutyl-piperazinium chloride.

Preferred piperazinium di salts according to the embodiment are N,N,N’,N’-alkyl piperazinium di salts of the general structure wherein R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R¹⁵ and R¹⁷ are selected from methyl or butyl, and R¹⁴ and R¹⁶ are selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R¹⁵ and R¹⁷ are selected from methyl or butyl and R¹⁴ and R¹⁶ are selected from methyl, ethyl or butyl, most preferably R¹⁴, R¹⁵, R¹⁶ and R¹⁷ are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. In the case of the structure of the piperazinium di salts displayed above, the two Z- anions together may also represent a dianion, such as for example a sulfate dianion, an oxalate dianion, a malonate dianion, a succinate dianion, a maleate dianion, a fumarate dianion, a tartrate dianion or a phthalate dianion. Optionally, the N,N,N’,N’-substituted piperazinium di salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C, 5-C or 6-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred N,N,N’,N’- substituted piperazinium di salt compounds are 1 ,1 ,4,4-tetramethyl-piperazinium dichloride, 1- ethyl-1 ,4,4-trimethyl-piperazinium dichloride, 1-butyl-1 ,4,4-trimethyl-piperazinium dichloride, 1-hexyl-1 ,4,4-trimethyl-piperazinium dichloride, 1 -octyl-1 ,4,4-trimethyl-piperazinium dichloride, 1-butyl-1-ethyl-4,4-dimethyl-piperazinium dichloride, 1 , 1 -dibutyl-4,4-dimethyl- piperazinium dichloride, 1-hexyl-1-butyl-4,4-dimethyl-piperazinium dichloride, and 1 -octyl-1 - butyl-4,4-dimethyl-piperazinium dichloride, 1 ,1 ,4-trimethyl-4-butyl-piperazinium dichloride, 1- ethyl-1 ,4-dimethyl-4-butyl-piperazinium dichloride, 1 ,4-dibutyl- 1 ,4-dimethyl-piperazinium dichloride, 1-hexyl-1 ,4-dimethyl-4-butyl-piperazinium dichloride, 1 -octyl-1 ,4-dimethyl-4-butyl- piperazinium dichloride, 1 ,4-dibutyl-1-ethyl-4-metylpiperazinium dichloride, 1 , 1 ,4-tributyl-4- methyl-piperazinium dichloride, 1-hexyl-1 ,4-dibutyl-4-methyl-piperazinium dichloride, and 1- octyl-1 ,4-dibutyl-4-methyl-piperazinium dichloride, 1 , 1 ,4-trimethyl-4-butyl-piperazinium dichloride, 1-ethyl-1 ,4-dimethyl-4-butyl-piperazinium dichloride, 1 ,4-dibutyl-1 ,4-dimethyl- piperazinium dichloride, 1-hexyl-1 ,4-dimethyl-4-butyl-piperazinium dichloride, 1-octyl-1 ,4- dimethyl-4-butyl-piperazinium dichloride, 1 ,4-dibutyl-1-ethyl-4-methyl-piperazinium dichloride,

1 .1.4-tributyl-4-methyl-piperazinium dichloride, 1 -hexyl-1 ,4-dibutyl-4-methyl-piperazinium dichloride, and 1 -octyl-1 , 4-dibutyl-4-methyl-piperazinium dichloride, 1 , 1 -dimethyl-4,4-dibutyl- piperazinium dichloride, 1-ethyl-1-methyl-4,4-dibutyl-piperazinium dichloride, 1 ,4,4-tributyl-1 - methyl-piperazinium dichloride, 1 -hexyl-1 -methyl-4,4-dibutyl-piperazinium dichloride, 1-octyl- 1-methyl-4,4-dibutyl-piperazinium dichloride, 1 ,4,4-tributyl-1-ethyl-piperazinium dichloride,

1.1.4.4-tetrabutyl-piperazinium dichloride, 1 -hexyl-1 , 4, 4-tributyl-piperazinium dichloride, and 1 -octyl-1 , 4, 4-tributyl-piperazinium dichloride.

In a further preferred embodiment according to the invention, the ionic liquid is selected from 1 -substituted imidazolium salts and 1 -substituted pyridinium salts, preferably from 1 ,3- substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, more preferably 1 -alkyl substituted, 1-alkyl-3-substituted, 1-alkyl-2,3-substituted, 1 -alkyl-2,3,4- substituted and 1-alkyl-2,3,4,5-substituted imidazolium salts, even further preferably from 1 ,3- alkyl-substituted imidazolium salts, in particular from 1 ,3-alkyl-substituted imidazolium salts having a C1-C12 alkyl substituent at the 1-position and a methyl group at the 3-position, still further preferably selected from 1 -methyl-, 1 -ethyl-, 1 -propyl-, 1 -butyl-, 1 -pentyl-, 1 -hexyl-, 1- octyl- , 1 -decyl- and 1-dodecyl-3-methylimidazolium salts, and most preferably from EthylMIMCI and HexMlMCI. Preferably, the counter anion in an imidazolium-based ionic liquid or pyridinium-based ionic liquid is selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably from chloride, bromide and tetrafluoroborate.

According to the embodiment, the 1 -substituted pyridinium salt is preferably a compound of the general structure wherein R³ is independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R³ is selected from methyl or butyl, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion.

Optionally, the N,N-substituted pyridinium salts can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C, 3-C or 4-C ring atom, more preferably a methyl, ethyl or butyl residue.

Specifically preferred N-substituted pyridinium compounds are 1-methyl-pyridinium chloride,

1 -ethyl- pyridinium chloride, 1 -butyl- pyridinium chloride, 1 -hexyl- pyridinium chloride, and 1- octyl-pyridinium chloride.

Specifically preferred N-substituted pyridinium compounds bearing a further substituent at the

2-C ring atom are 1 ,2-dimethyl-pyridinium chloride, 1-ethyl-2-methyl-pyridinium chloride, 1- butyl-2-methyl-pyridinium chloride, 1-hexyl-2-methyl-pyridinium chloride, 1-octyl-2-methyl- pyridinium chloride, 1 -butyl-2-butyl- pyridinium chloride, 1-hexyl-2-butyl-pyridinium chloride, and 1-octyl-2-butyl-pyridinium chloride, preferred N-substituted pyridinium compounds bearing a further substituent at the 3-C ring atom are 1 ,3-dimethyl-pyridinium chloride, 1-ethyl-3- methyl-pyridinium chloride, 1-butyl-3-methyl-pyridinium chloride, 1-hexyl-3-methyl-pyridinium chloride, 1-octyl-3-methyl- pyridinium chloride, 1 -butyl-3-butyl- pyridinium chloride, 1-hexyl-3- butyl- pyridinium chloride, and 1-octyl-3-butyl-pyridinium chloride, and preferred N-substituted pyridinium compounds bearing a further substituent at the 4-C ring atom are 1 ,4-dimethyl- pyridinium chloride, 1-ethyl-4-methyl-pyridinium chloride, 1-butyl-4-methyl-pyridinium chloride, 1-hexyl-4-methyl-pyridinium chloride, 1-octyl-4-methyl-pyridinium chloride, 1-butyl-4-butyl- pyridinium chloride, 1-hexyl-4-butyl-pyridinium chloride, and 1-octyl-4-butyl-pyridinium chloride.

Further according to the embodiment, the 1 ,3-substituted imidazolium salt is preferably a compound of the general structure wherein R¹ and R² are independently selected from methyl, ethyl, butyl, hexyl and octyl residues, preferably R¹ is selected from methyl or butyl and R² is selected from methyl, ethyl, butyl, hexyl and octyl residues, further preferably R¹ is selected from methyl or butyl and R² is selected from methyl, ethyl or butyl, most preferably R¹ and R² are independently selected from methyl and butyl residues, and Z is preferably selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfonate anions, most preferably Z is a chloride anion. Optionally, the 1 ,3-substituted imidazolium salt can bear one or more further C1-C12 alkyl substituents on one or more of the ring carbon atoms, preferably they further bear one further methyl, ethyl, butyl, hexyl and octyl residue at the 2-C ring atom or 4-C ring atom, more preferably a methyl, ethyl or butyl residue. Specifically preferred 1 ,3- substituted imidazolium compounds are 1 ,3-dimethyl imidazolium chloride, 1-ethyl-3-methyl- imidazolium chloride, 1-butyl-3-methyl- imidazolium chloride, 1-hexyl-3-methyl-imidazolium chloride, 1-octyl-3-methyl- imidazolium chloride, 1-butyl-3-ethyl-imidazolium chloride, 1 ,3- dibutyl-imidazolium chloride, 1-hexyl-3-butyl-imidazolium chloride, and 1-octyl-3-butyl- imidazolium chloride. Specifically preferred 1 ,3-substituted imidazolium compounds bearing a further substituent at the 2-C ring C-atom are 1 ,2,3-trimethyl imidazolium chloride, 1-ethyl-2,3- dimethyl- imidazolium chloride, 1-butyl-2,3-dimethyl-imidazolium chloride, 1-butyl-2-methyl-3- ethyl-imidazolium chloride, 1 ,3-dibutyl-2-methyl-imidazolium chloride, 1 ,3-dimethyl-2-butyl- imidazolium chloride, 1-ethyl-2-butyl-3-methyl-imidazolium chloride, 1 ,2-dibutyl-3-methyl- imidazolium chloride, 1 ,2-dibutyl-3-ethyl-imidazolium chloride, 1 ,2,3-tributyl-imidazolium chloride. Specifically preferred 1 ,3-substituted imidazolium compounds bearing a further substituent at the 4-C ring C-atom are 1 ,3,4-trimethyl imidazolium chloride, 1-ethyl-3,4- dimethyl- imidazolium chloride, 1-butyl-3,4-dimethyl-imidazolium chloride, 1 -butyl-3-ethyl-4- methyl-imidazolium chloride, 1 ,3-dibutyl-4-methyl-imidazolium chloride, 1 ,3-dimethyl-4-butyl- imidazolium chloride, 1-ethyl-3-methyl-4-butyl-imidazolium chloride, 1 ,4-dibutyl-3-methyl- imidazolium chloride, 1 ,4-dibutyl-3-ethyl-imidazolium chloride, 1 ,3,4-tributyl-imidazolium chloride. The most preferred ionic liquid compounds according to the embodiment are 1-ethyl- 3-methyl imidazolium chloride (EthylMIMCI) and 1-hexyl-3-methyl imidazolium chloride (HexMlMCI).

In an embodiment according to the invention, the ionic liquid has a melting point of below about 150 °C, preferably below about 100°C, more preferably below about 80 °C, still more preferably below about 60 °C, even more preferably below about 40 °C, and most preferably below about 30 °C.

As the heterocyclic ionic liquid is defined as being liquid at the temperature at which the process is carried out, the heterocyclic liquid according to this embodiment has a melting point below about 150 °C, which is generally preferred according to the embodiment invention as the process according to the embodiments of the invention is preferably performed at a temperature below about 150 °C.

In an embodiment according to the invention, the amount of the one or more ionic liquids in relation to the one or more compounds (B) in the reaction mixture is in the range of about 0.1 mol-% to about 1500 mol-%, preferably about 0.2 mol-% to about 1000 mol-%, more preferably about 0.4 mol-% to about 600 mol-%, even more preferably about 0.7 mol-% to about 300 mol- %, further preferably about 0.7 mol-% to about 100 mol-%, even further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol-%.

Preferably, the starting material of the reaction does not comprise further components in addition to the one or more silane compounds (B), the one or more metal hydrides (C) and the one or more heterocyclic ionic liquid in the amount relative to the one or more compounds (B) as cited above.

In an embodiment according to the invention, the process is carried out in the absence of ether solvents, preferably in the absence of ether solvents and linear or cyclic aliphatic hydrocarbon solvents, more preferably in the absence of ether solvents and linear or cyclic aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents, most preferably in the absence of any further solvent other than the one or more ionic liquids.

There may be various reasons for the use of solvents in a chemical process, e.g. the objective to provide a reaction mixture in which the starting material is homogeneously dissolved, the objective of controlling the conversion rate and the thermal effects associated with exothermic reactions, and many more which are well-known to the skilled person. Likewise, however, there may be numerous disadvantages associated with the need to use a solvent, e.g. the toxic properties of many organic solvents, the cost for the provision of the solvents, and problems in removing the solvent from the desired products. In the case of ether solvents, there is an additional risk of peroxide formation, which may render the use of such solvents hazardous, in particular on an industrial scale. Accordingly, as the use of additional solvent is not required and in order to avoid the problems cited above, the process according to this embodiment is carried out in the absence of ether solvents, and most preferably in the absence of any further solvent other than the one or more heterocyclic ionic liquid. While the process according to the other embodiments of the invention does not generally exclude the presence of any solvents in the reaction mixture, it is generally preferred according to the embodiments of the invention that no further solvents are present in addition to the heterocyclic ionic liquids required by the process.

In an embodiment according to the invention, the process is carried out in the absence of acyclic quaternary ammonium salts and acyclic quaternary phosphonium salts.

Acyclic quaternary ammonium salts and acyclic quaternary phosphonium salts are known in the art as catalysts for redistribution reactions of silanes, which are used in the presence of organic solvents, in particular of ether compounds. In the process of the present invention, the presence of heterocyclic ionic liquids does not only enable the use of otherwise too unreactive metal hydrides for the reduction of halosilanes, but also renders the presence of further redistribution catalysts and solvents obsolete, thus reducing the process complexity and improving performance and efficiency of the process.

In an embodiment according to the invention, the reaction is carried out at a temperature in a range of about 0 to about 150 °C, preferably about 10 to about 150 °C, more preferably about 20 to about 150 °C, even more preferably about 20 to about 125 °C, and most preferably in a range of about 50 to about 125°C. As defined herein, the temperature at which the reaction is carried out is the temperature of the reaction mixture, i.e. the temperature measured inside the reaction vessel in which the reaction is conducted.

In an embodiment according to the invention, the reaction is carried out at a pressure in a range of about 0.1 to about 20 bar, preferably about 0.3 to about 20 bar, more preferably about 1 to about 20 bar, even more preferably about 1 to about 10 bar, and most preferably in a range of about 1 to about 5 bar. As defined herein, the indicated pressure ranges refer to the pressure measured inside the reaction vessel used when conducting the process of the embodiments of the invention. In an embodiment according to the invention, the process is carried out under inert conditions. As defined herein, the term “under inert conditions” means that the process is partially or completely carried out under the exclusion of surrounding air, in particular of moisture and oxygen. In order to exclude ambient air from the reaction mixture and the reaction products, closed reaction vessels, reduced pressure and/or inert gases, in particular nitrogen or argon, or combinations of such means may be used.

In an embodiment according to the invention, the process is carried out continuously or discontinuously, such as batchwise. Preferably, the process of the embodiment is carried out in a batchwise manner, for example in a batch reactor fabricated in steel, stainless steel, glass- lined steel, glass or another suitable alloy different from steel.

In an embodiment according to the invention, the process is carried out in the absence of milling or sonication of the reaction mixture.

The reduction of halosilanes by metal hydrides in many cases requires the activation of the metal hydrides, which is usually effected by the addition of activating agents, for example aluminum chloride (AlC ), the addition of a solvent promoting such reaction, for example ether compounds, by mechanical activation of the metal hydride, or a combination of such means. As means of mechanical activation, milling and sonication have been found to be particularly effective. “Milling” herein generally refers to any treatment aimed at size-reduction of a solid material by mechanical forces, and comprises in particular performing a reaction in a ball-mill. The term “sonication” as defined herein applies to any treatment in which sound energy is applied to the reaction mixture, in particular ultrasonic frequencies, i.e. ultrasonication. When ultrasound is applied to a medium, the sound waves are transformed into mechanical energy. Both milling and sonication promote the reaction of metal hydrides with halosilanes by mechanical removal of metal halide forming a passivated layer on the surface of metal hydride particles submitted to a reaction with halosilanes, thus allowing the reaction to continue. By breaking up the metal hydride into smaller particles and thus increasing the overall surface of the metal hydride particles, sonication and in particular milling further promote the reaction of metal hydrides and halosilanes. However, both milling and ultrasound require non-standard equipment and thus increase the complexity of the reaction. The presence of heterocyclic ionic liquids when submitting halosilanes, in particular organochloromonosilanes, to a reaction with metal hydrides, preferably alkaline metal hydrides and alkaline earth metal hydrides, in particular CaH2, allows to obtain the desired reduction products in the absence of further chemical or mechanical activation, in particular in the absence of milling and sonication. This allows to save cost and effort when performing said reactions. The process of the embodiment of the invention is thus carried out in the absence of milling or sonication of the reaction mixture according to this embodiment, which is generally preferred for the process according to the embodiments of the invention.

In an embodiment according to the invention, the process is carried out without supply of hydrogen chloride and/or in the absence of a metal catalyst, preferably in the absence of aluminum chloride or a palladium catalyst.

The presence of hydrogen chloride or a metal catalyst, in particular of AlC or a palladium catalyst, is not required in order to successfully perform the process according to the embodiments of the invention. AlCh is has been used in conventional processes in order to enable the reduction of MeSiCh by MgH2; under the conditions of the process according to the embodiments of the invention, however, such activation is not required. The presence of AlC further induces the redistribution of organyl groups of the silane compounds (A) and (B) present in the reaction mixture, which is not desired.

The presence of AlCh also causes technical problems because it is difficult to separate it from the product formed due to its high solubility in chlorosilanes and its low sublimation temperature. In this embodiment, the process is thus carried out without supply of hydrogen chloride and/or in the absence of a metal catalyst, in particular a palladium catalyst or AlCh, which is generally preferred according to the invention and for all embodiments thereof.

In embodiment according to the invention, the silane compounds having at least one Si-H bond (A) formed, preferably Me2SiHCI, are separated from the reaction mixture by distillation and/or condensation.

The term “distillation” as defined herein relates to any process for separating components or substances from an at least partially liquid mixture by selective evaporation and condensation. Therein, distillation may result in practically complete separation of the constituents of a mixture, thus leading to the isolation of nearly pure compounds, or it may be a partial separation that increases the concentration of selected constituents of the mixture in the distillate when compared to the mixture submitted to distillation. Preferably, the distillation processes which may constitute a separation step for isolating or enriching the desired silane compounds having at least one Si-H bond (A) are selected from simple distillation, fractional distillation, vacuum distillation, short path distillation or any other kind of distillation known to the skilled person. Also preferably, the step of separating the desired silane compounds having at least one Si-H bond (A) according to the embodiment of the invention can comprise one or more batch distillation steps, or can comprise a continuous distillation process. Further preferably, the term “condensation” may comprise separation or enrichment of one or more silane compounds having at least one Si-H bond (A) from the reaction mixture by evaporation from the reaction vessel and condensation as a liquid and/or solid in a refrigerated vessel from which it can be subsequently recovered by distillation, or by solution in a solvent.

In an embodiment of the invention, the starting material submitted to the process contains at about 75 wt-% or more of one or more compounds (B), preferably about 85 wt-% or more of one or more compounds (B), more preferably about 90 wt-% or more of one or more compounds (B), most preferably about 95 wt-% or more of one or more compounds (B).

The term “starting material”, unless further specified, for example as “silane starting material (B)”, refers to all compounds submitted to the reaction of the process according to the invention except the metal hydride (C) and the heterocyclic ionic liquid. The amount of the one or more compounds (B) given in wt-% thus refers to the ratio of compounds falling under the definition of the silane compounds (B) to the total amount of compounds falling under (B) and further additives, solvents and impurities, excluding the metal hydride (C) and the heterocyclic ionic liquid. Accordingly, the amount of additional additives, e.g. solvents, and impurities according to the embodiment is lower than about 25 wt-%, preferably lower than about 15 wt-%, more preferably lower than about 10 wt-%, and most preferably lower than about 5 wt-%.

In an embodiment according to the invention, the starting material submitted to the process contains 75 wt-% or more of an organomonochlorosilane (B), preferably about 85 wt-% or more of an organomonochlorosilane (B), more preferably about 90 wt-% or more of an organomonochlorosilane (B), even more preferably about 95 wt-% or more of an organomonochlorosilane (B), most preferably about 95 wt-% or more of Me2SiCl2.

The amount given in wt-% relates to the mass of organomonochlorosilanes (B) in relation to the total amount of silane starting materials having one or more Si-X bonds (B) submitted to the process, excluding the one or more metal hydrides (C) and the heterocyclic ionic liquids. Other solvents than the ionic liquids, i.e. organic compounds which are inert under reaction conditions and liquid at the reaction temperature, may be present in general, but are considered unnecessary. Further, the starting material may contain compounds which are impurities from the previous production of the organomonochlorosilanes. While the presence of such impurities and solvents is not necessarily detrimental to the performance of the process, it is considered preferable that the amount of the organochloromonosilane (B) in the starting material is as high as possible in view of reaction control, the necessity of adding excess metal hydride to compensate hydride consumption in undesired reactions of impurities, and of the ease of purification of the desired products. In an embodiment according to the invention, compound (A) is Me2SiHCI, the compound (B) is Me2SiCl2, and the metal hydride is CaH2.

In this embodiment of the invention, the heterocyclic ionic liquid is particularly important as a redistribution catalyst in order to shift the ratio of the reduction products Me2SiHCI and Me2SiH2 towards the target product /hSiHCl. The starting material Me2SiCl2 may be either submitted to the process as a substantially pure compound, or as a component of a mixture of compounds. For example, the compound may be submitted to the process according to the embodiment in the form of crude product obtained from the Direct Process or fraction obtained from the purification of the Me2SiCl2 produced by the direct process, for example the so-called direct process residue (DPR) containing higher-boiling side-products such as methylchlorodisilanes and methylchlorooligosilanes. Preferably, the molar ratio of CaH2 to Me2SiCl2 is in the range from about 0.1 to about 1.1 , preferably about 0.2 to about 0.9, more preferably about 0.25 to about 0.7, and even more preferably about 0.3 to about 0.65, unless the starting material contains substantial amounts of further compounds that consume hydride ions besides Me2SiCl2. As defined herein, such substantial amount of further compounds is any amount greater than about 2 wt-% based on the mass of the starting material containing Me2SiCl2.

In an embodiment according to the invention, the compound (A) is MeSibhCI or MeSiHCh, the compound (B) is MeSiCh, and the metal hydride is CaH2.

Starting from MeSiCh or a mixture of compounds comprising the same, both of the compounds MeSibhCI and MeSiHCh can be obtained, wherein the ratio of the mono- and the dihydrogenated product can be adjusted by the amount of CaH2 added to the reaction mixture. Using CaH2 as hydride source renders the process according to the embodiment particularly cost-efficient. In this embodiment of the invention, the heterocyclic ionic liquid is particularly important as a redistribution catalyst in order to obtain a desirable ratio of the reduction products MeSiF^CI and MeSiHCh. This function of the ionic liquid is particularly important because the partially hydrogenated species MeSiHCh and MeSib^CI present in the reaction mixture of the process are more prone to further hydrogenation by hydride ions than the starting material MeSiCh, and thus without redistribution an undesirable product distribution with a major amount of MeSib is obtained. Preferably, the molar ratio of CaFh to MeSiCh is in the range from about 0.1 to about 2.0, preferably about 0.2 to about 1.5, more preferably about 0.25 to about 1.0, and even more preferably about 0.3 to about 0.8, unless the starting material contains substantial amounts of further compounds besides Me2SiCh that consume hydride ions. When the desired main product of the process of the embodiment is MeSiHCh, it is preferred that the molar ratio of CaFh to MeSiCh is in the range from about 0.1 to about 1.1 , preferably about 0.2 to about 0.9, more preferably about 0.25 to about 0.7, and even more preferably about 0.3 to about 0.65, when the desired main product of the process is MeSiH2CI, it is preferred that the molar ratio of CaH2 to MeSiC is in the range from about 0.3 to about 2.0, preferably about 0.5 to about 1.5, more preferably about 0.6 to about 1.3, and even more preferably about 0.8 to about 1 .2.

In an embodiment according to the invention, the process comprises the cleavage of one or more Si-Si bonds of one or more di- or polysilane compounds (B) and/or of one or more Si-C bonds of one or more carbodisilane compounds (B).

By the cleavage of one or more Si-Si bonds, it is possible to obtain monosilanes from disilane, polysilane or carbodisilane starting materials (B). In particular, it is possible to obtain organohalomonosilanes starting from organohalodisilanes and organohalopolysilanes. In the process of the embodiment of the invention, the cleavage of one or more Si-Si allows to obtain monosilane compounds (A) from disilane and polysilane starting materials (B), in particular organomonosilanes from organodisilanes and organopolysilanes, preferably organochloromonosilanes from organochlorodisilanes and organochloropolysilanes. In the course of the process of this embodiment comprising the cleavage of disilanes and/or polysilanes, the conversion of one or more Si-X moieties of the compound(s) (B) to Si-H moieties may take place before, during or after the cleavage of one or more Si-Si bonds, and it may take place either by a reduction reaction with the one or more metal hydrides (C), or by a redistribution reaction with a monosilane or a di-, poly- or carbodisilane bearing at least one Si-H bond. The same applies in full analogy to the cleavage of one or more Si-C bonds in carbodisilanes (B). Accordingly, the process according to this embodiment provides chlorohydridomonosilanes starting from chlorodisilanes, chlorohydridodisilanes, chloropolysilanes and chlorohydridopolysilanes, in particular organohydridomonosilanes starting from organochlorodisilanes, organochlorohydridodisilanes, organochloropolysilanes and organochlorohydridopolysilanes, According to the embodiment, preferably organochlorohydridomonosilanes are produced starting from organochlorodisilanes and/or organochloropolysilanes, more preferably one or more monosilanes (A) selected from Me2SiHCI, MeSiHCh and MeSiH2CI are obtained starting from methylchlorodisilanes and/or methylchloropolysilanes, i.e. disilanes and/or polysilanes bearing chloro substituents and methyl substituents exclusively. The cleavage of the Si-Si bonds of a di-, oligo-, or polysilanes or of the Si-C bonds in carbodisilanes thus preferably takes place at the same time as the reduction reactions and redistribution reactions involved in the transformation of the silane compound having at least one Si-CI bond (B) to the compound having at least one Si-H bond (A), e.g. in the same reaction step and/or in the same reaction vessel. According to the embodiment of the invention, it is preferred that the heterocyclic ionic liquid used in the process acts as a solvent, a reaction promoter, a redistribution catalyst and a cleavage catalyst at the same time. While an additional cleavage catalyst such as

- a quaternary Group 15 onium compound R4QX, wherein each R is independently a hydrogen or an organyl group, Q is nitrogen, phosphorus, arsenic, antimony or bismuth, and X is a halide selected from the group consisting of F, Cl, Br and I,

- a heterocyclic amine,

- a heterocyclic ammonium halide,

- a mixture of R3P and RX, wherein R is as defined above, and X is as defined above,

- alkali metal halides,

- alkaline earth metal halides,

- alkali metal hydride or alkaline earth metal hydride, optionally in the presence of hydrogen chloride (HCI), may be used in the process of the afore-described embodiments, it is preferred that such further cleavage catalyst is absent from the reaction mixture, as it renders the process less cost-efficient and more complex with regard to the formation of by-products and the purification of the desired products.

In an embodiment according to the invention, the compound (A) is selected from Me2SiHCI, MeSiF^CI and MeSiHCh, and the compound (B) is selected from methylchlorodisilanes and methylchloropolysilanes, preferably methylchlorodisilanes, and therein the metal hydride is preferably CaH2 or MgH2.

As defined herein, the term “methylchlorodisilanes” comprises the compounds MeSi2Cl5, Me2Si2Cl4, Me3Si2C , Me4Si2Cl2 and MesSiCI, wherein the formula

MeSi2Cl5 denotes the structure MeChSi-SiC , the formula Me2Si2Cl4 denotes the structures Me2CISi-SiC and MeChSi-SiChMe, the formula Me3Si2C denotes the structures MesSi-SiC and Me2CISi-SiCl2Me, the formula Me4Si2Cl2 denotes the structures MeChSi-SiMes and Me2CISi-SiCIMe2, and the formula Me5Si2CI denotes the structure Me2CISi-SiMe3. Therein, it is preferred according to this embodiment that each Si atom bears one or more methyl groups and one or more chloro groups. As defined herein, the term “methylchloropolysilane” comprises any type of silane having three or more silicon atoms bonded to each other in a linear manner, wherein the further substituents of the silicon atoms are selected from methyl groups and chloro groups exclusively. Therein, it is preferred according to this embodiment that each Si atom bears one or more methyl groups and one or more chloro groups. As described in the previous embodiment in general, the process comprising the cleavage of Si- Si bonds allows to produce the desired monosilane compounds (A) Me2SiHCI, MeSib^CI and MeSiHCh starting from compounds (B) being methylchlorodisilanes and methylchloropolysilanes. Such compounds are produced in vast quantities as by-product of the Direct Process for the production of methylchlorosilane. Further, with regard this embodiment, the product mixture of the Direct Process may be submitted to the process of the embodiment of the invention directly without prior separation of the main product dimethyldichlorosilane and the di-, oligo and polysilane side products usually denoted as high boiling residue according to its boiling point characteristics in the separation process. Both the main product Me2SiCl2 as well as the side products MeSiC , methylchlorodisilanes and methylchlorodisilanes contained in the Direct Process product mixture can be converted to the target compounds (A) selected from Me2SiHCI, MeSib^CI and MeSiHCh by cleavage of Si-Si bonds. From an economical perspective, it is preferable to use the low cost reductants MgH2 or CaH2, even more preferable CaH2 in the process according to this embodiment.

In a particularly preferred embodiment according to the invention, a compound (A) selected from Me2SiHCI, MeSib^CI and MeSiHCh is obtained by submitting methyldichlorosilanes constituting the compound (B), preferably selected from Me2Si2Cl4, Me3Si2C and Me4Si2Cl2, to a reaction with CaH2 in the presence of a heterocyclic ionic liquid, which is preferably selected from N-heterocyclic ionic liquids, even more preferably from the group of 1 -substituted imidazolium salts, even further preferably from 1 ,3-alkyl-substituted imidazolium salts, in particular having a C1-C12 alkyl substituent at the 1 -position and a methyl group at the 3- position, most preferably selected from 1 -methyl-, 1 -ethyl-, 1 -propyl-, 1 -butyl-, 1 -pentyl-, 1- hexyl-, 1 -octyl and 1 -decyl and 1-dodecyl-3-methylimidazolium salts. Preferably, the counter anion in an imidazolium-based ionic liquid is selected from chloride, bromide, acetate, trifluoroacetate, tetrafluoroborate, hexafluorophosphate or methylsulfate anions, most preferably from chloride, bromide and tetrafluoroborate. It is further preferred that no additional cleavage agents, redistribution catalysts or activating agents are added to the reaction mixture. The methylchlorodisilanes (B) may be submitted to the reaction of the process according to this embodiment as substantially pure single compounds or a mixture of several methylchlorodisilanes (B), or as a mixture of one or more methylchlorosisilanes with further silane compounds, e.g. the high boiling residue obtained when performing the Direct Process for the production of methylchlorosilanes, and/or further compounds not falling under the definition of compound (B). It is considered useful when the material submitted to the process containing one or more compounds (B) to the process contains about 5 weight-% or more of methylchlorodisilanes, more preferably about 20 weight-% or more, even more preferably about 50 weight-% or more, and still more preferred more than about 75 weight-%, and most preferably about 95 weight-% or more of methylchlorodisilanes. According to the invention, a compound is considered to be substantially pure having less than about 2 weight-% of impurities based on the total weight of the compound and the impurities contained. Preferably, the presence of the one or more heterocyclic liquids enables the cleavage of Si-Si bonds required to convert the compounds (B) selected from methylchlorodisilanes or methylchloropolysilanes to methylmonosilanes in the absence of further cleavage catalysts, as described with regard to the previous embodiment.

In a further aspect, the invention relates to compositions comprising

- one or more silane compounds (A’) having at least one Si-H bond and at least one Si- X bond, wherein X is a halogen atom,

- one or more metal halides (C’),

- one or more heterocyclic ionic liquids,

- optionally one or more silane compounds (A”) having at least two Si-H bonds and no Si-X bond. Preferably, the compound (A”) is a silane compound obtained from the corresponding silane compound (A’) by the replacement of any Si-X bonds by Si-H bonds.

Such compositions can be obtained by the process according to the invention as described above in detail.

Silane compounds (A’)

The term “one or more compounds having at least one Si-H bond and at least one Si-X bond (A’)” as defined herein comprises any compound containing at least one Si-H bond and at least one Si-X bond (B), wherein X is a halogen, i.e. a fluoro, chloro, bromo or iodo group, preferably chloro, and mixtures of two or more such compounds present in the composition.

Accordingly, silane compounds (A’) may be selected from monosilanes, disilanes, oligo- or polysilanes and carbodisilanes having at least one Si-H bond and at least one Si-X bond, wherein monosilanes, di-, oligo- and polysilanes are preferred compounds (A’), mono- and disilanes are more preferred compounds (A’), and monosilanes are generally the most preferred compounds (‘) in the composition according to the invention.

The silane compound (A’) comprised by the composition can be a silane compound with substituents exclusively selected from halogen atoms and hydrogen atoms, but preferably the composition comprises organosilanes, i.e. compounds (A’) further having at least one Si-R bond, wherein R is an organyl group.

Metal halides (O’)

Metal halides (C’) are compounds comprising one or more metals and one or more halides, preferably they are ionic compounds comprising one or more metal cations and one or more halide anions.

In an embodiment of the invention, the metal halides (C’) are selected from binary metal halides, preferably selected from alkali metal halides and earth alkaline metal halides, more preferably selected from alkali metal chlorides and earth alkaline metal chlorides, even more preferably from the group of lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, even further preferably from magnesium chloride, sodium chloride or calcium chloride, most preferably the metal hydride is calcium chloride.

Metal halides (C’) are formed in the process of the invention as described above by exchange of hydride and halide substituents of metal hydrides and halosilanes.

Heterocyclic ionic liquids

As already defined above, a heterocyclic ionic liquid is a salt comprising a heterocyclic anion and/or cation which is liquid under the conditions of the process according to the invention. Usually, the salt or ionic liquid has a melting point of below about 150°C, preferable below about 140°C, more preferable below about 120°C, still more preferable below about 100°C, and most preferable below about 50°C.

According to an embodiment of the invention, the heterocyclic structure of the ionic liquid is not restricted in any way except that a cyclic structure containing one or more heteroatoms needs to be present in the ionic liquid, i.e. at least one atom different from a carbon atom and a hydrogen atom, is necessarily included as a ring member, wherein the cyclic structure may be aromatic or non-aromatic.

A ring structure consisting of carbon atoms exclusively having one or more heteroatom substituents is not considered a heterocycle according to the invention. The heteroatoms are typically selected from oxygen atoms (O), sulfur atoms (S), phosphorus atoms (P), and nitrogen atoms (N), wherein P-heterocycles and N-heterocycles are generally preferred.

With regard to the composition of the invention, the same heterocyclic ionic liquids are utilized and preferred as described above for the process of the invention.

In an embodiment according to the invention, each X in the silane compounds (A’) is a chlorine atom, and the metal halide (C’) is a metal chloride.

In a further embodiment according to the invention, the silane compound (A’) is a monosilane, preferably an organohydridochloromonosilane.

According to this embodiment of the invention, the silane compound (A’) is an organohydridohalosilane having the formula RSiX2H, RSiXH2 and R2SiXH. Therein, the organyl substituent R is preferably independently selected from C1-C12 alkyl groups or phenyl groups, more preferably from methyl, ethyl, isopropyl, tert-butyl, cyclopentyl, cyclohexyl or phenyl groups, most preferably from methyl and phenyl groups.

According to the embodiment, at the same time X is independently selected from F, Cl, Br or I substituents, preferably every X represents a Cl atom.

The most preferred silane compounds (A’) according to the embodiment are MeSib CI, MeSiHCh and Me₂SiHCI.

In a more specific embodiment according to the invention, the silane compound (A’) is selected from monosilanes of the general formula

RxSiHyCIz (I’), wherein R is an organyl group, x = 0 to 2, preferably 1 or 2, y = 1-3, preferably 1 or 2, z = 1-3, preferably 1 or 2, and x + y +z = 4.

The monosilanes (A’) according to the embodiment can be chlorosilanes which do not bear any organyl group R, i.e. x = 0 in the general formula (I). Preferred halomonosilanes according to the embodiment are HSiCh, HSiBrs and HSih, wherein SiCk and HSiCh are most preferred. It is more preferred that the monosilanes (A’) are organomonosilanes wherein x is 1 or 2, and y is preferably 1 or 2.

Preferably, the silane compound (A’) is selected from organomonosilanes of the general formula

RxSiHyCIz (I’), wherein R is an organyl group, x = 1 to 2, y = 1 or 2, z = 1 or 2, and x + y +z = 4.

Preferred organomonosilanes according to the embodiment are R2SiHCI, RSiH2CI and RSiHCh. Further preferably, the organyl group R is selected from methyl, ethyl, phenyl and vinyl. The most preferred monosilane products (A’) are Me2SiHCI, MeSiHCh and MeSib^CI.

In an embodiment according to the invention, the composition of the invention as described herein further comprises one or more monosilane compounds (A”) of the general formula

RxSiH_y (I”), wherein R is an organyl group, x = 0 to 2, preferably 1 or 2, and y = 2 to 4, preferably 2 or 3, and x + y = 4.

The monosilane compounds having the Formula (I”) are usually formed in the process of the invention by the full reduction of chlorosilanes. It is preferred that the amount of the hydridomonosilanes of the Formula (I”) is as low as possible in relation to the amount of the hydridochloromonosilanes of the Formula (I’).

Preferably, the silane compound (A”) is selected from organomonosilane compounds of the general formula

RxSiHy (I”), wherein x = 1 or 2, y = 2 or 3, x + y = 4. Preferred organomonosilanes of the Formula (I”) according to the embodiment are R2SiH2 and RSiHs. Preferably, the organyl group R is selected from methyl, ethyl, phenyl and vinyl. The most preferred monosilane compounds (I”) are Me2SiH2 and MeSiHs.

Also preferably, the organyl group or groups R of the organomonosilane compound (A”) of the general formula (I”) RxSiH_y (I”), wherein x = 1 or 2, y = 2 or 3, x + y = 4, are the same as in the organomonosilane compound (A’) comprised by the composition.

Further preferably, the compound (A”) is a silane compound formed from the corresponding silane compound (A’) by the replacement of any Si-X bonds by Si-H bonds.

In an embodiment according to the invention, the molar ratio of the compound (A’) to the compound (A”) is about 5:1 or more, preferably about 8:1 or more, more preferably about 10:1 or more, even more preferably about 15:1 or more.

In another embodiment according to the invention, the one or two organyl groups R of the silane compound (A’) selected from monosilanes of the general formula RxSiHyCIz (I’), wherein R is an organyl group, x = 0 to 2, preferably 1 or 2, y = 1-3, preferably 1 or 2, z = 1-3, preferably 1 or 2, and x + y +z = 4, are independently selected from the group consisting of an alkyl group, cycloalkyl group or phenyl group, preferably R is a methyl, ethyl vinyl or phenyl group, most preferably R is a methyl group.

In still another embodiment according to the invention, the compound (A’) is selected from Me2SiHCI, MeSibkCI, MeSiHCh, preferably the compound (A’) is Me2SiHCI.

In an embodiment according to the invention, the metal halide (C’) is selected from alkaline metal chlorides and alkaline earth metal chlorides, preferably the metal halides (C’) are selected from LiCI, NaCI, KCI, MgCh and CaCh, most preferably the metal chloride (C’) is CaCI₂.

In another embodiment according to the invention, the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic quaternary ammonium ionic liquids and P-heterocyclic phosphonium ionic liquids, preferably the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic quaternary ammonium ionic liquids and P-heterocyclic aromatic quaternary phosphonium ionic liquids.

More preferably, the heterocyclic ionic liquid is selected from the group of aromatic heterocyclic quaternary ammonium salts comprising pyridinium salts, imidazolium salts, 1 ,2,3-triazolium salts, imidazolinium salts, pyrrolium salts, the group of non-aromatic heterocyclic quaternary ammonium salts comprising morpholinium salts, piperidinium salts, piperazinium salts and pyrrolidinium salts, and the group of aromatic heterocyclic quaternary phosphonium salts comprising phosphininium salts, preferably the ionic liquid is selected from 1 -substituted imidazolium salts and 1 -substituted pyridinium salts, preferably from 1 ,3-substituted, 1 ,2,3- substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, more preferably 1- alkyl substituted 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5- substituted imidazolium salts, and even more preferably EthylMIMCI and HexMlMCI.

In an embodiment according to the invention, the silane compound (A’) is an organomonosilane compounds (A’) of the general formula

RxSiHyCIz (I’), wherein R is an organyl group, x = 1 to 2, y = 1 or 2, z = 1 or 2, and x + y +z = 4, the metal halide (C’) is CaCh, and the heterocyclic ionic liquid is an N-heterocyclic quaternary ammonium ionic liquid.

In another embodiment according to the invention, the molar ratio of the one or more heterocyclic ionic liquid compounds to the one or more silane compounds (A’) having at least one Si-H bond and at least one Si-X bond is in the range of about 0.1 mol-% to about 1500 mol-%, preferably about 0.2 mol-% to about 1000 mol-%, more preferably about 0.4 mol-% to about 600 mol-%, even more preferably about 0.7 mol-% to about 300 mol-%, further preferably about 0.7 mol-% to about 100 mol-%, even further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol-%.

In a further embodiment according to the invention, the compound (A’) is Me2SiHCI, the compound (A”) is Me2SiH2, and the metal halide is CaCh.

In still a further embodiment according to the invention, the compound (A’) is MeSiH2CI or MeSiHCh, the compound (A”) is MeSiHs, and the metal halide is CaCh.

In a preferred embodiment according to the invention, the silane compound (A’) is Me2SiHCI, the metal halide (C’) is CaCh, the heterocyclic ionic liquid is an N-heterocyclic quaternary ammonium ionic liquid, the molar ratio of the N-heterocyclic quaternary ammonium ionic liquid to Me2SiHCI is in the range of about 0.7 mol-% to about 300 mol-%, preferably about 0.7 mol-% to about 100 mol-%, further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol- % to about 100 mol-%, and the composition comprises Me2SiH2, wherein the molar ratio of Me2SiHCI to Me2SiH2 is about 5:1 or more, preferably about 8:1 or more, more preferably about 10:1 or more, even more preferably about 15:1 or more.

It will be understood that any numerical range recited herein includes all sub-ranges within that range and any combination of the various endpoints of such ranges or sub-ranges, be it described in the examples or anywhere else in the specification.

It will also be understood herein that any of the components of the invention herein as they are described by any specific genus or species detailed in the examples section of the specification, can be used in one embodiment to define an alternative respective definition of any endpoint of a range elsewhere described in the specification with regard to that component, and can thus, in one non-limiting embodiment, be used to supplant such a range endpoint, elsewhere described.

It will be further understood that any compound, material or substance which is expressly or implicitly disclosed in the specification and/or recited in a claim as belonging to a group of structurally, compositionally and/or functionally related compounds, materials or substances includes individual representatives of the group and all combinations thereof.

While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art may envision many other possible variations that are within the scope and spirit of the invention as defined by the claims appended hereto. Summary of preferred embodiments of the invention

In the following the preferred embodiments of the invention are summarized:

1. Process for the production of one or more silane compounds having at least one Si-H bond (A), comprising a step of subjecting one or more compounds having at least one Si-X bond (B), wherein X is a halogen atom, to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids.

2. Process according to embodiment 1, wherein each X is independently selected from a chlorine atom, a bromine atom or an iodine atom, preferably a chlorine atom, more preferably every X in the compound (B) is a chlorine atom.

3. Process according to any of the previous embodiments, wherein the compound having at least one Si-H bond (A) is an organomonosilane compound, preferably an organohydridochloromonosilane.

4. Process according to any of the previous embodiments, wherein the compound having at least one Si-X bond (B) is an organosilane compound, preferably an organoperchlorosilane, more preferably an organoperchloromonosilane compound.

5. The process according to any of the previous embodiments, wherein the product (A) is selected from monosilanes of the general formula (I)

RxSiHyCIz (I), wherein R is an organyl group, x = 0 to 3, preferably 0, 1 , 2 and 3, y = 1 to 4, preferably 1 to 2, most preferred 1 z = 0 to 3, preferably 0, 1 , 2 and 3, and x + y + z = 4.

6. The process according to any of the previous embodiments, wherein the product (A) is selected from monosilanes of the general formula (I)

RxSiHyCIz (I), wherein R is an organyl group, x = 1 to 3, preferably 1 to 2, y = 1 to 3, preferably 1 to 2, z = 0 to 2, preferably 1 to 2, and x + y + z = 4. 7. Process according to any of the previous embodiments, wherein the compound having at least one Si-X bond (B) is selected from organochloromonosilanes of the general formula (II)

RaSiH_bClc (II) wherein R is as defined above, a = 1 to 3, b = 0 to 2, c = 1 to 3, and a + b + c = 4.

8. Process according to any of the previous embodiments, wherein R is independently selected from an alkyl group, cycloalkyl group or phenyl group, preferably R is a methyl group.

9. Process according to any of the previous embodiments, wherein the compound (A) is selected from Me2SiHCI, MeSiH2CI, MeSiHCh, HSiC , MesSiH, preferably the compound (A) is Me₂SiHCI.

10. Process according to any of the previous embodiments, wherein the compound (B) is selected from Me2SiCl2, MeSiC , SiCk and MesSiCI, preferably the compound (B) is Me2SiCh.

11. Process according to any of the previous embodiments, wherein the metal hydride (C) is selected from alkaline metal hydrides, alkaline earth metal hydrides or complex metal hydrides comprising alkaline metal or alkaline earth metal cations, preferably the metal hydride (C) is selected from LiH, NaH, KH, MgH2, CaH2 and UAIH4, most preferably the metal hydride (C) is CaH2.

12. The process according to any of the previous embodiments, wherein the process is carried out in the absence of any metal hydride reagent (C) other than CaH2.

13. The process according to any of the previous embodiments, wherein the molar ratio of hydride ions of the one or more metal hydrides in relation to halogen atoms, preferably chlorine atoms, of the one or more compounds (B) in the reaction mixture is in the range of about 0.01 to about 300, more preferably about 0.1 to about 10, even more preferably about 0.4 to about 6, and most preferably about 0.7 to about 3.

14. The process according to any of the previous embodiments, wherein the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic ionic liquids and P- heterocyclic ionic liquids.

15. The process according to any of the previous embodiments, wherein the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic ionic liquids and P- heterocyclic aromatic ionic liquids. 16. The process according to any of the previous embodiments, wherein the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic quaternary ammonium ionic liquids and P-heterocyclic phosphonium ionic liquids.

17. The process according to any of the previous embodiments, wherein the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic quaternary ammonium ionic liquids and P-heterocyclic aromatic quaternary phosphonium ionic liquids.

18. The process according to any of the previous embodiments, wherein the heterocyclic ionic liquid is selected from the group of aromatic heterocyclic quaternary ammonium salts comprising pyridinium salts, imidazolium salts, 1 ,2,3-triazolium salts, imidazolinium salts, pyrrolium salts, the group of non-aromatic heterocyclic quaternary ammonium salts comprising morpholinium salts, piperidinium salts, piperazinium salts and pyrrolidinium salts, and the group of aromatic heterocyclic quaternary phosphonium salts comprising phosphininium salts.

19. The process according to any of the previous embodiments, wherein the ionic liquid is selected from 1 -substituted imidazolium salts and 1 -substituted pyridinium salts, preferably from 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, more preferably 1 -alkyl substituted 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, and even more preferably EthylMIMCI and HexMlMCI.

20. The process according to any of the previous embodiments, wherein the ionic liquid has a melting point of below about 150 °C, preferably below about 100°C, more preferably below about 80 °C, still more preferably below about 60 °C, even more preferably below about 40 °C, and most preferably below about 30 °C.

21. The process according to any of the previous embodiments, wherein the amount of the one or more ionic liquids in relation to the one or more compounds (B) in the reaction mixture is in the range of about 0.1 mol-% to about 1500 mol-%, preferably about 0.2 mol- % to about 1000 mol-%, more preferably about 0.4 mol-% to about 600 mol-%, even more preferably about 0.7 mol-% to about 300 mol-%, further preferably about 0.7 mol-% to about 100 mol-%, even further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol-%.

22. The process according to any of the previous embodiments, wherein the process is carried out in the absence of ether solvents, preferably in the absence of ether solvents and linear or cyclic aliphatic hydrocarbon solvents, more preferably in the absence of ether solvents and linear or cyclic aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents, most preferably in the absence of any further solvent other than the one or more ionic liquids. The process according to any of the previous embodiments, wherein the process is carried out in the absence of acyclic quaternary ammonium salts and acyclic quaternary phosphonium salts. The process according to any of the previous embodiments, wherein the reaction is carried out at a temperature in a range of about 0 to about 150 °C, preferably about 10 to about 150 °C, more preferably about 20 to about 150 °C, even more preferably about 20 to about 125 °C, and most preferably in a range of about 50 to about 125°C. The process according to any of the previous embodiments, wherein the reaction is carried out at a pressure in a range of about 0.1 to about 20 bar, preferably about 0.3 to about 20 bar, more preferably about 1 to about 20 bar, even more preferably about 1 to about 10 bar, and most preferably in a range of about 1 to about 5 bar. A process according to any of the previous embodiments, wherein the process is carried out under inert conditions. A process according to any of the previous embodiments, wherein the process is carried out continuously or discontinuously, such as batchwise. The process according to any of the previous embodiments, wherein the process is carried out in the absence of milling or sonication of the reaction mixture. The process according to any of the previous embodiments, wherein the process is carried out without supply of hydrogen chloride and/or in the absence of a metal catalyst, preferably in the absence of aluminum chloride or a palladium catalyst. The process according to any of the previous embodiments, wherein the silane compounds having at least one Si-H bond (A) formed, preferably Me2SiHCI, are separated from the reaction mixture by distillation and/or condensation. The process according to any of the previous embodiments, wherein the starting material contains about 75 wt-% or more of one or more compounds (B), preferably about 85 wt-% or more of one or more compounds (B), more preferably about 90 wt-% or more of one or more compounds (B), most preferably about 95 wt-% or more of one or more compounds (B). The process according to any of the previous embodiments, wherein the starting material contains about 75 wt-% or more of an organomonochlorosilane (B), preferably about 85 wt-% or more of an organomonochlorosilane (B), more preferably about 90 wt-% or more of an organomonochlorosilane (B), even more preferably about 95 wt-% or more of an organomonochlorosilane (B), most preferably about 95 wt-% or more of Me2SiCl2. Process according to any of the previous embodiments, wherein compound (A) is Me2SiHCI, the compound (B) is Me2SiCl2, and the metal hydride is CaH2. Process according to any of the previous embodiments 1 to 32, wherein compound (A) is MeSiH2CI or MeSiHCh, the compound (B) is MeSiC , and the metal hydride is CaH2. Process according to any of the previous embodiments 1 to 32, wherein the process comprises the cleavage of one or more Si-Si bonds of one or more di- or polysilane compounds (B) and/or of one or more Si-C bonds of one or more carbodisilane compounds (B). Process according to the previous embodiments 1 to 32 and 35, wherein the compound (A) is selected from Me2SiHCI, MeSiH2CI and MeSiHCh, and the compound (B) is selected from methylchlorodisilanes and methylchloropolysilanes, preferably methylchlorodisilanes, and wherein the metal hydride is preferably CaH2 or MgH2. A composition comprising

- one or more silane compounds (A’) having at least one Si-H bond and at least one Si-X bond, wherein X is a halogen atom,

- one or more metal halides (C’),

- one or more heterocyclic ionic liquids,

- optionally one or more silane compounds (A”) having at least two Si-H bonds and no Si- X bond. The composition according to the embodiment 37, wherein each X is a chlorine atom, and the metal halide (C’) is a metal chloride. The composition according to the embodiments 37 and 38, wherein the silane compound (A’) is a monosilane, preferably an organohydridochloromonosilane. The composition according to the embodiments 37 to 39, wherein the silane compound (A’) is selected from monosilanes of the general formula

RxSiHyCIz (I’), wherein R is an organyl group, x = 0 to 2, preferably 1 or 2, y = 1-3, preferably 1 or 2, z = 1-3, preferably 1 or 2, and x + y +z = 4. The composition according to the embodiments 37 to 40, wherein the silane compound (A’) is selected from organomonosilanes of the general formula

RxSiHyCIz (I’), wherein R is an organyl group, x = 1 to 2, y = 1 or 2, z = 1 or 2, and x + y +z = 4. The composition according to the embodiments 37 to 41 , wherein the composition further comprises one or more monosilane compounds (A”) of the general formula

RxSiH_y (I”), wherein R is an organyl group, x = 0 to 2, preferably 1 or 2, and y = 2 to 4, preferably 2 or 3, and x + y = 4, wherein preferably, the silane compound (A”) is selected from organomonosilane compounds of the general formula RxSiHy (I”), wherein x = 1 or 2, y = 2 or 3, x + y = 4, and wherein preferably the organyl group or groups of the organomonosilane compound (A”) are the same as in the organomonosilane compound (A’). The composition according to the embodiments 37 to 42, wherein the compound (A”) is a silane compound formed from the corresponding silane compound (A’) by the replacement of any Si-X bonds by Si-H bonds. The composition according to the embodiments 37 to 43, wherein the one or two organyl groups R of the silane compound (A’) are independently selected from the group consisting of an alkyl group, cycloalkyl group or phenyl group, preferably R is a methyl, ethyl vinyl or phenyl group, most preferably R is a methyl group. The composition according to the embodiments 37 to 44, wherein the compound (A’) is selected from Me2SiHCI, MeSiH2CI, MeSiHCh, preferably the compound (A’) is Me2SiHCI. The composition according to the embodiments 37 to 45, wherein the metal halide (C’) is selected from alkaline metal chlorides and alkaline earth metal chlorides, preferably the metal halides (C’) are selected from LiCI, NaCI, KCI, MgCh and CaCh, most preferably the metal chloride (C’) is CaCh. The composition according to the embodiments 37 to 46, wherein the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic quaternary ammonium ionic liquids and P-heterocyclic phosphonium ionic liquids, preferably the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic quaternary ammonium ionic liquids and P-heterocyclic aromatic quaternary phosphonium ionic liquids. 48. The composition according to the embodiments 37 to 47, wherein the silane compound (A’) is an organomonosilane compounds (A’) of the general formula

49. The composition according to the embodiments 37 to 48, wherein the heterocyclic ionic liquid is selected from the group of aromatic heterocyclic quaternary ammonium salts comprising pyridinium salts, imidazolium salts, 1 ,2,3-triazolium salts, imidazolinium salts, pyrrolium salts, the group of non-aromatic heterocyclic quaternary ammonium salts comprising morpholinium salts, piperidinium salts, piperazinium salts and pyrrolidinium salts, and the group of aromatic heterocyclic quaternary phosphonium salts comprising phosphininium salts, preferably the ionic liquid is selected from 1 -substituted imidazolium salts and 1-substituted pyridinium salts, preferably from 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, more preferably 1 -alkyl substituted 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, and even more preferably EthylMIMCI and HexMlMCI.

50. The composition according to the embodiments 37 to 49, wherein the molar ratio of the compound (A’) to the compound (A”) is 5:1 or more, preferably 8:1 or more, more preferably 10:1 or more, even more preferably 15:1 or more.

51. The composition according to the embodiments 37 to 50, wherein the molar ratio of the one or more heterocyclic ionic liquid compounds to the one or more silane compounds (A’) having at least one Si-H bond and at least one Si-X bond is in the range of about 0.1 mol- % to about 1500 mol-%, preferably about 0.2 mol-% to about 1000 mol-%, more preferably about 0.4 mol-% to about 600 mol-%, even more preferably about 0.7 mol-% to about 300 mol-%, further preferably about 0.7 mol-% to about 100 mol-%, even further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol- %.

52. The composition according to the embodiments 37 to 51 , wherein the compound (A’) is Me2SiHCI, the compound (A”) is Me2SiH2, and the metal halide is CaCh.

53. The composition according to the embodiments 37 to 51 , wherein the compound (A’) is MeSiH2CI or MeSiHCh, the compound (A”) is MeSiHs, and the metal halide is CaCh. 54. The composition according to the embodiments 37 to 52, wherein silane compound (A’) is Me₂SiHCI, the metal halide (C’) is CaCh, the heterocyclic ionic liquid is an N-heterocyclic quaternary ammonium ionic liquid, the molar ratio of the N-heterocyclic quaternary ammonium ionic liquid to Me2SiHCI is in the range of about 0.7 mol-% to about 300 mol-%, preferably about 0.7 mol-% to about 100 mol-%, further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol-%, and the composition comprises Me2SiH2, wherein the molar ratio of Me2SiHCI to Me2SiH2 is about 5:1 or more, preferably about 8:1 or more, more preferably about 10:1 or more, even more preferably about 15:1 or more.

The process of the present invention will be explained in more detail by the examples in the following.

EXAMPLES

The present invention is further illustrated by the following examples, without being limited thereto. General

All reactions were carried out in a 100ml Hastelloy pressure reactor equipped with a magnetic stirrer, manometer, a RTD Sensor (Platinum Resistance Thermometer sensor) Pt 100 from TC Company and a three way inlet/outlet valve.

1-Ethyl-3-methylimidazolium chloride (ethyl MIM Cl) (98%) and 1-hexyl-3-methylimidazolium chloride (hexyl MIM Cl) (97%) were both purchased from Sigma-Aldrich.

Products were analyzed and characterized by standard procedures, especially by GC and GC/MS analyses.

Analysis of products Products were analyzed by GC-MS.

The method applied is described by the following table:

Table 1. GC-MS method description

Under the given GC conditions, the retention times were as follows:

Me₂SiH₂ (H2) 0.908min

Me₂SiHCI (H1) 0.997min

Me₂SiCI₂ (precursor) 1.192min

In addition, the identity of the compounds Me₂SiH₂ and Me₂SiHCI was confirmed by MS fragmentation analysis:

Characteristic GC-MS fragments for H2 and H1

Me₂SiH₂ (H2) M=60 fragments found 59 (M-H) and 58 (M-2H) Me₂SiHCI (H1) M=94.5 fragments found 93 (M-H) and 79 (M-CH3)

Example 1 (Comparative Example):

Reaction of Me₂SiCI₂ with LiH and BU4PCI in THF

0.19 g (0.6 mmol) BU4PCI were dissolved in 15ml dry THF and placed in the reactor.

0.2 g (25.2 mmol H') LiH were added. The autoclave was closed and cooled to 4 °C. 3 g Me₂SiCI₂ were injected through a three way valve using a syringe. The temperature of the reaction mixture immediately increased to 17 °C. Additional 13.2 g Me₂SiCI₂ were injected (in total 16.2 g Me₂SiCI₂ = 126 mmol), the reactor was closed and heated to 120 °C for 4 h. After cooling to room temperature the composition of the liquid phase (which contained the silanes, the ether solvent and some salts) was analyzed by means of GC (-10% solution in dry toluene; detailed GC method description in Table 1). The area ratio H1 : H2 of the target product Me₂SiHCI (H1) to the undesired intermediate Me₂SiH₂ (H2) was determined. The result is shown in Table 2. Example 2 (Comparative Example)

Reaction of MeaSiCh with CaHa and BmPCI in THF

0.19 g (0.6 mmol) BiuPCI were dissolved in 15ml dry THF and placed in the reactor. 0.53g (25.2 mmol H') CaH2 were added. The autoclave was closed and cooled to 4 °C. 16.2g (126 mmol) Me2SiCl2 were injected through a three way valve using a syringe. The temperature of the reaction mixture immediately increased to 13 °C. The reactor was closed and heated to 120 °C for 4 h. After cooling to room temperature the composition of the liquid phase (which contained silanes, the ether solvent and some salts) was analyzed by means of GC (-10% solution in dry toluene; detailed GC method description in Table 1). The area ratio H1 : H2 of the target product Me2SiHCI (H1) to the undesired intermediate Me2SiH2 (H2) could not be determined since neither Me2SiHCI nor Me2SiH2 were formed in detectable quantities.

Example 3

Reaction of MeaSiCh with CaHa in 1-ethyl-3-methylimidazolium chloride (EthylMIM Cl)

15 g of 1-ethyl-3-methylimidazolium chloride (98%) were mixed with 0.53 g (25.2 mmol H') CaH2 and placed in the reactor. 16.2 g Me2SiCl2 (126 mmol) were injected through a three way valve, the reactor closed and heated to 120 °C for 4 h. Afterwards, the reaction mixture was cooled to room temperature. It consisted of a solid phase which was well separated from a liquid phase. The composition of the liquid silane phase was analyzed by means of GC. Again, the area ratio H1 : H2 of the target product Me2SiHCI (H1) to the undesired intermediate Me2SiH2 (H2) was determined.

Example 4

Reaction of MeaSiCh with CaHa in 1-hexyl-3-methylimidazolium chloride (HexMlM Cl)

15 g of 1-hexyl-3-methylimidazolium chloride (97%) were mixed with 0.53 g (25.2 mmol H') CaH2 and placed in the reactor. 16.2 g Me2SiCl2(126 mmol) were injected through a three way valve, the reactor closed and heated to 120 °C for 4 h. Afterwards, the reaction mixture was cooled to room temperature. It consisted of a solid phase which was well separated from a liquid phase. The composition of the liquid silane phase was analyzed by means of GC. The area ratio H1 : H2 of the target product Me2SiHCI (H1) to the undesired intermediate Me2SiH2 (H2) was determined. The higher the ratio the more target product in relation to the intermediate was formed. The following Tab. 2 summarizes the reaction parameters and the composition H1 : H2.

The data show that CaH2 is non-reactive under state of the art conditions suitable for Li H

(see Comp. Ex.1 and 2). However, CaH2 in combination with sufficiently polar heterocyclic ionic liquids can be used to synthesize selectively Me2SiHCI from Me2SiCl2 under moderate conditions without any ether solvent or additional activation step (see Ex. 3 and 4).

The volatile silane mixture can be distilled off the ionic liquid/CaCh mixture under vacuum and directly processed since there are no organic solvents present. The data also show that the efficiency of the ionic liquid is not a straight function of the melting point. Both, the low melting (-75°C for 1-hexyl-3-methylimidazolium chloride) and the high melting ionic liquid (77-79°C for 1-ethyl-3-methylimidazolium chloride ) in combination with CaH2 yield the target product Me2SiHCI in high proportions thus giving access to a straight forward low cost route. Not wishing to be bound to the theory, a combination of a sufficiently high flowability of the mixture at reaction temperature in cooperation with a sufficiently high polarity is the key for a successful reaction.

Claims

1 . Process for the production of one or more silane compounds having at least one Si-H bond (A), comprising a step of subjecting one or more compounds having at least one Si-X bond (B), wherein X is a halogen atom, to a reaction with one or more metal hydrides (C) in the presence of one or more heterocyclic ionic liquids.

2. Process according to claim 1 , wherein the compound having at least one Si-H bond (A) is an organomonosilane compound, preferably an organohydridochloromonosilane.

3. The process according to any of the previous claims, wherein the product (A) is selected from monosilanes of the general formula (I)

RxSiHyCIz (I), wherein R is an organyl group, x = 1 to 3, preferably 1 to 2, y = 1 to 3, preferably 1 to 2, z = 0 to 2, preferably 1 to 2, and x + y + z = 4, wherein preferably R is independently selected from an alkyl group, cycloalkyl group or phenyl group, preferably R is a methyl group.

4. Process according to any of the previous claims, wherein the compound (A) is selected from Me2SiHCI, MeSiH2CI, MeSiHCh, HSiC , MesSiH, preferably the compound (A) is Me₂SiHCI.

5. Process according to any of the previous claims, wherein the metal hydride (C) is selected from alkaline metal hydrides, alkaline earth metal hydrides or complex metal hydrides comprising alkaline metal or alkaline earth metal cations, preferably the metal hydride (C) is selected from LiH, NaH, KH, MgH2, CaH2 and UAIH4, most preferably the metal hydride (C) is CaH₂, wherein preferably the molar ratio of hydride ions of the one or more metal hydrides in relation to halogen atoms, preferably chlorine atoms, of the one or more compounds (B) in the reaction mixture is in the range of about 0.01 to about 300, more preferably about 0.1 to about 10, even more preferably about 0.4 to about 6, and most preferably about 0.7 to about 3. The process according to any of the previous claims, wherein the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic ionic liquids and P-heterocyclic ionic liquids, wherein preferably the heterocyclic ionic liquid is selected from the group consisting of N-heterocyclic aromatic ionic liquids and P-heterocyclic aromatic ionic liquids. The process according to any of the previous claims, wherein the ionic liquid is selected from 1 -substituted imidazolium salts and 1 -substituted pyridinium salts, preferably from 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, more preferably 1 -alkyl substituted 1 ,3-substituted, 1 ,2,3-substituted, 1 ,2,3,4-substituted and 1 ,2,3,4,5-substituted imidazolium salts, and even more preferably EthylMIMCI and HexMlMCI. The process according to any of the previous claims, wherein the amount of the one or more ionic liquids in relation to the one or more compounds (B) in the reaction mixture is in the range of about 0.1 mol-% to about 1500 mol-%, preferably about 0.2 mol-% to about 1000 mol-%, more preferably about 0.4 mol-% to about 600 mol-%, even more preferably about 0.7 mol-% to about 300 mol-%, further preferably about 0.7 mol-% to about 100 mol- %, even further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol-%. Process according to any of the previous claims, wherein compound (A) is Me2SiHCI, the compound (B) is Me2SiCl2, and the metal hydride is CaH2. Process according to any of the previous claims 1 to 8, wherein compound (A) is MeSiH2CI or MeSiHCh, the compound (B) is MeSiC , and the metal hydride is CaH2. Process according to any of the previous claims 1 to 8, wherein the process comprises the cleavage of one or more Si-Si bonds of one or more di- or polysilane compounds (B) and/or of one or more Si-C bonds of one or more carbodisilane compounds (B). Process according to the previous claims 1 to 8 and 11 , wherein the compound (A) is selected from Me2SiHCI, MeSiH2CI and MeSiHCh, and the compound (B) is selected from methylchlorodisilanes and methylchloropolysilanes, preferably methylchlorodisilanes, and wherein the metal hydride is preferably CaH2 or MgH2. A composition comprising

- one or more metal halides (C’),

- one or more heterocyclic ionic liquids,

- optionally one or more silane compounds (A”) having at least two Si-H bonds and no Si- X bond. The composition according to claim 13, wherein the silane compound (A’) is an organomonosilane compounds (A’) of the general formula

RxSiHyCIz (I’), wherein R is an organyl group, x = 1 to 2, y = 1 or 2, z = 1 or 2, and x + y +z = 4, the metal halide (C’) is CaCh, and the heterocyclic ionic liquid is an N-heterocyclic quaternary ammonium ionic liquid. The composition according to claims 13 and 14, wherein the silane compound (A’) is Me₂SiHCI, the metal halide (C’) is CaCh, the heterocyclic ionic liquid is an N-heterocyclic quaternary ammonium ionic liquid, the molar ratio of the N-heterocyclic quaternary ammonium ionic liquid to Me2SiHCI is in the range of about 0.7 mol-% to about 300 mol-%, preferably about 0.7 mol-% to about 100 mol-%, further preferably about 2 mol-% to about 100 mol-%, and most preferably about 5 mol-% to about 100 mol-%, and the composition comprises Me2SiH2, wherein the molar ratio of Me2SiHCI to Me2SiH2 is about 5:1 or more, preferably about 8:1 or more, more preferably about 10:1 or more, even more preferably about 15:1 or more.