RU2785123C2 - Integrated method for production of methylchlorohydridemonosilanes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to an integrated method for the production of methylchlorohydridemonosilanes. A method for the production of methylchlorohydridemonosilanes of at least one silane selected from monosilanes, disilanes, oligosilanes, and carbodisilanes is proposed, provided that at least one of silanes contains a chlor-containing substitute. The method is carried out by a reaction of hydration, when using at least one hydride donor source, and a reaction of redistribution in the presence of at least one catalyst, optionally, a reaction of cleavage of Si-Si bonds of di- or oligosilanes or Si-C bond of carbosilanes, and a stage of separation of methylchlorohydridemonosilanes, where the method is carried out in the presence of one or more solvents, in the absence of AlCl₃.

EFFECT: method for selective production of methylhydridechlorosilanes is developed, allowing for reduction in a number of side products.

17 cl, 44 tbl, 24 ex

Description

The present invention relates to a new integrated process for the preparation of methylchlorohydride monosilanes selected from Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl, in particular from products of the direct Müller-Rochow process (MHS or DPS or direct synthesis, Rochow process or Müller-Rochow process), in particular from the stream of complete products of the direct Müller-Rochow process or from partial parts or fractions from the direct Müller-Rochow process, such as higher silane fractions or the so-called residues of the SSR process. Using the process of the present invention, methylchlorohydridesilanes, especially key intermediates such as Me ₂ Si(H)Cl [M2H] or MeSi(H)Cl ₂ [MH], can be produced in a more cost-effective manner and with fewer unwanted by-products.

Technical problems

Key intermediates in the preparation of functionalized silicones are, in particular, Me ₂ Si(H)Cl [M2H] or MeSi(H)Cl ₂ [MH]. Due to their SiH groups, they allow the functionalization of silicones, such as in the case of PDMS-based polymers obtained by hydrolysis and condensation or co-condensation with the participation of a chlorine-containing substituent, in order to introduce, for example, organic functional groups. These organic functional groups can be used to adjust the properties of the final silicone product over a wide range. Organic functional groups are introduced as a result of a catalyst-mediated hydrosilylation reaction with unsaturated organic compounds. Therefore, the economical and easy availability of such methylchlorohydridesilanes is of paramount importance in achieving a highly diversified range of silicone products.

The direct MCS process itself (Müller-Rochow process, MCS=methylchlorosilanes) does not produce commercially sufficient volumes of these useful and desirable SiH-containing intermediates. All resulting components should be separated using a distillation column in order to isolate the methylchlorohydridesilanes of interest (eg M2H and MH). Unwanted components of lesser value are subsequently reintroduced back into the redistribution process. As a matter of fact, in accordance with the given chemical redistribution mechanism, the compounds MH (MeSi(H)Cl ₂ ) and Mono (Me ₃ SiCl) must be sacrificed in order to produce a highly valuable and more commercially desirable intermediate compound M2H (see: MH + Mono → M2H + Di (Me ₂ SiCl ₂ )). In addition, as a result of the production of an equivalently valuable compound M2H, the less desirable compound Me ₂ SiCl ₂ [Di] is also formed. Thus, the economics of the overall process can be judged to be relatively inefficient, and no other large-scale production routes are currently available for these methylchlorohydridesilane components.

JP H03 24091 A) describes a process for producing R ₂ SiHCl by subjecting R ₂ SiCl ₂ to partial reduction in a molten salt comprising lithium chloride and potassium chloride using lithium hydride as a reducing agent. In a second embodiment, in a first step, the dialkyldichlorosilanes are produced by complete reduction of the dialkyldichlorosilanes using lithium hydride in the presence of a molten metal salt capable of forming a molten salt with lithium chloride, and then in a separate step for the dialkyldichlorosilanes thus produced and the dialkyldichlorosilanes used in as feedstock materials, a redistribution reaction is carried out in a separate reactor to produce R ₂ SiHCl in the presence of a catalyst such as Lewis acid catalysts. The process in the reduction step requires the use of high temperatures, and there is no indication of a process which is carried out in a solvent, leaving out a process in which reduction and redistribution are carried out simultaneously.

Publication EP 0878476A1 relates to a method for the preparation of dimethylmonochlorosilane (CH ₃ ) ₂ Si(H)Cl, where for a reaction mixture containing dimethyldichlorosilane (CH ₃ ) ₂ SiCl ₂ , magnesium hydride and aluminum chloride, in an inert liquid organic carrier, partial hydrogenation of dimethyldichlorosilane is carried out. The presence of AlCl ₃ leads to technical problems due to the difficulty of its separation from the resulting product, which is due to the high solubility in chlorosilanes and low sublimation temperature. The amount of unwanted dimethylsilane is also comparatively high.

In AJ CHALK, JOURNAL OF ORGANOMETALLIC CHEMISTRY, vol. 21, no. 1, 1 January 1970 discloses the reduction of a wide range of chlorosilanes to the corresponding silicon hydrides using sodium hydride in hexamethylphosphoric acid triamide (HMPT), tetramethylurea (TMU) and related solvents. There is no description of the production of Me ₂ Si(H)Cl, MeSi(H)Cl ₂ or MeSi(H) ₂ Cl.

Gerard Simon et al., Journal of Organometallic Chemistry, 1 January 1981, pages 279-286 report on the incomplete reduction of MeSiCl ₃ and Me ₂ SiCl ₂ using CaH ₂ or (TiH ₂ ) _n at high temperature (300°C ), which leads to the production of MeSiHCl ₂ and Me ₂ SiHCl with a low proportion. In the presence of AlCl ₃ as a catalyst, the reaction promotes the formation of chlorosilanes Me ₂ SiCl ₂ and Me ₃ SiCl, as a result of which the amount of the formed MeSiHCl ₂ compound decreases. Also, the presence of AlCl ₃ leads to technical problems due to the difficulty of its separation from the resulting product, which is caused by high solubility in chlorosilanes and low sublimation temperature.

CN 104 892 659 A discloses a process for the synthesis of dialkylmonochlorosilane from dialkyldichlorosilane by reduction using aluminum hydride/aluminum chloride, lithium aluminum hydride/aluminum chloride, sodium hydride/aluminum chloride, and aluminum hydride/lithium aluminum hydride in a solvent amido- or ureido-based - methylpyrrolidone, ethylpyrrolidone or N, N-dimethylimidazolidinone. There is no indication in such a document of a redistribution reaction occurring other than a hydrogenation reaction, and, as expected, methylpyrrolidone, ethylpyrrolidone, or N,N-dimethylimidazolidinone lacks sufficient nucleophilicity to catalyze the redistribution reaction.

Publication US 5136070 in accordance with paragraph 1 of the claims relates to a process for the disproportionation of cycloorganosilanes in the presence of a catalyst based on sodium borohydride. Methylsilanes are not used as feedstock materials.

Publication EP0301678 relates to the selective and stepwise reduction of polyhalosilanes using alkyltin hydrides. The reduction of (CH ₃ )SiCl ₃ using (CH ₃ ) ₃ SnH produces only a trace amount of (CH ₃ )SiCl ₂ H. For chloromethylsilanes, no redistribution occurs. Despite reference to redistribution in some places in the publication EP0301678, it refers exclusively to the exchange of halogens in halosilanes.

Publication US3627803 relates to the reaction between aluminum alkyls and halogen and/or alkoxysilanes at a temperature of 300°C or more to obtain silanes containing SiH groups without alkylation of silicon. There is no redistribution stage in such a document.

Publication GB851013A relates to a process for the reduction of a reducible silicon compound, which includes the reaction at a temperature in the range from 175° to 350°C between sodium hydride and silane. There is no indication of a stage of redistribution.

According to JE Hengge et al., Monatshefte für Chemie, 1 January 1995, pages 549-555, trialkyltin hydrides such as Bu ₃ SnH can be used to hydrogenate Si-Cl bonds in mono- and disilanes, where depending on of the desired catalyst (tertiary amines, N-heterocycles, λ ³ -phosphorus compounds, ammonium and phosphonium salts) only hydrogenation can take place, or (if strongly nucleophilic catalysts are used) the Si-Si bond can also be cleaved. In one example, 1,2-dimethyltetrachlorodisilane and tri-n-butyltin hydride result in MeSi(H)Cl ₂ (20%), MeSi(Cl)H ₂ (40%) and MeSiH ₃ (10%) at a fraction in the range 70 to 80% of the total amount of silicon used, and the reaction solution still contains residues of the feedstock material, as well as hydrogenated di- and oligosilanes. In such a document, there is no indication of a redistribution reaction, and a relatively high excess of trialkyltin hydride is necessary. In addition, the amount of MeSiH ₃ and by-products is relatively large, and from an environmental point of view, tin-containing catalysts are not desirable.

In MICHAEL N. MISSAGHI ET AL., ORGANOMETALLICS, vol. 27, no. 23, 8 December 2008 (2008-12-08), pages 6364-6366 discloses the preparation of organofunctional silicon halides R(CH ₃ )SiHCl. No hydrogenation step is carried out.

Publication RU 2 436 788 C1 discloses the reaction between trimethylchlorosilane and lithium hydride in the presence of tetrakis(diethylamidophosphonium) bromide in toluene at 65-74°C, resulting in trimethylsilane. Any redistribution is not described. US 2013/172593A1 does not disclose the hydrogenation step.

While redistribution reactions are useful for accessing alkylhydride halosilanes, and specifically methyldichlorosilane [MH] and dimethylchlorosilane [M2H], these reactions depend on limited by-product input from the conventional direct Rochow-Müller process. The latter is carried out for the production of dimethyldichlorosilane as the main product. Modifications to the direct Rochow-Müller process to increase the production of methyldichlorosilane [MH] and dimethylchlorosilane [M2H] have been disclosed by Lewis, et al. US Publication 4,973, 725 and Halm, et al. in US Publications 4,966,986 and 4,965,388. In all of these disclosures, methyldichlorosilane [MH] is produced in greater quantities than dimethylchlorosilane [M2H]. However, what is required is a process characterized by increased selectivity for dimethylchlorosilane [M2H]. Particularly desirable is a process in which dimethylchlorosilane [M2H] is produced in excess of methyldichlorosilane [M2H]. The present invention seeks to achieve this objective by carrying out a reaction, in particular, between a mixture produced using the conventional direct Rochow-Müller process and LiH to convert the predominant dimethyldichlorosilane [Di] ingredient to dimethylchlorosilane [M2H]. Thus, the composition of the products of the direct Rochow-Müller process can be modified in order to increase the selectivity for methylhydridechlorosilanes, and in particular also to obtain dimethylchlorosilane in excess of methyldichlorosilane.

The technical goal achieved in this case is, in particular, to find an economically viable and efficient way for the selective production of methylhydridechlorosilanes, in particular from the product or partial parts of the product of the direct Rochow-Müller process. The desired product should produce M2H and MH in high yields and should reduce the formation of unwanted by-products.

Resolution of technical problems

Surprisingly, these objectives have been achieved using the method for preparing methylchlorohydride monosilanes selected from Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl, preferably Me ₂ Si(H)Cl and MeSi (H)Cl ₂ , and most preferably Me ₂ Si(H)Cl, which includes:

holding for a silane feedstock comprising at least one silane selected from the group consisting of:

(i) monosilanes,

(ii) disilanes,

(iii) oligosilanes,

(iv) carbodisilanes,

provided that at least one of the silanes (i) to (iv) contains at least one chlorine-containing substituent,

a) hydrogenation reactions using at least one source of a hydride donor and

b) redistribution reactions and

c) optionally cleavage reactions of Si-Si bonds of di- or oligosilanes or Si-C bonds of carbodisilanes and

d) separation steps of methylchlorohydridsilanes,

where the method is carried out in the presence of one or more solvents, preferably selected from solvents based on ethers, in the absence of AlCl ₃ where

(i) monosilanes are selected from compounds described by the general formula (I),

Me _x SiH _y Cl _z , (I)

where

x=from 1 to 3,

y=0 to 3,

z=0 to 3, and

x+y+z=4,

(ii) disilanes are selected from compounds described by the general empirical formula (II),

Me _m Si ₂ H _n Cl _o , (II)

where

m=1 to 6,

n=0 to 5,

o=0 to 5, and

m+n+o=6,

(iii) the oligosilanes are selected from linear or branched oligosilanes described by the general empirical formula (III),

Me _p Si _q H _r Cl _s , (III)

where

q=3-7,

p=q to (2q+2),

r, s=0 to (q+2),

r+s = (2q+2) - p,

(iv) carbodisilanes are selected from compounds described by the general formula (IV),

(Me _a SiH _b Cl _e )-CH ₂ -(Me _c SiH _d Cl _f ), (IV)

where

a, c independently of each other are in the range from 1 to 3,

b, d independently of each other are in the range from 0 to 2,

e, f independently of each other are in the range from 0 to 2,

a+b+e=3,

c+d+f=3.

The integrated process in particular makes it possible to convert the complete or partial product stream(s) of the direct Müller-Rochow process directly into the desired methylchlorohydride monosilanes in the sense that it combines a hydrogenation reaction with a redistribution reaction and - in particular in the presence of a higher silane fraction(s) ) from the direct Müller-Rochow process in silane feedstock - in addition to this, with a cleavage reaction. That is, in one preferred embodiment of the invention, for direct Mueller-Rochow process full product streams, a hydrogenation reaction, a cleavage reaction, and a redistribution reaction are simultaneously carried out in a one-pot reaction, where the desired methylchlorohydride monosilanes can be obtained and isolated in high yields using this method. In a further particularly preferred embodiment, lithium hydride (LiH) is used as the hydrogenation additive, which can be efficiently recovered from the formed lithium chloride (LiCl).

Preferred embodiments of the invention:

In accordance with the present invention, the term "redistribution reaction" describes the redistribution of substituents representing hydrogen atoms, chlorine atoms, and/or organic groups, preferably substituents representing hydrogen and chlorine atoms, associated with the silicon atoms of one or more silane compounds contained in the reaction mixtures, as a result of the exchange of these substituents. The exchange can be monitored, in particular, using ²⁹ Si NMR, GC and/or GC/MS methods. The redistribution reactions are preferably catalyzed using the redistribution catalysts described below.

The redistribution reaction for silanes in the context of the present invention includes, in particular, co-proportionation for two different methylsilanes (a compound containing only a chlorine atom as additional substituents, and a compound containing only a hydrogen atom as additional substituents) to obtain one particular chlorohydride methylsilane, such as , in particular:

Me ₂ SiCl ₂ + Me ₂ SiH ₂ → 2Me ₂ SiHCl

2MeSiCl ₃ +MeSiH ₃ → 3MeSiHCl ₂

as opposed to the undesirable disproportionation where the chlorohydride methylsilane reacts to form two different methylsilanes (a compound containing only a chlorine atom as additional substituents and a compound containing only a hydrogen atom as additional substituents):

2Me ₂ SiHCl → Me ₂ SiCl ₂ + Me ₂ SiH ₂

3MeSiHCl ₂ → 2MeSiCl ₃ +MeSiH ₃

In a preferred embodiment of the process according to the invention, the silane redistribution reaction comprises co-proportionation for two different methylsilanes, in particular one methylsilane containing only a chlorine atom as additional substituents and one methylsilane containing only a hydrogen atom as additional substituents, resulting in the formation of one particular chlorohydride methylsilane.

In the present invention, the silanes in the silane feedstock to which the process of the invention is carried out comprise at least one of the silanes selected from the group consisting of

(i) monosilanes, which are selected from compounds described by the general formula (I),

Me _x SiH _y Cl _z , (I)

where

x=from 1 to 3,

y=0 to 3,

z=0 to 3, and

x+y+z=4,

(ii) disilanes which are selected from compounds described by the general empirical formula (II),

Me _m Si ₂ H _n Cl _o , (II)

where

m=1 to 6,

n=0 to 5,

o=0 to 5, and

m+n+o=6,

(iii) oligosilanes, which are selected from linear or branched oligosilanes, described by the general empirical formula (III),

Me _p Si _q H _r Cl _s , (III)

where

q=3-7,

p=q to (2q+2),

r, s=0 to (q+2),

r+s = (2q+2) - p, and

(iv) carbodisilanes which are selected from compounds described by the general empirical formula (IV),

(Me _a SiH _b Cl _e )-CH ₂ -(Me _c SiH _d Cl _f ), (IV)

where

a, c independently of each other are in the range from 1 to 3,

b, d independently of each other are in the range from 0 to 2,

e, f independently of each other are in the range from 0 to 2,

a+b+e=3,

c+d+f=3,

with the proviso that at least one of the silanes represented by formulas (I) to (IV) contains at least one chlorine-containing substituent.

In one preferred embodiment, the silane starting material consists of silanes represented by formulas (I) to (IV). More preferably, the silane feedstock is Me ₂ SiCl ₂ .

Disilanes described by the general empirical formula (II),

Me _m Si ₂ H _n Cl _o (II)

can also be illustrated using the structural formula:

,

,

where the substituents R' are independently selected from methyl (Me), a hydrogen atom (H) and a chlorine atom (Cl), where the number of methyl m=1 to 6, the number of hydrogen atoms n=0 to 5, and the number of chlorine atoms o= from 0 to 5, and the set m+n+o=6.

Oligosilanes described by the general formula (III),

Me _p Si _q H _r Cl _s (III)

are oligosilanes that include a linear or branched silane backbone, where q=3 to 7 silicon atoms, which are linked to each other using single bonds, and the free valencies of the silane backbone are saturated substituents selected from methyl (Me), atom hydrogen (H) and chlorine atom (Cl), provided that the number of methyl groups p=from q to (2q+2), which corresponds to the case when each silicon atom contains one methyl group (p=q), and the case permethylated silanes (p=2q+2), and which means the presence of at least 3 methyl groups up to 16 methyl groups (ie, in the form of Si ₇ Me ₁₆ ) in the silanes; and the number of hydrogen atoms (r) and chlorine atoms (s) independently of each other is in the range from 0 to (q+2), and r+s = (2q+2) - p, where q is the number of silicon atoms, and p is the number of methyl groups, again with the preferred proviso that each Si atom bears at least one methyl group.

In the collective application, the meaning of the term "empirical formula" is intended to mean that the formulas do not represent structural formulas, but simply summarize the chemical groups or atoms present in the molecule. For example, the empirical formula R ₂ Si ₂ Cl ₄ may include structural formulas:

и

and

More preferably, in one embodiment, the silane feedstock for which the method of the present invention is carried out comprises at least one of the following silanes:

(i) monosilanes, which are selected from compounds described by the formulas:

MeSiCl ₃ , Me ₂ SiCl ₂ , Me ₃ SiCl, MeSiHCl ₂ , Me ₂ SiHCl, MeSiH ₂ Cl, MeSiH ₃ , Me ₂ SiH ₂ and Me ₃ SiH,

(ii) disilanes, which are selected from compounds described by the formulas:

Cl ₂ MeSi-SiMeCl ₂ , Cl ₂ MeSi-SiMe ₂ Cl, Cl ₂ MeSi-SiMe ₃ , ClMe ₂ Si-SiMe ₂ Cl, Me ₃ Si-SiMe ₂ Cl, HMe ₂ Si-SiMe ₂ Cl, H ₂ MeSi- SiMeClH, HClMeSi-SiMeClH, ClHMeSi-SiMeCl ₂ , H ₂ MeSi-SiMeCl ₂ , HMe ₂ Si-SiMeCl ₂ , ClMe ₂ Si-SiMeH ₂ , HMe ₂ Si-SiMeClH, ClMe ₂ Si-SiMeClH, Me ₃ Si-SiMeClH, HMe ₂ Si-SiMe ₂ H, H ₂ MeSi-SiMeH ₂ , HMe ₂ Si-SiMeH ₂ , Me ₃ Si-SiMeH ₂ and Me ₃ Si-SiMe ₂ H,

(iii) oligosilanes, which are selected from compounds described by the formulas:

ClMe ₂ Si-SiMe ₂ -SiMe ₂ Cl, ClMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ Cl, (ClMe ₂ Si) ₃ SiMe, (Cl ₂ MeSi) ₂ SiMeCl, (Cl ₂ MeSi) ₃ SiMe, ( Cl ₂ MeSi) ₂ SiMe-SiClMe-SiCl ₂ Me, [(Cl ₂ MeSi) ₂ SiMe] ₂ , [(Cl ₂ MeSi) ₂ SiMe] ₂ SiClMe, (Cl ₂ MeSi) ₂ SiMe-SiMe ₂ Cl, ClMe ₂ Si-SiMe ₂ SiMe ₂ H, HMe ₂ Si-SiMe ₂ -SiMe ₂ H, HMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ H, (HMe ₂ Si) ₃ SiMe, (H ₂ MeSi) ₂ SiMeH, ( H ₂ MeSi) ₃ SiMe, (H ₂ MeSi) ₂ SiMe-SiHMe-SiH ₂ Me, [(H ₂ MeSi) ₂ SiMe] ₂ , [(H ₂ MeSi) ₂ SiMe] ₂ SiHMe and (H ₂ MeSi) ₂ SiMe-SiMe ₂ H, and

(iv) carbodisilanes, which are selected from compounds described by the formulas:

Cl ₂ MeSi-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeCl ₂ , Me ₃ Si-CH ₂ -SiMe ₂ Cl, HClMeSi-CH ₂ -SiMeClH, HMe ₂ Si-CH ₂ -SiMeCl ₂ , HMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeClH, H ₂ MeSi-CH ₂ -SiMeH ₂ , HMe ₂ Si-CH ₂ -SiMeH ₂ , HMe ₂ Si-CH ₂ -SiMe ₂ H, Me ₃ Si-CH ₂ -SiMeH ₂ and Me ₃ Si-CH ₂ -SiMe ₂ H, provided that at least , one of the silanes used in the process contains at least one chlorine-containing substituent.

More preferably, the silane feedstock for which the method of the present invention is carried out comprises at least two, preferably at least three, more preferably at least four, silanes, of which at least one, preferably of which all containing at least one chlorine atom substituent are preferably selected from the aforementioned silanes.

In one preferred embodiment of the invention, the silane feedstock comprises at least one silane selected from the group consisting of disilanes (ii), oligosilanes (iii), and carbodisilanes (iv).

In one further preferred embodiment of the invention, the silane feedstock comprises at least one, preferably more than one, silane selected from the group consisting of MeSiCl ₃ , Me ₂ SiCl ₂ , Me ₃ SiCl, MeSiHCl ₂ , Me ₂ SiHCl , MeSiH ₂ Cl, MeSiH ₃ , Me ₂ SiH ₂ , Me ₃ SiН, Cl ₂ MeSi-SiMeCl ₂ , Cl ₂ MeSi-SiMe ₂ Cl, Cl ₂ MeSi-SiMe ₃ , ClMe ₂ Si-SiMe ₂ Cl, Me ₃ Si -SiMe ₂ Cl, Cl ₂ MeSi-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeCl ₂ and Me ₃ Si- CH ₂ -SiMe ₂ Cl.

In one further preferred embodiment of the invention, the silane feedstock comprises one or more products (or product streams), preferably the complete direct Mueller-Rochow product.

Representing the value of the reaction of the direct method of Muller-Rochow are (Me=CH ₃ ):

xMeCl+Si → Me ₃ SiCl, Me ₂ SiCl ₂ , MeSiCl ₃ and other products.

The most important products of the direct process are monosilanes, such as the corresponding compounds described by the above formula (I), in particular, dichlorodimethylsilane Me ₂ SiCl ₂ obtained with a yield of approximately 70-90% (wt.) (wt. = when calculating to mass). The next largest product is MeSiCl ₃ at about 3-15% (wt.) of the total amount. Other products include Me ₃ SiCl (about 2 - about 4% (wt.)), MeHSiCl ₂ (about 0.9 - about 4% (wt.)), Me ₂ HSiCl (about 0.1 - about 0.5% (mass)). In one embodiment, these monosilanes are separated by fractional distillation. Up to about 10% (wt.), more preferably from about 0.1 to about 10% (wt.), products of the direct Muller-Rochow process are formed from higher silanes, such as the corresponding compounds described by formulas (II) to ( IV), which are mainly disilanes.

Accordingly, one preferred silane feedstock for which the method of the present invention is carried out includes, for example:

- from about 2% (wt.) to about 10% (wt.) of higher silanes containing more than one silicon atom, such as the corresponding compounds described by the above formulas from (II) to (IV), and

- from about 80% (wt.) to 96% (wt.) monosilanes, such as the corresponding compounds described by the above formula (I),

wherein each percentage is obtained based on the total amount of said silanes.

More specifically, one preferred silane feedstock for which the method of the present invention is carried out includes, for example:

- Me ₂ SiCl ₂ : about 70% (wt.) - about 90% (wt.),

- MeSiCl ₃ : about 3% (wt.) - about 15% (wt.),

- Me ₃ SiCl: about 2% (wt.) - about 4% (wt.),

- MeHSiCl ₂ : about 0.9% (wt.) - about 4% (wt.),

- Me ₂ HSiCl: about 0.1% (wt.) - about 0.5% (wt.), and

- higher silanes, including to a greater extent such corresponding compounds as described by formulas (II) to (IV): from about 4% (wt.) to about 10% (wt.),

wherein each percentage is obtained based on the total amount of said silanes. The silane feedstock may include other silanes not specifically mentioned here, in a total amount up to, for example, up to 3 parts based on 100 parts of the aforementioned composition, that is, a composition of

- Me ₂ SiCl ₂ : about 70% (wt.) - about 90% (wt.),

- MeSiCl ₃ : about 3% (wt.) - about 15% (wt.),

- Me ₃ SiCl: about 2% (wt.) - about 4% (wt.),

- MeHSiCl ₂ : about 0.9% (wt.) - about 4% (wt.),

- Me ₂ HSiCl: about 0.1% (wt.) - about 0.5% (wt.), and

- higher silanes, including to a greater extent such appropriate compounds as described by formulas (II) to (IV): from about 4% (wt.) to about 10% (wt.).

In one additional preferred embodiment of the invention, the silane feedstock for which the process of the present invention is carried out is the entire product of the direct Müller-Rochow process or a portion (fraction or product stream) of the product of the direct Müller-Rochow process.

In the most preferred embodiment of the invention, the process of the present invention is carried out on the complete product of the direct Muller-Rochow process.

In one additional preferred embodiment of the invention, the silane feedstock for which the method of the present invention is carried out comprises one or more monosilane fractions or a complete monosilane fraction of the product of the direct Müller-Rochow process.

It is also possible to carry out the process of the present invention with only the silane feedstock, which is part or all of the higher silane fraction (silanes containing ≥ 2 Si atoms) of the product of the direct Müller-Rochow process.

It is also possible to carry out the process of the present invention only for the silane feedstock, which is the oligosilane fraction (silanes containing ≥3 Si atoms) and the carbodisilane fraction of the product of the direct Müller-Rochow process.

In one additional preferred embodiment of the invention, the silane feedstock for which the method of the present invention is carried out is the highest silane fraction (silanes containing ≥ 2 Si atoms) of the product of the direct Müller-Rochow process, from which at least one component has been separated in whole or in part, and the component of which is preferably selected from the group consisting of disilanes containing ≥3 chlorine atoms and disilanes containing ≥3 methyl groups.

In one further preferred embodiment of the present invention, the silane feedstock comprises a product or product fraction of a direct Mueller-Rochow process from which at least one component has been separated in whole or in part, where this component is selected from the group consisting of Me _n SiCl _{4 - n} where n=1-3, Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl. That is, in one embodiment, one or more monosilanes considered valuable in accordance with current needs are separated, including, in particular, the desired methylchlorohydride silanes (Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and/or MeSi( H) ₂ Cl) before the product of the direct Müller-Rochow process is carried out with the process of the present invention. In a further preferred embodiment of the present invention, it is also possible to carry out first the hydrogenation reaction a) and then, before the redistribution and optional cleavage step, the methylchlorohydridesilanes are separated from the reaction mixture.

The process of the present invention is preferably carried out in the presence of one or more solvents, preferably selected from ether based solvents.

In accordance with the present invention, ether solvents may be selected from ether compounds, preferably selected from the group consisting of linear and cyclic aliphatic ether compounds.

In the present invention, the term "ether compound" shall mean any organic compound containing an ether group -O-, in particular, described by the formula R ¹ -OR ² , where R ¹ and R ² are independently selected from the organic group R.

Preferably, in the present invention, R is an organic group which is bonded to the silicon atom through a carbon atom, and where this organic group may be identical or different from other relevant groups. Preferably the organic group is an optionally substituted, more preferably unsubstituted group selected from the groups consisting of: alkyl, aryl, alkenyl, alkynyl, alkaryl, aralkyl, aralkenyl, aralkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cycloaralkyl, cycloaralkenyl and cycloaralkynyl, even more preferably selected from alkyl, cycloalkyl, alkenyl and aryl, more preferably still selected from methyl, vinyl and phenyl, and most preferably R is a methyl group (herein abbreviated as Me).

Preferably R ¹ and R ² are substituted or unsubstituted straight or branched alkyl groups or aryl groups which may further contain heteroatoms such as oxygen, nitrogen or sulfur atoms. In the case of compounds that are cyclic ethers, R ¹ and R ² may together form an optionally substituted alkylene or arylene group, which may furthermore contain heteroatoms such as oxygen, nitrogen or sulfur atoms.

Ether compounds may be symmetrical or asymmetric with respect to substituents on the ether group -O-.

In another preferred embodiment of the process of the present invention, the organic solvent in which step A) is carried out is a mixture of one or more ether compounds and one or more non-ether compounds.

Preferably, the one or more non-ether compounds admixed with the one or more ether compounds are selected from solvents that are less polar than the ether compounds used, particularly preferably from aliphatic or aromatic hydrocarbons.

In one further preferred embodiment of the process according to the invention, the ether compounds used as solvents are selected from the group consisting of linear, cyclic or complexing ether compounds.

As used herein, a linear ether compound is a compound containing an R ¹ -OR ² ether group, which corresponds to the above definition of the invention, in which case there is no connection between the R ¹ and R ² groups except through an oxygen atom of an ether group, such as, for example, in symmetrical ethers Et ₂ O, n-Bu ₂ O, Ph ₂ O or diisoamyl ether (isopentyl ₂ O) in which R ¹ =R ² , or in unsymmetrical ethers such as tert-BuOMe (methyl tert-butyl ether, MTBE) or PhOMe (methyl phenyl ether, anisole).

A cyclic ether compound used as a solvent is a compound in which one or more ether groups are included in a ring formed by a sequence of atoms such as, for example, tetrahydrofuran, tetrahydropyran or 1,4-dioxane, which may be substituted , for example, alkyl groups.

More than one ether group may also be included in linear ether compounds to form a di-, tri-, oligo-, or polyester compound, where R ¹ and R ² are organic groups when they are terminal groups of compounds, and alkylene or arylene groups when they are internal groups. As used herein, an end group is defined as any group bonded to one oxygen atom that is part of an ether group, while an internal group is defined as any group bonded to two oxygen atoms that is a constituent of ether groups.

Preferred examples of such compounds are dimethoxyethane, glycol diesters (glymes), in particular diglyme or tetraglyme, without limitation.

In the sense of the present invention, the term "chelating ether" is understood to be an ether compound which corresponds to the above definition of the invention and which is capable of complexing cations, preferably metal cations, more preferably alkali and alkaline earth metal cations, even more preferably alkali metal cations, and most preferably lithium cations. Preferred examples of such chelating ethers according to the invention are glycol diesters (glymes), in particular diglyme, triglyme, tetraglyme or pentaglyme, or crown ethers, in particular 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, and diaza-18-crown-6, without limitation.

The term "complexing ether" is understood to be equivalent to the term "complexing ether". In yet another preferred embodiment of the process according to the invention, an ether compound is used as solvent and is selected from the group consisting of linear ethers such as diethyl ether, di-n-butyl ether, complexing ethers such as dimethoxyethane, diethylene glycol dimethyl ether (diglyme) or tetraethylene glycol dimethyl ether (tetraglyme), alkylated polyethylene glycols (alkylated PEG compounds), cyclic ethers such as dioxane, preferably 1,4-dioxane, 2-methyltetrahydrofuran, tetrahydrofuran or tetrahydropyran.

In one particularly preferred embodiment of the process according to the invention, the ether compound is a high boiling ether compound, preferably diglyme or tetraglyme.

In accordance with the present invention, the term “high boiling ether compound” is defined as an ether compound as defined above and having a boiling point at 1.01325 bar (normal atmospheric pressure) of preferably at least about 70°C, more preferably at least about 85°C, even more preferably at least about 100°C, and most preferably at least about 120°C. High boiling ethers can facilitate the separation of desired products from a reaction mixture containing solvent and residual feedstock materials. In general, the products have lower boiling points than the feedstock materials, and these products also have lower boiling points than the high boiling ethers defined above.

For example, the corresponding boiling points (at normal atmospheric pressure) of selected representative products are approximately 35°C (Me ₂ SiHCl) and approximately 41°C (MeSiHCl ₂ ), while diglyme as a representative compound, which is a higher boiling simple ether , is characterized by a boiling point of approximately 162°C, and the boiling point of unreacted methylchlorodisilanes, in principle formed from isomers of trimethyltrichlorodisilane and dimethyltetrachlorodisilanes, is in the range from approximately 151 to approximately 158°C. The use of higher boiling ether compounds as solvents makes it possible to use higher reaction temperatures and makes it easier to separate the desired products from the reaction mixture by distillation.

In accordance with the present invention, the term "hydrogenation reaction a)" refers to the exchange of one or more chlorine atom substituents on the silicon atom of the silane feedstock for the same number of hydrogen atom substituents.

In accordance with the present invention, the term "hydride donor source" refers to any compound that is capable of donating at least one hydride anion in a reaction between a hydride donor source and a feedstock of the invention, resulting in the conversion of at least one Si-Cl bond into a Si-H bond.

In one embodiment, preferably, the hydrogenation reaction a) of the process according to the invention is carried out using a source of hydride donor selected from the group consisting of metal hydrides, in this case preferably binary metal hydrides such as LiH, NaH, KH, CaH ₂ or MgH ₂ , complex metal hydrides such as LiAlH ₄ or NaBH ₄ , and organometallic hydride reagents such as n-Bu ₃ SnH, i-Bu ₂ AlH or sodium bis(2-methoxyethoxy)aluminum hydride, or a hydride donor source selected from boron-containing hydride donors, more preferably selected from organohydride boranes, hydride boranes, hydride boronates, and hydride borates, even more preferably hydride boranes, hydride boronates, and hydridobrates formed from the corresponding boronates, boronates, and borates, which are the Lewis acid-formed portion of the detuned Lewis acid/Lewis base pair, and H ₂ .

In accordance with the present invention, the term "metal hydride" refers to any source of a hydride donor containing at least one metal atom or metal ion and at least one hydride ion.

The binary metal hydrides of the present invention are metal hydrides composed solely of one particular metal ion and hydride ion.

Preferably the metal hydrides according to 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 consisting of lithium hydride, sodium hydride, potassium hydride, magnesium hydride, calcium hydride, more more preferably lithium hydride and sodium hydride, most preferably the metal hydride is lithium hydride.

The term "complex metal hydrides" according to the invention refers to metal salts, where the anions include hydride anions. Usually complex metal hydrides contain more than one type of metal or metalloid. Due to the lack of both a standard definition of metalloid and full agreement on elements properly classified as such, the term "metalloid" for the purposes of the present invention includes the elements boron, silicon, germanium, arsenic, antimony, tellurium, carbon, aluminium, selenium, polonium and astatine.

The term "organometallic hydride reagent" refers to compounds which contain bonds between carbon and metal atoms and which are capable of donating at least one hydride anion in the hydrogenation reaction in hydrogenation step a).

In a preferred embodiment of the invention, the hydride donor source used to influence the hydrogenation reaction a) is selected from metal hydrides, most preferably lithium hydride. In one preferred embodiment of the process according to the invention, the amount of the hydride donor source, in particular the metal hydride, preferably LiH, in the hydrogenation reaction a) relative to the silane feedstock compounds described by the general formulas (I), (II), (III ) and (IV) ranges from about 1% (mol.) to about 600% (mol.), preferably from about 1 to about 400% (mol.), more preferably from about 1 to about 200% (mol. .), most preferably from about 25 to about 150% (mol.), based on the total molar number of chlorine atoms present in the compounds of the initial silane raw materials, described by the General formulas (I), (II), (III) and (IV ). To determine this ratio, all compounds described by the general formulas (I), (II), (III) and (IV) are considered, regardless of whether they will be offered together with other silanes not covered by these formulas.

More preferably, the amount of the source of the hydride donor, in particular, the metal hydride, preferably LiH, in the hydrogenation reaction a) in relation to the compounds of the initial silane feedstock described by the general formulas (I), (II), (III) and (IV), when calculating on the total molar number of chlorine atoms present in the compounds of the initial silane raw materials, described by the General formulas (I), (II), (III) and (IV), is less than about 100% (mol.), preferably less than about 90% (mol.), more preferably less than about 80% (mol.), in order to leave enough chlorine atoms for subsequent redistribution reactions in order to obtain the desired silanes.

Most preferably, the amount of the hydride donor source, in particular metal hydride, preferably LiH, in the hydrogenation reaction a) in relation to the compounds of the initial silane feedstock described by the general formulas (I), (II), (III) and (IV), when calculating on the total molar number of chlorine atoms present in the compounds of the original silane raw materials, described by General formulas (I), (II), (III) and (IV), is less than about 75% (mol.). Preferably, for the synthesis of monohydrogenated silanes such as MeSiHCl ₂ and Me ₂ SiHCl, LiH must be used in a stoichiometric deficit (preferably at less than about 50% (mol.), preferably at less than about 25% (mol.)), for increasing the amount of monosilane MeSiH ₂ Cl molar amount is preferably in the range from about 25 to about 75% (mol.).

In one preferred embodiment of the invention, the mass ratio for the source of the hydride donor, in particular the metal hydride, preferably LiH, in the hydrogenation reaction a) in relation to the compounds of the initial silane feedstock, described by the General formulas (I), (II), (III) and (IV) ranges from about 1:100 to about 100:1, preferably from 10:90 to about 90:10, more preferably from 20:80 to about 80:20.

In this document, this weight ratio is defined as

m (hydride donor source, in particular metal hydride, preferably LiH) / m (silane feedstock compounds represented by the general formulas (I), (II), (III) and (IV)). To determine this ratio, all compounds described by the general formulas (I), (II), (III) and (IV) are considered, regardless of whether they will be offered together with other silanes not covered by these formulas.

In yet another preferred embodiment of the method of the invention, the weight ratio between the silane feedstock and the organic solvent is in the range of about 0.01 to about 100, preferably in the range of about 0.1 to about 10, more preferably about 0, 5 to about 4, most preferably from about 0.5 to about 1.

In this document, this weight ratio is defined as

m (compounds of the initial silane raw materials, described by the general formulas (I), (II), (III) and (IV)) / m (organic solvents).

To determine this ratio, all compounds described by the general formulas (I), (II), (III) and (IV) are considered, regardless of whether they will be offered together with other silanes not covered by these formulas.

In a preferred embodiment of the invention, the optional cleavage reaction c) for Si-Si bonds of di- or oligosilanes or Si-C bonds of carbodisilanes is preferably carried out in a one-pot reaction simultaneously with the hydrogenation reaction a) and the redistribution reaction b). Such a cleavage reaction c) may be suitable for use only if (ii) disilanes, (iii) oligosilanes and/or (iv) carbodisilanes containing at least one chlorine-containing substituent in at least one silane.

In the method of the present invention, the redistribution reaction b) is carried out in the presence of at least one redistribution catalyst.

In accordance with the above description of the invention in the present invention, the term "redistribution reaction b)" describes the redistribution, in particular, representing hydrogen and chlorine atoms, substituents associated with silicon atoms of one or more compounds included in the original silane feedstock, as a result of the exchange of substituents . The exchange of methyl groups is also possible, but usually undesirable or to be avoided.

Preferably by a redistribution reaction b) from silanes containing only chlorine substituents on silicon atoms and silanes containing only hydrogen substituents on silicon atoms, and/or from silanes containing hydrogen and chlorine substituents on silicon atoms formed under the reaction conditions, the yield of the desired methylchlorohydride monosilanes increases. In the present invention, the redistribution catalysts are usually different from the solvent used in the reaction. In some cases, the redistribution catalysts can also function as a hydride donor source, in particular in the case of metal hydrides, but preferably the redistribution catalysts are different from the hydride donor source. In some cases, the redistribution catalysts can also function as splitting catalysts, but it is also possible to use different redistribution catalyst and splitting catalyst.

Redistribution catalysts are, in particular, compounds that catalyze the following reactions:

Me ₂ SiCl ₂ + Me ₂ SiH ₂ → 2Me ₂ SiHCl

2MeSiCl ₃ +MeSiH ₃ → 3MeSiHCl ₂

in particular the reactions

Me ₂ SiCl ₂ + Me ₂ SiH ₂ → 2Me ₂ SiHCl

at a given temperature. For example, if Me ₂ SiCl ₂ and Me ₂ SiH ₂ do not react at a certain temperature, but actually react at a given temperature in the presence of some compound, said compound will act as a redistribution catalyst.

Preferably the redistribution catalysts are selected from the group consisting of:

- R ₄ PCl, where R represents a hydrogen atom or an organic group, where this substituent may be identical or different in comparison with other corresponding substituents, more preferably an aromatic group or an aliphatic hydrocarbon group, even more preferably an n-alkyl group, and most preferably n-butyl group,

- triorganophosphines, where R represents a hydrogen atom or an organic group, preferably PPh ₃ or n-Bu ₃ P,

- triorganoamines, where R represents an organic group, preferably n-Bu ₃ N or NPh ₃ ,

- N-heterocyclic amines, preferably non-N-substituted methylimidazoles such as 2-methylimidazole and 4-methylimidazole, preferred are N-heterocyclic amines having a free nucleophilic electron pair on the nitrogen atom, which means no decrease in nucleophilicity on the nitrogen atom in such N -heterocyclic amines as a result of inductive or mesomeric interactions. In particular, cyclic amides are generally not suitable for use as redistribution catalysts,

- quaternary ammonium compounds, preferably n-Bu ₄ NCl,

- alkali metal halide,

- alkaline earth metal halide,

- alkali metal hydride and

- alkaline earth metal hydride.

In one embodiment, one or more redistribution catalysts may be used, in particular a combination of two redistribution catalysts is preferred.

Since metal hydrides can also function as redistribution catalysts, it may not be necessary to add a redistribution catalyst in addition to the hydride donor source added in hydrogenation reaction a). However, generally the addition of a redistribution catalyst in addition to the hydride donor source added to the hydrogenation reaction a) is preferred. According to the preferred reaction sequences of a) hydrogenation reaction, b) redistribution reaction and c) cleavage reaction, it is preferred to add a redistribution catalyst together with a source of hydride donor and an optional cleavage catalyst.

It may also be the case that the redistribution catalyst simultaneously performs the function of a cleavage catalyst, which corresponds to the following description of the invention.

In one preferred embodiment, the redistribution catalyst is selected from the group consisting of:

- R ₄ PCl, where R represents a hydrogen atom or an organyl group, where this substituent may be identical or different in comparison with other corresponding substituents, more preferably an aromatic group or an aliphatic hydrocarbon group, even more preferably an n-alkyl group, and most preferably n-butyl group,

- triorganophosphines, where R represents a hydrogen atom or an organic group, preferably PPh ₃ ,

- triorganoamines, where R represents an organic group, preferably n-Bu ₃ N,

- N-heterocyclic amines, preferably non-N-substituted methylimidazoles such as 2-methylimidazole and 4-methylimidazole, preferred are N-heterocyclic amines having a free nucleophilic electron pair on the nitrogen atom, which means no decrease in nucleophilicity on the nitrogen atom in such N -heterocyclic amines as a result of inductive or mesomeric interactions. In particular, cyclic amides are generally not suitable for use as redistribution catalysts, and

- Quaternary ammonium compounds, preferably n-Bu ₄ NCl.

In the preferred redistribution catalysts selected from compounds described by the general formula R ₄ PCl, R represents hydrogen or an organic group, where R may be identical or different in comparison with other appropriate substituents, preferably R represents an aromatic group such as phenyl, tolyl , and/or an aliphatic hydrocarbon group, more preferably R is an alkyl group such as methyl, ethyl, n- or isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-pentyl, t-pentyl, neopentyl , isopentyl, sec-pentyl, n-, iso- or sec-hexyl, n-, iso- or sec-heptyl, n-, iso- or sec-octyl and the like, even more preferably R is an n-alkyl group , and most preferably the compound represented by the general formula R ₄ PCl is n-Bu ₄ PCl.

In preferred redistribution catalysts selected from the PR ₃ triorganophosphines, R is a hydrogen atom or an organic group and may be identical or different from other appropriate substituents, more preferably R is an alkyl such as described above, a cycloalkyl or aryl group, most preferably the organophosphine is PPh ₃ or n-Bu ₃ P.

In preferred redistribution catalysts selected from NR ₃ triorganoamines, R is an organic group, more preferably R is an alkyl group, and most preferably the triorganoamine is n-Bu ₃ N or NPh ₃ .

Preferred redistribution catalysts selected from N-heterocyclic amines are non-N-substituted methylimidazoles such as 2-methylimidazole and 4-methylimidazole, most preferably 2-methylimidazole.

In preferred redistribution catalysts selected from NR ₄ Cl quaternary ammonium compounds, R is a hydrogen atom or an organic group and is identical or different from other appropriate substituents, more preferably R is an alkyl group, and most preferably the quaternary ammonium compound is n-Bu ₄ NCl.

In one preferred embodiment of the present invention, a combination of quaternary ammonium compounds NR ₄ Cl and methylimidazoles can be used as catalysts.

In one preferred embodiment of the present invention, the optional cleavage reaction c) is carried out in the presence of at least one cleavage catalyst. Preferred cleavage catalysts are selected from the group consisting of:

- a quaternary onium compound of an element from the group 15 R ₄ QX, where each R independently represents a hydrogen atom or an organic group, Q represents a phosphorus, arsenic, antimony or bismuth atom, and X represents a halide selected from the group consisting of F, Cl, Br and I,

- heterocyclic amine,

- heterocyclic ammonium halide,

- mixtures of R ₃ P and RX,

where R corresponds to the above definition of the invention, and X corresponds to the above definition of the invention,

- alkali metal halide,

- alkaline earth metal halide,

- alkali metal hydride,

- alkaline earth metal hydride or mixtures thereof, and optionally in the presence of hydrogen chloride (HCl).

Obviously, there is a possibility of overlapping definitions of redistribution catalysts and cleavage catalyst or compounds. Accordingly, as stated above, compounds that act as redistribution catalysts can also act as cleavage catalysts, and vice versa. In one preferred embodiment of the invention, the redistribution catalysts also function as a cleavage catalyst or compounds.

In addition, as is to be understood, hydride donor sources, in particular metal hydrides such as LiH, can also function as cleavage compounds.

The cleavage reaction is used to describe the conversion in which, for the production of monomeric silanes, a reaction is carried out for disilanes (ii), such as the corresponding compounds described by the general formula (II), oligosilanes (iii), such as the corresponding compounds described by the general formula (III) , and carbodisilanes (iv) such as the corresponding compounds described by the general formula (IV). In the case of disilanes having the general formula (II) and organosilanes having the general formula (III), the term "silicon-silicon bond(s) cleavage reaction" further indicates the cleavage performed according to the present invention for the aforementioned feedstock as a result of breaking the bond connecting the silicon atoms of these disilanes and oligosilanes. In the case of carbodisilanes represented by the general formula (III), the term "silicon-carbon cleavage reaction" indicates a cleavage reaction by breaking one or both of the bonds between the silyl groups of the compounds and the methylene group linking the silyl groups. Such cleavage methods include, in particular, hydrochlorination and hydrogenolysis reactions.

The cleavage reaction is preferably carried out in the presence of one or more cleavage catalyst compounds.

Preferably, the cleavage catalyst compounds are selected from the group consisting of:

- a quaternary onium compound of an element from the group 15 R ₄ QX, where each R independently represents a hydrogen atom or an organic group, Q represents a phosphorus, arsenic, antimony or bismuth atom, and X represents a halide selected from the group consisting of F, Cl, Br and I,

- heterocyclic amine,

- heterocyclic ammonium halide,

- mixtures of R ₃ P and RX, where R corresponds to the above definition of the invention, and X corresponds to the above definition of the invention,

- alkali metal halides,

- alkaline earth metal halides,

- an alkali metal hydride or an alkaline earth metal hydride, and optionally

- in the presence of hydrogen chloride (HCl)

and

mixtures of the above compounds.

It has been found that the cleavage catalysts can also act as reactants under certain conditions, ie they are consumed in the cleavage reactions, and as a result the quantity of the desired hydride monosilanes, such as, in particular, Me ₂ SiHCl, is greatly increased. Therefore, cleavage catalysts are sometimes also referred to as "cleavage compounds".

The cleavage reaction can also under certain circumstances be carried out in the presence of hydrogen chloride (HCl), in particular in the presence of hydrogen chloride and an ether compound such as the ether solvents described above.

Preferred cleavage catalysts or cleavage compounds include, but are not limited to, the following:

- phosphonium chlorides R ₄ PCl, where R represents a hydrogen atom or an organic group, where this substituent may be identical or different in comparison with other corresponding substituents, more preferably an aromatic group or an aliphatic hydrocarbon group, even more preferably an n-alkyl group, and most preferably an n-butyl group,

- N-heterocyclic amines, more preferably methylimidazoles such as 2-methylimidazole, 4-methylimidazole and 1-methylimidazole, and

- Quaternary ammonium compounds, more preferably n-Bu ₄ NCl,

- and their mixtures.

As explained above, the hydrogenation reaction a), the redistribution reaction b) and the cleavage reaction c) can only be affected by the addition of a hydride donor source, since the hydride donor source or its reaction products, such as metal halides, can also function. catalysts for the redistribution reaction b) and the splitting reaction c); an HCl compound may optionally be added to allow the cleavage reaction to proceed.

As for the molar ratio for the redistribution catalyst with respect to the silane feedstock compounds, it is preferably in the range from about 0.0001% (mol.) to about 600% (mol.), more preferably from about 0.01% (mol. .) up to about 20% (mol.), even more preferably from about 0.05% (mol.) to about 2% (mol.), and most preferably from about 0.05% (mol.) to about 1% (mol.).

In this document, this molar ratio, when expressed in %, is defined as

[n (molar amount of redistribution catalyst) / n (molar amount of silane feedstock compounds represented by the general formulas (I), (II), (III) and (IV))]×100.

To determine this ratio, all redistribution catalysts and all silane feedstock compounds described by the general formulas (I), (II), (III) and (IV) are considered, regardless of whether they will be offered as part of a mixture containing other silane compounds which do not fall within the description of the general formulas (I), (II), (III) or (IV).

Similarly, the mole ratio for the cleavage catalyst to the silane feedstock compounds is preferably in the range of from about 0.0001% (mol.) to about 600% (mol.), more preferably from about 0.01% (mol.) to about 20% (mol.), even more preferably from about 0.05% (mol.) to about 2% (mol.), and most preferably from about 0.05% (mol.) to about 1% (mol. .).

In this document, this molar ratio, when expressed in %, is defined as

[n (molar amount of cleavage catalyst) / n (molar amount of silane feedstock compounds represented by the general formulas (I), (II), (III) and (IV))]×100.

These amounts also apply to the case in which a compound is used that functions as both a redistribution catalyst and a cleavage catalyst compound.

In one preferred embodiment corresponding to the invention, the redistribution catalyst is described by the formula R ₄ PCl.

Preferably in the formula R ₄ PCl, R is hydrogen or an organic group, where this substituent may be identical or different in comparison with other corresponding substituents, more preferably R is an aromatic group or an aliphatic hydrocarbon group, even more preferably R is an alkyl or a cycloalkyl group, in addition, even more preferably R is an n-alkyl group, and most preferably a compound having the general formula R ₄ PCl is n-Bu ₄ PCl.

In yet another preferred embodiment according to the invention, the compounds described by the formula R ₄ PCl are obtained "in situ" from compounds described by the formulas R ₃ P and RCl, where R represents H or an organic group.

In accordance with the invention, R in the compound R ₄ PCl obtained "in situ" may be identical or different in comparison with other appropriate substituents, and preferably R is identical in comparison with other appropriate substituents, and RCl is HCl or chloroalkane, more preferably RCl is 1-chloroalkane of up to about 20 carbon atoms, even more preferably RCl is 1-chloroalkane of up to 10 carbon atoms, and most preferably RCl is 1-chlorobutane. The term "in situ" as used herein refers to the preparation of R ₄ PCl from R ₃ P and RCl by combining the compounds in a reaction vessel in which reaction step A) is carried out.

In one also preferred embodiment according to the invention, the process is carried out in the presence of at least one compound represented by the formula R ₄ PCl and lithium hydride.

Preferably, the invention is carried out in the presence of lithium hydride and at least one compound having the formula R ₄ PCl, where R is an organic group and may be identical or different from other appropriate substituents.

In one additional preferred embodiment corresponding to the invention, the method is carried out in the presence of n-Bu ₄ PCl.

In the present invention, n-Bu ₄ PCl has been found to be a particularly effective redistribution catalyst.

Preferably the invention is carried out in the presence of n-Bu ₄ PCl and in the presence of lithium hydride as the alkali metal hydride, more preferably in the presence of lithium hydride and a high boiling ether compound, most preferably in the presence of lithium hydride and a high boiling ether compound selected from the group consisting of diglyme, tetraglyme and 1,4-dioxane.

In one preferred embodiment of the present invention, the hydrogenation reaction a), the redistribution reaction b) and optionally the cleavage reaction c) are carried out simultaneously and/or step by step, preferably simultaneously.

In one most preferred embodiment, the hydrogenation reaction a), the redistribution reaction b) and the cleavage reaction c) are carried out simultaneously for the composition of the complete products of the direct Müller-Rochow process and the desired methylchlorohydride monosilanes are isolated from the resulting product by fractional distillation.

However, depending on the particular silane feedstock used in the process of the present invention, specifically adapted reaction sequences may be selected from, for example, one or more of the following process options:

the hydrogenation reaction a) and the redistribution reaction b) are carried out simultaneously, the optional cleavage reaction c) is carried out subsequently,

the hydrogenation reaction a), the redistribution reaction b) and the cleavage reaction c) are carried out simultaneously,

first separately carry out the hydrogenation reaction a), and then simultaneously or separately carry out the redistribution reaction b) and optionally the cleavage reaction c), optionally in this embodiment after the hydrogenation reaction a) the methylchlorohydride monosilanes already obtained can be separated before inducing the passage of the redistribution reaction b) and optional cleavage reaction c),

the hydrogenation reaction a) is carried out first, then optionally the cleavage reaction c) is carried out, and then the redistribution reaction b) is carried out optionally in this embodiment after the hydrogenation reaction a) the methylchlorohydride monosilanes already produced can be separated before inducing the cleavage reaction c) to proceed, and redistribution reactions b),

the silane feedstock is selected from monosilanes, and such feedstock is first subjected to a hydrogenation reaction a) and subsequently a redistribution reaction b), or such feedstock is subjected to a hydrogenation reaction a) and a redistribution reaction b) simultaneously.

As is obvious, in the case of using monosilane raw materials (such as the monosilanes described by formula (I)) the cleavage reaction can usually be dispensed with.

Thus, the integrated method for producing methylchlorohydride monosilanes of the present invention shows great flexibility with respect to any type of chlorine-containing silane feedstock, which correspond to the above description of the invention and production, in particular, as a product (or incomplete product) of the direct Muller-Rochow process.

In one preferred embodiment of the present invention, the process comprises an additional step of separating monosilanes containing more than one hydrogen atom, in particular perhydrogenated methyl monosilanes such as Me ₂ SiH ₂ and MeSiH ₃ , which are then subjected to a reaction selected from the group consisting of from:

- chlorination reactions, preferably using an ether/HCl system, and/or

- redistribution reactions using silanes containing at least one chlorine atom, for which redistribution catalysts can be used, which correspond to the above description of the invention.

In this embodiment, solvents can also be used, which correspond to the above description of the invention.

In another preferred embodiment of the present invention, the method includes an additional step of separating disilanes and/or oligosilanes, each of which contains more than one hydrogen atom, which are then subjected to a reaction selected from the group consisting of:

- cleavage reactions, preferably in the presence of an ether/HCl system, and/or

- redistribution reactions when using silanes containing at least one chlorine atom.

In these reactions, redistribution catalysts and a cleavage catalyst can be used, as well as solvents that correspond to the above description of the invention.

In one additional preferred embodiment of the invention, the method includes the step of separating carbodisilanes containing at least one hydrogen atom, which are then subjected to a reaction selected from the group consisting of:

- cleavage reactions, preferably in the presence of a metal hydride, and/or

- redistribution reactions when using silanes containing at least one chlorine atom.

For these reactions, each of the metal hydrides, redistribution catalysts, and solvents, as described above, can be used.

If Me ₃ SiH is desired as a by-product, in one further preferred embodiment of the present invention, the process will include the step of separating Me ₃ SiH, in particular after the hydrogenation reaction a).

In accordance with the above description of the invention, in one embodiment of the process of the present invention, the most preferred hydride donor source is LiH, which is converted to lithium chloride (LiCl).

In one particular preferred embodiment of such a method using lithium hydride, the resulting LiCl compound is subjected to separation and purification steps, optionally mixing with KCl to obtain a eutectic LiCl-KCl composition, electrolysis of the eutectic or molten LiCl compound to obtain the metallic element Li, and reclaiming LiH from thus obtained element Li.

A particular advantage of this embodiment is that it makes the process of the present invention economical and efficient, including in particular the conversion reaction (DI → M2H), by recycling and improving the quality of LiCl accumulation and its conversion back to LiH. Therefore, the cost of Li metal appearing in both components (LiH and LiCl) is excluded from consideration of the total cost, and only the conversion cost involved in converting LiCl back to LiH should be considered. In addition, recycling accompanies the current LiH manufacturing route. Strictly speaking, the hydride substance is obtained from LiCl in two successive steps: a) electrolysis of LiCl in the form of a eutectic system (together with, for example, KCl, a method using a Downs cell), which results in the production of metal Li; followed by step b) hydrogenation of Li metal at elevated temperatures using hydrogen gas (H ₂ ), which results in LiH (schematically):

(Full stoichiometry:

2LiCl → 2Li+Cl ₂

2Li+H ₂ → 2LiH)

Other sources of metal hydrides form by-products which to a large extent must be removed (eg in the case of LiAlH ₄ → LiCl and AlCl ₃ ) and thus costly purification steps will interfere with the economics of the process. In addition, the formation of AlCl ₃ is undesirable, since its presence induces a redistribution of the Me groups, which will result in a mixture of products with a wide composition distribution (see, for example, publications US 5,856,548 or US 5,654,459A).

The method of the present invention is preferably carried out at a temperature in the range from about -40°C to about 250°C. Even more preferably, the process of the present invention is carried out at at least two different temperatures, preferably at a first temperature which is less than the second temperature. The temperatures are generally chosen according to the requirements of the hydrogenation reaction a), the redistribution reaction b) and the optional cleavage reaction c).

In one preferred embodiment of the method of the invention, the reactions (hydrogenation reaction, redistribution reaction, and optional cleavage reaction) are carried out over a combined time period of more than about 4 hours, preferably more than about 6 hours, preferably more than about 10 hours, and preferably more than about 12 hours.

In a further preferred embodiment of the method of the invention, the reactions (hydrogenation reaction, redistribution reaction, and optional cleavage reaction) are carried out over a combined time period of more than about 4 hours, preferably more than about 6 hours, at a temperature that, at least partially exceeds at least about 200°C, or the reactions in step A) are carried out for more than about 10 hours, preferably more than about 12 hours, at a temperature that is at least partially exceeds at least about 100°C, preferably more than about 150°C.

The process according to the present invention is preferably carried out at a pressure in the range from about 0.1 to about 10 bar.

The method of the present invention is preferably carried out under inert conditions.

The process of the present invention may be carried out continuously or intermittently, such as intermittently.

In one embodiment, the method of the present invention includes a separation step for separating methyl chloride. In one preferred embodiment of the process according to the invention, the separation step of the methylchlorohydridsilanes is carried out by distillation and/or condensation.

The term "distillation" according to the present invention refers to any process for separating components or substances from a liquid mixture by selective evaporation and condensation. In this case, the distillation may result in a substantially complete separation of the ingredients of the mixture, thus resulting in the isolation of almost pure compounds, or it may be an incomplete separation, which increases the concentration of the selected ingredients of the mixture in the distillate in comparison with the fact that occurs in the distilled mixture.

Preferably, the distillation methods may be simple distillation, fractional distillation, vacuum distillation, molecular distillation, or any other type of distillation known to those skilled in the art.

Also preferably, the separation step of the methylchlorohydridesilanes of the invention may include one or more batch distillation steps, or may include a continuous distillation process.

Further preferably, the term "condensation" may include separating methylchlorohydridesilanes from the reaction mixture or enriching the reaction mixture thereon by evaporation from the reaction vessel and condensation as a liquid and/or solid in a refrigerated vessel, from which they can subsequently be recovered as a result of distillation or by dissolving in an ether solvent.

Alternatively, it is preferred that the methylchlorohydridesilanes be absorbed into the ether solvent contained in the refrigerated container.

In one preferred embodiment of the process according to the invention, the process is carried out under inert conditions.

In accordance with the present invention, the term "carry out under inert conditions" means the partial or complete implementation of the method with the exclusion of ambient air, in particular moisture and oxygen. In order to exclude ambient air from the reaction mixture and reaction products, closed reaction vessels, reduced pressure and/or inert gases, in particular nitrogen or argon, or combinations of such means can be used.

Preferred embodiments of the invention:

The following summary summarizes the preferred embodiments of the invention:

1. Process for preparing methylchlorohydride monosilanes selected from Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl, preferably Me ₂ Si(H)Cl and MeSi(H)Cl ₂ , and most preferably Me ₂ Si(H)Cl, including:

conducting for the initial silane raw materials, including at least one silane selected from the group consisting of:

(i) monosilanes,

(ii) disilanes,

(iii) oligosilanes,

(iv) carbodisilanes,

provided that at least one of the silanes (i) to (iv) contains at least one chlorine-containing substituent,

a) hydrogenation reactions using at least one source of a hydride donor and

b) redistribution reactions and

c) optionally cleavage reactions of Si-Si bonds of di- or oligosilanes or Si-C bonds of carbodisilanes and

d) separation steps of methylchlorohydridsilanes,

where the process is carried out in the presence of one or more solvents, preferably selected from ether-based solvents, in the absence of AlCl ₃ (also preferably in the absence of a transition metal compound, and even more in the absence of any metal compound except for metal compounds used as a donor source hydride, redistribution catalysts or cleavage catalysts, which are in accordance with the description of the invention herein), where

(i) monosilanes are selected from compounds described by the general formula (I),

Me _x SiH _y Cl _z , (I)

where

x=from 1 to 3,

y=0 to 3,

z=0 to 3, and

x+y+z=4,

(ii) disilanes are selected from compounds described by the general empirical formula (II),

Me _m Si ₂ H _n Cl _o , (II)

where

m=1 to 6,

n=0 to 5,

o=0 to 5, and

m+n+o=6,

(iii) the oligosilanes are selected from linear or branched oligosilanes described by the general empirical formula (III),

Me _p Si _q H _r Cl _s , (III)

where

q=3-7,

p=q to (2q+2),

r, s=0 to (q+2),

r+s = (2q+2) - p,

(iv) carbodisilanes are selected from compounds described by the general formula (IV),

(Me _a SiH _b Cl _e )-CH ₂ -(Me _c SiH _d Cl _f ), (IV)

where

a, c independently of each other are in the range from 1 to 3,

b, d independently of each other are in the range from 0 to 2,

e, f independently of each other are in the range from 0 to 2,

a+b+e=3,

c+d+f=3.

2. The method according to Embodiment 1, wherein the silane feedstock consists of silanes represented by formulas (I) to (IV). More preferably, the silane feedstock is Me ₂ SiCl ₂ .

3. A method according to any of the preceding embodiments, wherein

(i) monosilanes are selected from compounds described by the formulas:

MeSiCl ₃ , Me ₂ SiCl ₂ , Me ₃ SiCl, MeSiHCl ₂ , Me ₂ SiHCl, MeSiH ₂ Cl, MeSiH ₃ , Me ₂ SiH ₂ and Me ₃ SiH,

(ii) disilanes are selected from compounds described by the formulas:

Cl ₂ MeSi-SiMeCl ₂ , Cl ₂ MeSi-SiMe ₂ Cl, Cl ₂ MeSi-SiMe ₃ , ClMe ₂ Si-SiMe ₂ Cl, Me ₃ Si-SiMe ₂ Cl, HMe ₂ Si-SiMe ₂ Cl, H ₂ MeSi- SiMeClH, HClMeSi-SiMeClH, ClHMeSi-SiMeCl ₂ , H ₂ MeSi-SiMeCl ₂ , HMe ₂ Si-SiMeCl ₂ , ClMe ₂ Si-SiMeH ₂ , HMe ₂ Si-SiMeClH, ClMe ₂ Si-SiMeClH, Me ₃ Si-SiMeClH, HMe ₂ Si-SiMe ₂ H, H ₂ MeSi-SiMeH ₂ , HMe ₂ Si-SiMeH ₂ , Me ₃ Si-SiMeH ₂ and Me ₃ Si-SiMe ₂ H,

(iii) oligosilanes are selected from compounds described by the formulas:

ClMe ₂ Si-SiMe ₂ -SiMe ₂ Cl, ClMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ Cl, (ClMe ₂ Si) ₃ SiMe, (Cl ₂ MeSi) ₂ SiMeCl, (Cl ₂ MeSi) ₃ SiMe, ( Cl ₂ MeSi) ₂ SiMe-SiClMe-SiCl ₂ Me, [(Cl ₂ MeSi) ₂ SiMe] ₂ , [(Cl ₂ MeSi) ₂ SiMe] ₂ SiClMe, (Cl ₂ MeSi) ₂ SiMe-SiMe ₂ Cl, ClMe ₂ Si-SiMe ₂ SiMe ₂ H, HMe ₂ Si-SiMe ₂ -SiMe ₂ H, HMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ H, (HMe ₂ Si) ₃ SiMe, (H ₂ MeSi) ₂ SiMeH, ( H ₂ MeSi) ₃ SiMe, (H ₂ MeSi) ₂ SiMe-SiHMe-SiH ₂ Me, [(H ₂ MeSi) ₂ SiMe] ₂ , [(H ₂ MeSi) ₂ SiMe] ₂ SiHMe and (H ₂ MeSi) ₂ SiMe-SiMe ₂ H,

(iv) carbodisilanes are selected from compounds described by the formulas:

Cl ₂ MeSi-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeCl ₂ , Me ₃ Si-CH ₂ -SiMe ₂ Cl, HClMeSi-CH ₂ -SiMeClH, HMe ₂ Si-CH ₂ -SiMeCl ₂ , HMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeClH, H ₂ MeSi-CH ₂ -SiMeH ₂ , HMe ₂ Si-CH ₂ -SiMeH ₂ , HMe ₂ Si-CH ₂ -SiMe ₂ H, Me ₃ Si-CH ₂ -SiMeH ₂ and Me ₃ Si-CH ₂ -SiMe ₂ H,

provided that at least one of the silanes used in the process contains at least one chlorine-containing substituent.

4. The process according to any of the preceding embodiments wherein the silane feedstock comprises at least one silane selected from the group consisting of disilanes (ii), oligosilanes (iii), and carbodisilanes (iv).

5. A process according to any of the preceding embodiments wherein the silane feedstock comprises at least one, preferably more than one, silane selected from the group consisting of MeSiCl ₃ , Me ₂ SiCl ₂ , Me ₃ SiCl, MeSiHCl ₂ , Me ₂ SiHCl, MeSiH ₂ Cl, MeSiH ₃ , Me ₂ SiH ₂ , Me ₃ SiН, Cl ₂ MeSi-SiMeCl ₂ , Cl ₂ MeSi-SiMe ₂ Cl, Cl ₂ MeSi-SiMe ₃ , ClMe ₂ Si-SiMe ₂ Cl, Me ₃ Si-SiMe ₂ Cl, Cl ₂ MeSi-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeCl ₂ and Me ₃ Si-CH ₂ -SiMe ₂ Cl.

6. The method according to any of the preceding embodiments, wherein the method is carried out in the presence of one or more ether solvents.

7. A method according to any of the preceding embodiments wherein the hydride donor source is selected from metal hydrides, preferably lithium hydride.

8. The method according to any of the preceding embodiments wherein the cleavage reaction c) of Si-Si bonds of di- or oligosilanes or Si-C bonds of carbodisilanes is carried out.

9. The method according to any of the preceding embodiments, wherein the redistribution reaction b) is carried out in the presence of at least one redistribution catalyst.

10. The method according to any of the preceding embodiments, wherein the redistribution reaction b) is carried out in the presence of at least one redistribution catalyst selected from the group consisting of:

- R ₄ PCl, where R represents a hydrogen atom or an organic group, where this substituent may be identical or different in comparison with other corresponding substituents, more preferably an aromatic group or an aliphatic hydrocarbon group, even more preferably an n-alkyl group, and most preferably n-butyl group,

- triorganophosphines, where R represents a hydrogen atom or an organic group, preferably PPh ₃ or n-Bu ₃ P,

- triorganoamines, where R represents an organic group, preferably n-Bu ₃ N or NPh ₃ ,

- N-heterocyclic amines, preferably non-N-substituted methylimidazoles such as 2-methylimidazole and 4-methylimidazole,

- quaternary ammonium compounds, preferably n-Bu ₄ NCl,

- alkali metal halide,

- alkaline earth metal halide,

- alkali metal hydride and

- alkaline earth metal hydride.

11. The method according to any of the preceding embodiments, wherein the cleavage reaction c) is carried out in the presence of at least one cleavage catalyst.

12. The process according to any of the preceding embodiments wherein the cleavage reaction c) is carried out in the presence of at least one cleavage catalyst selected from the group consisting of:

- a quaternary onium compound of an element from the group 15 R ₄ QX, where each R independently represents a hydrogen atom or an organic group, Q represents a phosphorus, arsenic, antimony or bismuth atom, and X represents a halide selected from the group consisting of F, Cl, Br and I,

- heterocyclic amine,

- heterocyclic ammonium halide,

- mixtures of R ₃ P and RX,

where R corresponds to the above definition of the invention, and X corresponds to the above definition of the invention,

- alkali metal halide,

- alkaline earth metal halide,

- alkali metal hydride,

- alkaline earth metal hydride or mixtures thereof,

optionally in the presence of hydrogen chloride (HCl).

13. The method according to any of the preceding embodiments, wherein the hydrogenation reaction a), the redistribution reaction b) and optionally the cleavage reaction c) are carried out simultaneously and/or step by step, preferably simultaneously.

14. A method according to any of the preceding embodiments, wherein the reaction sequence is selected from one or more of the following process options:

the hydrogenation reaction a) and the redistribution reaction b) are carried out simultaneously, the optional cleavage reaction c) is carried out subsequently,

the hydrogenation reaction a), the redistribution reaction b) and the cleavage reaction c) are carried out simultaneously,

first separately carry out the hydrogenation reaction a), and then simultaneously or separately carry out the redistribution reaction b) and optionally the cleavage reaction c), optionally in this embodiment after the hydrogenation reaction a) the methylchlorohydride monosilanes already obtained can be separated before inducing the passage of the redistribution reaction b) and optional cleavage reaction c),

the hydrogenation reaction a) is carried out first, then optionally the cleavage reaction c) is carried out, and then the redistribution reaction b) is carried out optionally in this embodiment after the hydrogenation reaction a) the methylchlorohydride monosilanes already produced can be separated before inducing the cleavage reaction c) to proceed, and redistribution reactions b),

the silane feedstock is selected from monosilanes, and such feedstock is first subjected to a hydrogenation reaction a) and subsequently a redistribution reaction b), or such feedstock is subjected to a hydrogenation reaction a) and a redistribution reaction b) simultaneously.

15. A process according to any of the preceding embodiments, wherein the methylchlorohydridsilanes are separated after the hydrogenation step a).

16. A process according to any of the preceding embodiments wherein the silane feedstock comprises a direct Mueller-Rochow product.

17. The process according to any of the preceding embodiments, wherein the silane feedstock comprises a complete direct Mueller-Rochow product or a portion (fraction) of a direct Muller-Rochow product.

18. A process according to any of the preceding embodiments wherein the silane feedstock comprises a monosilane fraction of a direct Mueller-Rochow product.

19. The method according to any of the preceding embodiments, wherein the silane feedstock is the highest silane fraction (silanes containing ≥ 2 Si atoms) of the product of the direct Mueller-Rochow process.

20. A process according to any of the preceding embodiments wherein the silane feedstock is an oligosilane cut (silanes containing ≥ 3 Si atoms) and a carbodisilane cut from a direct Mueller-Rochow process product.

21. The process according to any of the preceding embodiments, wherein the silane feedstock is the highest silane fraction (silanes containing ≥ 2 Si atoms) of the product of the direct Müller-Rochow process from which at least one component has been completely or partially separated , where this component is selected from the group consisting of disilanes containing ≥3 chlorine atoms, and disilane containing ≥3 methyl groups.

22. A process according to any of the preceding embodiments, wherein the silane feedstock comprises a fraction of a direct Mueller-Rochow process product from which at least one component has been completely or partially separated, wherein the component is selected from the group consisting of Me _n SiCl _{4 - n} , where n=1-3, Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl.

23. The method according to any of the preceding embodiments, which includes the additional step of separating monosilanes containing more than one hydrogen atom, for which a reaction is carried out selected from the group consisting of:

- chlorination reactions, preferably using an ether/HCl system, and/or

- redistribution reactions when using silanes containing at least one chlorine atom.

24. The method according to any of the preceding embodiments, which includes an additional step of separating disilanes and/or oligosilanes, each of which contains more than one hydrogen atom, for which a reaction is carried out selected from the group consisting of:

- cleavage reactions, preferably in the presence of an ether/HCl system, and/or

- redistribution reactions when using silanes containing at least one chlorine atom.

25. The method according to any of the preceding embodiments, which includes separating carbodisilanes containing at least one hydrogen atom, for which a reaction is carried out selected from the group consisting of:

- cleavage reactions, preferably in the presence of a metal hydride, and/or

- redistribution reactions when using silanes containing at least one chlorine atom.

26. A method according to any of the preceding embodiments which includes the step of separating Me ₃ SiH.

27. The method according to any of the preceding embodiments, wherein the hydride donor source is LiH.

28. The method according to any of the preceding embodiments, wherein the source of the hydride donor is LiH, and wherein the method includes the step of separating the resulting LiCl compound.

29. The method according to any of the preceding embodiments, wherein the source of the hydride donor is LiH, and wherein the method comprises the step of separating the resulting LiCl compound and the step of regenerating LiH from the separated LiCl compound.

30. The method according to any of the preceding embodiments, wherein the method is carried out at a temperature in the range from about -40°C to about 250°C.

31. The method according to any of the preceding embodiments, wherein the method is carried out at at least two different temperatures, preferably at a first temperature which is less than the second temperature.

32. A method according to any of the preceding embodiments, wherein the method is carried out at a pressure in the range of from about 0.1 to about 10 bar.

33. A method according to any of the preceding embodiments, wherein the method is carried out under inert conditions.

34. A method according to any of the preceding embodiments, wherein the method is carried out continuously or intermittently, such as intermittently.

35. Methylchlorohydride monosilanes selected from Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl, which can be obtained using a method corresponding to any of the preceding embodiments.

36. Compositions containing at least one methylchlorohydride monosilane selected from Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl, which can be obtained using a method corresponding to any of the preceding options implementation.

As it is to be understood, any numerical range provided herein includes all subranges within that range and any combination of the various breakpoints of such ranges or subranges, whether described in the examples or elsewhere in the specification.

As is also to be understood herein, any of the components of the invention herein, when described using any particular genus or species detailed in the exemplary section of the specification, may be used in one embodiment to establish an alternative corresponding definitions of any endpoint of the range described elsewhere in the description of the invention in relation to this component, and thus, in one non-limiting embodiment, can be used to replace such endpoint of the range described elsewhere.

As it is further to be understood, any compound, material or substance which is explicitly or implicitly disclosed in the description of the invention and/or listed in a claim as representatives belonging to the group of structurally, compositionally and/or functionally related compounds , materials or substances include individual members of the group and all combinations thereof.

Despite the inclusion in the above description of the invention of many specific characteristics, these specific characteristics should not be taken as limitations on the scope of the invention, but simply as illustrative examples of its preferred embodiments. Many other possible variations can be envisaged by those skilled in the relevant art that fall within the scope and spirit of the invention as defined in the claims appended hereto.

The method of the present invention will be explained in more detail using the following examples.

Examples

The present invention is further illustrated using the following examples, without limitation.

a common part

Various initial silane raw materials, which are formed in the direct method for producing methylchlorosilanes, were introduced into the reaction. All used reagents and solvents were thoroughly dried in accordance with methods known from the literature. The studied reactions were generally carried out in sealed ampoules for the NMR method, primarily to prevent the evaporation of low-boiling reaction products and to determine the reaction conditions (temperature, time) for the cleavage of the silicon-silicon bond. Subsequently, these conditions were converted to the preparative scale by way of example: (i) in a closed system, preferably a sealed glass ampoule, to avoid evaporation of low-boiling precipitates and reaction products, for example, organochlorine and organohydride silanes. After completion of the reactions, the ampoule was opened frozen under vacuum and the resulting products were isolated using combined condensation/distillation techniques. (ii) in an open system, preferably a multi-neck flask equipped with a magnetic stir bar, thermometer, addition funnel and reflux condenser, which is connected to a cold trap to collect low temperature reaction products. The resulting products were isolated using combined condensation/distillation techniques. The products were analyzed and characterized using standard techniques, in particular using NMR spectroscopy and GC/MS analyses.

Product identification

The products were analyzed using ¹ H, ²⁹ Si and ¹ H- ²⁹ Si-HSQC NMR spectroscopy. The spectra were recorded using a Bruker AV-500 spectrometer equipped with a Prodigy BBO 500 S1 probe. The ¹ H-NMR spectra were calibrated by proton resonance for the residual solvent ([D ₆ ] benzene δ _H = 7.16 ppm). Product identification was further provided using GC-MS analyzes and confirmed the identification of major products. GC/MS analyzes were measured using a Thermo Scientific Trace GC Ultra coupled to an ITQ 900MS mass spectrometer. The stationary phase (Machery-Nagel PERMABOND Silane) was 50 m long with an internal diameter of 0.32 mm. A 1 μm solution of the analyte was injected, it was transferred at 1/25 to the column at a flow rate of 1.7 ml/min using a gaseous helium carrier. The column temperature was first maintained at 50° C. for 10 minutes. After that, the temperature was increased at a rate of 20°C/min up to 250°C and maintained at this temperature for another 40 minutes. After leaving the column, the substances were ionized at 70 eV and the cationic fragments were measured within the range of 34-600 m/z (mass per charge). Prior to measurement, product mixtures were diluted using benzene.

Table 1 lists the characteristic ²⁹ Si NMR chemical shifts and ¹ J{ ²⁹ Si- ¹ H} coupling constants for raw materials reacted with alkali and alkaline earth metal salts and products obtained.

Table 1: Identification of raw materials and products

No. Si compound ^A -Si ^B δ ²⁹ Si [m. e.] ^one J (Si-H) [Hz] BUT AT BUT AT one Cl ₂ MeSi-SiMeCl ₂ 17.5 - 2 ClMe ₂ Si-SiMeCl ₂ 15.0 24.6 - 3 ClMe ₂ Si-SiMe ₂ Cl 17.1 - four Me ₃ Si-SiMeCl ₂ 34.0 - 14.1 - 5 Me ₃ Si-SiMe ₂ Cl 22.5 - 18.6 - 6 Me ₃ Si-SiMe ₃ - 20.1 - 7 MeSiCl ₃ 12.3 - eight MeSiHCl ₂ 10.9 280.2 9 _MeSiH2Cl -11.4 229.4 ten MeSiH ₃ - 65.5 194.1 eleven Me ₂ SiCl ₂ 31.5 - 12 Me ₂ SiHCl 11.0 223.3 13 Me ₂ SiH ₂ - 38.1 187.6 fourteen Me ₃ SiCl 30.1 - fifteen Me ₃ SiH - 16.6 182.9 16 H ₂ MeSi-SiMeH ₂ - 67.8 185.8 17 HMe ₂ Si-SiMeH ₂ - 39.9 - 66.7 180.9 180.5 eighteen HMe ₂ Si-SiMe ₂ H - 39.5 177.5 19 Me ₃ Si-SiMeH ₂ - 18.3 - 66.0 - 177.7 twenty Me ₃ Si-SiMe ₂ H - 19.2 - 39.4 - 172.5 21 ClMe ₂ Si-SiMe ₂ H 23.0 - 39.0 - 176.4 22 Cl ₂ MeSi-SiMeClH 23.8 - 6.7 - 227.4 23 HClMeSi-SiMeClH - 3.9 - 4.3 211.7 24 Cl ₂ MeSi-SiMeH ₂ 32.1 - 61.4 - 196.7 25 HClMeSi-SiMeH ₂ 0.6 - 64.7 215.0 203.3 26 ClMe ₂ Si-SiMeClH 17.6 - 3.7 - 221.3 27 Cl ₂ MeSi-SiMe ₂ H 33.8 - 35.5 - 191.3 28 ClMe ₂ Si-SiMeH ₂ 22.6 - 64.6 - 195.6 29 HMe ₂ Si-SiMeClH 1.83 - 38.2 181.3 198.4 thirty Cl ₂ MeSi-CH ₂ -SiMeCl ₂ 26.2 - 31 ClMe ₂ Si-CH ₂ -SiMeCl ₂ 28.1 25.7 - - 32 ClMe ₂ Si-CH ₂ -SiMe ₂ Cl 28.3 - 33 Me ₃ Si-CH ₂ -SiMeCl ₂ 30.6 - 0.5 - - 34 Me ₃ Si-CH ₂ -SiMe ₂ Cl 30.0 - 0.4 - - 35 Me ₃ Si-CH ₂ -SiMe ₃ - 0.5 -

Example 1

In an NMR ampoule cooled to -196°C (liquid nitrogen), LiH (3.0 mmol), Me ₂ SiCl ₂ (1.7 mmol), tetraglyme (0.35 ml) and catalytic amounts of n-Bu ₄ PCl (0.02 mmol). After evacuation, the ampoule for the NMR method was sealed and heated to room temperature. When the sample was heated, the feedstock materials reacted and the progress of the reduction/redistribution reaction for chlorosilane was monitored using NMR spectroscopy.

table 2

No. Silane 80 C, 0.25 hours 120°C, + 2 hours 120°C, + 2.5 hours 120°C, + 6 hours 13 Me ₂ SiH ₂ 31 35 47 55 eleven Me ₂ SiCl ₂ 57 twenty 7 3 12 Me ₂ SiHCl 12 45 46 42

As can be seen from table 2, the formation of hydridesilane (13) steadily increased with increasing temperature and reaction time. The maximum molar amount (expressed as %) of chlorosilane 12 (Me ₂ Si(H)Cl) essentially formed from the redistribution for hydridesilane (13) using dichlorosilane 11 is approximately 46%. At 120° C./10 hours, the molar amount of Me ₂ SiCl ₂ was reduced to a yield of only 3%, which is thus hardly available for further redistribution using the Me ₂ SiH ₂ compound present at 55% (mol.) in the data reaction conditions. As mentioned above, for Me ₂ SiH ₂ , in turn, a chlorination reaction can be carried out, preferably using an ether/HCl system, or a redistribution reaction using silanes containing at least one chlorine atom, for which redistribution catalysts that correspond to the above description of the invention.

Example 2

The reaction was carried out in the same manner as the reaction of example 1, except for the use of diglyme as a solvent.

Table 3 covers experimental discoveries regarding the progress of the reaction, which corresponds to the description of the invention. The yield of target compound 12 was 55% at 120°C/+ 2 hours.

Table 3

No. Silane 80 C, 0.25 hours 120°C, + 2 hours 120°C, + 2.5 hours 120°C, + 6 hours 13 Me ₂ SiH ₂ 37 24 36 45 eleven Me ₂ SiCl ₂ 51 21 13 5 12 Me ₂ SiHCl 12 55 51 fifty

Example 3

By analogy with the reaction of example 1 in the ampoule for the NMR method, cooled to - 196°C (liquid nitrogen), were placed MeSiCl ₃ (1.7 mmol), tetraglyme (0.35 ml) and catalytic amounts of n-Bu ₄ PCl ( 0.02 mmol), then LiH (2.5 mmol) was added; the ampoule for the NMR method was evacuated, sealed, and heated to room temperature. When the sample was heated, the feedstock materials reacted and the progress of the reduction/redistribution reaction for chlorosilane was monitored using NMR spectroscopy.

Table 4

No. Silane 80 C, 0.25 hours 120°C, + 2 hours 120°C, + 2.5 hours 120°C, + 6 hours 7 MeSiCl ₃ 55 33 12 eight eight _MeSiH2Cl - - fourteen 23 9 MeSiHCl ₂ 45 67 74 67 ten MeSiH ₃ - - - 2

As shown in Table 4, the molar amount of methyltrichlorosilane (7) steadily decreased with increasing reaction temperatures and reaction times, and the amount of the target compound MeSiHCl ₂ (9) increased to 74% while MeSiH ₂ Cl (8) was formed at a yield of 14% at 120°C (+ 4.5 hours). At longer reaction times, chlorosilane 7 was reduced almost quantitatively. At longer reaction times at 120°C, the amount of compound 9 decreased (60%) due to excess LiH, which confirmed the formation of hydridechlorosilanes 8 (32%) and hydridesilane 10 (5%).

Example 4

The reaction was carried out by analogy with the reaction of example 3, but using diglyme as a solvent and 2.7 mmol LiH. Table 5 covers the results with regard to the progress of the reaction, which corresponds to the description of the invention, showing comparable trends and presenting similar results as those obtained in example 3. Namely, even with a short reaction time, the total hydrogenation is approximately 90%. At longer reaction times, the equilibrium between silanes 8 and 9 shifted, suggesting the formation of the target product as a result of simply controlled reaction conditions.

Table 5

No. Silane 80 C/0.25 hours +120°C/2 hours 120°C, + 2.5 hours 120°C, + 6 hours 120°C, + 60 hours 7 MeSiCl ₃ 9 5 3 2 eight _MeSiH2Cl 23 28 37 41 9 MeSiHCl ₂ 66 63 53 48 ten MeSiH ₃ 2 3 7 9

Example 5

In an NMR vial that had been cooled to -196°C (liquid nitrogen) were placed LiH (1.5 mmol), Me ₂ SiCl ₂ (1.6 mmol), diglyme (0.4 ml) and a catalytic amount of n -Bu ₄ NCl (0.02 mmol). After evacuation in a vacuum, the ampoule for the NMR method was sealed and heated to room temperature. When the sample was heated, the feedstock materials reacted and the progress of the reduction/redistribution reaction for chlorosilane was monitored using NMR spectroscopy.

Table 6

No. Silane 120°C, 22 hours 160°C, + 40 hours 13 Me ₂ SiH ₂ 7 ten eleven Me ₂ SiCl ₂ 42 41 12 Me ₂ SiHCl 52 49

After 22 hours at 120°C, dimethyldichlorosilane was subjected to hydrogenation to obtain dimethylsilane 13, which was subsequently subjected to redistribution using dimethyldichlorosilane 11 to obtain Me ₂ SiHCl (12) with a yield of 52%. Increasing the reaction temperature and time led to further hydrogenation of the chlorosilanes, but did not significantly change the product distribution (Table 6).

Example 6

The reaction was carried out in the same manner as the reaction of example 5, except for the use of PPh ₃ (0.02 mmol) as a redistribution catalyst.

Table 7

No. Silane 120 C, 13 hours 160°C, + 22 hours 160°C, + 40 hours 13 Me ₂ SiH ₂ 32 fourteen eleven eleven Me ₂ SiCl ₂ 66 47 33 12 Me ₂ SiHCl 2 39 56

As can be seen from table 7, the formation of Me ₂ SiHCl (12) steadily increased with increasing temperature and reaction time. The maximum amount of chlorosilane 12, essentially formed as a result of redistribution for hydridesilane 13 when using dichlorosilane 11, was approximately 56% after 62 hours at 160°C.

Example 7

The reaction was carried out in the same manner as the reaction of example 5, except for the use of n-Bu ₃ P (0.02 mmol) as the redistribution catalyst.

Table 8

No. Silane 120 C, 13 hours 160°C, + 22 hours 160°C, + 40 hours 13 Me ₂ SiH ₂ 34 25 16 eleven Me ₂ SiCl ₂ 64 48 thirty 12 Me ₂ SiHCl 2 27 54

Similar to example 6, the maximum amount of chlorosilane 12 formed as a result of redistribution was 54% after 62 hours at 160°C (table 8).

Example 8

The reaction was carried out in the same manner as the reaction of example 5, except for the use of 2-methylimidazole (0.02 mmol) as a redistribution catalyst.

Table 9

No. Silane 120 C, 13 hours 160°C, + 22 hours 200°C, + 40 hours 13 Me ₂ SiH ₂ 34 39 21 eleven Me ₂ SiCl ₂ 65 57 24 12 Me ₂ SiHCl one four 52 not identified - 3

In contrast to examples 6 and 7, Me ₂ SiHCl (12) was formed only at a molar amount of 4% after 22 hours/160°C. Increasing the reaction temperature and time to 200° C./40 hours finally resulted in compound 12 in a 52% yield (Table 9).

Example 9

In the ampoule for the NMR method, cooled to - 196°C (liquid nitrogen), were placed Me ₂ SiCl ₂ (0.8 mmol), Me ₂ ClSi-SiClMe ₂ (0.8 mmol), LiH (2.5 mmol), diglyme (0.4 ml) and catalytic amounts of n-Bu ₄ PCl (0.04 mmol). After evacuation, the NMR ampoule was sealed and heated, and the reaction progress was monitored using NMR spectroscopy.

Table 10

No. Silane 120 C, 13 hours 120°C, + 22 hours 13 Me ₂ SiH ₂ 17 35 eleven Me ₂ SiCl ₂ 9 6 12 Me ₂ SiHCl 44 42 3 (Me ₂ ClSi) ₂ 9 one eighteen (Me ₂ HSi) ₂ four 6 21 Me ₂ ClSi-SiHMe ₂ 17 5 trisilanes - 5

At 120° C./13 hours, Me ₂ ClSi-SiClMe ₂ was cleaved and partially and completely hydrogenated to give compound 18 in 4% yield and compound 21 in 17% yield. Target product Me ₂ SiHCl (12) was obtained with a yield of 44% along with obtaining Me ₂ SiH ₂ (13) with a yield of 17%. Longer reaction times (+22 hours) led to further hydrogenation using LiH to form hydridesilane 13 at a molar amount of 35%, while the target product 12 was reduced to 42%. The amount of disilanes 3 and 21 decreased to a yield of 1% and 5%, respectively, while the molar amount of fully hydrogenated disilane 18 increased slightly (6%). Trisilanes were obtained at a yield of 5% (Table 10).

Example 10

In an ampoule for the NMR method, cooled to - 196 ° C (liquid nitrogen), MeCl ₂ Si-SiCl ₂ Me (0.6 mmol), MeSiCl ₃ (0.6 mmol), LiH (1.5 mmol), diglyme (0.4 ml) and PPh ₃ (0.05 mmol) as a redistribution catalyst. After evacuation, the NMR ampoule was sealed and heated, and the reaction progress was monitored using NMR spectroscopy.

Table 11

No. Silane 160 C, 16 hours 220°C, + 15 hours 7 MeSiCl ₃ 42 29 eight _MeSiH2Cl eight eleven 9 MeSiHCl ₂ fifty 56 Not identified - four

After 16 hours at 160°C, the initial disilane MeCl ₂ Si-SiCl ₂ Me (1) was quantitatively split and, as a result of redistribution reactions, the target products MeSiHCl ₂ (8) and MeSiH ₂ Cl (9) were obtained with a yield of 50% and eight%. With longer reaction times (+15 hours) at 220°C, the molar amounts of compounds 8 and 9 further increased to 56% and 11%, while unidentified products were formed at a molar amount of 4% (table 11).

Example 11

0.6 mmol of a complex mixture of chlorocarbodisilanes (the distribution over carbodisilanes is presented in table 12), Me ₂ SiCl ₂ (0.8 mmol), LiH (1.6 mmol), n-Bu ₃ P (0.05 mmol) and diglyme (0.3 ml). After evacuation in a vacuum, the ampoule for the NMR method was sealed and heated to room temperature. When the sample was heated, the feedstock materials reacted and the progress of the reduction/redistribution reaction for chlorosilane was monitored using NMR spectroscopy.

Table 12

No. Silane Recovery (%) thirty (Cl ₂ MeSi) ₂ -CH ₂ 45 31 ClMe ₂ Si-CH ₂ -SiMeCl ₂ 31 32 (Me ₂ ClSi) ₂ -CH ₂ fourteen 34 Me ₃ Si-CH ₂ -SiMe ₂ Cl ten

Table 13

No. Silane 160°C, 16 hours 220°C, + 15 hours 13 Me ₂ SiH ₂ 34 5 eleven Me ₂ SiCl ₂ 36 25 12 Me ₂ SiHCl eight 34 9 _MeSiH2Cl - 7 eight MeSiHCl ₂ - 7 ten MeSiH ₃ 2 9 Carbodisilanes twenty 13

After 16 hours at 160°C, the target product Me ₂ SiHCl (12) was obtained, as well as dimethylsilane, with a yield of 8% and 34%, respectively. Hydrogenation and cleavage of chlorocarbodisilanes led to the production of methylsilane 10 with a yield of 2%. With longer reaction times (+ 15 hours) at 220°C, the molar amount of compound 12 increased to 34%, while the amount of Me ₂ SiH ₂ (13) decreased (5%) due to redistribution reactions using chlorosilanes. Carbodisilanes were further cleaved (remaining 13%) to obtain silanes 8, 9 and 10, respectively, at a yield of 7%, 7% and 9% (table 13).

Example 12

MeSiCl ₃ (1.7 mmol) and tetraglyme (0.35 ml) were placed in an NMR vial cooled to −196° C. (liquid nitrogen), after which LiH (2.5 mmol) was added; the ampoule for the NMR method was evacuated, sealed, and heated to room temperature. When the sample was heated, the feedstock materials reacted and the progress of the reduction/redistribution reaction for chlorosilane was monitored using NMR spectroscopy. As shown in Table 14, the target compounds MeSiHCl ₂ (8.11%) and MeSiH ₂ Cl (9.28%) were obtained at 160°C, but longer reaction times were required.

Table 14

No. Silane 60 C, 2 minutes 100°C, + 19 hours 120°C, + 40 hours 160°C, + 40 hours 7 MeSiCl ₃ 75 60 54 36 9 _MeSiH2Cl 2 6 ten 28 eight MeSiHCl ₂ one four 5 eleven ten MeSiH ₃ 22 thirty 31 25

Example 13

Example of post-treatment of perhydrogenated by-products such as Me ₂ SiH ₂ , resulting from chlorination using HCl in ether based solvents

After heating the Me ₂ SiH ₂ compound to room temperature, it was evaporated into a 1 L flask filled with HCl/diglyme reagent (170 g, 4.7 mol HCl in 540 ml diglyme), which was cooled to -45°C. After completion (1.5 hours), the reaction mixture was stirred for 4 hours, and after that she was allowed to warm up to 15°C over a period of time of 8 hours. The HCl/diglyme flask was connected to a cold trap (−78° C.) and after a total reaction time of 12 hours a mixture of 16.85 g (0.28 mol) Me ₂ SiH ₂ , 0.83 g (9 mmol ) Me ₂ SiHCl and 0.13 g (3 mmol) of methyl chloride. The volatile compounds from the HCl/diglyme solution were condensed under vacuum in a cold trap (approximately -196°C) which was connected to another trap cooled to approximately -78°C. The condensed mixture (approximately -196°C) was allowed to warm up to room temperature at normal pressure (approximately 1013 mbar), separating the resulting dimethylchlorosilane from gaseous hydrogen chloride: Me ₂ SiHCl was collected in a cooling trap at -78°C while the excess HCl was sent directly by evaporating to a 1 L flask filled with diglyme used for the chlorination reaction at the start. The Me ₂ SiHCl compound collected in the trap at −78° C. was condensed into an ampule having a Young valve to give 59 g (0.62 mol) of Me ₂ SiHCl along with trace amounts of methyl chloride and Me ₂ SiCl ₂ , which is like this apparently obtained by double chlorination of Me ₂ SiH ₂ .

The Me ₂ SiH ₂ compound collected in a cold trap at −78° C. after the chlorination reaction (16.85 g, see above) was further evaporated into a (recycled) HCl/diglyme mixture and reacted and treated according to the above description of the invention, which gives 25 g (0.27 mol) compounds Me ₂ SiHCl contaminated with trace amounts of methyl chloride. Combining both Me ₂ SiHCl fractions and final distillation using a 50 cm Vigreux column at normal pressure gave 74 g (0.89 mol) Me ₂ SiHCl (boiling point: 35° C.) at a yield of 99% for the chlorination step.

Example 14

A mixture of 112 mg of highly chlorinated disilanes as 69% (mol.) Cl ₂ MeSi-SiMeCl ₂ , 26% (mol.) ClMe ₂ Si-SiMeCl ₂ , 4% (mol.) ClMe ₂ Si-SiMe ₂ Cl and 1% (mol.) Me ₃ Si-SiMeCl ₂ was introduced into the reaction with 8.1 mg of LiH (50% (mol.), relative to the level of chlorine in the mixture) in diglyme as a solvent. Recovery, redistribution, and cleavage for chloromono- and -disilanes started at room temperature, as indicated by warming up the reaction mixture. The resulting products are listed in Table 15. The breakdown of disilanes occurs almost quantitatively, only the highly methylated disilane ClMe ₂ Si-SiMe ₂ Cl remained in trace amounts (~ 1%). Monosilane MeSiH ₂ Cl is the main product followed by monosilane 8.

Table 15

No. Silane % (mol.) eight MeSiHCl ₂ 21 12 Me ₂ SiHCl 9 9 _MeSiH2Cl 33 eleven Me ₂ SiCl ₂ 19 fourteen Me ₃ SiCl 2 7 MeSiCl ₃ 2 ten MeSiH ₃ 13 3 ClMe ₂ Si-SiMe ₂ Cl one

Example 15

The reaction between the methylchlorodisilane mixture (183 mg) of the sample from Example 14 and LiH in diglyme can easily be controlled using the amount of LiH introduced into the reaction. The reduction of LiH to 41% (mol.) (10 mg, relative to the level of chlorine in the mixture (compared to example 14)) avoids the formation of low-boiling monosilane MeSiH ₃ , instead the dichlorosilanes MeSiHCl ₂ and Me ₂ SiCl ₂ became the main products . The composition of the total products is presented in table 16, approximately 2% (mol.) disilanes remained unreacted. The reaction took place at room temperature with the passage of self-heating of the sample to approximately 40°C.

Table 16

No. Silane % (mol.) eight MeSiHCl ₂ 37 12 Me ₂ SiHCl 7 9 _MeSiH2Cl 6 eleven Me ₂ SiCl ₂ 34 fourteen Me ₃ SiCl 2 7 MeSiCl ₃ eleven one Cl ₂ MeSi-SiMeCl ₂ 0.5 3 ClMe ₂ Si-SiMe ₂ Cl 1.5

Example 16

The results from example 15 are further investigated by treating a mixture of disilanes (110 mg - 159 mg) from example 14 using various molar amounts of LiH (25% (mol.), 50% (mol.), 75% (mol.), 100% (mol.) and 400% (mol.), in relation to the level of chlorine content in the mixture) in diglyme. All reactions took place at room temperature with the passage of self-heating of the samples. The resulting products are listed in Table 17 and demonstrate further conversion of the resulting chlorinated monosilanes to hydrogen-substituted monosilanes using LiH after silicon-silicon bond cleavage.

The higher the degree of substitution by chlorine on the Si atom, the faster hydrogenation will take place: MeSiCl ₃ > Me ₂ SiCl ₂ > Me ₃ SiCl. The same is true for only partially hydrogenated monosilanes MeH ₂ SiCl > MeSiHCl ₂ > Me ₂ SiHCl. In particular, the latter compound reacts very slowly, since the molar amount of a given chlorosilane remains almost constant in all reactions carried out. At a high excess of LiH (approximately 40% (mol.)) All chlorine-substituted monosilanes completely react with perhydrogenated silanes Me ₂ SiH ₂ (6%), MeSiH ₃ (78%) and perhydrogenated disilanes H ₂ MeSi-SiMeH ₂ , HMe ₂ Si-SiMeH ₂ , HMe ₂ Si-SiMe ₂ H and Me ₃ Si-SiMeH ₂ .

The results of this series of experiments are listed in Table 17. Summarizing the above, for the synthesis of monohydrogenated silanes such as MeSiHCl ₂ and Me ₂ SiHCl, the LiH compound must be used at a stoichiometric deficit (< about 25% (mol.)) to increase the amount monosilane MeSiH ₂ Cl the molar amount of LiH in the best case will be in the range from about 25% (mol.) to about 75% (mol.). For complete formation of perhydridemethylsilanes (MeSiH ₃ and Me ₂ SiH ₂ ), the LiH compound must be used in excess, but this is not desirable in accordance with the present invention.

Table 17

LiH concentration [% (mol.)] 25 fifty 75 100 400 No. Silane % (mol.) % (mol.) % (mol.) % (mol.) % (mol.) eight MeSiHCl ₂ thirty 21 6 2 - 12 Me ₂ SiHCl eleven 13 12 12 - 9 _MeSiH2Cl eighteen 35 thirty 24 - 13 Me ₂ SiH ₂ - - 2 3 6 ten MeSiH ₃ 7 13 41 56 78 eleven Me ₂ SiCl ₂ 21 fifteen 7 2 - fourteen Me ₃ SiCl 2 2 one trace amounts - 3 ClMe ₂ Si-SiMe ₂ Cl one one one one - 16 H ₂ MeSi-SiMeH ₂ - - - trace amounts eight 17 H ₂ MeSi-SiMe ₂ H - - - - 5 19 Me ₃ Si-SiMeH ₂ - - - - 2 eighteen HMe ₂ Si-SiMe ₂ H - - - - one

Example 17

A reaction was carried out between a complex mixture (131-238 mg) of mainly highly chlorinated disilanes and monosilanes, which corresponds to the display in table 18, and 41% (mol.) or 73% (mol.) LiH (in relation to the level of chlorine in mixture), respectively, in diglyme at room temperature with the passage of self-heating. The products obtained are listed in Table 19 and show the formation of monosilanes with a molar amount of 96%, while 4% (mol.) of tetramethyldichloro- and pentamethylchlorodisilane remained unreacted. Increased amounts of LiH lead to an increase in the amount of hydrogen-substituted silanes as a result of Si-Cl → Si-H reduction.

Table 18

No. Silane % (mol.) eleven Me ₂ SiCl ₂ 7.9 5 Me ₃ Si-SiMe ₂ Cl 2.0 3 ClMe ₂ Si-SiMe ₂ Cl 3.5 one Cl ₂ MeSi-SiMeCl ₂ 49.5 2 ClMe ₂ Si-SiMeCl ₂ 33.7 four Me ₃ Si-SiMeCl ₂ 3.0 6 Me ₃ Si-SiMe ₃ 0.4

Table 19

LiH concentration [% (mol.)] 41 73 No. Silane % (mol.) % (mol.) eight MeSiHCl ₂ 17 eleven 12 Me ₂ SiHCl fourteen 21 9 _MeSiH2Cl twenty 26 13 Me ₂ SiH ₂ - 2 ten MeSiH ₃ 6 16 eleven Me ₂ SiCl ₂ 35 16 fourteen Me ₃ SiCl four four 3 ClMe ₂ Si-SiMe ₂ Cl 2 2 5 Me ₃ Si-SiMe ₂ Cl 2 2 6 Me ₃ Si-SiMe ₃ trace amounts trace amounts

Example 18

For the hydrogenation of methylchlorodisilanes, tributyltin hydride was used as a reducing agent. For n-Bu ₃ SnH see U. Herzog, G. Roewer and U. Pätzold, Katalytische Hydrierung chlorhaltiger Disilane mit Tributylstannan, J. Organomet. Chem. 1995, 494, 143-147.

Disilane (ClMe ₂ Si-SiMe ₂ Cl, mixed with 5% (mol.) Me ₃ Si-SiMe ₂ Cl) (4.04 g) was reacted at a molar ratio of 1/1 with tin hydride in diglyme and tetraphenylphosphonium chloride ( Ph ₄ PCl, 3% (mass.)) as a catalyst at room temperature. After treatment, a mixture of disilanes ClMe ₂ Si-SiMe ₂ Cl (15% (mol.)), Me ₃ Si-SiMe ₂ Cl (4% (mol.)), ClMe ₂ Si-SiMe ₂ H (72% (mol.) .)) and Me ₃ Si-SiMe ₂ H (9% (mol.)). 200 mg of these disilanes were subsequently reacted with tetrabutylphosphonium chloride (n-Bu ₄ PCl, 25 wt %) in a sealed NMR ampoule at 180° C. for 9 hours. As listed in Table 20, the hydriddisilane ClMe ₂ Si—SiMe ₂ H was almost completely decomposed into monosilanes Me ₂ SiHCl and Me ₂ SiH ₂ , which were obtained in a yield of 68% (mol.). Chlorosilane Me ₃ SiCl is the result of the splitting of disilane Me ₃ Si-SiMe ₂ Cl. Small amounts of unidentified oligosilanes were detected.

Table 20

No. Silane % (mol.) 12 Me ₂ SiHCl 37 13 Me ₂ SiH ₂ 31 fourteen Me ₃ SiCl fourteen eleven Me ₂ SiCl ₂ eight fifteen Me ₃ SiH one Extractions, oligosilanes 9

A mixture of disilanes ClMe ₂ Si-SiMe ₂ Cl (15% (mol.)), Me ₃ Si-SiMe ₂ Cl (4% (mol.)), ClMe ₂ Si-SiMe ₂ H (72% (mol.)) and Me ₃ Si-SiMe ₂ H (9% (mol.)), which was obtained above as a result of hydrogenation, (200 mg) was introduced into the reaction with 2-methylimidazole (2-MIA, 16% (wt.)) in a sealed ampoule for the NMR method at 220°C for 9 hours. The amount of chlorosilane Me ₂ SiHCl was less than in the reaction in the presence of tetrabutylphosphonium chloride, the main product obtained was dimethylsilane Me ₂ SiH ₂ followed by Me ₃ SiCl (13.2% (mol.)). The remaining disilanes Me ₃ Si-SiMe ₂ Cl and Me ₃ Si-SiMe ₂ H were 15.0% (mol.) and 8.2% (mol.), respectively. Namely, perhydrogenated disilane HMe ₂ Si-SiMe ₂ H was detected at 1.0% (mol) (Table 21).

Longer reaction times (69 hours) lead to an almost quantitative separation of H-substituted disilanes, as well as the conversion of tri- and tetrasilanes (ClMe ₂ Si-SiMe ₂ -SiMe ₂ Cl and ClMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ Cl), called "oligosilanes" in the table, into monomers. The resulting products are listed in table 22 and prove the formation of Me ₂ SiHCl (~ 40% (mol.)) as the main component.

Table 21

No. Silane % (mol.) 12 Me ₂ SiHCl 17.1 13 Me ₂ SiH ₂ 31.5 fourteen Me ₃ SiCl 13.2 eleven Me ₂ SiCl ₂ 8.8 21 ClMe ₂ Si-SiMe ₂ H 15.0 twenty Me ₃ Si-SiMe ₂ H 8.2 eighteen HMe ₂ Si-SiMe ₂ H 1.0 Oligosilanes 5.2

Table 22

No. Silane % (mol) 12 Me ₂ SiHCl 39.5 13 Me ₂ SiH ₂ 34.0 fourteen Me ₃ SiCl 13.4 eleven Me ₂ SiCl ₂ 7.3 21 ClMe ₂ Si-SiMe ₂ H 5.8

Example 19

hydrogenation reaction

To model the mono- and disilane fraction obtained from the direct Muller-Rochow process, a mixture (1.10 g) of the compounds listed in Table 24, (1.19 g) Me ₂ SiCl ₂ monosilane and highly chlorinated disilanes listed in Table 25 , and (1.07 g) of the compounds listed in Table 23 were mixed and reacted with various molar amounts of n-Bu ₃ SnH to replace 25, 50, and 75% (mole) of all chlorine atom substituents on the silicon atom . After reduction, the products were isolated by condensation/distillation to form mixtures of products IV, V and VI listed in Table 26.

Table 23

No. Silane % (mol.) eleven Me ₂ SiCl ₂ 12.4 fourteen Me ₃ SiCl 2.2 7 MeSiCl ₃ 11.5 5 Me ₃ Si-SiMe ₂ Cl 16.8 3 ClMe ₂ Si-SiMe ₂ Cl 22.6 one Cl ₂ MeSi-SiMeCl ₂ 16.2 2 ClMe ₂ Si-SiMeCl ₂ 7.1 four Me ₃ Si-SiMeCl ₂ 2.7 6 Me ₆ Si ₂ 2.4 34 Me ₃ Si-CH ₂ -SiMe ₂ Cl 3.1 thirty (Cl ₂ MeSi) ₂ -CH ₂ 0.4 31 ClMe ₂ Si-CH ₂ -SiMeCl ₂ 0.9 33 Me ₃ Si-CH ₂ -SiMeCl ₂ 0.4 35 Me ₃ Si-CH ₂ -SiMe ₃ 1.3

Table 24

No. Silane % (mol.) eleven Me ₂ SiCl ₂ 6.8 fourteen Me ₃ SiCl 7.1 7 MeSiCl ₃ 12.5 12 Me ₂ SiHCl 4.3 eight MeSiHCl ₂ 1.4 5 Me ₃ Si-SiMe ₂ Cl 3.9 3 (ClMe ₂ Si) ₂ 17.9 one (Cl ₂ MeSi) ₂ 1.4 6 Me ₆ Si ₂ 0.2 34 Me ₃ Si-CH ₂ -SiMe ₂ Cl 3.9 32 (ClMe ₂ Si) ₂ -CH ₂ 5.2 thirty (Cl ₂ MeSi) ₂ -CH ₂ 14.7 31 ClMe ₂ Si-CH ₂ -SiMeCl ₂ 11.4 33 Me ₃ Si-CH ₂ -SiMeCl ₂ 1.8 35 Me ₃ Si-CH ₂ -SiMe ₃ 7.5

Table 25

No. Silane % (mol.) eleven Me ₂ SiCl ₂ 7.9 5 Me ₃ Si-SiMe ₂ Cl 2.0 3 ClMe ₂ Si-SiMe ₂ Cl 3.5 one Cl ₂ MeSi-SiMeCl ₂ 49.5 2 ClMe ₂ Si-SiMeCl ₂ 33.7 four Me ₃ Si-SiMeCl ₂ 3.0 6 Me ₃ Si-SiMe ₃ 0.4

Table 26

No. Silane Sample IV, % (mol.) Sample V, % (mol.) Sample VI, % (mol.) 3 ClMe ₂ Si-SiMe ₂ Cl eighteen 9 7 eleven Me ₂ SiCl ₂ eighteen twenty 27 5 Me ₅ Si ₂ Cl 16 23 28 7 MeSiCl ₃ 13 7 9 16 H ₂ MeSi-SiMeH ₂ 9 eighteen - 2 ClMe ₂ Si-SiMeCl ₂ four - - 33 Cl ₂ MeSi-CH ₂ -SiMe ₃ four 2 3 9 _MeSiH2Cl 3 - - 24 H ₂ MeSi-SiMeCl ₂ 3 3 one 17 HMe ₂ Si-SiMeH ₂ 3 2 one 6 Me ₃ Si-SiMe ₃ 2 5 four 31 ClMe ₂ Si-CH ₂ -SiMeCl ₂ 2 2 6 four Me ₃ Si-SiMeCl ₂ one 2 four eighteen HMe ₂ Si-SiMe ₂ H one one 2 thirty Cl ₂ MeSi-CH ₂ -SiMeCl ₂ one 3 2 31 ClMe ₂ Si-CH ₂ -SiMe ₂ Cl one 2 four 34 ClMe ₂ Si-CH ₂ -SiMe ₃ one one 3

Redistribution and splitting reaction

The redistribution and cleavage reactions using a mixture of sample IV from Table 26 (280 mg) were carried out using n-Bu ₄ PCl (6% (wt.)) in a sealed NMR ampoule. NMR measurements were carried out at room temperature, 140°C (+ 23 hours) and 220°C (+ 16 hours). Cleavage reactions already started at room temperature, and only trace amounts of Me ₃ Si-SiMe ₃ (~ 1% (mol.)) remained unreacted at 220°C (table 27).

Table 27

No. Silane Room temperature / 1 hour, % (mol.) 140°С / + 23 hours, % (mol.) 220°С / + 16 hours, % (mol.) 3 ClMe ₂ Si-SiMe ₂ Cl 12.1 - 12 Me ₂ SiHCl 16.5 20.8 21.6 fourteen Me ₃ SiCl 1.1 5.0 11.3 eleven Me ₂ SiCl ₂ 10.1 37.5 40.2 7 MeSiCl ₃ - - - eight MeSiHCl ₂ 16.7 10.2 7.4 9 _MeSiH2Cl 14.4 11.1 11.3 13 Me ₂ SiH ₂ - - 1.9 ten MeSiH ₃ 8.8 5.6 2.7 6 Me ₃ Si-SiMe ₃ 0.9 0.6 1.1 5 Me ₃ Si-SiMe ₂ Cl 7.5 2.8 - Carbodisilanes 11.9 6.4 2.5

Table 28 lists the results for comparable cleavage and redistribution reactions for Samples V and VI.

Table 28

Pattern V Sample VI No. Silane Room temperature, 1 hour, % (mol.) 140°С, + 23 hours, % (mol.) 220°С, + 16 hours, % (mol.) Room temperature, 1 hour, % (mol.) 140°С, + 23 hours, % (mol.) 220°С, + 16 hours, % (mol.) 3 ClMe ₂ Si-SiMe ₂ Cl 13.1 - - 18.1 - - 12 Me ₂ SiHCl 18.6 36.4 29.7 14.3 29.5 27.3 fourteen Me ₃ SiCl 1.6 11.3 17.4 2.6 13.6 22.9 eleven Me ₂ SiCl ₂ 11.3 28.9 29.2 15.4 37.8 37.2 eight MeSiHCl ₂ 6.2 1.5 2.0 1.1 0.8 1.2 9 _MeSiH2Cl 6.3 1.6 4.3 0.7 - 2.7 13 Me ₂ SiH ₂ 1.1 2.5 7.2 2.5 1.5 2.3 ten MeSiH ₃ 11.4 5.4 6.9 5.2 2.3 1.7 6 Me ₃ Si-SiMe ₃ 1.3 2.0 1.2 2.0 2.6 1.3 5 Me ₃ Si-SiMe ₂ Cl 16.9 2.4 - 19.7 1.5 - Carbodisilanes 12.2 8.0 2.1 18.4 10.4 3.4

As it obviously follows from the reactions for samples IV-VI, with an increase in the substitution of Cl with respect to H in methylchlorodisilanes Me _n Si ₂ Cl _{6 - n} at Cl≥3, partially hydride-substituted disilanes split much faster. Cleavage of disilanes at Me≥4 (partially hydrogenated or perhydrogenated) required the use of higher temperatures. At approximately 140° C., the chlorosilanes Me ₂ SiCl ₂ , Me ₃ SiCl, Me ₂ SiHCl and MeSiHCl ₂ were mainly obtained. Reaction studies using ³¹ P-NMR spectroscopy proved the activity of n-Bu ₄ PCl as a real catalyst only at a temperature of 220 ° C or more, the latter fully reacted with the formation of n-Bu ₃ P, trace amounts of n-Bu ₂ PH and 1-butene and hydrogen chloride, which is responsible for the final formation of H/Cl-substituted monosilanes.

Example 20

In a 50 ml flask, a mixture of disilanes Cl ₂ MeSi-SiMeCl ₂ (69% (mol.)), ClMe ₂ Si-SiMeCl ₂ (26% (mol.)), ClMe ₂ Si-SiMe ₂ Cl (4% (mol.) .)) and Me ₃ Si-SiMeCl ₂ (1% (mol)) (244 mg) were reacted with Ph ₄ PCl (25.3 mg) and LiH (202 mg) in 0.5 ml of diglyme. Already at room temperature, 75% (mol.) of monosilanes were obtained, while compound 8 was obtained in an amount of 40% (mol.). 25% (mol.) of disilanes remained uncleaved, 10% (mol.) of them were reduced (SiCl → SiH) (table 29). The MeSiH ₃ compound that could be formed evaporated in the open system due to its low boiling point (-57°C). That is why the same disilane mixture (122 mg) was reacted with the catalyst/LiH (1% (wt.)/4% (wt.)) system in a sealed NMR ampoule at room temperature. In this case, monosilane 10 was detected at a yield of 13% (mol.), compound 8 was obtained at a yield of 21% (mol.), and compound 9 at a yield of 33% (mol.).

Table 29

No. Silane % (mol.) eight MeSiHCl ₂ 40 12 Me ₂ SiHCl 9 9 _MeSiH2Cl ten eleven Me ₂ SiCl ₂ ten fourteen Me ₃ SiCl 2 7 MeSiCl ₃ four one Cl ₂ MeSi-SiMeCl ₂ four 3 ClMe ₂ Si-SiMe ₂ Cl one 2 ClMe ₂ Si-SiMeCl ₂ 9 four Me ₃ Si-SiMeCl ₂ one 24 MeH ₂ Si-SiMeCl ₂ 2 25 MeH ₂ Si-SiMeHCl 6 17 HMe ₂ Si-SiMeH ₂ one 16 MeH ₂ Si-SiMeH ₂ one

Example 21

This example 21 illustrates the desirable changes in product composition from the direct Rochow-Müller synthesis resulting from the treatment of the crude methylchlorosilane mixture with LiH. The implementation of the direct Rochow-Muller process at 290° C./4 atm in a commercial scale fluidized bed reactor containing approximately 45 metric tons of copper-activated silicon is contemplated. The silicon conversion is 4.5%/hour, resulting in approximately 9300 kg/hour of crude methylchlorosilane. All or part of this crude material is treated with LiH to increase the formation of methylchlorohydridesilanes, in particular Me ₂ SiHCl.

Table 30 presents the compositions of two samples of crude methylchlorosilanes, as well as the amounts (in grams per metric ton) of each component. The molar quantities per metric ton and the combined moles of chloride are shown in Table 31. These data make it possible to calculate the molar and gravimetric quantities of LiH required to produce the desired quantities of methylchlorohydridesilanes.

TABLE 30

Composition of products from direct Rochow-Müller synthesis, determined using the gravimetric method

COMPOUND SAMPLE A SAMPLE B % (mass) g/t % (mass) g/t (CH ₃ ) ₄ Si trace amounts trace amounts _HSiCl3 trace amounts trace amounts (CH ₃ ) ₂ SiHCl (M2H) 0.09 901.35 1.10 11024.2 CH ₃ SiHCl ₂ (MH) 1.34 13420.1 4.69 46902.96 (CH ₃ ) ₃ SiCl (M) 1.76 17626.4 2.05 20545.1 CH ₃ SiCl ₃ (T) 3.96 39559.25 5.17 51713.52 (CH ₃ ) ₂ SiCl ₂ (D) 90.19 901850.75 82.87 828719.18 (CH ₃ ) ₃ SiSi(CH ₃ ) ₃ 0.01 90.16 0.01 123.71 (CH ₃ ) ₃ SiSi(CH ₃ ) ₂ Cl 0.05 452.04 0.06 620.28 Cl(CH ₃ ) ₂ SiSi(CH ₃ ) ₂ Cl 0.09 876.33 0.12 1202.49 (CH ₃ ) ₃ SiSi(CH ₃ )Cl ₂ 0.07 737.97 0.10 1012.62 Cl(CH ₃ ) ₂ SiSi(CH ₃ )Cl ₂ 0.94 9386.70 1.29 12880.25 Cl ₂ (CH ₃ )SiSi(CH ₃ )Cl ₂ 1.51 15056.80 2.07 20660.65 T/D 0.044 0.062

ton=metric ton (1000 kg)

In this case, it is appropriate to use a reminder that

methylchlorodisilanes are reduced and cleaved using LiH,

the order of reactivity for methylchlorosilanes using LiH is CH ₃ SiCl ₃ > (CH ₃ ) ₂ SiCl ₂ > (CH ₃ ) ₃ SiCl,

and CH ₃ SiН ₂ Cl > CH ₃ SiНCl ₂ > CH ₃ SiCl ₃ ,

and (CH ₃ ) ₂ SiНCl > (CH ₃ ) ₂ SiCl ₂ .

TABLE 31

Molar composition of products from direct Rochow-Müller synthesis

COMPOUND SAMPLE A, mol/t SAMPLE B, mol/t (CH ₃ ) ₂ SiHCl (M2H) 9.53 116.51 CH ₃ SiHCl ₂ (MH) 116.67 407.75 (CH ₃ ) ₃ SiCl (M) 162.25 189.11 CH ₃ SiCl ₃ (T) 264.65 345.96 (CH ₃ ) ₂ SiCl ₂ (D) 6987.84 6421.19 (CH ₃ ) ₃ SiSi(CH ₃ ) ₃ 0.62 0.85 (CH ₃ ) ₃ SiSi(CH ₃ ) ₂ Cl 2.71 3.72 Cl(CH ₃ ) ₂ SiSi(CH ₃ ) ₂ Cl 4.68 6.42 (CH ₃ ) ₃ SiSi(CH ₃ )Cl ₂ 3.94 5.41 Cl(CH ₃ ) ₂ SiSi(CH ₃ )Cl ₂ 45.21 62.04 Cl ₂ (CH ₃ )SiSi(CH ₃ )Cl ₂ 66.03 90.61 TOTAL CHLORIDE, mol/t 15351.56 14645.26 LiH (g) for use at 55% (mol) 67125 64036 LiH (g) for use at 110% (mole) 134249 128073

The remaining calculations are based on using ~67 kg LiH (value from table 31, row 14) to process 1 metric ton of crude MCS compound having the compositions shown in table 30.

TABLE 32

Recovery of methylchlorosilanes using LiH

PRODUCTS RECEIVED. DATA IN % (mol.) SILAN LiH, % (mol.) (CH ₃ ) ₃ SiCl (CH ₃ ) ₃ SiH (CH ₃ ) ₃ SiCl 55 fifty fifty 110 0 100 (CH ₃ ) ₂ SiCl ₂ (CH ₃ ) ₂ SiHCl (CH ₃ ) ₂ SiH ₂ (CH ₃ ) ₂ SiCl ₂ 55 48 four 48 110 0 0 100 CH ₃ SiCl ₃ CH ₃ SiHCl ₂ CH ₃ SiH ₂ Cl CH ₃ SiH ₃ CH ₃ SiCl ₃ 55 49 one 2 48 110 0 0 0 100

²⁹ Si NMR spectroscopy was used to obtain the data disclosed in Table 32 regarding the reaction between individual methylchlorosilanes and LiH. Using ²⁹ Si NMR spectroscopy, the cleavage of individual methylchlorodisilanes using LiH was also investigated. The data is displayed in table 33.

TABLE 33

Cleavage of individual methylchlorodisilanes using LiH

DISILAN REACTION WITH LiH, % PRODUCTS RECEIVED. DATA IN % (mol.) (CH ₃ ) ₃ SiX (CH ₃ ) ₂ SiX ₂ CH ₃ SiX ₃ (CH ₃ ) ₃ SiSi(CH ₃ ) ₂ Cl 5 * 95 5 Cl(CH ₃ ) ₂ SiSi(CH ₃ ) ₂ Cl ten * 5 95 (CH ₃ ) ₃ SiSi(CH ₃ )Cl ₂ 75 90 ten Cl(CH ₃ ) ₂ SiSi(CH ₃ )Cl ₂ 75 90 ten Cl ₂ (CH ₃ )SiSi(CH ₃ )Cl ₂ 80 one 99

* Highly methylated disilanes only react with LiH to a limited extent. X=Cl, H.

The data in Tables 32 and 33 are used in connection with results from other redistribution experiments in applications co-pending with this application to produce the final compositions shown in Table 34.

TABLE 34

Final compositions of products after reduction, splitting and redistribution

COMPOUND SAMPLE A SAMPLE B % (mass) g/t % (mass) g/t CH ₃ SiH ₃ 0.01 103.56 0.03 195.07 (CH ₃ ) ₂ SiH ₂ 8.69 64147.05 7.87 55750.15 CH ₃ SiH ₂ Cl 3.36 24805.64 4.60 32537.87 (CH ₃ ) ₃ SiH 0.00 0 0.00 0 (CH ₃ ) ₂ SiHCl (M2H) 61.79 456374.71 60.75 430182.72 CH ₃ SiHCl ₂ (MH) 0.10 737.63 0.17 1215.78 (CH ₃ ) ₃ SiCl (M) 6.30 46549.75 8.51 60233.16 CH ₃ SiCl ₃ (T) 0.00 0 0.00 0 (CH ₃ ) ₂ SiCl ₂ (D) 19.75 145838.12 18.07 127955.50 T/D 0 0 TOTAL WEIGHT MCS, g 738556.45 708070.24 TOTAL PRODUCED COMPOUND LiCl, g 325407 310436

As the results of these experiments demonstrate, the use of only 6.7 weight percent LiH can change the composition of the direct Rochow-Müller product from predominantly dimethyldichlorosilane (D) to predominantly dimethylchlorosilane (M2H).

Methyltrichlorosilane (T) is consumed and the amount of trimethylchlorosilane (M) is increased. The product yield is in the range of approximately 71-74%. Volatile hydridesilanes (CH ₃ SiH ₃ , (CH ₃ ) ₂ SiH ₂ and CH ₃ SiH ₂ Cl) can be recovered and added to the fresh direct Rochow-Müller product or reused in redistribution using methylchlorosilanes. In general, more valuable monomers are obtained. In addition to this, the produced LiCl compound (>300 kg) can be extracted and used to produce Li and LiH.

Example 22

(IN REGARD TO THE EXTRACTION OF LiCl TO OBTAIN Li AND LiH)

This example illustrates the recovery, purification and characterization of the produced compound LiCl using LiH to reduce (CH ₃ ) ₂ SiCl ₂ to obtain (CH ₃ ) ₂ SiHCl and (CH ₃ ) ₂ SiH ₂ in accordance with the descriptions of inventions in applications located under consideration in conjunction with this application.

A solid was recovered from the reaction mixture by filtration and treated with diglyme saturated with HCl gas to convert any unreacted LiH to LiCl. The solid was then washed four times with dry pentane and dried in vacuo at 630° C. for one hour.

LiCl was dissolved in diglyme and a C ₆ D ₆ compound characterized by a ⁷ Li NMR spectrum recorded on a Bruker AV-500 spectrometer.

The observed single resonance (δ = 0.23 ppm) can be attributed to the chemical shift for LiCl as a result of comparison with an authentic sample of LiCl (δ = 0.20 ppm).

The dried LiCl compound was mixed with KCl at the proportions shown in the table below. The melting characteristics of the samples were recorded using a camera attached to an OptiMelt MPA 100 automated melting point apparatus. For comparison, the melting characteristics of authentic LiCl-KCl samples were also measured. Both datasets are shown in Table 35.

TABLE 35

MASS RATIO, LiCl:KCl MELTING TEMPERATURES, °C, FOR THE EXTRACTED SYSTEM LiCl:KCl MELTING POINTS, °C, FOR AUTHENTIC LiCl:KCl SYSTEM 40:60 355.3 354.8 50:50 356.1 355.6 60:40 355.9 356.6

The observed melting points for the recovered and control samples are in good agreement with each other. Sample 40:60 LiCl-KCl corresponds to the eutectic composition. The observed melting point is consistent with published values (see S. Zemczuzny, et al., Zeitschrift für Anorganische Chemie, 46 (1910) 403-428 ). The melting temperature data prove that the extracted LiCl compound forms a pure eutectic with KCl and, thus, satisfies one of the quality criteria for the electrolytic extraction of Li.

Example 23

To prove the assumption from Example 21 and to clarify the optimal reaction conditions for producing Me ₂ SiHCl at high yields, the complex crude mixture from the direct Rochow-Muller process was modeled by mixing individual compounds at the molar ratio shown in Table 36, where Me ₂ SiCl ₂ was present in as the main component (91.65% (mol.)) and MeSiCl ₃ was present at 4.85% (mol.).

Table 36

Compound M [g/mol] Integrals in the method ²⁹ Si-NMR % (mol.) M for mixture [g/mol] Chlorine in the mixture Density [g/ml] Density of mixture [g/ml] Me ₂ SiCl ₂ 129.06 one 91.646 118.28 1.832928 1.064 0.97511 Me ₃ SiCl 108.64 0.0216 1,980 2.15 0.019795 0.856 0.01694 MeSiCl ₃ 149.48 0.0529 4,848 7.25 0.145442 1.273 0.06171 Me ₅ Si ₂ Cl 166.8 0.0003 0.027 0.05 0.000274 0.862 0.00023 (ClMe ₂ Si) ₂ 187.21 0.0003 0.027 0.05 0.000549 1.006 0.00027 (Cl ₂ MeSi) ₂ 228.04 0.01025 0.939 2.14 0.037575 1.269 0.01192 ClMe ₂ Si-SiMeCl ₂ 207.63 0.0055 0.504 1.05 0.015121 1.13 0.00569 Me ₃ Si-SiMeCl ₂ 187.21 0.0003 0.027 0.05 0.000549 1.006 0.00027 Total - 1.09115 100 131.01 2.052238 - 1.072

Chlorosilane reduction, disilane cleavage reaction, and Si-H/Si-Cl redistribution using about 1 to about 5 wt.% n-Bu ₄ PCl were carried out in sealed NMR ampoules to prevent evaporation of low-boiling components such as Me ₂ SiH ₂ and MeSiH ₃ . In the case of decomposition of n-Bu ₄ PCl, the reactions will form n-Bu ₃ P in addition to (poly)but-1-ene and hydrogen chloride, which is responsible for increasing the formation of hydride-substituted monosilanes and / or additional chlorination of Si-H bonds (mono- and disilanes) with the formation of Si-Cl fragments. The products obtained by heating the reaction mixtures and the conversion of lithium hydride are presented in % (mol.) and are listed in table 37 for diglyme as a solvent.

Table 37 ¹⁾

Diglim,
40% (mol.) LiH Me ₂ SiCl ₂ Me ₃ SiCl Me ₂ SiHCl MeSiHCl _{2 MeSiH2Cl} Me ₂ SiH ₂ MeSiH ₃ LiH conversion [%] Notes Room temperature, 12.6 hours 74.1 1.5 9.6 0.7 1.5 5.9 6.7 42 0% decomposition of n-Bu ₄ PCl 60°C, 2 hours 52.5 1.6 27.8 - 0.8 8.9 8.4 68 1% decomposition of n-Bu ₄ PCl 70°C, 2 hours 41.2 1.3 40.3 - 1.6 8.2 7.4 76 2% decomposition of n-Bu ₄ PCl 70°C, 2 hours 37.3 1.9 44.4 1.5 8.2 6.7 79 2% decomposition of n-Bu ₄ PCl 80°C, 2 hours 34.1 1.7 48.5 - 2.4 7.2 6.1 80 3% decomposition of n-Bu ₄ PCl 90°C, 2 hours 32.0 1.6 52.4 - 1.9 6.4 5.8 81 3% decomposition of n-Bu ₄ PCl 100°C, 2 hours 30.3 1.8 53.7 - 1.8 6.7 5.8 83 3% decomposition of n-Bu ₄ PCl 110°C, 2 hours 25.9 1.6 54.1 - 2.1 9.8 6.5 91 5% decomposition of n-Bu ₄ PCl 120°C, 2 hours 25.3 1.7 55.0 - 2.0 8.8 7.0 92 5% decomposition of n-Bu ₄ PCl 130°C, 2 hours 25.2 1.3 54.9 - 2.0 9.3 7.3 93 5% decomposition of n-Bu ₄ PCl 130°C, 2 hours 24.0 1.7 54.7 - 1.9 10.1 7.7 95 5% decomposition of n-Bu ₄ PCl 135°C, 4 hours 23.5 1.4 54.9 - 1.9 10.3 8.0 96 5% decomposition of n-Bu ₄ PCl 140°C, 2 hours 21.7 1.3 54.8 - 1.7 12.1 8.4 100 5% decomposition of n-Bu ₄ PCl 150°C, 4 hours 21.8 1.5 54.7 - 1.7 12.2 8.1 100 5% decomposition of n-Bu ₄ PCl

¹⁾ Reaction on the scale of the NMR method to prove the conditions for carrying out reduction, splitting and redistribution reactions. For the conversion reaction, 40% (mole) LiH was used (based on the total level of chlorine present in the silane mixture). The LiH concentration was 17 mol/l relative to the solvent. C ₆ D ₆ (0.2 ml) was added as NMR standard. Compound C ₆ D ₆ is unable to dissolve LiH or LiCl and should not have any effect on the reactions. The reactions were started at room temperature and were controlled in a controlled manner as the temperature increased from 60°C in steps of 10°C. ⁷ Li-NMR shifts for LiCl are in diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm between 5 and 10% (wt.).

Table 38 contains data obtained for comparative reactions, but in the presence of 7% (mol.) simple crown ether 12-crown-4 in the reaction mixture. In the latter case, the reduction of chlorosilane started only at 80°C, at 100°C the amount of Me ₂ SiHCl is > 40% (mol.), while the molar concentration of Me ₂ SiH ₂ is very low (3.2% (mol. )). At a temperature of more than 110°C, the intense formation of solids prevents further studies of the mixture of products using the NMR method.

Table 38 ¹⁾

Diglim
+ 7% (mol.) crown Me ₂ SiCl ₂ Me ₃ SiCl Me ₂ SiHCl MeSiHCl _{2 MeSiH2Cl} Me ₂ SiH ₂ MeSiH ₃ LiH conversion [%] Notes Room temperature, 12.6 hours 92.9 2.8 - - - - - 0 0% decomposition of n-Bu ₄ PCl
3.8% MeSiCl ₃ <1% disilanes 60°C, 2 hours 92.9 2.8 - - - - - 0 0% decomposition of n-Bu ₄ PCl
3.8% MeSiCl ₃ <1% disilanes 80°C, 2 hours 84.7 1.7 0.9 - - 5.1 6.8 40 0% decomposition of n-Bu ₄ PCl
0.9% _MeSiCl3 90°C, 2 hours 74.1 1.5 16.3 - - 1.5 6.7 49 0% decomposition of n-Bu ₄ PCl 100°C, 2 hours 45.2 1.8 41.2 1.8 3.2 3.2 3.6 83 1% decomposition of n-Bu ₄ PCl 110°C, 2 hours Analysis using NMR was not possible due to the excessive amount of solids in the NMR ampoule - 120°C, 2 hours Analysis using NMR was not possible due to the excessive amount of solids in the NMR ampoule -

¹⁾ Reaction on the scale of the NMR method to prove the conditions for carrying out reduction, splitting and redistribution reactions. For the conversion reaction, 40% (mole) LiH was used (based on the total level of chlorine present in the silane mixture). The LiH concentration was 17 mol/l relative to the solvent. C ₆ D ₆ (0.2 ml) was added as NMR standard. Compound C ₆ D ₆ is unable to dissolve LiH or LiCl and should not have any effect on the reactions. The reactions were started at room temperature and were controlled in a controlled manner as the temperature increased from 60°C in steps of 10°C. ⁷ Li-NMR shifts for LiCl are in diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

Table 39 ¹⁾

1,4-dioxane Me ₂ SiCl ₂ Me ₃ SiCl Me ₂ SiHCl MeSiHCl _{2 MeSiH2Cl} Me ₂ SiH ₂ MeSiH ₃ LiH conversion [%] Notes Room temperature, 12.6 hours 60.6 1.8 21.8 - 0.6 7.9 7.3 63 0% decomposition of n-Bu ₄ PCl 60°C, 2 hours 42.0 1.3 42.8 - - 8.4 5.5 79 0% decomposition of n-Bu ₄ PCl 70°C, 2 hours 34.6 1.7 49.5 - 1.4 6.6 6.2 87 1% decomposition of n-Bu ₄ PCl 70°C, 2 hours 32.3 1.6 53.4 - 0.7 6.5 5.5 88 2% decomposition of n-Bu ₄ PCl 80°C, 2 hours 31.2 1.3 54.5 - 0.3 6.5 6.2 90 2% decomposition of n-Bu ₄ PCl 90°C, 2 hours 29.4 1.2 55.8 - - 7.1 6.5 93 2% decomposition of n-Bu ₄ PCl 100°C, 2 hours 30.0 1.2 55.6 - - 6.9 6.3 92 2% decomposition of n-Bu ₄ PCl 110°C, 2 hours 28.9 1.4 55.4 - - 8.1 6.1 93 2% decomposition of n-Bu ₄ PCl 120°C, 2 hours 27.9 1.4 55.0 - - 8.1 7.5 97 2% decomposition of n-Bu ₄ PCl 130°C, 2 hours 28.7 1.4 55.5 - - 7.2 7.2 95 2% decomposition of n-Bu ₄ PCl 130°C, 2 hours 27.7 1.7 54.3 - 1.4 8.0 6.9 97 2% decomposition of n-Bu ₄ PCl 135°C, 4 hours 27.8 1.7 55.0 - - 8.0 7.5 97 2% decomposition of n-Bu ₄ PCl 140°C, 2 hours 27.9 1.4 54.5 - - 8.4 7.8 98 2% decomposition of n-Bu ₄ PCl 150°C, 4 hours 26.7 1.6 53.3 - 2.1 8.3 8.0 100 2% decomposition of n-Bu ₄ PCl

¹⁾ Reaction on the scale of the NMR method to prove the conditions for carrying out reduction, splitting and redistribution reactions. For the conversion reaction, 48% (mol) of LiH (based on the total level of chlorine present in the silane mixture) was used. The LiH concentration was 17 mol/l relative to the solvent. C ₆ D ₆ (0.2 ml) was added as NMR standard. Compound C ₆ D ₆ is unable to dissolve LiH or LiCl and should not have any effect on the reactions. The reactions were started at room temperature and were controlled in a controlled manner as the temperature increased from 60°C in steps of 10°C. ⁷ Li-NMR shifts for LiCl are in diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

Table 39 covers results for comparable reactions but in 1,4-dioxane as solvent. Table 40 shows the results obtained with the addition of 7% (mol.) simple 12-crown-4-ether. In this case, the observations made were largely similar to the corresponding results described for the reaction in diglyme with the addition of a simple 12-crown-4-ether, (table 38).

Table 40 ¹⁾

dioxane
+ 7% (vol.) Crown Me ₂ SiCl ₂ Me ₃ SiCl Me ₂ SiHCl MeSiHCl _{2 MeSiH2Cl} Me ₂ SiH ₂ MeSiH ₃ LiH conversion [%] Notes Room temperature, 12.6 hours 92.9 2.8 - - - - - 0 0% decomposition of n-Bu ₄ PCl
3.8% MeSiCl ₃ <1% disilanes 60°C, 2 hours 92.9 2.8 - 0.6 - - - one 0% decomposition of n-Bu ₄ PCl
3.2% MeSiCl ₃ <1% disilanes 80°C, 2 hours 75.6 2.3 13.7 - 0.8 1.5 6.0 46 0% decomposition of n-Bu ₄ PCl 90°C, 2 hours 60.6 1.8 16.4 - - 14.5 6.7 82 0% decomposition of n-Bu ₄ PCl 100°C, 2 hours 40.6 1.7 45.1 - 2.0 5.3 5.3 95 1% decomposition of n-Bu ₄ PCl 110°C, 2 hours 35.5 1.4 49.2 - 1.1 7.1 5.7 111 1% decomposition of n-Bu ₄ PCl 120°C, 2 hours Analysis using NMR was not possible due to the excessive amount of solids in the NMR ampoule -

¹⁾ Reaction on the scale of the NMR method to prove the conditions for carrying out reduction, splitting and redistribution reactions. For the conversion reaction, 40% (mole) LiH was used (based on the total level of chlorine present in the silane mixture). The LiH concentration was 17 mol/l relative to the solvent. C ₆ D ₆ (0.2 ml) was added as NMR standard. Compound C ₆ D ₆ is unable to dissolve LiH or LiCl and should not have any effect on the reactions. The reactions were started at room temperature and were controlled in a controlled manner as the temperature increased from 60°C in steps of 10°C. ⁷ Li-NMR shifts for LiCl are in diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

Reactions carried out in THF as solvent are listed in Table 41 and the corresponding reactions in the presence of 12-crown-4-ether are presented in Table 42. Reactions carried out in THF generally show high conversions of LiH and formation of the title compound Me ₂ SiHCl in high yields under moderate reaction conditions.

Table 41 ¹⁾

THF Me ₂ SiCl ₂ Me ₃ SiCl Me ₂ SiHCl MeSiHCl _{2 MeSiH2Cl} Me ₂ SiH ₂ MeSiH ₃ LiH conversion [%] Notes Room temperature, 12.6 hours 54.9 1.7 23.7 - - 11.5 8.2 61 0% decomposition of n-Bu ₄ PCl 60°C, 2 hours 30.6 1.5 48.0 - - 12.3 7.6 81 1% decomposition of n-Bu ₄ PCl 70°C, 2 hours 22.4 1.3 55.1 - 1.3 11.6 7.6 88 2% decomposition of n-Bu ₄ PCl 70°C, 2 hours 21.2 1.2 57.2 - 1.4 11.9 7.1 89 2% decomposition of n-Bu ₄ PCl 80°C, 2 hours 20.8 1.5 56.6 - 1.6 12.0 7.5 90 2% decomposition of n-Bu ₄ PCl 90°C, 2 hours 20.4 1.4 56.9 - 1.2 12.4 7.7 90 2% decomposition of n-Bu ₄ PCl 100°C, 2 hours 19.9 1.4 57.6 - 0.8 12.9 7.4 91 2% decomposition of n-Bu ₄ PCl 110°C, 2 hours 18.7 1.3 57.1 - 1.1 13.9 7.9 93 2% decomposition of n-Bu ₄ PCl 120°C, 2 hours 18.2 1.4 56.0 - 1.1 14.6 8.7 95 3% decomposition of n-Bu ₄ PCl 130°C, 2 hours 18.4 1.3 56.1 - 1.1 14.8 8.3 95 3% decomposition of n-Bu ₄ PCl 130°C, 2 hours 17.4 1.4 55.6 - 0.7 16.5 8.5 97 3% decomposition of n-Bu ₄ PCl 135°C, 4 hours 17.0 1.4 56.4 - - 16.6 8.6 97 3% decomposition of n-Bu ₄ PCl 140°C, 2 hours 16.7 1.5 56.2 - - 16.5 9.2 99 3% decomposition of n-Bu ₄ PCl 150°C, 4 hours 16.4 1.3 54.2 - 1.3 18.2 8.5 100 3% decomposition of n-Bu ₄ PCl

¹⁾ Reaction on the scale of the NMR method to prove the conditions for carrying out reduction, splitting and redistribution reactions. For the conversion reaction, 59% (mol) of LiH (based on the total level of chlorine present in the silane mixture) was used. The LiH concentration was 17 mol/l (relative to the solvent). C ₆ D ₆ (0.2 ml) was added as NMR standard. Compound C ₆ D ₆ is unable to dissolve LiH or LiCl and should not have any effect on the reactions. The reactions were started at room temperature and were controlled in a controlled manner as the temperature increased from 60°C in steps of 10°C. ⁷ Li-NMR shifts for LiCl are in diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

Table 42 ¹⁾

THF
+ 7% (vol.) crown Me ₂ SiCl ₂ Me ₃ SiCl Me ₂ SiHCl MeSiHCl _{2 MeSiH2Cl} Me ₂ SiH ₂ MeSiH ₃ LiH conversion [%] Notes Room temperature, 12.6 hours 92.9 2.8 - - - - - 0 0% decomposition of n-Bu ₄ PCl
3.8% MeSiCl ₃ <1% disilanes 60°C, 2 hours 92.9 2.8 0.2 1.0 - - - 2 0% decomposition of n-Bu ₄ PCl
2.6% MeSiCl ₃ <1% disilanes 80°C, 2 hours 75.8 1.5 4.5 - - 11.4 6.8 58 0% decomposition of n-Bu ₄ PCl 90°C, 2 hours 54.0 1.6 34.6 0.5 2.7 2.2 4.3 70 1% decomposition of n-Bu ₄ PCl 100°C, 2 hours 45.0 1.8 41.0 1.4 3.1 3.2 4.5 83 1% decomposition of n-Bu ₄ PCl 110°C, 2 hours 44.0 1.8 43.6 0.4 2.7 2.7 4.8 84 3% decomposition of n-Bu ₄ PCl 120°C, 2 hours 43.7 1.7 44.1 - 3.1 3.1 4.4 84 3% decomposition of n-Bu ₄ PCl 130°C, 2 hours 38.7 1.6 48.1 - 3.0 3.9 4.7 92 3% decomposition of n-Bu ₄ PCl 130°C, 2 hours 39.2 1.6 47.8 - 3.1 3.1 5.1 91 3% decomposition of n-Bu ₄ PCl 130°C, 2 hours 38.9 1.6 47.9 - 3.1 3.5 5.1 92 3% decomposition of n-Bu ₄ PCl 130°C, 2 hours 37.2 1.5 48.7 - 3.0 4.1 5.6 96 3% decomposition of n-Bu ₄ PCl 135°C, 4 hours 36.2 1.5 49.0 - 2.9 4.3 6.0 99 3% decomposition of n-Bu ₄ PCl 140°C, 2 hours 35.0 1.4 50.7 - 1.7 4.9 6.3 100 3% decomposition of n-Bu ₄ PCl 150°C, 4 hours 34.6 1.7 50.5 - 2.8 5.2 5.2 100 3% decomposition of n-Bu ₄ PCl

¹⁾ Reaction on the scale of the NMR method to prove the conditions for carrying out reduction, splitting and redistribution reactions. For the conversion reaction, 41% (mol.) LiH (in relation to the total level of chlorine present in the silane mixture) was used. The LiH concentration was 17 mol/l (relative to the solvent). C ₆ D ₆ (0.2 ml) was added as NMR standard. Compound C ₆ D ₆ is unable to dissolve LiH or LiCl and should not have any effect on the reactions. The reactions were started at room temperature and were controlled in a controlled manner as the temperature increased from 60°C in steps of 10°C. ⁷ Li-NMR shifts for LiCl are in diglyme: 0.56 ppm, in 1,4-dioxane: 1.11 ppm and in THF: 0.87 ppm.

Example 24

Based on the experiments of Example 23, which were carried out using from about 1 to about 5% (wt.) n-Bu ₄ PCl in sealed ampoules for the NMR method in only small amounts of reagents, similar experiments were carried out in sealed reaction ampoules with varying amounts chlorosilanes in grams, the composition expressed in moles is presented in table 36. In a detailed study, various reaction conditions were studied, which are listed in the "Notes" column in the tables.

Table 43 covers the results obtained for reactions in various glymes as solvents: reaction temperatures were in the range between 110°C and 150°C for 60-65 hours. LiH conversions were in the range of 60-90% (mol), the lower the LiH concentration (in mol/l), the greater the conversions. The resulting yields of Me ₂ SiHCl were in the range of 30-55% (mol.), in the case of adding the amount of Me ₂ SiH ₂ (< 30% (mol.)) the output of Me ₂ SiHCl will almost quantitatively include reactions after processing, such as reactions with ether/HCl reagent (from patent pending) or redistribution using Me ₂ SiCl ₂ . In some cases, there is a noticeable rather strong decomposition of n-Bu ₄ PCl with the formation of n-Bu ₃ P along with other phosphine compounds and but-1-ene, while the HCl compound formed “in situ” acts as a chlorination reagent that retranslates bonds Si-H to Si-Cl.

Table 43

Weight MCS [g] H/Cl exchange [% (mol.)] LiH concentration [mol/l] M2 M3 M2H MH MH2 M2H2 MH3 LiH conversion [%] (± 3%) Notes 13.8 51 16.9 50.5 2.0 37.0 2.0 4.0 2.0 3.0 60 Solvent: diglyme, 110°C, 65 hours
4% decomposition of n-Bu ₄ PCl
corresponds to 30% (mol.) LiH 9.8 48 10.6 48.3 1.9 38.2 1.9 3.9 1.9 3.9 66 Solvent: diglyme, 110°C, 65 hours
3% decomposition of n-Bu ₄ PCl
corresponds to 31% (mol.) LiH 10.9 48 10.6 46.3 1.9 40.7 1.9 3.2 2.3 3.7 67 Solvent: triglyme, 110°C, 65 hours
3% decomposition of n-Bu ₄ PCl
corresponds to 31% (mol.) LiH 9.4 48 10.6 48.3 1.9 40.1 1.0 2.9 1.9 3.9 65 Solvent: tetraglyme, 110°C, 65 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 31% (mol.) LiH 5.0 81 25.7 28.5 2.0 54.70 - 1.1 9.7 4.0 56 Solvent: diglyme
110°C, 4 hours; 130°C, 65 hours
44% decomposition of n-Bu ₄ PCl
corresponds to 44% (mol.) LiH 4.8 81 5.0 20.0 1.8 56.4 - 1.0 16.0 4.8 65 Solvent: diglyme
110°C, 4 hours; 130°C, 65 hours
26% decomposition of n-Bu ₄ PCl
corresponds to 52% (mol.) LiH 4.0 81 2.0 9.3 1.3 53.1 - - 28.3 8.0 83 Solvent: diglyme
110°C, 4 hours; 130°C, 65 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 64% (mol.) LiH 7.5 43 10.0 59.2 1.8 30.2 2.4 3.5 1.1 1.8 57 Solvent: diglyme, 130°C, 60 hours
5% decomposition of n-Bu ₄ PCl
corresponds to 24% (mol.) LiH 5.7 65 10.0 40.5 1.6 46.6 0.8 1.6 4.9 4.0 56 Solvent: diglyme, 130°C, 60 hours
30% decomposition of n-Bu ₄ PCl
corresponds to 35% (mol.) LiH 5.3 86 10.0 25.6 2.3 39.3 - 1.0 24.4 7.4 65 Solvent: diglyme, 130°C, 60 hours
30% decomposition of n-Bu ₄ PCl
corresponds to 54% (mol.) LiH 3.8 118 25.0 22.4 1.6 43.3 - 0.2 28.9 3.6 49 Solvent: diglyme, 150°C, 60 hours
100% decomposition of n-Bu ₄ PCl
corresponds to 56% (mol.) LiH 6.1 47 1.25 34.5 2.0 48.3 - 3.8 4.8 6.4 89 Solvent: diglyme, 130°C, 62 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 42% (mol.) LiH 6.8 39 1.25 47.6 1.9 38.1 1.4 3.8 2.4 4.7 84 Solvent: diglyme, 120°C, 62 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 33% (mol.) LiH 5.0 48 1.25 35.1 1.8 47.7 - 2.8 6.0 6.6 89 Solvent: diglyme, 120°C, 62 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 43% (mol.) LiH 8.5 thirty 1.25 56.2 1.7 31.5 2.2 3.9 1.1 3.4 88 Solvent: diglyme, 120°C, 62 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 27% (mol.) LiH 4.9 51 17 35.2 2.1 47.9 1.4 2.8 3.9 6.7 80 Solvent: diglyme
12-crown-4 10% (vol.), 130°C, 65 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 41% (mol.) LiH 5.4 51 17 47.2 1.9 38.7 1.9 3.8 1.9 4.7 64 Solvent: diglyme
addition of KCl, 130°C, 65 hours
0% decomposition of n-Bu ₄ PCl
corresponds to 33% (mol.) LiH

M2=Me ₂ SiCl ₂ , M3=Me ₃ SiCl, M2H=Me ₂ SiHCl, MH=MeSiHCl ₂ , MH2=MeSiH ₂ Cl, M2H2=Me ₂ SiH ₂ and MH3=MeSiH ₃

More efficient are comparable reactions in THF as solvent (Table 44), which give high conversions of LiH, for example, when using 17% molar concentrations of LiH - in some cases in the presence of crown ether - they reach 100% (mol .). In this case, the yield of Me ₂ SiHCl is ~ 56% (mol.), Me ₂ SiH ₂ is formed at ~ 17% (mol.): with the inclusion of the subsequent processing of dihydridesilanes, the total yield of Me ₂ SiHCl will be approximately 90% (mol.). In the presence of crown ether, a solid residue forms in the formation of the LiCl adduct, which can be further thermally separated at ~100°C into feedstock materials and thus quantitatively recycled (G. Shore et al., Inorg. Chem. 1999, 38, 4554-4558). Similarly, 1,4-dioxane, together with LiCl, forms a heat-labile complex which will separate into adduct-forming components at elevated temperatures (S. Yamashita et al., Mass Spectroscopy, 11, 106 (1963); 28, 211-216 (1965)). These two discoveries explain the intense formation of solids when using 1,4-dioxane as a solvent, especially in the presence of simple crown ethers. This could facilitate the separation of the products, since the chlorosilanes could easily be separated from the "solid" solvent and/or simple crown ether in the subsequent sending of ethers for recycling at ~ 100°C.

Table 44

Weight MCS [g] H/Cl exchange [% (mol.)] LiH concentration [mol/l] M2 M3 M2H MH MH2 M2H2 MH3 LiH conversion [%] (± 3%) Notes 4.7 51 17 35.5 2.0 50.8 0.7 2.0 8.8 3.2 82 Solvent: THF, 130°C, 65 hours
36% decomposition of n-Bu ₄ PCl
corresponds to 42% (mol.) LiH 4.1 51 17 46.3 1.9 41.6 1.9 2.3 2.3 3.7 63 Solvent: DME, 130°C, 65 hours
26% decomposition of n-Bu ₄ PCl
corresponds to 32% (mol.) LiH 7.6 53 17 24.9 2.1 45.6 0.0 1.0 21.6 4.81 101 Solvent: THF
12-crown-4 5% (vol.), 130°C, 65 hours
10% decomposition of n-Bu ₄ PCl 18.4 1.8 56.1 - 1.1 17.1 5.5 103 After condensation of all volatile compounds (treatment) 8.8 51 17 46.7 1.9 41.1 1.0 2.3 2.3 4.7 64 Solvent: DME
12-crown-4 5% (vol.), 130°C, 65 hours
10% decomposition of n-Bu ₄ PCl
corresponds to 33% (mol.) LiH 12.0 51 17 46.5 1.9 39.5 1.9 3.7 2.8 3.7 64 Solvent: dioxane, 130°C, 65 hours
7% decomposition of n-Bu ₄ PCl
corresponds to 33% (mol.) LiH 48.3 1.9 40.6 1.9 3.4 1.9 2.9 60 After condensation of all volatile compounds (treatment) 13.7 51 17 41.7 1.7 43.3 0.8 3.3 3.8 3.4 73 Solvent: dioxane
12-crown-4 2% (vol.), 130°C, 65 hours
6% decomposition of n-Bu ₄ PCl
corresponds to 73% (mol.) LiH 12.1 51 ten 41.2 1.6 43.6 0.8 2.9 5.8 4.1 73 Thinner: THF 130°C, 65 hours
76% decomposition of n-Bu ₄ PCl
corresponds to 37% (mol.) LiH 16.8 39 eleven 55.2 1.7 33.2 2.2 3.8 1.2 2.9 69 Solvent: dioxane (1:1 (mol) dioxane: LiH), 130°C, 64 hours
5% decomposition of n-Bu ₄ PCl
corresponds to 27% (mol.) LiH 17.9 39 fourteen 53.9 1.7 33.6 2.2 3.2 2.2 3.2 72 Solvent: dioxane/THF (1:1), 130°C, 64 hours
2% decomposition of n-Bu ₄ PCl
corresponds to 28% (mol.) LiH 12.2 39 fourteen 50.8 2.0 35.6 2.0 4.0 2.0 3.6 78 Solvent: dioxane/THF (1:1),
12-crown-4 3% (vol.), 130°C, 64 hours
2% decomposition of n-Bu ₄ PCl
corresponds to 28% (mol.) LiH 4.6 51 17 Solvent: DMF, 130°C, 65 hours; reaction with DMF results in 90% unidentified compounds 8.8 51 17 Solvent: DMF, 12-crown-4 5% (v/v), 130°C, 65 hours; reaction with DMF results in 90% unidentified compounds

M2=Me ₂ SiCl ₂ , M3=Me ₃ SiCl, M2H=Me ₂ SiHCl, MH=MeSiHCl ₂ , MH2=MeSiH ₂ Cl, M2H2=Me ₂ SiH ₂ and MH3=MeSiH ₃

As can be seen in Table 44, dimethoxyethane (DME) can also be used as a solvent, but has not been shown to exert significant force compared to other ethers used in Applicant's studies. The same is true for mixtures of ethers, as is exemplified for reactions carried out in mixtures of 1,4-dioxane and THF at a mixing ratio of 1/1.

Claims (87)

1. A method for producing methylchlorohydride monosilanes selected from Me ₂ Si(H)Cl, MeSi(H)Cl ₂ and MeSi(H) ₂ Cl, including: conducting for the initial silane raw materials, including at least one silane selected from the group consisting of: (i) monosilanes, (ii) disilanes, (iii) oligosilanes, (iv) carbodisilanes, provided that at least one of the silanes (i) to (iv) contains at least one chlorine-containing substituent, a) hydrogenation reactions using at least one source of a hydride donor and b) redistribution reactions and c) optionally cleavage reactions of Si-Si bonds of di- or oligosilanes or Si-C bonds of carbodisilanes and d) separation steps of methylchlorohydridsilanes, where the method is carried out in the presence of one or more solvents, in the absence of AlCl ₃ , and where (i) monosilanes are selected from compounds described by the general formula (I), Me _x SiH _y Cl _z , (I) where x=from 1 to 3, y=0 to 3, z=0 to 3, and x+y+z=4, (ii) disilanes are selected from compounds described by the general empirical formula (II), Me _m Si ₂ H _n Cl _o , (II) where m = 1 to 6, n = 0 to 5, o = 0 to 5, and m+n+o=6, (iii) the oligosilanes are selected from linear or branched oligosilanes described by the general empirical formula (III), Me _p Si _q H _r Cl _s , (III) where q = 3-7, p = q to (2q+2), r, s = 0 to (q+2), r+s = (2q+2)-p, (iv) carbodisilanes are selected from compounds described by the general formula (IV), (Me _a SiH _b Cl _e )-CH ₂ -(Me _c SiH _d Cl _f ), (IV) where a, c independently of each other are in the range from 1 to 3, b, d independently of each other are in the range from 0 to 2, e, f independently of each other are in the range from 0 to 2, a+b+e=3, c+d+f=3, and where the redistribution reaction b) is carried out in the presence of at least one redistribution catalyst selected from the group consisting of: - R ₄ PCl, where R represents a hydrogen atom or an organic group, where this substituent may be identical or different and represents an aromatic group or an aliphatic hydrocarbon group, more preferably an n-alkyl group, most preferably an n-butyl group, - triorganophosphines, where R represents a hydrogen atom or an organic group, preferably PPh ₃ or n-Bu ₃ P, - triorganoamines, where R represents an organic group, preferably n-Bu ₃ N or NPh ₃ , - N-heterocyclic amines, preferably non-N-substituted methylimidazoles such as 2-methylimidazole and 4-methylimidazole, - Quaternary ammonium compounds, preferably n-Bu ₄ NCl. 2. The process according to claim 1, wherein the silane feedstock consists of silanes represented by formulas (I) to (IV), preferably the silane feedstock is Me ₂ SiCl ₂ . 3. A method according to any one of the preceding claims, wherein (i) monosilanes are selected from compounds described by the formulas: MeSiCl ₃ , Me ₂ SiCl ₂ , Me ₃ SiCl, MeSiHCl ₂ , Me ₂ SiHCl, MeSiH ₂ Cl, MeSiH ₃ , Me ₂ SiH ₂ and Me ₃ SiH, (ii) disilanes are selected from compounds described by the formulas: Cl ₂ MeSi-SiMeCl ₂ , Cl ₂ MeSi-SiMe ₂ Cl, Cl ₂ MeSi-SiMe ₃ , ClMe ₂ Si-SiMe ₂ Cl, Me ₃ Si-SiMe ₂ Cl, HMe ₂ Si-SiMe ₂ Cl, H ₂ MeSi- SiMeClH, HClMeSi-SiMeClH, ClHMeSi-SiMeCl ₂ , H ₂ MeSi-SiMeCl ₂ , HMe ₂ Si-SiMeCl ₂ , ClMe ₂ Si-SiMeH ₂ , HMe ₂ Si-SiMeClH, ClMe ₂ Si-SiMeClH, Me ₃ Si-SiMeClH, HMe ₂ Si-SiMe ₂ H, H ₂ MeSi-SiMeH ₂ , HMe ₂ Si-SiMeH ₂ , Me ₃ Si-SiMeH ₂ and Me ₃ Si-SiMe ₂ H, (iii) oligosilanes are selected from compounds described by the formulas: ClMe ₂ Si-SiMe ₂ -SiMe ₂ Cl, ClMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ Cl, (ClMe ₂ Si) ₃ SiMe, (Cl ₂ MeSi) ₂ SiMeCl, (Cl ₂ MeSi) ₃ SiMe, ( Cl ₂ MeSi) ₂ SiMe-SiClMe-SiCl ₂ Me, [(Cl ₂ MeSi) ₂ SiMe] ₂ , [(Cl ₂ MeSi) ₂ SiMe] ₂ SiClMe, (Cl ₂ MeSi) ₂ SiMe-SiMe ₂ Cl, ClMe ₂ Si-SiMe ₂ SiMe ₂ H, HMe ₂ Si-SiMe ₂ -SiMe ₂ H, HMe ₂ Si-SiMe ₂ -SiMe ₂ -SiMe ₂ H, (HMe ₂ Si) ₃ SiMe, (H ₂ MeSi) ₂ SiMeH, ( H ₂ MeSi) ₃ SiMe, (H ₂ MeSi) ₂ SiMe-SiHMe-SiH ₂ Me, [(H ₂ MeSi) ₂ SiMe] ₂ , [(H ₂ MeSi) ₂ SiMe] ₂ SiHMe and (H ₂ MeSi) ₂ SiMe-SiMe ₂ H, (iv) carbodisilanes are selected from compounds described by the formulas: Cl ₂ MeSi-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeCl ₂ , Me ₃ Si-CH ₂ -SiMe ₂ Cl, HClMeSi-CH ₂ -SiMeClH, HMe ₂ Si-CH ₂ -SiMeCl ₂ , HMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeClH, H ₂ MeSi-CH ₂ -SiMeH ₂ , HMe ₂ Si-CH ₂ -SiMeH ₂ , HMe ₂ Si-CH ₂ -SiMe ₂ H, Me ₃ Si-CH ₂ -SiMeH ₂ and Me ₃ Si-CH ₂ -SiMe ₂ H, provided that at least one of the silanes used in the process contains at least one chlorine-containing substituent. 4. Process according to any of the preceding claims, wherein the silane feedstock comprises at least one, preferably more than one silane selected from the group consisting of MeSiCl ₃ , Me ₂ SiCl ₂ , Me ₃ SiCl, MeSiHCl ₂ , Me ₂ SiHCl, MeSiH ₂ Cl, MeSiH ₃ , Me ₂ SiH ₂ , Me ₃ SiН, Cl ₂ MeSi-SiMeCl ₂ , Cl ₂ MeSi-SiMe ₂ Cl, Cl ₂ MeSi-SiMe ₃ , ClMe ₂ Si-SiMe ₂ Cl, Me ₃ Si-SiMe ₂ Cl, Cl ₂ MeSi-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMeCl ₂ , ClMe ₂ Si-CH ₂ -SiMe ₂ Cl, Me ₃ Si-CH ₂ -SiMeCl ₂ and Me ₃ Si -CH ₂ -SiMe ₂ Cl. 5. The method according to any one of the preceding claims, wherein the hydride donor source is selected from metal hydrides, preferably the hydride donor source is lithium hydride. 6. The method according to any of the preceding claims, wherein the redistribution reaction for the silanes comprises co-proportionation for two different methyl silanes, in particular one methyl silane containing only a chlorine atom as additional substituents, and one methyl silane containing only a hydrogen atom as additional substituents, resulting in to obtain one particular chlorohydridemethylsilane. 7. Process according to any one of the preceding claims, wherein the cleavage reaction c) is carried out in the presence of at least one cleavage catalyst, preferably selected from the group consisting of: - a quaternary onium compound R ₄ QX of an element from group 15, where each R independently represents a hydrogen atom or an organic group, Q represents a phosphorus, arsenic, antimony or bismuth atom, and X represents a halide selected from the group consisting of F, Cl, Br and I, - heterocyclic amine, - heterocyclic ammonium halide, - mixtures of R ₃ P and RX, where R is as defined above and X is as defined above, - alkali metal halide, - alkaline earth metal halide, - alkali metal hydride, - alkaline earth metal hydride or mixtures thereof, optionally in the presence of hydrogen chloride (HCl). 8. Process according to any one of the preceding claims, wherein the hydrogenation reaction a), the redistribution reaction b) and optionally the cleavage reaction c) are carried out simultaneously and/or step by step, preferably simultaneously. 9. A method according to any one of the preceding claims, wherein the sequence of reactions is selected from one or more of the following process options: the hydrogenation reaction a) and the redistribution reaction b) are carried out simultaneously, the optional cleavage reaction c) is carried out subsequently, the hydrogenation reaction a), the redistribution reaction b) and the cleavage reaction c) are carried out simultaneously, first separately carry out the hydrogenation reaction a), and then simultaneously or separately carry out the redistribution reaction b) and optionally the cleavage reaction c), optionally in this embodiment after the hydrogenation reaction a) already obtained methylchlorohydride monosilanes can be separated before inducing the passage of the redistribution reaction b) and optional cleavage reaction c), the hydrogenation reaction a) is carried out first, then optionally the cleavage reaction c) is carried out, and then the redistribution reaction b) is carried out optionally in this embodiment after the hydrogenation reaction a) the methylchlorohydride monosilanes already produced can be separated before inducing the cleavage reaction c) to proceed, and redistribution reactions b), the silane feedstock is selected from the monosilanes, and for a given feedstock, a hydrogenation reaction a) is carried out first, followed by a redistribution reaction b), or a hydrogenation reaction a) and a redistribution reaction b) are carried out simultaneously for a given feedstock. 10. A process according to any one of the preceding claims, wherein the silane feedstock comprises a direct Mueller-Rochow product. 11. The process according to any one of the preceding claims, wherein the silane feedstock comprises a complete product of the direct Mueller-Rochow process or a portion (fraction) of the product of the direct Muller-Rochow process. 12. A process according to any one of the preceding claims, wherein the silane feedstock comprises a monosilane fraction of a direct Mueller-Rochow product. 13. The process according to any one of the preceding claims, wherein the silane feedstock is the highest silane fraction (silanes containing ≥2 Si atoms) of the product of the direct Mueller-Rochow process. 14. The method according to any one of the preceding claims, wherein the source of the hydride donor is LiH, and wherein the method comprises the step of separating the resulting LiCl compound and the step of recovering LiH from the separated LiCl compound. 15. The method according to any one of the preceding claims, wherein the methylchlorohydride monosilanes are selected from Me ₂ Si(H)Cl and MeSi(H)Cl ₂ . 16. The method according to any one of the preceding claims, wherein the methylchlorohydride monosilane is selected from Me ₂ Si(H)Cl. 17. A process according to any one of the preceding claims, wherein the one or more solvents are selected from ether based solvents.