A low-temperature method for the safe conversion of Siemens process by-product mixtures to chloromonosilanes.

Abstract

The present invention provides one or more compounds of formula H containing at least one Si—H bond. x Si2CI 6-x and optionally further silanes, in particular a by-product mixture of the Siemens process or a fraction thereof, with a reaction promoter selected from: an ether / HCl solution; an amine, a phosphine, or a mixture thereof; an ammonium halide, a phosphonium halide, or a mixture thereof, at a temperature below 200°C. 4-n SiCl n The present invention relates to a method for producing monosilane.

Description

[Technical field]

[0001] The present invention relates to a method for the preparation of chlorosilane monomers, in particular trichlorosilane, at low temperatures by cleavage of silicon-silicon bonds starting from hydridochlorodisilane and further chlorosilane species contained in the mixture of by-products of the Siemens process, in the presence of a further compound containing at least one Si-H bond as a reaction promoter and optionally a hydrogen source. [Background technology]

[0002] Hydridochloromonosilanes are useful starting materials in synthetic organosilicon chemistry and other applications, and trichlorosilane in particular is utilized in the production of high purity polycrystalline silicon using the Siemens process.

[0003] High purity semiconductor grade silicon is primarily produced by the "Siemens process", in which elemental silicon is first reacted with hydrogen chloride to produce trichlorosilane HSiCl3, which is then reduced in the presence of hydrogen and deposited onto a heated silicon rod (HSiCl3+H2->Si+3HCl; 4HSiCl3->Si+3SiCl4+2H2). In this process, only about one-third to one-quarter of the silicon delivered as HSiCl3 is deposited as elemental silicon, the rest consisting of typically more than 85 mol% unreacted trichlorosilane, 5-15 mol% SiCl4 formed by dehydrogenation of HSiCl3, and up to about 1 mol% chlorodisilane H o SiCl 6-o(o=0-6) and particulate silicon exit the reactor. US 6,013,235 (Dow Corning, 2000) reports that the high-boiling residue can be as much as 10% by weight of HSiCl3 in the current commercial operation of this process. Not only does the high-boiling fraction consist of hexachlorodisilane and hydridochlorodisilane, but a typical composition of such a high-boiling residue can include 68% by weight of disilane and 31% by weight of disiloxane, 0.5% by weight of other high-boiling silicon-containing compounds, and 0.5% by weight of silicon, low levels of metals such as Al, Ca, Fe, etc., and solid particles containing their compounds.

[0004] In the reaction of silicon with hydrogen chloride, a mixture of chlorosiloxanes is obtained, consisting mainly of hexachlorodisiloxane and pentachlorodisiloxane. These chlorosiloxanes are formed by the reaction of chlorosilanes with water, which enter the manufacturing process as moisture with moist raw materials such as chlorine, hydrogen chloride, or silicon metal, or enter the manufacturing equipment with moist air when the reactor is filled or cleaned in a discontinuous process. Usually, the SiCl4 and HSiCl3 leaving the reactor are separated from the above by-products by distillation. This results in a mixture of chlorosiloxanes, metal chlorides, and ash, which must be disposed of together with a small amount of SiCl4. In the CVD process, the effluent gas is separated by distillation into a low-boiling fraction, mainly H2SiCl2 and HSiCl3, which is recycled to the CVD reactor, and the high-boiling fraction, consisting of SiCl4, chlorodisilanes, chlorodisiloxanes, and particulate silicon. This latter fraction is further processed to separate the remaining disilanes (and disiloxanes), which are decomposed with hydrogen chloride in a catalyzed high-temperature step, e.g., Si2Cl6+HCl->SiCl4+HSiCl3, and particulate silicon is separated therefrom by spray drying. A catalyst, e.g., palladium on a solid support, results in conversion to monosilanes. In another method, the high-boiling disilane fraction serves as starting material for isolating high-purity hexachloro-, pentachloro-, and tetrachlorodisilanes. Considering the fact that polycrystalline silicon production increased from 18,200 tonnes in 2000 to 391,000 tonnes in 2016, and further economic growth of more than 15% per year is expected worldwide, there is a global need for a preparative, easy low-temperature conversion of the high-boiling by-products of the Siemens process to HSiCl3 in high yields to increase economic benefits and minimize environmental pollution. The need for an easy, non-hazardous, low-temperature method for the conversion of the mixture obtained from the Siemens process reactor is driven by the fact that many of the compounds normally contained in the by-product mixture or formed on contact with air and moisture, particularly the hydrolysis products of Si2Cl6 and chlorohydrodisilane, are difficult to handle and can cause serious accidents.Storage of the by-product mixture and aging of the polymers contained in the by-product mixture further exacerbate the aforementioned problems (see X. Zhou et al, in: Study on the Shock Sensitivity of the Hydrolysis Products of Hexachlorodisilane, Ind. Eng. Chem. Res. 2018, 57, 10354-10364).

[0005] 1) US 6,013,235 discloses the conversion of direct process high boiling residues to monosilanes. The process involves contacting the high boiling residue resulting from the reaction of HCl with silicon metalloid with H2 gas in the presence of a catalytic amount of AlCl3 effective to promote the conversion of the residue to monosilanes. 2) US Pat. No. 4,719,093 discloses a process for cleaving chlorosiloxanes, primarily hexachlorodisiloxane and pentachlorodisiloxane, in the presence of HCl or Cl2 gas at high temperatures to produce HSiCl3 and SiCl4. 3) DE 102010043646 A1 discloses a method for the preparation of trichlorosilane by reaction and catalysis of perchlorinated polysilanes with hydrogen chloride at 90° C. 4) WO2016 / 011993A1 discloses a method for cleaving silicon-silicon and / or silicon-chlorine bonds of monosilanes, polysilanes, and / or oligosilanes by using an ether / HCl solution. Summary of the Invention

[0006] Problems to be solved The problem solved by the present invention is the provision of a method for the production of chloromonosilanes, in particular tetrachlorosilane, trichlorosilane and dichlorosilane, very particularly trichlorosilane, by subjecting a starting material composition comprising one or more hydridochlorodisilanes and optionally further disilanes, monosilanes, oligosilanes and polysilanes and disiloxanes to reaction conditions in which the desired product is obtained by Si-Si bond cleavage at low temperatures. In particular, it is an object of the present invention to provide a new process for utilizing the by-product mixture of the Siemens process as starting material, whereby -Atomic economy -Energy consumption and efficiency -Safety of the method and -Avoidance of environmental pollution To provide a method having improved performance compared to conventional methods for

[0007] The present invention aims to provide a method with improved product yields, product purity, product selectivity of conversion, convenience of work-up procedures, ease of handling of reagents, and cost-effectiveness of the method compared to conventional methods. The problem solved is the provision of such an improved method, applicable in particular to the utilization of the by-product mixture of the Siemens process or its fractions, in which a high yield of trichlorosilane is obtained, which is environmentally friendly, less hazardous, and less demanding in terms of the reactor materials used, due to the low reaction temperature of the method. Furthermore, the problem solved includes the provision of a method that allows to obtain high yields of tetra-, tri-, and dichlorosilanes from disilanes from the by-product mixture of the Siemens process, which solves the safety problems usually associated with the treatment of by-products of the Siemens process by completely converting the dangerous components formed during storage of the by-products and their precursors under the reaction conditions of the method, thus avoiding the very dangerous handling of the so-called "popping gels" by converting these compounds and their precursors instead of disposing of them by combustion.

[0008] According to the present invention, this problem is solved as described below. [Brief description of the drawings]

[0009] [Figure 1] 29Si NMR spectra of the starting disilane mixture 2 (top) and the product mixture after reaction with 5M HCl / 1.4-dioxane solution (bottom, Example 8). [Diagram 2] 29Si NMR spectra of the starting disilane mixture 2 (top) and the separated volatile product mixture after reaction of disilane mixture 2 with nBu3P (bottom, Example 5). [Diagram 3] 29Si NMR spectra of the starting disilane mixture 6 (top) and the product mixture after reaction with 2.5M HCl / nBu2O (bottom, Example 10c) with spectral broadening in the range of +15 to -1 ppm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Detailed Description of the Invention The present invention relates to a method for the preparation of chloromonosilanes by cleavage of silicon-silicon bonds and redistribution reactions at low temperatures, starting from hydridodisilanes and optionally further disilanes, disiloxanes, monosilanes, oligosilanes and polysilanes or mixtures thereof.

[0011] (1) The subject of the present invention is a process for the preparation of chlorosilanes of general formula (I), H 4-n SiCl n (I) where n=2, 3, and 4, preferably n=3; A) a disilane of general formula (II), H o SiCl 6-o (II) where o=0-6, preferably o=0-2, most preferably 0-1; and wherein o≧1 for one or more disilanes, comprising one or more substrates selected from and optionally B) Disiloxanes of general formula (III) or (IV) (H p SiCl 5-p )2O(III) (H q Cl 3-q Si)2O(IV) Wherein p=0-5, preferably p=0-1, q=0-2, more preferably q=0-1; C) Chlorominosilane of general formula (V) SiH r Cl 4-r (V) where r=0-2, preferably r=0-1, most preferably r=0, D) Perchlorinated oligosilanes and polysilanes of general formula (VI) S s Cl 2s+2 (VI) where s=3-6, E) chloro-, hydrido- and hydroxy-substituted polysilanes, including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, and chloro-, hydrido- and hydroxy-substituted polysiloxanes; The starting material composition further comprises: -ether / HCl solution, amines, phosphines or mixtures thereof, and ammonium halides, phosphonium halides, or mixtures thereof, F) one or more reaction promoters selected from the group consisting of Optional G) Monosilane of general formula (VII) R t SiCl u H 4-(t+u) (VII) where t=0-3, preferably 1-3, more preferably 2; u=0-2, preferably 0; t+u=0-3, preferably 1-3, more preferably 2; R is an organic residue; H) Disilane of general formula (VIII) R v SiCl w H 6-(v+w) (VIII) where v=0-5, preferably 1-5, w=0-5, preferably 0; v+w=1-5, R is as defined above, in the optional presence of one or more additional compounds containing at least one Si—H bond selected from This method involves carrying out the reaction at a temperature below 200°C.

[0012] The reaction according to the invention mainly involves the cleavage of hydridodisilanes of general formula (II) with o≧1 which are essentially contained in the starting material composition, but may also involve the cleavage of further disilanes A), disiloxanes B), perchlorinated oligo- and polysilanes D), chloro-, hydrido- and hydroxy-substituted polysilanes E), including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, and disilanes H), if added to the starting material composition.

[0013] According to the invention, the term "cleavage" is used to describe the transformation in which the compounds of the above components A), B), D) and E) react to produce monomeric silanes represented by the general formula (I) and, in the case of disilane H), monomeric silanes of the general formula (I) and their analogs substituted with organic residues R. In the case of disilanes, oligosilanes and polysilanes, the cleavage reaction is carried out by cleaving the bonds connecting the silicon atoms of these disilanes, oligosilanes and polysilanes. In the case of disiloxanes, the term "cleavage" also applies to the cleavage of the Si-O bonds. In general, the cleavage reactions of the method according to the invention include, in particular, hydrochlorination and hydrogenolysis reactions.

[0014] The reaction according to the invention may also include redistribution reactions, depending on the applied reaction promoter F) and the particular components A)-E) and G)-H) present in the starting material composition. According to the invention, the term "redistribution reaction" refers to the redistribution of hydrogen and chlorine substituents attached to the silicon atoms of one or more silane and / or siloxane compounds contained in the reaction mixture, by exchange of these substituents. The exchange is in particular 29 The redistribution reaction can be catalyzed by a reaction promoter F).

[0015] Disilanes A) of general formula (II) are H o SiCl 6-o (II) It can also be represented by the following structural formula: [ka] wherein the substituents R' are independently selected from hydrogen (H) and chlorine (Cl), and wherein the number of hydrogen atoms o=0 to 6, and the number of chlorine atoms 6-o=0 to 6.

[0016] Preferably, the number of hydrogen atoms is o=0-2, i.e., formula (II) preferably represents one or both isomers of hexachlorodisilane, pentachlorodisilane, and tetrachlorodisilane, and most preferably, o=0-1, i.e., formula (II) most preferably represents hexachlorodisilane and pentachlorodisilane. According to the present invention, the presence of one or more disilanes having one or more Si-H bonds, i.e., the presence of a hydridodisilane, in the starting material composition is essential.

[0017] Optionally, the starting material composition may include disiloxanes B) of general formulas (III) and (IV).

[0018] The disiloxane of general formula (III) is (H p SiCl 5-p )2O(III) It can also be represented by the following structural formula: [ka] wherein the substituents R″ are independently selected from hydrogen (H) and chlorine (Cl), and wherein the number of hydrogen atoms per disilyl unit is p=0-5, and the number of chlorine atoms is 5-p=0-5.

[0019] Preferably, the number of hydrogen atoms per disilyl unit is p=0-1, and as a result, the preferred total number of hydrogen atoms per disiloxane of formula (III) is 0 to 2.

[0020] The disiloxane of general formula (IV) is (H q Cl 3-q Si)2O(IV) It can also be represented by the following structural formula: [ka] wherein the substituents R''' are independently selected from hydrogen (H) and chlorine (Cl), and wherein the number of hydrogen atoms per silyl unit is q=0-2 and the number of chlorine atoms is 3-q=1-3.

[0021] Preferably, the number of hydrogen atoms per silyl unit is q=0-1, resulting in a preferred total number of hydrogen atoms per disiloxane of formula (IV) of 0 to 2.

[0022] Disiloxanes, particularly those of general formulas (III) and (IV) above, may constitute components of the by-product mixture obtained from the Siemens process.

[0023] Accordingly, the terms "by-product mixture resulting from the Siemens process," "Siemens process by-product mixture," "Siemens process CVD reactor effluent," and "Siemens process reactor effluent" will be used synonymously unless the specific composition of each is given in the context.

[0024] The amount of disiloxanes found in the by-product mixture of the Siemens process will depend on the particular reaction parameters selected for the process, particularly the amount of water present during the reaction due to wet starting materials or moisture in the reaction atmosphere. For purposes of this invention, disiloxanes formed immediately upon exit of the by-product mixture from the Siemens process reactor by contact with ambient air and during handling of the by-product mixture are also considered to have been formed during the Siemens process.

[0025] Optionally, the starting material composition may further comprise a chloromonosilane C) of general formula (V), SiH r Cl 4-r (V) Here, r=0-2, preferably r=0-1, and most preferably r=0.

[0026] This means that di-, tri- and tetrachlorosilane are preferably included in the starting material composition, more preferably the starting material composition includes trichlorosilane and tetrachlorosilane, and most preferably the starting material composition includes tetrachlorosilane.

[0027] In many cases, the effluent exiting the Siemens process reactor contains over 85 mole % unreacted trichlorosilane and 5-15 mole % SiCl4 formed by dehydrogenation of HSiCl3. In other cases, tetrachlorosilane may constitute the major component by weight of the effluent exiting the Siemens process reactor.

[0028] When the low-boiling components of the by-product mixture of the Siemens process are removed, in particular by distillation or condensation, the chloromonosilanes C) are present in the starting material composition only in small amounts or are absent before such substrates are subjected to the process according to the invention as starting material composition.

[0029] However, if steps are not taken to remove the lower boiling components of the Siemens process by-product mixture, the chloromonosilanes C) may constitute a major portion of the starting material composition.

[0030] In such a case, it is preferred that the reaction process is carried out in the presence of one or more additional compounds containing at least one Si-H bond selected from G) or H), and a reaction promoter F) selected from an amine, a phosphine, an ammonium halide, a phosphonium halide or mixtures thereof is present in the reaction mixture.

[0031] Particularly preferably, the additional compound containing at least one Si-H bond selected from G) or H) is selected from methylhydridosilane or methylhydridodisilane, most preferably it is dimethylsilane.

[0032] It is also preferred that the molar ratio of hydrogen atoms bonded to Si atoms of the additional compound containing at least one Si-H bond to chlorine atoms bonded to Si atoms of the chloromonosilanes C) present in the starting material composition is in the range of 0.5 to 2.0.

[0033] Optionally, the starting material composition according to the invention may further comprise perchlorinated oligo- and polysilanes D) of general formula (VI), S s Cl 2s+2 (VI) Here s=3-20.

[0034] Perchlorinated oligo- and polysilanes D) are further typical components of the by-product mixture of the Siemens process. They are present both in the effluent from the reactor and in the high-boiling fraction obtained when removing the low-boiling monosilanes. The conversion of such residues to monosilanes usually requires high-temperature processes, but according to the invention it can be achieved at temperatures below 200°C.

[0035] Another component optionally included by the starting material composition according to the invention is chloro-, hydrido- and hydrido-substituted polysilanes, including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, and chloro-, hydrido- and hydroxy-substituted polysiloxanes E). Such compounds may be formed during the Siemens process, in particular during storage of the Siemens process by-product mixtures containing chloro-oligo- and chloro-polysilanes, in the presence of moisture and / or oxygen, in particular at high temperatures. The residues formed by aging of the polymeric components obtained in the Siemens process as by-products under the above conditions are generally called "popping gels", which refers to the dangerous properties of such gels, in particular their explosiveness. In order to prevent the formation of popping gels by aging of the polymeric compounds contained in the by-product mixture and to destroy such compounds already formed, the by-product mixtures of the Siemens process are often treated by combustion at high temperatures, resulting in an economically less efficient and environmentally unharmful process. In the process according to the invention, the formation of popping gels is prevented by the direct conversion of all precursor compounds and already formed compounds E) following the Siemens process, in particular by the direct utilization of the effluent leaving the CVD reactor of the Siemens process in the process according to the invention.

[0036] In the process according to the invention, the cleavage reaction and, optionally, the redistribution reaction to produce the desired product, are carried out by reacting one or more disilane substrates A) and optional further components B) to E) of the starting material composition with: -ether / HCl solution, amines, phosphines or mixtures thereof, and - Ammonium halides, phosphonium halides, or mixtures thereof The reaction is carried out in the presence of one or more reaction promoters F) selected from the group consisting of:

[0037] The term "ether / HCl solution" according to the present invention refers to any reagent containing an ether compound and HCl, regardless of whether the HCl is absorbed by the ether compound or dissolved in the ether solvent. The terms "absorption" or "absorption" respectively refer to the process in which one material (the absorbent), in this case hydrogen chloride, is held by another material (the absorbent), in this case an ether compound. The terms dissolution or dissolution respectively mean that two phases mix to form one new homogeneous phase, which in this case is a solution of hydrogen chloride in an ether compound.

[0038] The ether / HCl reagent can be prepared in advance and then applied to the process according to the invention, or the ether can be added to the reaction mixture or reactor followed by the addition of HCl gas to form the ether / HCl reagent in situ.

[0039] According to the present invention, the term "ether compound" is intended to mean any organic compound containing an ether group -O-, in particular of the formula R1-O-R2, where R1 and R2 are independently selected from monovalent organyl groups linked to oxygen via a carbon atom. Preferably, R1 and R2 are substituted or unsubstituted linear or branched alkyl or aryl groups, which may have additional heteroatoms such as oxygen, nitrogen or sulfur. In the case of cyclic ether compounds, R1 and R2 together may constitute an optionally substituted alkylene or arylene group, which may have additional heteroatoms such as oxygen, nitrogen or sulfur.

[0040] The ether compounds can be symmetrical or asymmetrical with respect to the substituents of the ether group -O-.

[0041] Preferably, the ether compound according to the present invention is selected from the group consisting of linear and cyclic ether compounds.

[0042] As used herein, a linear ether compound is a compound containing an ether group R1OR2 as defined above, where there is no connection between the R1 and R2 groups, except at the oxygen atom of the ether group, e.g., symmetrical ethers Et2O, n-Bu2O, Ph2O, or diisoamyl ether (i-pentyl2O), where R1=R2, or unsymmetrical ethers such as t-BuOMe (methyl t-butyl ether, MTBE) or PhOMe (methyl phenyl ether, anisole).

[0043] Cyclic ether compounds according to the present invention are compounds in which one or more ether groups are contained in a ring formed by a series of atoms, such as 1,4-dioxane, which can be substituted, for example, by alkyl groups.

[0044] Also preferably, the ether compound is selected from the group consisting of diethyl ether, di-n-butyl ether, dioxane, preferably diethyl ether and di-n-butyl ether.

[0045] In a further preferred embodiment, the ether compound is selected from 1,4-dioxane, diethyl ether or di-n-butyl ether.

[0046] More preferably, the process according to the invention is carried out with an ether compound saturated with HCl.

[0047] In the sense of the present invention, the term "saturated" refers to a saturated solution of hydrogen chloride in the ether compound applied, and is defined as a solution having the same concentration of solute as that in equilibrium with the undissolved solute at a particular value of temperature and pressure. In the sense of the present invention, solutions close to saturation are also included in the term "saturated". Such saturated solutions can be prepared by passing gaseous hydrogen chloride through the corresponding ether compound (e.g., diethyl ether, di-n-butyl ether) at about -10 to about +10°C. The ether is saturated when excess HCl gas evaporates over the overpressure valve as fast as it is introduced into the solvent.

[0048] Preferably, the HCl content of the ether solvent in reaction step A) is > about 0.1 mol / l, more preferably > about 1.0 mol / l, even more preferably > about 3 mol / l, and most preferably the ether solvent is saturated with HCl as defined above.

[0049] In the context of the present invention, it also refers to EtO used as a solvent containing HCl as the HCl / diethyl ether reagent, it refers to di-n-butyl ether used as a solvent containing HCl as the HCl / di-n-butyl ether reagent, and it refers to 1,4-dioxane used as a solvent containing HCl as the HCl / 1,4-dioxane reagent.

[0050] Preferably, the reaction of the process according to the invention is carried out with di-n-butyl ether or 1,4-dioxane saturated with HCl serving as the ether solvent saturated with HCl.More preferably, the saturation of di-n-butyl ether or 1,4-dioxane with hydrogen chloride is carried out as described above by passing gaseous hydrogen chloride through di-n-butyl ether or 1,4-dioxane.

[0051] According to the present invention, when referring to the reaction promoter F), the term "amine" means an amine R 1 3N, where R 1 is hydrogen or an organyl group and may be the same or different, preferably it refers to a tertiary amine R3N, where R is an organyl group and may be the same or different, for example n-Bu3N or NPh3.

[0052] In the preferred compounds F) selected from the triorganoamines NR3, R is an organyl group and may be the same or different, more preferably R is an alkyl, cycloalkyl or aryl group, most preferably the organoamine is NPh3 or n-Bu3N. Furthermore, the term "amine" according to the present invention includes heterocyclic amines.

[0053] According to the present invention, when referring to the reaction promoter F), the term "phosphine" means a phosphine R 1 3P, where R 1 is hydrogen or an organyl group and may be the same or different, preferably R3P, where R is as defined above and may be the same or different, for example PPh3.

[0054] In the preferred compounds F) selected from the triorganophosphines PR3, R is an organyl group and may be the same or different, more preferably R is an alkyl, cycloalkyl or aryl group, most preferably the organophosphine is Cy3P, PPh3 or n-Bu3P.

[0055] In accordance with the present invention, the terms "ammonium halide" and "phosphonium halide" refer to onium compounds R4QX, where each R is independently hydrogen or an organyl group, Q is nitrogen or phosphorus, and X is a halide selected from the group consisting of F (fluorine), Cl (chlorine), Br (bromine), and I (iodine). Additionally, the terms include heterocyclic ammonium halides.

[0056] In the sense of the present invention, an organyl group is any organic substituent, regardless of functional group, which has one free valence at a carbon atom.

[0057] Preferably, the quaternary compound R4QX, where Q=N,P, is represented by the formula R4PCl, where R is independently a hydrogen group or an organyl group, more preferably a hydrogen group, an aromatic group preferably having up to about 30 carbon atoms, or an aliphatic hydrocarbon group preferably having up to about 30 carbon atoms.

[0058] Even more preferably, R is independently hydrogen or an alkyl, cycloalkyl, aryl or alkaryl group having from about 1 to about 30 carbon atoms, preferably from about 2 to about 16 carbon atoms. Preferred groups R include methyl, butyl such as n-butyl, isobutyl, hexyl such as n-hexyl, tetradecyl such as n-tetradecyl, and octyl such as n-octyl.

[0059] Particularly preferred examples of ammonium or phosphonium halides according to the invention are tetra(n-butyl)phosphonium chloride, tetra(n-butyl)phosphonium bromide, trihexyl(tetradecyl)phosphonium bromide, methyltri(isobutyl)phosphonium bromide, methyltri(isobutyl)phosphonium chloride, tetra(n-octyl)phosphonium chloride, tri(n-butyl)tetradecylphosphonium chloride, and octyltri(n-butyl)phosphonium chloride.

[0060] Preferably, the heterocyclic amines according to the invention have at least one nitrogen atom in at least one 4- to 8-membered hydrocarbon ring, where the ring atom adjacent to the nitrogen is carbon or nitrogen, and the hydrocarbon ring or rings are, independently of each other, aromatic or non-aromatic hydrocarbon rings.

[0061] More preferably, the heterocyclic amine contains a 5-membered ring having from 1 to 3 nitrogen atoms.

[0062] Even more preferably, the heterocyclic amine is an imidazole or substituted imidazole selected from the group consisting of 1-methylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropyl-imidazole, 4-methylimidazole, 2,4-dimethylimidazole, 2-(2-imidazolyl)imidazole, 2-phenylimidazole, imidazoline, imidazolidine, pyrazole, 3-methylpyrazole, pyrrolidone, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidone, 1,2,3-triazole, and 1,2,4-triazole.

[0063] Preferably, the heterocyclic ammonium halide is derived from a heterocyclic amine having at least one nitrogen atom in at least one 4- to 8-membered hydrocarbon ring, where the ring atoms adjacent to the nitrogen are independently carbon or nitrogen atoms, and the hydrocarbon ring or rings are, independently of each other, aromatic or non-aromatic hydrocarbon rings, where the halide is fluoride, chloride, bromide.

[0064] More preferably, the heterocyclic ammonium halide is derived from a heterocyclic amine having from 1 to 3 nitrogen atoms in a 5-membered ring, and the halide is fluoride, chloride, bromide, or iodide.

[0065] Even more preferably, the heterocyclic ammonium halide is 1,2-dimethyl-3-(n-propyl)-imidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1,2-dimethyl-3-(n-butyl)imidazolium chloride, 1-butyl-3-methyl-imidazolium chloride, 1-(3-cyanopropyl)-3-methylimidazolium chloride, or 1-methylimidazolium chloride.

[0066] In another preferred embodiment according to the present invention, the ammonium or phosphonium halide is represented by the formula RPCl, where R is independently a hydrogen group or an organyl group, more preferably a hydrogen group, an aliphatic hydrocarbon group, or an aromatic group.

[0067] Preferably, R is independently hydrogen or an alkyl, cycloalkyl, aryl, or alkaryl group of from about 1 to about 30 carbon atoms, preferably from about 2 to about 16 carbon atoms. R includes methyl, butyl, such as n-butyl, isobutyl, hexyl, such as n-hexyl, tetradecyl, such as n-tetradecyl, and octyl, such as n-octyl.

[0068] Particularly preferred examples of ammonium or phosphonium halides according to the invention are tetra(n-butyl)phosphonium chloride, tetra(n-butyl)phosphonium bromide, trihexyl(tetradecyl)phosphonium bromide, methyltri(isobutyl)phosphonium bromide, methyltri(isobutyl)phosphonium chloride, tetra(n-octyl)phosphonium chloride, tri(n-butyl)tetradecylphosphonium chloride, and octyltri(butyl)phosphonium chloride.

[0069] When reaction promoter F) is selected from HCl / ether solutions, the ratio of HCl to disilanes, disiloxanes, oligo- and polysilanes in the starting material composition, based on the molar amount of HCl and the molar amount of Si-Si bonds contained in the compounds of the starting material composition, is preferably in the range of 0.1 to 20.0, more preferably in the range of 0.5 to 10.0, even more preferably in the range of 1.0 to 8.0, and most preferably in the range of 1.0 to 5.0, i.e., most preferably in the range of 1 HCl molecule per Si-Si bond (=1.0) to 5 HCl molecules per Si-Si bond (=5.0).

[0070] When the reaction promoter F) is selected from an amine, a phosphine, an ammonium halide or a phosphonium halide, the amount of catalyst is preferably in the range of 0.01% to 30% by weight, more preferably in the range of 1% to 20% by weight, even more preferably in the range of 3% to 15% by weight, and most preferably in the range of 5% to 10% by weight, based on the weight of the compounds of the starting material composition.

[0071] The reaction of the method according to the invention optionally comprises: G) Monosilane of general formula (VII) R t SiCl u H 4-(t+u) (VII) where t=0-3, preferably 1-3, more preferably 2; u=0-2, preferably 0; t+u=0-3, preferably 1-3, more preferably 2; R is an organic residue; H) Disilane of general formula (VIII) R v SiCl w H 6-(v+w) (VIII) where v=0-5, preferably 1-5, w=0-5, preferably 0; v+w=1-5, R is defined as above, The reaction is carried out in the presence of one or more additional compounds containing at least one Si-H bond selected from:

[0072] Preferably, the monosilane of general formula (VII) has from 1 to 3 organic residues, more preferably from 1 to 3 organic residues selected from C1-C6 alkyl or aryl groups, even more preferably from 1 to 3 organic residues independently selected from methyl, ethyl, or phenyl groups, and most preferably from 1 to 3 methyl groups.

[0073] Also preferably, the monosilane has 1 to 3 hydrogen atoms, more preferably 1 to 3 hydrogen atoms and no chlorine substituents, even more preferably 2 hydrogen atoms and 2 organic residues, and most preferably, monosilane G) is dimethylsilane.

[0074] According to the present invention, the disilane H) is preferably selected from the group of disilanes of general formula (VIII) having from 1 to 5 organic residues, more preferably having from 1 to 5 organic residues selected from C1-C6 alkyl or aryl groups, even more preferably having from 1 to 5 residues independently selected from methyl, ethyl or phenyl groups, most preferably having from 1 to 5 methyl groups.

[0075] Also preferably, disilane H) has 1 to 5 hydrogen atoms, more preferably 2 to 4 hydrogen atoms and no chlorine substituents, even more preferably 2 or 4 hydrogen atoms and 4 or 2 organic residues, with disilane H) being most preferably Me2Si2H4 and Me4Si2H2.

[0076] The more hydrogen-rich disilane, Me2Si2H4, of the most preferred disilane H) mentioned above, is advantageous in this respect since less disilane is required as hydrogen donor for a given starting material composition, and therefore smaller reactors may be sufficient. Furthermore, the valuable monosilane MeSiHCl2 is formed by cleavage of the partially or fully chlorinated redistribution products obtained from Me2Si2H4. However, the formation of organo-oligosilanes from Me2Si2H4 and its reaction products is a drawback of applying this Si-H bond-containing disilane as hydrogen donor.

[0077] On the other hand, Me4Si2H2 is not cleaved under the reaction conditions of the process, but functions only as a hydrogen transfer reagent, which is perchlorinated during the reaction and can be recycled by reaction with LiH to generate Me4Si2H2 again. Separation of the chlorinated product Me4Si2Cl2 from the desired product of general formula (I) is not an issue due to the rather high boiling point of Me4Si2Cl2 when compared to those of HSiCl3 and SiCl4.

[0078] The process according to the invention is carried out at a temperature below 200° C. In this specification, the reaction temperature according to the invention is the temperature of the reaction mixture, i.e. the temperature measured in the reaction vessel in which the reaction takes place.

[0079] The process according to the invention is characterized in that the starting material composition comprises one or more disilanes A) of general formula (II) where o≧1, i.e. containing at least one hydrogen atom bonded to the silicon atom.

[0080] (2) In a preferred embodiment of the process according to the invention, the disilane o≧1 is pentachlorodisilane, more preferably the disilane o≧1 is pentachlorodisilane and one or two tetrachlorodisilane isomers, even more preferably the disilane o≧1 is pentachlorodisilane, where hexachlorodisilane is also present in the starting material composition, and most preferably the disilane o≧1 is pentachlorodisilane and one or two tetrachlorodisilane isomers, where hexachlorodisilane is also present in the starting material composition.

[0081] Pentachlorodisilane and tetrachlorodisilane are typically present as hydrido-disilane components in the by-product mixture of the Siemens process, where they are usually accompanied by varying amounts of hexachlorodisilane.

[0082] They are also present in the high-boiling fraction of the Siemens process by-product mixture, where the term "high-boiling" indicates that the compounds contained in these fractions have boiling points much higher than the technically easier separation of the low-boiling chloromonosilanes SiCl4, HSiCl3, H2SiCl2, and H3SiCl by fractional distillation. According to the present invention, all compounds having a boiling point of 75° C. or higher at standard atmospheric pressure of 101325 Pa are considered to be part of the high-boiling fraction of the Siemens process by-product mixture.

[0083] The Siemens process by-product mixture obtained from the reactor or obtained after physical or chemical treatment such as filtration, distillation, condensation, storage or selective conversion or derivatization of certain components of the by-product mixture is a preferred starting material for the process according to the invention. Typically, the Siemens process by-product mixture is characterized by comprising at least one, and in most cases several, disilanes containing at least one Si-H bond.

[0084] (3) In a preferred embodiment of the process according to the invention, the temperature is in the range of from 10°C to 160°C, more preferably from 15°C to 130°C, even more preferably from 20°C to 100°C, and most preferably from 20 to 80°C.

[0085] As used herein, reaction temperature is the temperature of the reaction mixture, i.e., the temperature measured in the reaction vessel in which the reaction takes place.

[0086] Preferably, the reaction vessel can be, but is not limited to, an ampoule, a sealed tube, a flask, or any type of chemical reactor. The reaction vessel, particularly the reaction reactor or tube, can be designed for batch or continuous production mode.

[0087] More preferably, the reaction step is carried out in a suitably sized reactor made of a material resistant to corrosion by chlorides, such as glass or Hastelloy C. Means for vigorous stirring are provided to disperse or dissolve the reaction facilitator F) or a mixture of such agents in the solvent or, if carried out neat, in the starting material composition.

[0088] (4) In another preferred embodiment of the process according to the invention, the starting material composition comprises as a by-product the effluent leaving a Siemens process CVD reactor.

[0089] The Siemens process (HSiCl3+H2->Si+3HCl; 4HSiCl3->Si+3SiCl4+2H2), in which elemental silicon reacts with hydrogen chloride to produce trichlorosilane, HSiCl3, which is then reduced in the presence of hydrogen and Si is deposited on a heated silicon rod, is the primary commercial method for producing high purity polycrystalline silicon. In this process, only about one-third to one-quarter of the silicon supplied as HSiCl3 is deposited as elemental silicon, and the rest is unreacted trichlorosilane, or HSiCl3, chlorodisilane H o SiCl 6-o The high boiling fraction leaves the reactor as an effluent gas which typically contains disilane H with o=0,1 as the most preferred component and SiCl4 formed by dehydrogenation of particulate silicon. o SiCl 6-n (o=0-4), as disclosed in US 6,013,235, a typical composition of such a high-boiling residue may include 68% by weight disilane and 31% by weight disiloxane, 0.5% by weight other high-boiling silicon-containing compounds. The specific composition of the effluent leaving the Siemens process CVD reactor as a by-product, also referred to in accordance with the present invention as the "Siemens process by-product mixture", is highly dependent on the parameters selected for carrying out the process, but a composition containing SiCl4 and HSiCl3 as main components, with minor amounts of disilane as described, can be expected.

[0090] Particularly preferably, the Siemens process by-product mixture is the only constituent of the starting material composition according to the invention.

[0091] (5) In a further preferred embodiment of the process according to the invention, the starting material composition comprises as a by-product an effluent exiting a Siemens process CVD reactor, wherein the effluent comprises tetrachlorosilane as a major component.

[0092] In accordance with the present invention, the term "major component" refers to the compound in the composition having the highest weight percent, where weight percent refers to the ratio of the weight of the particular component contained in the Siemens process by-product mixture to the total weight of the Siemens by-product mixture.

[0093] Preferably, when the starting material composition comprises as a by-product the effluent leaving a CVD reactor of the Siemens process, in which the effluent comprises tetrachlorosilane as a main component, the process according to the invention is carried out in the presence of one or more additional compounds containing at least one Si-H bond selected from monosilanes G) of general formula (VII) and disilanes H) of general formula (VIII), more preferably selected from MeSiH3, MeSiH2Cl, Me2SiH2, Me3SiH, Me2Si2H4, Me3Si2H3, Me4Si2H2, Me5Si2H, even more preferably selected from MeSiH3, MeSiH2Cl, Me2SiH2, Me2Si2H4, Me4Si2H2, most preferably selected from MeSiH3, Me2SiH2, and Me4Si2H2.

[0094] The molar ratio of silicon-bonded hydrogen atoms of compounds H) and G) to silicon-bonded chlorine atoms of the starting material composition comprising the Siemens process by-product mixture is preferably in the range of 0.10 to 0.50, more preferably in the range of 0.10 to 0.25, and most preferably in the range of 0.15 to 0.25.

[0095] Also preferably, the Siemens process by-product mixture containing tetrachlorosilane as a major component is the only constituent of the starting material composition according to the present invention.

[0096] (6) In another embodiment of the process according to the invention, the starting material composition comprises as a by-product one or more fractions obtained by fractional distillation of the effluent leaving the Siemens process CVD reactor.

[0097] Typically, the low boiling fractions of the Siemens process by-product mixture, particularly SiCl4 and HSiCl3, are removed from the by-product stream immediately after leaving the CVD reactor by distillation for reuse or further processing. Furthermore, fractional distillation makes it possible to separate or concentrate certain starting materials present in the product stream, such as disilanes, disiloxanes, oligosilanes, etc., in order to subject them to the process according to the invention in a defined composition of starting materials.

[0098] Preferably, the one or more fractions obtained by fractional distillation of the effluent leaving the Siemens process CVD reactor as a by-product which serves as a starting material in the process according to the invention comprise, in the one or more combined fractions, less than 10% by weight of monosilane and more than 50% by weight of disilane.

[0099] Also preferably, the starting material composition of the process according to the invention consists exclusively of one or more fractions obtained by fractional distillation of the Siemens process by-product mixture, more preferably, one or more fractions which, when combined, contain less than 10 wt.% monosilane and more than 50 wt.% disilane, and most preferably, more than 70 wt.% disilane.

[0100] (7) In a preferred embodiment of the process according to the invention, the starting material composition comprises at least a disiloxane B) of general formula (III) or (IV) and / or a chloromonosilane C) of general formula (V).

[0101] In addition to disilanes, chloromonosilanes C) and disiloxanes B) may constitute the major components of the by-product mixture of the Siemens process, depending on the reaction parameters.

[0102] Disiloxanes B) are formed especially in the presence of moisture and, if present in the mixture, are present in the high-boiling disilane fraction during distillation. They can be converted to trichlorosilane and silicon tetrachloride at low temperatures by the process according to the invention.

[0103] (8) In yet another preferred embodiment of the process according to the present invention, the starting material composition comprises a high-boiling fraction of the Siemens process by-product mixture and contains disilane as a major component by weight, preferably hexachlorodisilane, pentachlorodisilane and tetrachlorodisilane as major components, more preferably hexachlorodisilane and pentachlorodisilane as major components, and most preferably hexachlorodisilane as a major component by weight.

[0104] In accordance with the present invention, hexachlorodisilane, pentachlorodisilane and tetrachlorodisilane are preferred components of the starting material composition because they are the primary disilane by-products typically formed in the Siemens process and because they are converted to the desired chloromonosilanes, particularly silicon tetrachloride, trichlorosilane and dichlorosilane, by the process according to the present invention.

[0105] (9) In a further preferred embodiment of the process according to the invention, the starting material composition comprises more than 30% by weight disilane, preferably more than 40% by weight disilane, more preferably more than 50% by weight disilane, even more preferably more than 60% by weight disilane, and most preferably more than 70% by weight disilane.

[0106] In the process according to the invention, disilane is the preferred starting material for conversion to chloromonosilanes of general formula (I). The disilane content of the starting material composition corresponds to the disilane content of the Siemens process by-product mixture, which is preferably used as starting material or the disilane content of the fraction obtained by fractional distillation of the Siemens process by-product mixture, which is also preferably used as starting material.

[0107] (10) In a preferred embodiment of the process according to the invention, the starting material composition comprises greater than 15% by weight hydridochlorodisilane, preferably greater than 25% by weight hydridochlorodisilane, more preferably greater than 30% by weight hydridochlorodisilane, even more preferably greater than 40% by weight hydridochlorodisilane, even more preferably greater than 50% by weight hydridochlorodisilane, and most preferably the starting material consists of a disilane having at least one hydrido substituent.

[0108] The process according to the invention is directed to the conversion of compositions comprising at least one disilane of general formula (II) with o≧1, which are usually formed as by-products during the Siemens process and which, upon aging and contact with air and / or moisture, are responsible for the formation of dangerous popping gels and which themselves are more difficult to handle in terms of flammability and explosiveness than organodisilanes, hexachlorodisilanes or long-chain perchlorooligosilanes, which usually have to be converted into monosilanes by high-temperature processes that are energy-intensive or disposed of by combustion, whereas the process according to the invention makes it possible to easily convert disilanes of general formula (II) with o≧1 into chlorosilanes of general formula (I) with n=2 to 4 at low temperatures.

[0109] (11) In a preferred embodiment of the process according to the invention, the reaction is carried out in the presence of one or more ether / HCl solutions which serve as reaction promoters F), preferably in the presence of a saturated ether / HCl solution.

[0110] The use of an ether / HCl solution as the reaction promoter F) has several advantages.

[0111] In particular, the handling of ether / HCl solutions is preparatively easy, and ether as a Lewis base activates hydrogen chloride to cleave disilanes A) of general formula (II) and chlorinated polysilanes D) and E) already at room temperature; increasing the reaction temperature is only recommended to complete the cleavage of disilanes and polysilanes and to shorten the reaction time. Thus, hexachlorodisilane, pentachlorodisilane and tetrachlorodisilane are reacted with ether / HCl solutions to obtain high yields of trichlorosilane, dichlorosilane and silicon tetrachloride already at room temperature. In such cleavage reactions using ether / HCl solutions, the protons of HCl promote the attack on silicon atoms with the highest degree of chlorination. As a result, dichlorosilane and trichlorosilane are formed by the cleavage of Cl2HSi-SiHCl2 (->H2SiCl2+HSiCl3) and Cl3Si-SiH2Cl (->HSiCl3+H2SiCl2), the amount of SiCl4 formed is mainly due to the cleavage of hexachlorodisilane (Cl3Si-SiCl3+HCl->HSiCl3+SiCl4), and HSiCl3 is quantitatively obtained by the cleavage of Cl3Si-SiHCl2.

[0112] If the starting material contains disiloxanes B) of general formula (III) or (IV), for example as contaminants of the high-boiling disilane fraction, they can be converted to monosilanes H by cleavage reaction with ether / HCl reagents. n SiCl 4-n (n=0-2) is a smaller siloxane [(H n Cl 3-n Si)2O(n=0,1)] and Si-O-containing polymers are simultaneously produced, which must be separated from the volatiles and transferred to deposition or high-temperature decomposition in order to produce essentially solid SiO2 plus SCl4 according to US 4,719,093.

[0113] Furthermore, highly viscous or solid chloropolysilanes, which are produced by the process according to the invention in an amount of about 15-20% by weight, based on the weight of the silicon-containing starting material, when amines, phosphines, ammonium or phosphonium salts are used as reaction promoters F), can be converted by reaction with ether / HCl solutions into monosilanes H n SiCl 4-n (n=0-2). In it, the necessary post-treatment procedures become increasingly difficult with the aging of the polymer. This requires higher cleavage temperatures (T>100 °C) and causes the formation of gaseous hydrogen. The unreacted dark brown polymer is incinerated or deposited, since this polymer sometimes ignites in air and / or causes violent explosions, even when treated with aqueous basic solutions to destroy the polymer. Treatment of the disilane mixture with ether / HCl solution directly prevents the formation of solid polymer, thus greatly minimizing the risk of fire and explosion.

[0114] Utilizing a saturated ether / HCl solution provides the maximum amount of HCl per volume unit of HCl solution, thus reducing the amount of ether required for the process. This helps to reduce the volume of the product stream and the size of the reactor used to carry out the process according to the invention, and also increases the reaction rate. Furthermore, utilizing a saturated or nearly saturated ether / HCl solution allows the process according to the invention to be carried out at low temperatures below 200°C, which is energy-saving compared to high-temperature post-treatment at 800 to 1300°C, and also reduces the material requirements of the reactor and allows the process to be carried out in reactors made of conventional materials.

[0115] Preferred ether / HCl solutions are HCl / nBu2O and HCl / 1,4-dioxane.

[0116] (12) In another preferred embodiment of the process according to the invention, the reaction is carried out in the presence of one or more ether / HCl solutions which serve as reaction promoters F), preferably in the presence of a saturated ether / HCl solution, and where no further reaction promoters F) are present in the reaction mixture.

[0117] Since HCl is the most economical hydrogen source for forming Si-H bonds during disilane cleavage, it may be desirable to select one or more HCl / ether solutions as reaction promoter F).

[0118] This is particularly preferred when the intermediate formation of polymeric products as described above must be avoided and when the introduction of additional hydrogen atoms into the reaction product via a redistribution reaction with additional Si-H containing compounds as hydrogen donors is not desirable or required due to the overall Si-H content of the constituents of the starting material composition matching the overall Si-H content of the chlorosilanes resulting from the process according to the invention.

[0119] (13) In another preferred embodiment of the process according to the invention, the reaction is carried out in the presence of one or more reaction promoters F) selected from the group of amines, phosphines, preferably chlorides, ammonium halides or phosphonium halides.

[0120] Compound H o SiCl 6-o (o=0-6), including Lewis bases such as triorganoamines and triorganophosphines, especially trialkylamines and trialkylphosphines, and the corresponding ammonium and phosphonium halides, especially ammonium and phosphonium chlorides. n SiCl 4-n Disilane cleavage of the pure high-boiling fraction free of (n=0-2) starts already at room temperature and is usually complete within 7 hours at 80 °C. As volatile product fractions, trichlorosilane is formed at about 70%, H2SiCl2 at about 3% and tetrachlorosilane at about 26%. The total amount of volatiles is more than 80%, with about 15 to 20% of a reddish-brown solid chloropolysilane mixture being formed at the same time. This mixture contains linear, cyclic and branched polymers. After separation of all volatiles from the product mixture by low-temperature distillation / condensation under reduced pressure, the volatiles are separated into monosilanes H n SiCl4-n (n=0,1,2) can be separated, for example by distillation under atmospheric pressure to reintroduce HSiCl3 into the CVD process; SiCl4 can be converted to HSiCl3 using silicon hydrides (see EP18193571.9). Solid silicon polymers can be obtained by the synthesis of monosilanes HSiCl3 using ether / HCl reagents under moderate conditions. n SiCl 4-n (n=0-2).

[0121] of the general formula H mixed with about 60% SiCl4 (and optionally residual HSiCl3). o SiCl 6-oWhen the effluent leaving the CVD reactor of the Siemens process containing disilanes A) (o=0-6) is used for chlorosilane production, silicon hydrides, such as dimethylsilane or diethylsilane, are added in such an amount that upon SiCl4 reduction by disilane cleavage and redistribution reaction, the target compound HSiCl3 is mainly formed. When organosilanes are added, chlorinated homologues, such as R2SiHCl (R=Me, Et) and R2SiCl2, are formed simultaneously and can be recycled, for example with LiH, to give silicon hydrides for use in the cyclic process. Et2SiH2 can be used because it is easy to handle as a liquid under normal pressure; when gaseous dimethylsilane Me2SiH2 is used, Me2SiHCl and Me2SiCl2, which are also valuable components in silicone production, are formed, thus increasing the overall economic value of the process. High-boiling hydridosilanes, such as phenylsilane, PhSiH3, or suitable methyldisilanes, can also be used as hydrogen-donating silicon hydrides. In these reactions, the use of a polar solvent such as high boiling diglyme, which facilitates the separation of the products, is recommended for better dissolution of the phosphonium / ammonium chlorides, but the presence of a solvent is not essential to carry out the cleavage / hydrogenation reaction. In general, the reactions of the method according to the invention work well without a solvent, and excess SiCl4 can be used as a solvent, while monopolar solvents such as benzene or other hydrocarbons require longer reaction times. In addition to the volatile monosilanes formed, solid chloropolysilanes are produced, which can be reconverted to monosilanes without aging using the ether / HCl reagent.

[0122] Preferred amines, phosphines, ammonium or phosphonium halides applied as reaction promoters F) are nBu3N, nBu3P, nBu4NCl or nBu4PCl.

[0123] (14) In yet another preferred embodiment of the process according to the invention, the process is carried out in the absence of an ether / HCl solution.

[0124] If there is a large amount of hydridomonosilanes in the starting material, it is preferable to carry out the process in the absence of ether / HCl solution, because phosphines, amines, and ammonium and phosphonium halides act as chlorination catalysts when HCl is present in the reaction mixture. Thus, if the reaction is prolonged, the hydridomonosilanes are gradually chlorinated.

[0125] (15) In a preferred embodiment of the process according to the invention, the one or more reaction promoters F) are represented by the formula R4XCl, where X=N or P, and R is independently a hydrogen or organyl group, more preferably a hydrogen, aromatic or aliphatic hydrocarbon group.

[0126] Examples of such preferred reaction promoters F) are nBu4NCl and nBu4PCl.

[0127] (16) In a further preferred embodiment of the process according to the invention, one or more reaction promoters F) of formula R4XCl, where X=N or P, are formed in situ from compounds of formula R3X, where R is as defined above.

[0128] As used herein, R independently represents hydrogen or any organyl group as defined above. More preferably, R independently represents hydrogen or an alkyl, cycloalkyl, aryl or alkaryl group of from about 1 to about 30 carbon atoms, preferably from about 2 to about 16 carbon atoms.

[0129] Such reaction promoters F) can be formed by adding HCl, preferably as part of an HCl / ether solution, or an organic chloride to an amine or phosphine of general formula R3X in the reaction mixture, without any particular order of addition.

[0130] This embodiment also includes in particular that the reaction of the process according to the invention is carried out with a mixture of a phosphine R3P, where R is as defined above, for example n-Bu3P, and HCl, preferably in an ether solvent.

[0131] Examples of such compounds are tributylammonium chloride and tributylphosphonium chloride, which can be formed in a reaction mixture by combining HCl / ether and tributylamine or tributylphosphine, respectively.

[0132] Further examples are tetra(n-butyl)phosphonium chloride, methyltri(isobutyl)phosphonium chloride, tetra(n-octyl)phosphonium chloride, tri(n-butyl)tetradecylphosphonium chloride, and octyltri(butyl)phosphonium chloride, tetramethylphosphonium chloride, tetraethylphosphonium chloride, and tetrapropylphosphonium chloride.

[0133] (17) In another preferred embodiment of the process according to the invention, the reaction promoter F) is selected from the group consisting of nBu3P, nBu3N, nBu4PCl and nBu4NCl.

[0134] These reaction promoters F) have been demonstrated to effectively accelerate the process according to the invention, are readily available at low cost and can therefore be considered as suitable agents from an economic point of view.

[0135] In general, the amines, phosphines, ammonium halides, and phosphonium halides, especially nBu3P, nBu3N, nBu4PCl, and nBu4NCl, are well soluble in silanes and ethers, and the phosphines and amines in particular are easy to handle on a large scale because they are liquids. They can therefore be pumped into pipelines to ensure handling under inert conditions, and they are less reactive to moisture than, for example, nBu4PCl, which is highly reactive to moisture and forms an oxide within seconds in ambient air.

[0136] More reactive ammonium and phosphonium halides are generally more effective as promoters F) and therefore usually require lower reaction temperatures in the redistribution reaction. The solubility of the ammonium and phosphonium halides can be increased by selecting long-chain alkyl residues as the organic residue R.

[0137] (18) In a preferred embodiment of the process according to the invention, the reaction is carried out in the presence of one or more additional compounds containing at least one Si-H bond selected from monosilanes G) and disilanes H), preferably in the presence of one or more additional organohydridosilanes, more preferably in the presence of one or more hydridomethylsilanes, even more preferably in the presence of one or more organohydridosilanes selected from methylsilane, dimethylsilane or trimethylsilane, most preferably in the presence of dimethylsilane.

[0138] The overall hydrogen content of the product of the process of general formula (I) can be increased by increasing the amount of silanes having one or more Si-H bonds in the reaction mixture. Thus, hydridochlorodisilanes, or in the case of reaction promoter F), which are also effective as redistribution promoters, can be added to hydridosilanes to increase the average number of Si-H bonds in the product silanes of general formula (I).

[0139] When the Siemens process by-product mixture is used as the starting material, the amount of silane in the starting material having Si-H bonds is predetermined by the parameters used in the Siemens process or, if the effluent from the Siemens process CVD reactor is subjected to fractional distillation before further processing, by the selection of the fraction used as the starting material. If the content of Si-H bonds in the silane starting material obtained from the Siemens process is too low to obtain the desired degree of hydrogen substitution of the product monosilane of general formula (I), the process can be optimized by adding hydridomonosilanes and / or hydridodisilanes to the reaction mixture that provide additional Si-bonded hydrogen atoms.

[0140] Preferably, the additional Si-H-containing compound is a monosilane or disilane having both hydrido and organic substituents, since such compounds are easier to handle than silanes that do not contain organic residues, and the reaction by-products obtained from the reaction of these reagents usually have high boiling points and can be separated from the target monosilane of general formula (I) by distillation. Furthermore, the by-products obtained from the conversion of the organohydridosilanes added to the reaction mixture as hydrogen donors, organochlorosilanes and / or difunctional organohydridochlorosilanes, are valuable compounds in themselves for the preparation of silicones and polyorganosiloxanes.

[0141] For example, if the starting material composition of the process according to the invention comprises a Siemens process by-product mixture containing, in addition to disilane of general formula (II), a large amount of SiCl4, and it is desired to obtain trichlorosilane as the main product of the process, then a sufficient amount of dimethylsilane can be added to the reaction mixture to convert silicon tetrachloride to trichlorosilane, according to the following reaction: SiCl4+Me2SiH2->HSiCl3+Me2SiHCl Or alternatively: 2SiCl4+Me2SiH2->2HSiCl3+Me2SiCl2

[0142] Similarly, silicon tetrachloride produced from the cleavage of hexachlorodisilane or the dehydrogenation of HSiCl in the process according to the invention can be converted to trichlorosilane or dichlorosilane by adding a sufficient amount of an appropriate hydridosilane, preferably a hydridoorganosilane, more preferably hydridomethylsilane.

[0143] (19) In a further preferred embodiment according to the invention, the starting material composition comprises at least 40% by weight of SiCl4 and the reaction is carried out in the presence of at least one additional compound containing at least one Si-H bond selected from monosilanes G) and disilanes H), preferably in the presence of one or more organohydridosilanes or organohydridodisilanes, more preferably in the presence of one or more methylhydridosilanes or methylhydridodisilanes, most preferably in the presence of dimethylhydridodisilanes.

[0144] In most cases, it is desirable to obtain trichlorosilane or dichlorosilane as the main product of the process according to the invention.Therefore, the presence of a large amount of silicon tetrachloride, for example at least 40% by weight of the starting material composition, requires the addition of a suitable hydrogen donor to the reaction mixture to achieve the exchange of chlorine atoms with hydrogen atoms.In addition to the Si-H bond-containing monosilane G) and disilane H), which are obtained, for example, from fractional distillation of the effluent leaving the Siemens process reactor, preferably, organohydridosilane or organohydridodisilane is applied, more preferably, methylhydridosilane or methylhydridodisilane is applied, and most preferably, dimethylhydridodisilane is applied as a reagent to increase the amount of Si-H bonds in the reaction mixture and thus in the silane of general formula (I) obtained as product.

[0145] (20) In another preferred embodiment of the process according to the invention, SiCl4, HSiCl3 and H2SiCl2 are obtained as the main products by weight of the process, preferably HSiCl3 is obtained as the main product by weight.

[0146] The product distribution of the process according to the invention is determined by the distribution of components in the starting material composition, in particular the amount of Si-H bonds found in the starting material silane, the type of reaction promoter F) applied, and the presence of additional Si-H bond-containing compounds acting as hydrogen donors.

[0147] In order to obtain trichlorosilane as the main product, it is preferable to select a starting material with a high content of pentachlorodisilane. When an ether / HCl solution is applied as reaction promoter F), pentachlorodisilane is quantitatively cleaved to produce HSiCl3 in the process according to the invention. Alternatively, further Si-H bond-containing starting materials and reaction promoter F) that can promote the redistribution of hydrogen atoms to SiCl4 present as starting materials or as intermediates from the cleavage of hexachlorodisilane, perchlorinated oligosilanes and polysilanes, or hexachlorodisiloxane during the reaction, are added to the reaction mixture of the process according to the invention.

[0148] (21) In a preferred embodiment of the process according to the invention, the SiCl4 obtained in this way is preferably converted in the same step or in a subsequent step into HSiCl3 by a redistribution reaction with a silicon hydride compound, more preferably with a Si-H bond containing compound G) or H).

[0149] As already mentioned above, SiCl4 may constitute the main component of the starting material composition, especially when the effluent from the CVD reactor of the Siemens process is used as the starting material. Likewise, large amounts of SiCl4 may be formed during the process, for example in the cleavage of hexachlorodisilane or perchlorinated oligo- and polysilanes.

[0150] To obtain HSiCl3 as product of the process according to the invention, the SiCl4 present in the reaction can be converted to HSiCl3 by adding a sufficient amount of one or more silicon hydride compounds, in particular hydridomonosilanes G) or hydridodisilanes H), in the presence of a reaction promoter F) capable of promoting the redistribution of hydrogen atoms bonded to the Si atoms and Cl atoms bonded to the Si atoms of the silanes present in the reaction mixture. Such reaction promoters F) according to the invention are amines, phosphines, phosphonium halides and ammonium halides.

[0151] Alternatively, the SiCl4 present in the product mixture of the process according to the invention described so far can be separated from the product mixture, in particular by fractional distillation, and then subjected separately to a redistribution reaction with a silicon hydride compound in order to obtain HSiCl3 as further product of the process.

[0152] (22) In further preferred embodiments of the process according to the invention, more than 40% of the Si atoms of the starting material composition are converted to HSiCl3, preferably more than 50% of the Si atoms of the starting material composition are converted to HSiCl3, more preferably more than 60% of the Si atoms of the starting material composition are converted to HSiCl3, and most preferably more than 70% of the Si atoms of the starting material composition are converted to HSiCl3.

[0153] The main objective of the present invention is to convert the mixture of hydridodisilane and optionally other silane and siloxane compounds as effectively as possible into the desired monochlorosilane of general formula (I) in order to provide an economically and ecologically advantageous process, which is particularly valuable when the by-product mixture of the Siemens process is used as the starting material composition. The effective recycling of these wastes is a long-standing problem, which also includes the problem of avoiding hazards when handling these materials. The effectiveness of a process directed at this problem can be measured by its atom economy, and therefore it is desirable to convert as many Si atoms of the starting material composition as possible into chlorosilanes of general formula (I). In general, the most desirable monosilane of formula (I) obtained from the process according to the invention is HSiCl3.

[0154] (23) In a further preferred embodiment of the process according to the invention, the reaction is carried out in the presence of one or more reaction promoters F) selected from amines, phosphines, ammonium halides or phosphonium halides, followed by removal of the volatile substances and subsequent conversion of the remainder to monosilanes by treatment with an ether / HCl solution.

[0155] Carrying out the reaction of the method according to the invention in the presence of one or more reaction promoters F) selected from amines, phosphines, ammonium halides or phosphonium halides not only allows the cleavage of hydridodisilanes and further substrates containing Si-Si and Si-O bonds, but also allows the redistribution of Si-bonded hydrogen atoms from silicon hydrides, in particular from components G) and H), to the perchlorinated silanes present in the reaction mixture. On the other hand, it has been found that the application of reaction promoters F) selected from amines, phosphines, ammonium halides or phosphonium halides leads to the formation of solid chloropolysilanes, which are obtained as residue after removal of volatiles from the product mixture.

[0156] (24) In another preferred embodiment of the process according to the invention, no additional solvent is used.

[0157] According to the present invention, the term "additional solvent" applies to all reagents which are liquid under normal and / or reaction conditions and which are not silane or siloxane compounds included in the definition of any of components A) to E) or H) and G) and which do not fall within the definition of reaction promoter F), in particular not falling within the definition of an HCl / ether solution.

[0158] (25) In yet another preferred embodiment of the process according to the invention, the reaction is carried out in the presence of an organic solvent, preferably a high-boiling ether compound, more preferably diglyme or tetraglyme, most preferably diglyme.

[0159] According to the present invention, the term "organic solvent" refers to any organic compound or mixture of compounds that is in liquid state at room temperature and is suitable as a medium for carrying out the reactions of the method. The organic solvent is therefore preferably inert to the reaction promoter F) applied according to the present invention under the reaction conditions. Furthermore, the starting materials of general formulae (II)-(VIII) and the products of general formula (I), respectively, are preferably soluble in the organic solvent or are fully miscible with the solvent.

[0160] Preferably, the organic solvent is selected from, but not limited to, optionally substituted, preferably unsubstituted, linear or cyclic aliphatic hydrocarbons, aromatic hydrocarbons or ether compounds, the term "ether compound" being defined above.

[0161] In the sense of the present invention, the term "high boiling ether compound" is defined as an ether compound according to the above definition having a boiling point at 1 bar (atmospheric pressure) of preferably at least about 30°C, more preferably at least about 60°C, even more preferably at least about 80°C, and most preferably at least about 100°C.

[0162] The application of high boiling ethers in the present invention is advantageous because it facilitates the separation of the desired products of general formula (I) from the reaction mixture containing the solvent and, under certain circumstances, residual starting materials. The products of general formula (I) generally have a lower boiling point than the starting materials, and the boiling points of these products are also lower than the boiling points of the high boiling ethers as defined above.

[0163] For example, the boiling point of the product of general formula (I) is about 8° C. (H2SiCl2), about 32° C. (HSiCl3), or about 58° C. (HSiCl3) under normal conditions, while the representative high-boiling ether solvent diglyme has a boiling point of about 162° C., and the boiling points of the isomeric mixture of hexachlorodisilane, pentachlorodisilane, and tetrachlorodisilane, which are preferred substrates of general formula (II), are about 145° C. at 760 mbar (Si2Cl6), 40-41° C. at 35 hPa (Si2HCl5), and 29-30° C. at 35 hPa (Si2H2Cl4). The application of higher boiling ether compounds as solvents allows for the utilization of higher reaction temperatures and simplifies the separation of the desired product from the reaction mixture by distillation.

[0164] It should be noted that the choice of the most preferred solvent also depends on the reaction promoter F) applied. 1,4-dioxane and nBu2O are stable when used as solvents or ethers in reactions applying HCl / ether solutions as reaction promoter F), whereas diglyme decomposes upon removal of MeCl and is therefore not preferred under these conditions. When amines, phosphines, ammonium halides or phosphonium halides are used as reaction promoters, diglyme is particularly preferred due to its stability under the reaction conditions, high boiling point and low hazard.

[0165] (26) In another preferred embodiment of the process according to the invention, the organic residue R of the silicon hydrides G) and H) is an alkyl or aryl group, more preferably a C1-C6 alkyl group, most preferably a methyl group.

[0166] The silicon hydrides G) and H) applied in the process according to the invention are selected depending on the content of Si-H bonds, the desired properties, such as, for example, boiling point, and having regard to the products obtained by the process.

[0167] In general, organosilicon hydrides of general formulae (VII) and (VIII), i.e., silicon hydrides having at least one organic residue R, are preferred, mainly because they have a lower tendency to ignite and are easier to handle compared to the analogous hydridomono- and hydridodisilanes that do not contain organic residues, since these compounds have higher boiling points than their unsubstituted analogues. The higher boiling points of the compounds also make it easier to separate the silicon hydrides (VII) and (VIII) and their derivatives contained in the product mixture from the desired product of the process having general formula (I).

[0168] The choice of the particular silicon hydrides G) and H) for the process according to the invention also depends on the availability and cost of monosilane G) and disilane H), respectively. For this reason, silicon hydrides G) and H) with a residue R that is an alkyl or aryl group, in particular a C1-C6 alkyl or phenyl group, are the preferred reactants for the process according to the invention. Silicon hydrides G) and H) with methyl substituents are most preferred, since these are the most technically relevant and industrially most commonly used compounds.

[0169] Another factor to be taken into account in the selection of monosilanes G) and H) is that the reaction of these additional compounds in the process according to the invention produces products that are valuable compounds in themselves. For example, chlorine / hydrogen exchange of dimethylsilane produces dimethylchlorosilane, likewise dimethylchlorosilane produces dimethyldichlorosilane, and application of methylsilane produces methylchlorosilane, methyldichlorosilane or methyldichlorosilane as by-products. Similarly, application of 1,1,2,2-tetramethyldisilane leads to the production of 1,1,2,2-tetramethyldichlorodisilane and dimethylchlorosilane / dimethyldichlorosilane (in small amounts) as by-products of the process according to the invention, and application of 1,2-dimethyldisilane leads to the formation of trichloromethylsilane, dichloromethylsilane, and chloromethylsilane, respectively. The formation of such by-products may contribute to the overall cost-effectiveness of the process according to the invention.

[0170] (27) In a preferred embodiment of the process according to the invention, the process is carried out under inert conditions.

[0171] In the sense of the present invention, the term "carried out under inert conditions" means that the method is carried out partially or completely with the exclusion of ambient air, in particular moisture and oxygen. To exclude ambient air from the reaction mixture and reaction products, a closed reaction vessel, reduced pressure and / or an inert gas, in particular nitrogen or argon, or a combination of such means can be used.

[0172] (28) In a further preferred embodiment of the process according to the invention, the reaction of the process is carried out at a pressure of 0.01 to 10 MPa, more preferably 0.05 to 1.0 MPa.

[0173] The pressure ranges indicated refer to the pressures measured in the reaction vessel used when carrying out the reactions of the process according to the invention.

[0174] (29) In another preferred embodiment of the process according to the invention, the reaction of the process is followed by a step of separating the obtained monosilane of general formula (I) by distillation, low-temperature condensation, or a combination thereof.

[0175] Particularly preferably, the distillation step also comprises the separation of organomonosilanes substituted with organic residues, originating from compounds G) and H), respectively, involved in the process according to the invention.

[0176] The term "distillation" in the sense of the present invention relates to any method for separating components or substances from a liquid mixture by selective evaporation and condensation, where distillation can result in a substantially complete separation of the components of the mixture, thus leading to the isolation of a nearly pure compound, or it can be a partial separation that increases the concentration of selected components of the mixture in the distillate when compared to the mixture subjected to distillation.

[0177] Preferably, the distillation method can be simple distillation, fractional distillation, vacuum distillation, short path distillation, or other types of distillation known to those skilled in the art.

[0178] Also preferably, the step of separating the monosilane of formula (I) according to the present invention from other compounds of the product mixture and / or from each other may comprise one or more batch distillation steps or may comprise a continuous distillation process.

[0179] More preferably, the term "low temperature condensation" may include separation or concentration of one or more compounds of general formula (I) from the reaction mixture by volatilization from the reaction vessel and condensation as liquid and / or solid in a cooling vessel from which it can then be recovered by distillation or by dissolving in an ether solvent. Alternatively, the monosilane may be absorbed in an ether solvent contained in the cooling vessel.

[0180] (30) In yet another preferred embodiment of the process according to the invention, the starting material composition comprises one or more disiloxanes B).

[0181] Disiloxane B) may be a component of the starting material composition and may be formed from monosilane and / or disilane when exposed to moisture, for example in the Siemens process when moisture enters the reactor in either the starting material stream or moist ambient air.

[0182] In such cases, disiloxanes are included in the effluent stream leaving the Siemens process CVD reactor, where the disiloxane content may vary. Similarly, disiloxanes may be formed during handling and storage of the Siemens process by-product mixture. By the process according to the invention, disiloxane B) is converted to monosilanes of general formula (I) at low temperatures.

[0183] (31) In yet another preferred embodiment of the process according to the invention, the starting material composition comprises one or more perchlorinated oligosilanes and polysilanes D).

[0184] Perchlorinated oligo- and polysilanes D) may be present in the starting materials of the process according to the invention, in particular because they may be formed during the Siemens process and, in such a case, are included in the effluent stream leaving the Siemens process CVD reactor, where the specific content of perchlorinated oligo- and polysilanes D) in the by-product mixture of the Siemens process may vary. By the process according to the invention, the perchlorinated oligo- and polysilanes D) are converted at low temperatures into monosilanes of general formula (I).

[0185] (32) In a preferred embodiment of the method according to the invention, the starting material comprises one or more chloro-, hydrido- and hydroxy-substituted polysilanes E), including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes.

[0186] Chloro-, hydrido- and hydroxy-substituted polysilanes E), including linear, branched, cyclic and cage-shaped chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, may be present in the starting materials of the process according to the invention, in particular because such polysilanes E) may be formed during the Siemens process and, in such a case, are included in the effluent stream leaving the Siemens process CVD reactor, where the specific content of polysilanes E) in the by-product mixture of the Siemens process may vary. Chloro-, hydrido- and hydroxy-substituted polysilanes E) may also be formed during handling and storage of the by-product mixture of the Siemens process. By the process according to the invention, chloro-, hydrido- and hydroxy-substituted polysilanes E), including linear, branched, cyclic and cage-shaped chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, are converted at low temperatures into monosilanes of general formula (I). Such a facile conversion of polysilanes E) is highly desirable, since many of these compounds are potentially hazardous due to their explosiveness, especially upon aging, and usually require energy-consuming high-temperature processes for conversion to silanes or are disposed of by combustion.

[0187] (33) In another preferred embodiment of the process according to the invention, the starting material composition consists of Siemens process by-products obtained as effluent leaving the Siemens process CVD reactor.

[0188] The process according to the invention is particularly suitable for converting the by-products of the Siemens process into the desired chloromonosilanes of general formula (I).

[0189] In this embodiment of the method, no further silicon-containing compounds are added to the by-product mixture that serves as the starting material composition, and the components of the effluent leaving the Siemens process CVD reactor are not removed by distillation, conversion or other means before being subjected to the method according to the invention.This is advantageous in this respect, since if the by-product mixture stream is led directly to the reaction unit of the method according to the invention when it leaves the Siemens process reactor, intermediate treatment or storage of the by-product mixture can be avoided.Furthermore, no technical equipment is required for removing specific fractions or components of the by-product mixture before carrying out the reaction according to the invention, or for adding additional Si-H-containing compounds G) or H) to the starting material composition.

[0190] (34) In a further preferred embodiment of the process according to the invention, the starting material composition consists of a by-product of the Siemens process obtained as effluent leaving the CVD reactor of the Siemens process, which is subjected directly to the process.

[0191] By subjecting the by-product mixture of the Siemens process directly to the process according to the invention, it is possible to avoid further handling and / or storage of the by-product mixture, which significantly reduces the risk of formation of "popping gels" formed by contacting the chlorinated and partially hydrogenated silanes, oligosilanes and polysilanes with moisture and oxygen, especially during long-term storage and aging of the by-product mixture. By directly converting the Siemens by-product mixture, potentially hazardous compounds contained in the effluent leaving the CVD reactor of the Siemens process are directly converted to the desired chloromonosilanes of general formula (I) and the formation of further hazardous compounds and mixtures is prevented.

[0192] (35) In a further preferred embodiment of the process according to the invention, the starting material composition consists of by-products of the Siemens process obtained as effluent leaving a CVD reactor of the Siemens process, which are subjected to the process after intermediate storage.

[0193] In many cases, it is unavoidable to store the by-product mixture of the Siemens process before further processing. In such cases, the process according to the invention is a valuable method for converting the by-product mixture, potentially containing potentially dangerous compounds generated by prolonged contact of the by-product mixture with moisture and / or oxygen, into chloromonosilanes of general formula (I), which is done at low temperatures, therefore with relatively low energy consumption and without the need for expensive reactors designed to carry out high temperature processes containing corrosive compounds. EXAMPLES

[0194] The present invention is further illustrated by the following examples, but is not limited thereto.

[0195] General: Disilane H o SiCl 6-oSix different samples were investigated for the low-temperature conversion of (n=0-6) to trichlorosilane. Silane mixture 1 contains the effluent leaving the Siemens process CVD reactor and contains tetrachlorosilane (63.5 mol-%) as the main component, in addition to unreacted trichlorosilane (2.0%) and some disilanes. Silane mixture 2 does not contain the two monosilanes mentioned above and consists only of disilanes with pentachlorodisilane (67.5%) as the main component. Silane mixture 3 consists of disilane mixture 2 mixed with SiCl4 (45.8%) and diethylsilane (Et2SiH2, 40%), silane mixture 4 treats silane mixture 2 mixed with Si2Cl6 (43%) and mixture 5 consists of silane mixture 4 with 33.3% elevated Si3Cl8 as the main component of the fraction. Silane mixture 6 contains hydridochlorodisilanes, Si2Cl6 and perchlorinated polysilanes. Except for mixture 3, mixtures 1, 2, and 4-6 represent various fractions obtained from the Siemens process. It should be noted that the molar amounts of components in the technical disilane fraction can vary depending on the various reaction conditions under which the Siemens process is carried out. This does not change the nature of the products formed, but leads to different molar ratios of the components. Thus, the cleavage of di-, oligo-, and polysilanes essentially leads to the formation of trichlorosilanes and silicon tetrachloride, with some dichlorosilanes in various molar ratios. Based on the results of the di-, oligo-, and polysilane cleavage reactions carried out and described in this application and on the knowledge of the composition of the high boilers of the Siemens process as starting materials, the expert in this field can predict the formation of products and their molar ratios. If the reactions described below give highly viscous or solid polysilanes, the subsequent reaction of these compounds with an ether / HCl solution always gives an almost quantitative HSiCl3 / SiCl4 mixture, but with different molar ratios with respect to the monosilanes. Reaction of silane mixture 1 was carried out in the presence of additional hydridosilane, e.g., diethylsilane, to obtain high yields of the target compound trichlorosilane from disilane cleavage and simultaneous selective reduction of SiCl4 to produce HSiCl3. Et2SiH2 was used in the experiments because it is easy to handle as a liquid under normal conditions.Other hydridosilanes can be used to simplify the separation of the products by distillation, due to the different boiling points of the reaction partners and products. The monosilane-free disilane mixture 2 was directly reacted with the reaction promoter F) to obtain a mixture of HSiCl3 and SiCl4 in addition to about 15-20 w% solid chloropolysilanes (based on the total weight of the disilane starting material). As already mentioned, solid chloropolysilanes react easily with the ether / HCl reagent. The direct reaction of the silane mixture 2 with ether / HCl as reaction promoter F) leads to the production of trichlorosilanes in up to 90% yield already at room temperature, without the formation of solid polysilanes. For the preparation of various ether / HCl solutions, see: AG Sturm et al, Lewis Based catalyzed selective Chlorination of Monosilanes, Chem. Eur. J. 2018, 24, 17796-17801.

[0196] The reactions were carried out in an NMR tube by mixing the reaction partners dissolved in C6D6 or a high boiling ether, e.g. diglyme, and the reaction promoter F). Due to the low solubility of phosphonium chloride and ammonium chloride in monopolar solvents (such as benzene), the reaction in diglyme as solvent is preferably recommended. After cooling the sample with liquid nitrogen (-196 °C), the NMR tube was evacuated under vacuum (about 0.1 mbar) and sealed to prevent the loss of low boiling monosilanes, e.g. HSiCl3 (boiling point 32 °C under normal conditions), H2SiCl2 (boiling point 8 °C under normal conditions), H3SiCl (boiling point -30 °C under normal conditions), SiH4 (boiling point -112 °C under normal conditions) and HCl (boiling point -85 °C under normal conditions, but soluble in ether for easy handling). The boiling point of SiCl4 is 57 °C under normal conditions. NMR spectra were recorded to elucidate the optimal reaction conditions in terms of reaction time and reaction temperature. The molar ratios of the products formed were determined by the integration of the NMR signals assigned to specific products within the mixture. The optimal reaction conditions were then transferred to a preparative scale in either closed glass ampoules or open systems.

[0197] Compound Identification The product is 1 H and 29 The compounds were analyzed by Si NMR spectroscopy. The spectra were recorded on a Bruker AV-500 spectrometer equipped with a Prodigy BBO 500 S1 probe.

[0198] of starting materials and reaction products formed 29 Si NMR chemical shifts and coupling constants 1 J 29 Si- 1 H} are shown in Table 1. Spectroscopic data for the silane starting material and the products formed are in agreement with published values. [Table 1]

[0199] Starting materials: Disilane mixtures 1 and 2 [Table 2]

[0200] Example 1): Reaction of effluent 1 with Et2SiH2 in the presence of different catalysts and C6D6 as solvent Preparation of stock solution: 1.9 ml of silane mixture 1 (silane distribution shown in Table 2) was mixed with 0.8 ml of Et2SiH2 and 2.8 ml of C6D6.

[0201] 0.55 ml of the stock solution and catalytic amounts (5-10 mol % based on the molar amount of silane in the starting material reacted) of nBu4PCl, nBu4NCl, nBu3P and nBu3N, respectively, were mixed in an NMR tube. The NMR tube was cooled to -196 °C, evacuated and sealed. Samples were reacted and analyzed by NMR spectroscopy, and the results are shown in Table 3. Notably, in all experiments, a small amount of reddish-brown polymeric solid was formed (15-20 w % based on the total weight of the disilane starting material). [Table 3]

[0202] After the sample was heated to 120°C, the NMR tube was opened to separate the solution from the solid that had formed. The liquid phase was transferred to a new NMR tube, and 5 mol% of the corresponding catalyst (based on the molar amount of disilane starting material used in the first place) was added again. The NMR tube was sealed and heated according to Table 4. [Table 4]

[0203] In a non-polar solvent (C6D6), the cleavage of disilane and reduction of SiCl4 with nBu3P and nBu3N occurred only slowly and stopped at 120 °C to give 20-26 mol% HSiCl3 (in the liquid phase of the product mixture). With phosphonium chloride catalysis, 66% HSiCl3 was obtained and Et2SiH2 was completely consumed to give Et2SiCl2. In all other cases, Et2SiH2 still remained in the reaction mixture and chlorination led to the formation of Et2SiHCl.

[0204] To cleave the polymer residue, all solids were combined in an NMR tube cooled to -196°C. Subsequently, 0.5 ml of 5M HCl / 1,4-dioxane solution was added and the NMR tube was evacuated and sealed. Heating the sample at 80°C for 2 h resulted in almost quantitative cleavage of the polymer residue and only small amounts of unreacted solid particles remained (approximately 10 wt%). NMR spectroscopic analysis of the sample revealed the following product distribution in the liquid phase: 64.7% SiCl4, 35.3% HSiCl3.

[0205] Example 2): Reaction of disilane mixture 2 with different cleavage catalysts in C6D6 as solvent Disilane mixture 2 (silane distribution shown in Table 2) and 0.2 ml of catalytic amount (5-10 mol %, based on the molar amount of silanes put into the reaction as starting materials) of each of nBu4PCl, nBu4NCl, nBu3P, and nBu3N were mixed with 0.4 ml of C6D6 as solvent in an NMR tube. The NMR tube was cooled to -196°C, evacuated, and sealed. The sample was started at room temperature (rt) and heated to 80°C for completion. Analysis by NMR spectroscopy was according to Table 5. [Table 5]

[0206] All samples were reacted already at room temperature to produce HSiCl3 (in the liquid phase) at about 70 mol%, and then heated to 80 °C to complete the cleavage of the disilane, ultimately producing the by-product SiCl4 at about 27 mol%. In all reactions, brown solid polymers were formed at 15-20 w% (based on the total weight of the disilane starting material) and were separated from the volatiles by cryogenic distillation / condensation in vacuum (0.1 mbar). Ether / HCl cleavage of the polymer gave a HSiCl3 / SiCl4 mixture in a molar ratio of 36 / 64.

[0207] Example 3): Reaction of chlorosilane / Et2SiH2 mixture (3) in the presence of different catalysts and diglyme as solvent Preparation of stock solution: 0.5 ml of disilane mixture 2 (silane distribution shown in Table 2) was mixed with 0.9 ml of SiCl4, 0.6 ml of Et2SiH2, and 1.0 ml of C6D6. The resulting silane distribution for this sample is shown in Table 6. [Table 6]

[0208] 0.2 ml of the chlorosilane / Et2SiH2 mixture 3 (silane distribution shown in Table 6) and catalytic amounts (5-10 mol % based on the molar amount of starting silanes being reacted) of each of nBu4PCl, nBu4NCl, nBu3P, and nBu3N were mixed with 0.4 ml of diglyme as solvent in an NMR tube. The NMR tube was cooled to -196°C, evacuated, and sealed. Samples were heated and analyzed by NMR spectroscopy, the results of which are shown in Table 7. [Table 7]

[0209] Disilane cleavage and SiCl4 hydrogenation started at room temperature, and Et2SiH2 was already completely consumed at 80 °C using phosphonium chloride and ammonium chloride as catalysts. Et2SiHCl was formed at 80 °C, while at 120 °C it reacted completely to Et2SiCl2. n-Tributylphosphine and n-tributylamine showed a decrease in efficiency even at 160 °C, and Et2SiHCl was still present in the mixture. With nBu3N, Et2SiCl2 was not formed at all, while for phosphines the molar ratio of HSiCl3 in the liquid phase was 63 mol%, and for amines it was 38 mol%. To show the influence of polar solvents on the cleavage / hydrogenation reactions, silane mixture 3 was reacted equivalently with nBu3P in 0.4 ml of C6D6 instead of diglyme as solvent. At 160°C, HSiCl3 was formed at about 33 mol% (instead of 63 mol% with diglyme), SiCl4 remained at 38 mol% (8 mol% with diglyme), and Et2SiH2 remained unreacted at 19 mol%. The product distribution is shown in Table 8. In this series of experiments, solid polymer was formed at about 15 w% based on the disilane reacted as the reactive starting material. [Table 8]

[0210] Example 4): Si2Cl6 with nBu3P as cleavage catalyst * Reaction of HSi2Cl5 with ( * (Reaction not according to the present invention) Si2Cl6 * 0.2 ml of catalytic amount (5-10 mol % based on the molar amount of Si2Cl6 in the starting material reacted) of nBu3P was mixed with 0.45 ml of C6D6 as solvent in an NMR tube. The NMR tube was cooled to -196 °C, evacuated and sealed. The mixture was reacted at room temperature for 12 hours and analyzed by NMR spectroscopy. The experiment was repeated similarly using HSi2Cl5 instead of Si2Cl6. The product distribution is shown in Table 9. [Table 9]

[0211] Hexachlorodisilane was almost completely cleaved, and rearrangement by Lewis base catalyst gave SiCl4 (96 mol% in the liquid phase) and about 2 mol% neo-Si5Cl. 12 While only HSiCl3 is produced, this overchlorinated precursor does not yield HSiCl3. Instead, pentachlorodisilane produces approximately 69 mol% HSiCl3 in the liquid phase, proving that the hydride substituents on the disilane backbone are required to form the desired compounds upon disilane cleavage. In both reactions, reddish-brown chlorinated polysilanes are formed as by-products (see Example 5).

[0212] Example 5): Synthesis of HSiCl3 from disilane mixture 2 on a preparative scale 14.78 g of disilane mixture 2 (disilane distribution is given in Table 2) was placed in a Schlenk flask connected to a distillation apparatus and a receiving flask. The disilane mixture was cooled to -196 °C, followed by the addition of 0.73 g (4.9 wt%) of nBu3P. When the reaction mixture was warmed to room temperature, the solution turned orange and the disilane had already started to cleave. The reaction mixture was slowly heated to 130 °C over 1 h, and the formed volatiles were continuously evaporated and trapped in the receiving flask (-196 °C). 11.95 g of low boiling volatiles were separated in the cooled receiving flask and analyzed by NMR spectroscopy. The product distribution is given in Table 10 and the corresponding29 The SiNMR spectrum is shown in Figure 2.

[0213] 2.65 g of a reddish-brown polymeric solid (17.9 wt % of the starting disilane mixture; excluding 0.73 g of nBu3P used) remained in the reaction flask, which is insoluble in common organic solvents. [Table 10]

[0214] The remaining solid was reacted with 20 ml of a 5 molar solution of HCl in 1,4-dioxane in a sealed glass ampoule fitted with an NMR tube at 120 °C for 48 h, resulting in an orange solution and a dark brown solid residue. After the product mixture was cooled to room temperature, 0.8 ml of the orange liquid phase was poured into the fitted NMR tube. The ampoule and NMR tube were frozen, and the NMR tube was removed. The product solution was analyzed by NMR spectroscopy and consisted of 35.4 mol % HSiCl3 and 64.6 mol % SiCl4.

[0215] Example 6): Reaction of silane mixture 1 with methylhydridodisilanes Me2Si2H4 and Me4Si2H2 in the presence of nBu4PCl and C6D6 as solvent 0.25 ml of silane mixture 1 (distribution of monosilanes and disilanes is shown in Table 2), 0.1 ml of tetramethyldisilane (Me2HSi-SiHMe2), and 10 wt% nBu4PCl (based on the total weight of the disilane starting material) were mixed with 0.35 ml of C6D6 as solvent in an NMR tube (cooled to -196°C). The NMR tube was evacuated and sealed. The mixture was heated according to Table 11 and analyzed by NMR spectroscopy. The experiment was repeated similarly using dimethyldisilane (MeH2Si-SiH2Me, 0.05 ml) instead of tetramethyldisilane. The product distribution is shown in Table 11. [Table 11]

[0216] Both methylhydridodisilanes react as hydrogen transfer agents, producing 17 mol % and 29 mol % HSiCl3 (in the liquid phase) after 30 min at 80 °C, respectively, and their corresponding chlorides. n SiCl 4-n The formation of (n=0-4), MeSiCl3, and MeSiHCl2 demonstrates the comparison of disilane cleavage, hydrogenation, and redistribution reactions using dimethyldisilane for Si-Cl reduction. Heating a sample containing tetramethyldisilane at 120 °C for 48 h resulted in quantitative chlorination of methyldisilane and an increase in the formation of HSiCl3 and H2SiCl2 to 54.5 and 20.3 mol% (in the liquid phase), respectively.

[0217] Example 7): Si2Cl6 * and reaction of HSi2Cl5 with HCl / 1,4-dioxane solution (5M) ( * (Reaction not according to the present invention) 0.1 ml of Si2Cl6 and 0.5 ml of 5M HCl / 1,4-dioxane solution were mixed with 0.1 ml of C6D6 in an NMR tube. The NMR tube was cooled to -196°C, evacuated and sealed. The mixture was reacted at room temperature for 36 hours and analyzed by NMR spectroscopy. The experiment was repeated similarly using HSi2Cl5 instead of Si2Cl6. The product distribution is shown in Table 12. [Table 12]

[0218] As expected, HSi2Cl5 was completely cleaved already at room temperature to give HSiCl3 quantitatively, while the cleavage of Si2Cl6 required a longer reaction time. After 66 h, Si2Cl6 remained at 15 mol % in the reaction mixture. Notably, no solid polymer was formed upon disilane cleavage.

[0219] Example 8): Reaction of disilane mixture 2 with HCl / 1,4-dioxane solution (5M) 0.1 ml of disilane mixture 2 (silane distribution shown in Table 1) and 0.2 ml of 5M HCl / 1,4-dioxane solution were mixed with 0.4 ml of C6D6 in an NMR tube. The NMR tube was cooled to -196°C, evacuated and sealed. The sample was reacted at room temperature for 7 hours, analyzed by NMR spectroscopy and further heated according to Table 13. [Table 13]

[0220] In particular, the Si-Si bond cleavage of hydridochlorodisilane by concentrated HCl / ether solutions occurs very rapidly already at room temperature. In this experiment, the cleavage of the remaining disilane led to long reaction times at high temperatures due to the very low HCl concentration, but ultimately yielded more than 87 mol% trichlorosilane without the formation of solid by-products.

[0221] In FIG. 1, starting mixture 2 29 An exemplary Si NMR spectrum is shown (top) and the results of disilane cleavage with HCl / 1,4-dioxane solution are shown below.

[0222] Example 9): Reaction of siloxane with HCl / 1,4-dioxane solution (2.5M) and nBu4PCl Preparation of siloxane stock solution: 1.0 ml of disilane mixture 2 (1.48 g, 6.5 mmol, silane distribution shown in Table 1) was placed in a Schlenk flask and stirred vigorously. Subsequently, 0.5 equivalents of H2O (0.06 ml, 3.33 mmol) diluted with 2.0 ml of 1,4-dioxane was added slowly via syringe. As the disilanes were hydrolyzed, solid siloxanes were formed, resulting in a suspension of liquid and solid siloxanes along with unreacted disilanes.

[0223] In experiment a), 0.2 ml of the siloxane stock solution was mixed with 10 wt. % nBu4PCl based on the total weight of the starting disilane equivalents and 0.4 ml of C6D6 as solvent in an NMR tube at -196°C. In experiment b), 0.2 ml of the siloxane stock solution was mixed with 0.5 ml of 2.5 M HCl / 1,4-dioxane solution and 0.1 ml of C6D6 as solvent in an NMR tube at -196°C. The NMR tube was evacuated, sealed, and heated at 120°C for 6 hours. In both experiments, the solid polysiloxane remained as an insoluble residue and was not investigated further. The results of the liquid phase NMR spectroscopic analysis are shown in Table 14. [Table 14]

[0224] In both experiments, HSiCl3 was formed as the main product (73 mol% and 82 mol%) in the liquid phase, in addition to HSiCl2 (19.6% and 12.1%) and small amounts of SiCl4 (3.6% and 1.6%). The formation of monosilanes occurs via cleavage of unhydrolyzed disilanes, according to the formula (H p SiCl 5-p )2O(p=0-2) disiloxane Si-Si bond cleavage and disiloxane (H q Cl 3-q It is caused by the cleavage of the Si-O bond in the compound Si)2O (q=0-2).

[0225] Example 10: Reaction of hydridochlorodisilanes with HCl / nBu2O reagent (2.5M) in the presence of Si2Cl6, Si3Cl8, and perchlorinated oligo- and polysilanes. Preparation of stock solutions: Preparation of a Si2Cl6 based stock solution: 0.8 ml of disilane mixture 2 (silane distribution shown in Table 2) was mixed with 0.65 ml of Si2Cl6. The solution (disilane mixture 4) was analyzed by NMR spectroscopy and the results are shown in Table 15.

[0226] Preparation of Si3Cl8-based stock solution: 0.3 ml of disilane mixture 4 (silane distribution shown in Table 15) was dissolved in 0.3 ml of Si3Cl8 (a trace of iso-Si4Cl8 as a model compound for branched oligosilanes). 10 The solution (Disilane Mixture 5) was analyzed by NMR spectroscopy and the results are shown in Table 15. [Table 15]

[0227] Preparation of a stock solution based on perchlorinated polysilanes: 0.6 g of perchlorinated polysilane (average chain length: 13 silicon atoms) was dissolved in 0.5 ml of disilane mixture 4. The solution (silane mixture 6) was analyzed by NMR spectroscopy. 29 The SiNMR spectrum is shown in Figure 3 (top).

[0228] Example 10a): Reaction of disilane mixture 4 with HCl / nBu2O reagent (2.5M) 0.1 ml of disilane mixture 4 (silane distribution is shown in Table 15) was mixed with 0.5 ml of HCl / nBu2O reagent (2.5 M) and 0.1 ml of C6D6 as solvent in an NMR tube at -196°C. The NMR tube was evacuated, sealed, and reacted at room temperature for 10 hours. After NMR spectroscopy, the sample was heated at 80°C for 4 hours, cooled to room temperature, and then reanalyzed by NMR spectroscopy. The results are shown in Table 16. [Table 16]

[0229] Example 10b): Reaction of disilane mixture 5 with HCl / nBu2O reagent (2.5M) Similar to Example 10a, 0.1 ml of disilane mixture 5 (silane distribution shown in Table 15) was mixed with 0.5 ml of HCl / nBu2O reagent (2.5 M) and 0.1 ml of C6D6 as solvent in an NMR tube at -196°C. The NMR tube was evacuated, sealed, and reacted at room temperature for 10 hours. After NMR spectroscopy, the sample was heated at 80°C for 4 hours, cooled to room temperature, and then reanalyzed by NMR spectroscopy. The results are shown in Table 17. [Table 17]

[0230] Example 10c): Reaction of silane mixture 6 (containing hydridochlorodisilanes and perchlorinated polysilanes) with HCl / nBu2O reagent (2.5M) As in Example 10a, 0.08 ml of silane mixture 6 was mixed with 0.5 ml of HCl / nBu2O reagent (2.5 M) and 0.1 ml of C6D6 as a solvent in an NMR tube at -196°C. The NMR tube was evacuated, sealed, and reacted at room temperature for 10 hours. After NMR spectroscopy, the sample was heated at 80°C for 4 hours, cooled to room temperature, and then reanalyzed by NMR spectroscopy. The results are shown in Table 18, and 29 The Si NMR spectrum is shown in Figure 3 (bottom). [Table 18]

[0231] In all three experiments (10a-c), HSiCl3 was formed as the main product (71 mol%, 66 mol%, and 72 mol%) already after 10 h at room temperature. Hexachlorodisilane remained at a maximum of 26 mol%, while all other disilanes, oligosilanes, and polysilanes were almost quantitatively cleaved. Heating the samples to 80 °C for another 4 h further increased the formation of HSiCl3, while only 1-2 mol% of Si2Cl6 remained (examples 10a and 10b). The product distribution in 10c) did not change significantly after heating, since almost all HCl had already been consumed during the first reaction period. Additional ether / HCl-solution almost quantitatively cleaved hexachlorodisilane, thus further increasing the amounts of tetrachlorosilane and trichlorosilane.

[0232] Preferred Embodiments of the Invention In the following, preferred embodiments of the present invention are presented.

[0233] EMBODIMENT 1 A process for producing chlorosilanes of general formula (I), comprising the steps of: H 4-n SiCl n (I) where n=2, 3, and 4, preferably n=3; A) Disilane of general formula (II) H o SiCl 6-o (II) where o=0-6, preferably o=0-2, most preferably 0-1; wherein o≧1 for one or more disilanes; comprising one or more substrates selected from And optionally, B) Disiloxanes of general formula (III) or (IV) (H p SiCl 5-p )2O(III) (H q Cl 3-q Si)2O(IV) Wherein p=0-5, preferably p=0-1, q=0-2, more preferably q=0-1; C) Chlorominosilane of general formula (V) SiH r Cl 4-r (V) where r=0-2, preferably r=0-1, most preferably r=0, D) Perchlorinated oligosilanes and polysilanes of general formula (VI) S s Cl 2s+2 (VI) where s=3-6, E) chloro-, hydrido- and hydroxy-substituted polysilanes, including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, and chloro-, hydrido- and hydroxy-substituted polysiloxanes; The starting material composition further comprises: -ether / HCl solution, amines, phosphines or mixtures thereof, and - one or more reaction promoters F) selected from the group consisting of ammonium halides, phosphonium halides, or mixtures thereof; Optionally, G) Monosilane of general formula (VII) R t SiCl u H 4-(t+u) (VII) where t=0-3, preferably 1-3, more preferably 2; u=0-2, preferably 0; t+u=0-3, preferably 1-3, more preferably 2; R is an organic residue; H) Disilane of general formula (VIII) R v SiCl w H 6-(v+w) (VIII) where v=0-5, preferably 1-5, w=0-5, preferably 0; v+w=1-5, R is as defined above. In the presence of one or more additional compounds containing at least one Si-H bond selected from The method comprises reacting at a temperature below 200°C.

[0234] EMBODIMENT 2 The process according to embodiment 1, wherein the disilane o≧1 is pentachlorodisilane, more preferably the disilane o≧1 is pentachlorodisilane and one or two tetrachlorodisilane isomers, even more preferably the disilane o≧1 is pentachlorodisilane, where hexachlorodisilane is also present in the starting material composition, and most preferably the disilane o≧1 is pentachlorodisilane and one or two tetrachlorodisilane isomers, where hexachlorodisilane is also present in the starting material composition.

[0235] EMBODIMENT 3 The process according to embodiment 1 or 2, wherein the temperature is in the range of from 10°C to 160°C, more preferably from 15°C to 130°C, even more preferably from 20°C to 100°C, and most preferably from 20 to 80°C.

[0236] EMBODIMENT 4 The method according to any of the previous embodiments, wherein the starting material composition includes the effluent exiting a Siemens process CVD reactor as a by-product.

[0237] EMBODIMENT 5 The method according to any of the previous embodiments, wherein the starting material composition comprises as a by-product an effluent exiting a Siemens process CVD reactor, wherein the effluent comprises tetrachlorosilane as a major component.

[0238] EMBODIMENT 6 The method according to any of the previous embodiments, wherein the starting material composition includes as a by-product one or more fractions obtained by fractional distillation of the effluent exiting a Siemens process CVD reactor.

[0239] EMBODIMENT 7 The method according to any of the previous embodiments, wherein the starting material composition comprises at least components B) and / or C).

[0240] EMBODIMENT 8 A process according to any of the previous embodiments, wherein the starting material composition comprises a high-boiling fraction of a Siemens process by-product and comprises disilane as a major component by weight, preferably hexachlorodisilane, pentachlorodisilane and tetrachlorodisilane as major components, more preferably hexachlorodisilane and pentachlorodisilane as major components, and most preferably hexachlorodisilane as a major component by weight.

[0241] EMBODIMENT 9 The method according to any of the previous embodiments, wherein the starting material composition comprises greater than 30% by weight disilane, preferably greater than 40% by weight disilane, more preferably greater than 50% by weight disilane, even more preferably greater than 60% by weight disilane, and most preferably greater than 70% by weight disilane.

[0242] EMBODIMENT 10 A method according to any of the previous embodiments, wherein the starting material composition comprises greater than 15% by weight hydridochlorodisilane, preferably greater than 25% by weight hydridochlorodisilane, more preferably greater than 30% by weight hydridochlorodisilane, even more preferably greater than 40% by weight hydridochlorodisilane, and even more preferably greater than 50% by weight hydridochlorodisilane, and most preferably the starting material consists of a disilane having at least one hydrido substituent.

[0243] EMBODIMENT 11 The process according to any of the previous embodiments, wherein the reaction is carried out in the presence of one or more ether / HCl solutions, preferably saturated ether / HCl solutions, which act as reaction promoter F).

[0244] EMBODIMENT 12 The process according to any of the previous embodiments, wherein the reaction is carried out in the presence of one or more ether / HCl solutions, preferably saturated ether / HCl solutions, which function as reaction promoter F), and wherein no further reaction promoter F) is present in the reaction mixture.

[0245] EMBODIMENT 13 The process according to embodiments 1-11, wherein the reaction is carried out in the presence of one or more reaction promoters F) selected from the group of amines, phosphines, ammonium or phosphonium halides, preferably chlorides.

[0246] EMBODIMENT 14 The method according to embodiments 1-10 and 13, wherein the method is carried out in the absence of an ether / HCl solution.

[0247] EMBODIMENT 15 The process according to embodiments 1-11 and 13-14, wherein the one or more reaction promoters F) are represented by the formula R4XCl, where X=N or P, and R is independently a hydrogen group or an organyl group, more preferably a hydrogen group, an aromatic group or an aliphatic hydrocarbon group.

[0248] EMBODIMENT 16 The method according to embodiment 15, wherein one or more reaction accelerants F) represented by the formula R4XCl, where X=N or P, are formed in situ from compounds of the formulae R3X and RCl.

[0249] EMBODIMENT 17 The process according to embodiments 1-11 and 13-16, wherein the reaction promoter F) is selected from the group consisting of nBu3P, nBu3N, nBu4PCl, and nBu4NCl.

[0250] EMBODIMENT 18 The process according to any of the previous embodiments, wherein the reaction is carried out in the presence of one or more additional compounds containing at least one Si-H bond selected from monosilanes G) and disilanes H), preferably in the presence of one or more additional organohydridosilanes, more preferably in the presence of one or more hydridomethylsilanes, even more preferably in the presence of one or more organohydridosilanes selected from methylsilane, dimethylsilane or trimethylsilane, most preferably in the presence of dimethylsilane.

[0251] EMBODIMENT 19 The method according to any of the previous embodiments, wherein the starting material comprises at least 40% by weight of SiCl4 and the reaction is carried out in the presence of at least one additional compound containing at least one Si-H bond selected from monosilanes G) and disilanes H), preferably in the presence of one or more organohydridosilanes or organohydridodisilanes, more preferably in the presence of one or more methylhydridosilanes or methylhydridodisilanes, most preferably in the presence of dimethylhydridodisilanes.

[0252] EMBODIMENT 20 The process according to any of the previous embodiments, wherein SiCl4, HSiCl3 and H2SiCl2 are obtained as the main products of the process by weight, preferably HSiCl3 is obtained as the main product by weight.

[0253] EMBODIMENT 21 The process according to any of the previous embodiments, wherein the SiCl4 obtained in the process is converted in the same or a subsequent step into HSiCl3, preferably by a redistribution reaction with a silicon hydride compound, more preferably a Si-H bond containing compound G) or H).

[0254] EMBODIMENT 22 A method according to any of the previous embodiments, wherein greater than 40% of the Si atoms of the starting material composition are converted to HSiCl3, preferably greater than 50% of the Si atoms of the starting material composition are converted to HSiCl3, more preferably greater than 60% of the Si atoms of the starting material composition are converted to HSiCl3, and most preferably greater than 70% of the Si atoms of the starting material composition are converted to HSiCl3.

[0255] EMBODIMENT 23 The process according to any of the previous embodiments, wherein the reaction is carried out in the presence of one or more reaction promoters F) selected from amines, phosphines, ammonium halides or phosphonium halides, followed by removal of volatiles and subsequent conversion of the remainder to monosilane by treatment with HCl / ether solution.

[0256] EMBODIMENT 24 The method according to any of the previous embodiments, wherein no additional solvent is used.

[0257] EMBODIMENT 25 The process according to embodiments 1 to 23, wherein the reaction is carried out in the presence of an organic solvent, preferably a high-boiling ether compound, more preferably 1,4-dioxane, di-n-butyl ether, diglyme or tetraglyme, most preferably diglyme.

[0258] EMBODIMENT 26 The process according to any of the previous embodiments, wherein the organic residue R of the silicon hydrides G) and H) is an alkyl or aryl group, more preferably a C1-C6 alkyl group, most preferably a methyl group.

[0259] EMBODIMENT 27 The method according to any of the previous embodiments, wherein the method is carried out under inert conditions.

[0260] EMBODIMENT 28 The process according to any of the previous embodiments, wherein the reaction of the process is carried out at a pressure of from 0.01 to 10 MPa, more preferably from 0.05 to 1.0 MPa.

[0261] EMBODIMENT 29 The process according to any of the previous embodiments, wherein the reaction of the process is followed by a step of separating the obtained monosilane of general formula (I) by distillation, low temperature condensation, or a combination thereof.

[0262] EMBODIMENT 30 The process according to any of the previous embodiments, wherein the starting material composition comprises one or more disiloxanes B).

[0263] EMBODIMENT 31 The method according to any of the previous embodiments, wherein the starting material composition comprises one or more perchlorinated oligosilanes and polysilanes D).

[0264] EMBODIMENT 32 The method according to any of the previous embodiments, wherein the starting material composition comprises one or more chloro-, hydrido- and hydroxy-substituted polysilanes E), including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes.

[0265] EMBODIMENT 33 The method according to any of the previous embodiments, wherein the starting material composition consists of a Siemens process by-product obtained as an effluent leaving a Siemens process CVD reactor.

[0266] EMBODIMENT 34 The process according to any of the previous embodiments, wherein the starting material composition consists of a Siemens process by-product obtained as an effluent leaving a Siemens process CVD reactor, which is subjected directly to the process.

[0267] EMBODIMENT 35 The process according to any one of the preceding embodiments, wherein the starting material composition is a by-product of the Siemens process obtained as an effluent leaving a CVD reactor of the Siemens process, which is subjected to the process after intermediate storage.

[0268] Any numerical range set forth herein will be understood to include all subranges within that range, and any combination of the various endpoints of such ranges or subranges, whether set forth in the examples or elsewhere in the specification.

[0269] It will also be understood that any component of the invention herein described by any particular genus or species detailed in the Examples section of this specification can be used in one embodiment to define the alternative respective definitions of any of the endpoints of the ranges described elsewhere herein for that component, and thus can be used in one non-limiting embodiment to replace the endpoints of such ranges as set forth elsewhere.

[0270] Any compound, material, or substance explicitly or implicitly disclosed in the specification and / or claimed herein as belonging to a group of structurally, compositionally and / or functionally related compounds, materials, or substances will be further understood to include each individual representative of that group, and all combinations thereof.

Claims

1. A process for producing chlorosilanes of general formula (I), comprising the steps of: H ４－ｎ SiCS ｎ (I) where n=2, 3, and 4, A) Disilane of general formula (II) H ｏ Si ２ Cl ６－ｏ (II) Here, o=0-2, and wherein o≧1 for one or more disilanes; comprising one or more substrates selected from And optionally, B) Disiloxanes of general formula (III) or (IV) (H ｐ Si ２ Cl ５－ｐ ) ２ O (--I) (H ｑ Cl ３－ｑ Si) ２ O (OV) Here, p=0-5, q=0-2, C) Chlorominosilane of general formula (V) SiH ｒ Cl ４－ｒ (V) where r=0-2, D) Perchlorinated oligosilanes and polysilanes of general formula (VI) Si ｓ Cl ２ｓ＋２ (VI) Here, s=3-6, E) Chloro-, hydrido- and hydroxy-substituted polysilanes, including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes, and chloro-, hydrido- and hydroxy-substituted polysiloxanes. The starting material composition further comprises: - ether / HCl solution, -amines, phosphines or mixtures thereof, and - ammonium halides, phosphonium halides or mixtures thereof, F) one or more reaction promoters selected from the group consisting of Optionally, G) Monosilane of general formula (VII) R ｔ SiCS ｕ H ４－（ｔ＋ｕ） (OII) Here, t=0-3, u=0-2, t+u=0−3, R is an organic residue; H) Disilane of general formula (VIII) ( ｖ 3) ２ . ｗ H ６－（ｖ＋ｗ） (().|) where v=0-5, w=0-5, v+w=1-5, R is as defined above. In the presence of one or more additional compounds containing at least one Si—H bond selected from reacting at a temperature below 200°C; wherein the reaction is carried out in the presence of one or more ether / HCl solutions which act as reaction promoters F), or The reaction is carried out in the presence of one or more reaction promoters F) selected from the group of amines, phosphines, ammonium halides or phosphonium halides, followed by removal of the volatile substances and subsequent conversion of the remainder to monosilanes by treatment with an HCl / ether solution, A method by which.

2. 2. A method for producing the chlorosilanes of claim 1, wherein n=3 in general formula (I).

3. 2. A method for producing the chlorosilanes of claim 1, wherein r=0-1 in general formula (V).

4. 2. A method for producing the chlorosilane of claim 1, wherein r=0 in general formula (V).

5. 2. The method of claim 1, wherein the disilane with o > 1 is pentachlorodisilane.

6. 6. The method of any one of claims 1 to 5, wherein the starting material composition comprises as a by-product the effluent exiting a Siemens process CVD reactor.

7. 7. The method of any of claims 1 to 6, wherein the starting material composition comprises one or more fractions obtained by fractional distillation of the effluent leaving a Siemens process CVD reactor as a by-product.

8. 8. The method of claim 1, wherein the starting material composition comprises at least components B) and / or C).

9. 9. The process according to any one of claims 1 to 8, wherein the reaction is carried out in the presence of a saturated ether / HCl solution.

10. 10. The process according to claims 1 to 9, wherein the reaction is carried out in the presence of one or more reaction promoters F) selected from the group of amines, phosphines, ammonium halides or phosphonium halides.

11. 11. The process according to claim 10, wherein the reaction is carried out in the presence of one or more reaction promoters F) selected from the group of ammonium chlorides or phosphonium chlorides.

12. The one or more reaction promoters F) are of the formula R ４ 12. The method of claim 1, wherein the compound is represented by XCl, where R is independently a hydrogen group or an organyl group.

13. 13. The method of claim 12, wherein R is a hydrogen group, an aromatic group, or an aliphatic hydrocarbon group.

14. Reaction accelerator F) is nBu ３ P, nBu ３ N, nBu ４ PCl and nBu ４ 13. The method of claim 12, wherein the compound is selected from the group consisting of NCl.

15. 15. The method according to any of claims 1 to 14, wherein the reaction is carried out in the presence of one or more additional compounds containing at least one Si-H bond selected from monosilanes G) and disilanes H).

16. 16. The method of claim 15 conducted in the presence of one or more additional organohydridosilanes.

17. 16. The method of claim 15 conducted in the presence of one or more hydridomethylsilanes.

18. 16. The method of claim 15 conducted in the presence of one or more organohydridosilanes selected from methylsilane, dimethylsilane, or trimethylsilane.

19. More than 40% of the Si atoms in the starting material composition are HSiCl ３ 19. The method of claim 1 , wherein

20. 20. The method of any of claims 1 to 19, wherein the starting material composition comprises one or more perchlorinated oligosilanes and polysilanes D).

21. 21. The method of any of claims 1 to 20, wherein the starting material composition comprises one or more chloro-, hydrido- and hydroxy-substituted polysilanes E), including linear, branched, cyclic and caged chloro-, hydrido- and hydroxy-substituted oligo- and polysilanes.

22. 22. The method of any of claims 1 to 21, wherein the starting material composition comprises a Siemens process by-product obtained as an effluent leaving a CVD reactor of a Siemens process.

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