EP2661415A1

EP2661415A1 - Hydrogenation of organochlorosilanes and silicon tetrachloride

Info

Publication number: EP2661415A1
Application number: EP11805007.9A
Authority: EP
Inventors: Norbert Schladerbeck; Ingo Pauli; Guido Stochniol; Yücel ÖNAL
Original assignee: Evonik Degussa GmbH
Current assignee: Evonik Operations GmbH
Priority date: 2011-01-04
Filing date: 2011-12-20
Publication date: 2013-11-13
Also published as: JP5933592B2; JP2014507367A; TW201245044A; CN103269976A; US20140178283A1; DE102011002436A1; CA2823662A1; CN103269976B; WO2012093029A1; KR20130133805A

Abstract

The invention relates to a method for producing trichlorosilane, characterized in that hydrogen and at least one organic chlorosilane are reacted in a pressure-driven reactor, which comprises one or more reactor pipes, which are made of gas-tight ceramic material.

Description

Hydrogenation of orqanochlorosilanes and silicon tetrachloride

The invention relates to a process for the preparation of trichlorosilane, characterized in that hydrogen and at least one organic chlorosilane are reacted in a pressure-operated reactor comprising one or more reactor tubes consisting of gas-tight ceramic material.

Trichlorosilane (TCS) is an important raw material for the production of hyperpure silicon, which is needed in the semiconductor and photovoltaic industry. The demand for TCS has risen steadily in recent years and for the foreseeable future a further increase in demand is forecast.

The separation of hyperpure silicon from TCS is carried out in a Chemical Vapor Deposition (CVD) process according to the Siemens method. Depending on the choice of process parameters, larger amounts of silicon tetrachloride (STC) are produced as coproduct. The TCS used is usually prepared by a chlorosilane process, i. H. Conversion of crude silicon with HCl at temperatures around 300 ° C in a fluidized bed reactor or recovered at 1000 ° C in a fixed bed reactor, the separation of other than coupling products formed chlorosilanes such. B. STC is carried out by downstream distillation. Organic impurities also result in the above processes in the formation of organic chlorosilanes as further by-products. In large quantities, organic chlorosilanes, such as. B.

Methyltrichlorosilane (MTCS), methyldichlorosilane (MHDCS) or propyltrichlorosilane (PTCS), in addition by Müller-Rochow synthesis of silicon and

Alkyl chlorides are produced.

To meet the increasing demand for TCS and increase the

Economies of processes for the production of hyperpure silicon therefore require processes that allow an efficient transfer of silicon tetrachloride and organochlorosilanes in TCS, so that the coupling products from the Siemens process and the chlorosilane process and streams of Müller-Rochow synthesis for the production of Pure silicon can be harnessed. Various methods for hydrodechlorination of STC to TCS are known. According to the technical standard, a thermally controlled process is used in which the STC is passed together with hydrogen in a graphite-lined reactor, the so-called "Siemens furnace". The in the reactor

located graphite rods are operated as resistance heating, so that

Temperatures of 1 100 ° C and higher can be achieved. Due to the high temperature and the proportional hydrogen content, the equilibrium position is shifted to the product TCS. The product mixture is passed out of the reactor after the reaction and separated in complex processes. The reactor is flowed through continuously, wherein the inner surfaces of the reactor made of graphite as a corrosion-resistant material. Metallic materials are insufficient for direct contact with chlorosilanes under the high reaction temperatures

Corrosion resistance. To stabilize the reactor, however, a

Outer shell of metal used. This outer wall must be cooled in order to suppress as far as possible the decomposition reactions occurring at the high temperatures on the hot reactor wall, which can lead to silicon deposits.

Process improvements include, in particular, the use of carbon-based engineering materials with a chemically inert

Coating, in particular SiC, to avoid degradation of the

Construction material and the contamination of the product gas mixture due to reactions of the carbon-based material with the chlorosilane / H ₂

Gas mixture.

Thus, in US 5,906,799 the use of SiC-coated

Carbon fiber composite materials proposed in addition to the

Improving the tolerance of the reactor design to heat shock are suitable.

DE 102005046703 A1 describes a process for the dehydrohalogenation of a chlorosilane in which a graphitic heating element and the surface of the reaction chamber, which come into contact with the chlorosilane, in one of the Dehydrohalogenation upstream step in-situ with a protective SiC layer by reaction of graphite with organosilanes be coated at temperatures above the reaction temperature of dehydrohalogenation. The arrangement of the heating element inside the reaction chamber increases the efficiency of the energy input of the electrical resistance heating.

The above method has in common that expensive coating processes are needed. Another disadvantage is that the described

Use of electrical resistance heaters compared to a

Direct heating by means of natural gas is uneconomical. The unwanted

Silicon deposits, resulting in the necessary very high

Form reaction temperature, also require regular cleaning of the reactor. In addition, the metallic pressure reactor has to be laboriously cooled on the one hand from the outside and be covered from the inside by a high temperature heat insulation, the cladding must simultaneously provide protection against corrosive attack.

Another disadvantage is the implementation of a purely thermally guided reaction, without a catalyst, which makes the above methods very inefficient overall. Accordingly, various methods are catalytic

Dehydrohalogenation of STC has been developed.

For example, WO 2005/102927 A1 and WO 2005/102928 A1 describe the use of Ca, Sr, Ba or their chlorides or of a metallic heating element, in particular of Nb, Ta, W or their alloys as

Catalysts for the conversion of a H ₂ / SiCl ₄ gas mixture to TCS with almost thermodynamic degrees of conversion at temperatures of 700 to 950 ° C. and pressures of 1 to 10 bar in flow reactors made of quartz glass. A separate earlier application further describes a method for

Hydrodehalogenation of SiCI ₄ to TCS in a pressure-operated reactor comprising one or more reactor tubes, which consist of gas-tight ceramic material. The pipe inner walls are preferably with a catalyst, the coated at least one active component selected from the metals Ti, Zr, Hf, Ni, Pd, Pt, Mo, W, Nb, Ta, Ba, Sr, Ca, Mg, Ru, Rh, Ir or combinations thereof or their silicide compounds wherein the tubes can optionally be filled with a fixed bed of analogously catalytically coated packing of the same ceramic material. The conversion to TCS takes place with almost

thermodynamic conversion and high selectivity at temperatures around 900 ° C. The reaction temperatures can advantageously be generated by arranging the reactor tubes in a combustion chamber which is heated by combustion of natural gas.

The above-described processes are for the dehydrohalogenation of

Chlorosilanes, in particular of STC. In view of the considerable amounts of organic chlorosilanes as by-products from the Siemens process or the chlorosilane process or, in particular, as products of a Müller-Rochow synthesis, it would be very desirable for the utilization of these sources for the

Recovery of hyperpure silicon to develop a process that also allows efficient hydrogenation of organic chlorosilanes to TCS.

According to DE 4343169 A1, transition metals or their silicides are, as it were, suitable as catalysts for the dehydrohalogenation of STC and for the hydrogenation of organochlorine compounds. The proposed method uses full contacts. This means a relatively high material consumption and incomplete utilization of the catalytically active component. The execution in a flow reactor under atmospheric pressure also requires a

comparatively low space-time yield.

Object of the present invention was therefore to provide an efficient and

To provide inexpensive process for the reaction of organic chlorosilanes with hydrogen to trichlorosilane, which allows a high space-time yield and selectivity to TCS.

To solve the problem, it has been found that a mixture of at least one organic chlorosilane and hydrogen by a pressure-driven tubular reactor can be performed with a catalytic

Wall coating provided and / or can be equipped with a fixed bed catalyst. According to the invention, it is particularly preferred that the reaction in the reactor is catalyzed by a reaction catalyzing the inner coating of the one or more reactor tubes. The reaction in the reactor can additionally be catalyzed by a conversion-catalyzing coating of a fixed bed arranged in the reactor or in the one or more reactor tubes. The combination of the use of a catalyst to improve the reaction kinetics and increase the selectivity and a pressure-driven reaction provide for an economically and ecologically very efficient

Litigation. Surprisingly, it was found that in the

Reaction system according to the invention high conversions of organic

Chlorosilane compounds are possible to TCS. By suitable adjustment of the reaction parameters such as pressure, residence time and molar ratios of the educts, a process can be represented in which high space-time yields of TCS with a high selectivity are obtained. Optionally, the reacted in the reactor mixture of at least one organic chlorosilane and

Hydrogen additionally contain STC as a further educt. It has been discovered that reactor tubes of certain hermetic ceramic materials specified below are useful for the hydrogenation of

Chlorosilanes, in particular organochlorosilanes can be used, since they are sufficiently inert even at the necessary reaction temperatures of about 700 ° C and able to ensure the pressure resistance of the reactor. The inner walls of the / the reactor tube (s), as well as the surface possibly in the tube interior filled packing of the same ceramic material in a simple manner without special equipment expense with a catalytically active

Be provided coating. Another advantage of using ceramic reactor tubes

Materials that are corrosion-resistant and gas-tight even at high temperatures, lies in the possibility of heating by means of natural gas burner whereby the required heat of reaction in comparison to electrical resistance heaters can be introduced significantly more economical. In addition, fuel gas heated systems are characterized by a uniform temperature control. electrical

Resistance heaters, however, may have local overheating, because the electrical resistance can not be maintained uniformly enough by geometric deviations of the resistance-heated components or by wear, resulting in local deposits and expensive shutdowns associated with cleaning the result. Finally, in comparison with graphite-based hydrohalogenation reactors, there is no need for a metallic outer wall to be cooled, which must be protected against corrosion.

The solution according to the invention of the above-mentioned object will be described in more detail below, including various or more preferred

Versions. The invention relates to a process for the preparation of trichlorosilane, characterized in that hydrogen and at least one organic

Chlorosilane in a pressure-operated reactor comprising one or more reactor tubes, which are made of gas-tight ceramic material reacted. In a specific embodiment of the process according to the invention, in admixture with the at least one organic chlorosilane additionally

Silicon tetrachloride reacted with hydrogen to trichlorosilane.

In these reactions of hydrogen with organochlorosilane (s), optionally in admixture with STC, in specific embodiments methyltrichlorosilane can be used as the only organic chlorosilane. The term "sole organic chlorosilane" here means that the cumulative amount of other organic chlorosilanes contained in the reaction mixture is less than 3 mol%, based on the molar amount of methyltrichlorosilane.

In all of the abovementioned variants of the process according to the invention, a hydrogen-containing feed gas and a feed gas containing at least one organic chlorosilane and, optionally, a silicon tetrachloride-containing feedstock may be used in the reaction Feedstock gas are reacted in a reactor by supplying heat to form a trichlorosilane-containing product gas, wherein the

Organochlorosilane-containing reactant gas and / or the hydrogen-containing educt gas and / or the silicon tetrachloride-containing educt gas are passed as pressurized streams into the pressure-operated reactor and the product gas is taken out as a pressurized stream from the reactor. In the product stream, in addition to trichlorosilane and organic compounds which by

Hydrogenolysis of Si-C bonds in the organochlorosilanes arise, such as alkanes in the case of alkylchlorosilanes, if appropriate, by-products such as HCl, tetrachlorosilane, dichlorosilane, monochlorosilane and / or silane and other organic chlorosilanes and / or organosilanes, which differ from the educts used to be included. The product stream generally also contains unreacted starting materials, ie the at least one organic chlorosilane, hydrogen and optionally silicon tetrachloride.

In all variants of the process of the invention described, the organochlorosilane-containing educt gas and the hydrogen-containing educt gas and, if present, the silicon tetrachloride-containing educt gas can also be conducted as a common stream into the pressure-operated reactor.

In the process according to the invention, the organochlorosilane-containing educt gas preferably contains organotrichlorosilanes of the formula RSlCl 3 where R is an alkyl group, in particular a linear or branched alkyl group having 1 to 8 C atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl, a phenyl group or an aralkyl group, thereby enabling high yields of the desired product TCS. Particularly preferred may in

Methyltrichlorosilane (MTCS), ethyltrichlorosilane (ETCS) and / or n-propyltrichlorosilane (PTCS) can be used as organochlorosilane according to the invention. These organic chlorosilanes can be taken individually or as a mixture, in particular as side streams, a chlorosilane process, the production of hyperpure silicon by the Siemens process and / or a Muller-Rochow synthesis after appropriate product gas treatment. In a particular embodiment, a silicon tetrachloride-containing educt gas is used in the process according to the invention in addition to the educt gas containing organochlorosilane. It can also be an organochlorosilane and

silicon tetrachloride-containing educt gas can be used. In these cases, the reaction with hydrogen takes place in the reactor by parallel sequence of the hydrogenation of the at least one organochlorosilane and the hydrodehalogenation of SiCl ₄ .

Silicon tetrachloride-containing educt gas can be obtained in particular from secondary streams of a chlorosilane process and / or the hyperpure silicon production by the Siemens process after appropriate product gas treatment.

Furthermore, the process according to the invention can also be used for the hydrogenation of di or higher substituted organochlorosilanes of the formula R _x SiCl _4-x with x = 2, 3 or 4 and R = alkyl group, in particular with 1 to 8 C atoms, phenyl group or aralkyl group, and / or organically substituted disilanes or higher silanes. However, in these cases, the product mixture will only have a relatively low proportion of TCS. In the product mixture here predominantly chlorosilanes with a higher hydrogen content or Si-Si bonds are included. The gas-tight ceramic material of the one or more

Reactor tubes of the reactor are preferably selected from SiC or Si3N ₄ , or mixed systems (SiCN) thereof. Pipes made of these materials are sufficiently inert, corrosion-resistant and pressure-stable, even at the high reaction temperatures of more than 700 ° C., so that the TCS synthesis can be operated from organic chlorosilanes and optionally STC at several bar overpressure. Basically, gastight materials are to be used as the reactor tube material. This also includes a possible use of suitable non-ceramic materials such. For example, a quartz glass. Especially reactors with SiC-containing reactor tubes are preferred because this material has a particularly good thermal conductivity and thus allows a uniform heat distribution and a good heat input for the reaction. In a suitable embodiment of the method according to the invention these may in particular be gas-tight reactor tubes made of Si-infiltrated SiC (SiSiC) or non-pressure sintered SiC (SSiC), without herewith

to be restrictive. Commercial sources for special ceramics ik are z. B. Saint-Gobain Industriekeramik Rödental GmbH: "Advancer®" pipes, Saint Gobain Ceramics "Hexoloy®"; MTC Haldenwanger "Halsic-I" and SSiC from Schunk Ingenieurkeramik GmbH.

The corrosion resistance of the materials mentioned can additionally be increased by a SiO ₂ layer with layer thicknesses in the range from 1 to 100 μm. In a specific embodiment, therefore, reactor tubes made of SiC, S13N4 or SiCN with a corresponding Si0 ₂ layer are used as a coating.

In a further variant of the method according to the invention, at least one reactor tube can be filled with random packings, which consist of the same gastight ceramic material as the tube. This inert bulk material can be used to optimize the flow dynamics. Bulk materials such as rings, spheres, rods or other suitable packing can be used as the bulk material.

In a particularly preferred embodiment of the invention

Method are the inner walls of at least one reactor tube and / or at least a portion of the packing with at least one material that the

Reaction of hydrogen with organochlorosilane (s) and optional

Silicon tetrachloride catalyzed to trichlorosilane, coated. In general, the tubes can be used with or without catalyst, wherein the catalytically coated tubes represent a preferred embodiment, since suitable catalysts lead to an increase in the reaction rate and thus to an increase in the space-time yield. Are the packing with a catalytically active

Coated, may optionally affect the catalytically active

Interior coating of the reactor tubes are dispensed with. However, it is also preferable in this case that the inner walls of the reactor tubes are included, since so the catalytically usable surface compared to purely supported

Catalyst systems (eg., By fixed bed), is increased. The catalytically active coating (s), ie for the inner walls of the

Reactor tubes and / or a fixed bed optionally used, preferably consist of a composition comprising at least one active component selected from the metals Ti, Zr, Hf, Ni, Pd, Pt, Mo, W, Nb, Ta, Ba, Sr, Ca, Mg, Ru, Rh, Ir or combinations thereof or their silicide compounds, if any exist. Particularly preferred active components here are Pt, Pt / Pd, Pt / Rh and Pt / Ir.

The application of the catalytically active coating to the inner walls of the reactor tubes and / or the optionally used fixed bed may comprise the following steps:

1 . Providing a suspension comprising a) at least one active

Component selected from the metals Ti, Zr, Hf, Ni, Pd, Pt, Mo, W, Nb, Ta, Ba, Sr, Ca, Mg, Ru, Rh, Ir or combinations thereof or their silicide compounds, b) at least one suspending agent , and optionally c) at least one auxiliary component, in particular for stabilizing the suspension, for improving the storage stability of the suspension, for improving the adhesion of the suspension to the surface to be coated and / or for improving the application of the suspension to the surface to be coated.

2. Applying the suspension to the inner wall of the one or more reactor tubes and / or on the surface of the packing.

3. drying the applied suspension.

4. Annealing the applied and dried suspension in a

Temperature in the range of 500 ° C to 1500 ° C under inert gas or

Hydrogen.

The tempered fillers may then be in the one or more

Reactor tubes are filled. The tempering and optionally also the previous drying can also be done with already filled in packing.

As suspending agent according to component b) of the suspension according to the invention, in particular suspending agent with binding character, advantageously thermoplastic polymeric acrylate resins, as described, for. B. also used in the paint and coatings industry can be used. These include, for example, compositions based on polymethyl acrylate, polyethyl acrylate,

Polypropylmethacrylat and / or Polybutylacrylat. It is commercially available systems as they are available, for example under the brand name Degalan ^® from Evonik Industries.

Optionally, as further components, i. H. in the sense of component c), advantageously one or more auxiliary components are used.

So you can use as auxiliary component c) solvents or diluents. Preferably, organic solvents, in particular aromatic Lösebzw. Diluents, such as toluene, xylenes, as well as ketones, aldehydes, esters, alcohols or mixtures of at least two of the aforementioned solvents or diluents.

If necessary, stabilization of the suspension can advantageously be achieved by inorganic or organic rheological additives. The preferred inorganic rheology additives as component c) include, for example, kieselguhr, bentonites, smectites and attapulgites, synthetic

Phyllosilicates, fumed silica or precipitated silica. To the

organic rheology additives or auxiliary components c) preferably include castor oil and its derivatives, such as polyamide-modified castor oil, polyolefin or polyolefin-modified polyamide, as well as polyamide and derivatives thereof, such as those sold under the brand name Luvotix®, and mixed systems of inorganic and organic rheology.

As auxiliary component c) for improving the adhesion of the suspension to the surface to be coated, suitable adhesion promoters from the group of silanes or siloxanes can be used. These include, for example, but not limited to, dimethyl, diethyl, dipropyl, dibutyl, diphenylpolysiloxane or mixed systems thereof, such as phenylethyl or phenylbutylsiloxanes or other mixed systems, and mixtures thereof. The suspension according to the invention can be obtained in a comparatively simple and economical manner, for example by mixing, stirring or kneading the starting materials, ie components a), b) and optionally c), in suitable apparatuses known to the person skilled in the art.

The reaction in the process according to the invention is typically carried out at a temperature in the range from 700 ° C. to 1000 ° C., preferably from 850 ° C. to 950 ° C. and / or a pressure in the range from 1 to 10 bar, preferably from 3 to 8 bar, particularly preferably carried out from 4 to 6 bar and / or a gas stream.

Temperatures higher than 1000 ° C should be avoided to avoid uncontrolled silicon deposition.

The molar ratio of hydrogen to the sum of organochlorosilane (s) and silicon tetrachloride is advantageously set to be in a range of from 1 to 8: 1, preferably from 2: 1 to 6: 1, particularly preferably from 3: 1 to 5: 1, in particular 4: 1, is located.

The dimensioning of the reactor tube and the design of the complete reactor are determined by the availability of the tube geometry, as well as by the requirements regarding the introduction of the required for the reaction

Warmth. In this case, both a single reactor tube and a combination of many reactor tubes can be arranged in a heating chamber. Another advantage of using pressure-resistant and corrosion-resistant ceramic

Flow tubes here is the possibility of direct or indirect heating by means of natural gas burners, which provide much more economically the necessary energy input as electric power. However, the heat input for the reaction in the reactor can in principle by electrical resistance heating or combustion of a fuel gas such. B. natural gas. An advantage of using fuel gas heated systems is the uniform temperature control. electrical

Wderstandsheizungen can have local overheating, because the electrical resistance can not be maintained evenly enough by geometric deviations of the resistance-heated components or by wear, so that it comes to deposits and expensive shutdowns associated with cleaning the Consequence are. In order to avoid local temperature peaks on the reactor tubes during heating by means of fuel gas, the burners should not be directed directly at the tubes. For example, they can be distributed and aligned over the heating chamber so that they point into the free space between parallel reactor tubes. The mechanical stability of the tubes made of ceramic materials described above is high enough to set pressure levels of several bar, preferably in the range of 1 -10 bar, more preferably in the range of 3- 8 bar, more preferably 4-6 bar. The need for a metallic wall to be cooled, which must be protected against corrosion, is in contrast to

above-described reactors with graphite-based lining of the reaction spaces not.

To increase energy efficiency, the reactor system can be connected to a

Heat recovery system to be connected. In a special

Embodiment for this purpose one or more of the reactor tubes on one side

closed and each contain a gas-supplying inner tube, which preferably consists of the same material as the reactor tubes. Between the closed end of the respective reactor tube and the pointing to this opening of the inner tube, this is a case

Flow reversal. In this arrangement, each heat from between

Inner wall of the reactor tube and outer wall of the inner tube flowing product gas mixture transmitted by thermal conduction of the ceramic inner tube on the inner tube flowing in educt gas. Also the integrated

Heat exchanger tube may be at least partially coated with the above-described catalytically active material.

The following examples are intended to explain the process of the invention in more detail, but in no way limit it. Examples

example 1

Preparation of the catalyst paste, example according to the invention

In a mixing vessel, a mixture of 54 wt .-% toluene, 0.3 wt .-%

Aerosil R 974, 6.0% by weight of phenylethylpolysiloxane, 16.8% by weight of aluminum pigment Reflaxal, 10.7% by weight of Degalan solution LP 62/03 and 12.2% by weight of tungsten silicide mixed intensively. Example 2

Applying the catalyst paste, example of the invention

A silicon carbide (SSiC) ceramic tube was coated by the recipe described in Example 1 by placing the catalyst mixture in the

Reaction tube was filled. By shaking the stopper closed

Pipe, the mixture was evenly distributed, then in air overnight

dried. The tube had an inner diameter of 15 mm and a total length of 120 cm. The isothermally heated zone was 40 cm. Example 3

Catalyst Formation and Hydrogenation, Inventive Examples

The reactor tube was mounted in an electrically heatable tube furnace.

First, the tube furnace with the respective tube was brought to 900 ° C, with nitrogen at 3 bar was passed through the reaction tube absolute. After two hours, the nitrogen was replaced by hydrogen. After another hour in a stream of hydrogen, also below 3.6 bar absolute, were

Methyltrichlorosilane or a mixture of methyltrichlorosilane with silicon tetrachloride from Aldrich pumped into the reaction tube. The temperature in the tube furnace had already been set to 900 ° C as was changed from nitrogen to educt. The hydrogen stream was adjusted to a molar excess of 4 to 1. The reactor effluent was analyzed by online gas chromatography and from it the amounts of trichlorosilane, silicon tetrachloride, dichlorosilane and Calculated methyldichlorosilane. The calibration of the gas chromatograph was carried out with the pure substances.

The resulting hydrogen chloride or other by-products were not evaluated. The results are shown in Table 1.

Table 1

Results of the catalytic conversion of MTCS, optionally mixed with STC, with hydrogen

STC = silicon tetrachloride

TCS = trichlorosilane

DCS = dichlorosilane

MHDCS = methyldichlorosilane

Claims

claims:

1 . Process for the preparation of trichlorosilane,

characterized,

that hydrogen and at least one organic chloride are reacted in a pressure-operated reactor comprising one or more reactor tubes made of gas-tight ceramic material.

2. The method according to claim 1,

characterized,

that in combination with the at least one organic Chiorsiian additionally silicon tetrachloride is reacted with hydrogen to trichlorosilane.

3. The method according to claim 1 or 2,

characterized,

that methyltrichlorosilane is used as the only organic Chiorsiian.

4. Method according to one of the preceding claims,

characterized,

that in the reaction a hydrogen-containing reactant gas and at least one organic Chiorsiian contained educt gas and optionally a

Siliziumium tetrachloride-containing educt gas are reacted in a reactor by supplying heat to form a product containing tnchlorsilan gas the organochlorosilane educt gas and / or the hydrogen-containing educt gas and / or the silicon tetrachloride educt gas are fed as pressurized streams in the pressure-operated reactor and the product gas as below Pressure current from the

Reactor is led out.

5. The method according to claim 4,

characterized, in that the organochlorosilane-containing educt gas and the hydrogen-containing educt gas and, if present, the silicon tetrachloride-containing educt gas are conducted in a common stream into the pressure-operated reactor.

6. The method according to any one of the preceding claims,

characterized,

that the molar ratio of hydrogen to the sum of

Organochlorosilane (s) and silicon tetrachloride in a range from 1: 1 to 8: 1, preferably 2: 1 to 6: 1, particularly preferably 3: 1 to 5: 1,

especially 4: 1, is.

7. The method according to any one of the preceding claims,

characterized,

that the reaction at a pressure of 1 to 10 bar and / or a

Temperature in the range of 700 ° C to 1000 ° C and / or a gas flow is performed.

8. The method according to any one of the preceding claims,

characterized,

in that the heat supply for the reaction in the reactor takes place by electrical resistance heating or combustion of a fuel gas.

9. Method according to one of the preceding claims,

characterized,

the gas-tight ceramic material from which the reactor tubes consist is selected from SiC or S13N4, or mixed systems (SiCN) thereof.

10. The method according to claim 9,

characterized,

the gas-tight ceramic material is selected from Si-infiltrated SiC (SiSiC) or non-pressure sintered SiC (SSiC). Method according to one of the preceding claims,

characterized,

in that at least one reactor tube is closed on one side and contains a gas-supplying inner tube.

Method according to one of the preceding claims,

characterized,

in that at least one reactor tube is filled with fillers which consist of the same gas-tight ceramic material as the tube.

Method according to one of the preceding claims,

characterized,

the inner walls of at least one reactor tube and / or at least part of the filler bodies are coated with at least one material which catalyzes the conversion of hydrogen with organochlorosilane (s) and optionally silicon tetrachloride to trichlorosilane.

Method according to claim 13,

characterized,

in that the catalytically active coating consists of a composition comprising at least one active component selected from the metals Ti, Zr, Hf, Ni, Pd, Pt, Mo, W, Nb, Ta, Ba, Sr, Ca, Mg, Ru, Rh , Ir or

Combinations thereof or their silicide compounds. 15. The method according to claim 13,

characterized,

the application of the catalytically active coating comprises the following steps:

- Providing a suspension containing a) at least one active

Component selected from the metals Ti, Zr, Hf, Ni, Pd, Pt, Mo, W, Nb,

Ta, Ba, Sr, Ca, Mg, Ru, Rh, Ir or combinations thereof or their silicide compounds, b) at least one suspending agent, and optionally c) at least one auxiliary component for stabilizing the suspension and / or to improve the storage stability of the suspension and / or to improve the adhesion of the suspension to the surface to be coated and / or to improve the application of the suspension to the surface to be coated;

- Applying the suspension to the inner wall of the one or more reactor tubes and / or on the surface of the packing

- drying the applied suspension;

- Annealing the applied and dried suspension in a

Temperature in the range of 500 ° C to 1500 ° C under inert gas or

Hydrogen;

optionally filling the tempered packing in the one or more reactor tubes, wherein the annealing and optionally also the previous drying can be done with already filled in packing.