KR20030050411A - A method for preparing mono-silane from residues with high boiling point - Google Patents

Abstract

PURPOSE: A method for preparing mono-silane from residues with high boiling point is provided, thereby converting the residues with high boiling point as wastes of direct synthesis of mono-silane to mono-silane useful commercially. CONSTITUTION: A method for preparing mono-silane of formula; RyHzSiCl4-y-z from residues with high boiling point comprises reacting the residues with high boiling point which are prepared by the reaction of organochloride and silicon metal with a catalyst composition consisting of hydrogen chloride, tertiary organic amine, and aluminium trichloride. In the formula, R is selected from the group consisting of alkyl and aryl having carbon number of 1 to 6, alkoxy having carbon number of 1 to 6, trimethylsillyl and trifluoropropyl; y is an integer of 0 to 4, z is an integer of 0 to 3, and y+z is 0 to 4. The reaction temperature and pressure are 150 to 500 deg. C and 0.69 to 34.5 Mpa(100 to 5000 psi), respectively.

Description

A method for preparing mono-silane from residues with high boiling point

The present invention relates to a method for preparing monosilane from a high boiling point residue produced by reacting organochloride and metal silicon by a direct synthesis method, and more particularly, high boiling point produced during reaction of organochloride and metal silicon. A method of preparing monosilane by adding a catalyst composition comprising aluminum trichloride and a catalytic amount of tertiary organic amine effective to promote the formation of monosilane to a mixture comprising a residue and hydrogen chloride.

The high boiling point residues mentioned in the present invention are residues boiling above 70 ° C, and higher than chloromethylsilanes and organochlorosilanes including dimethyldichlorosilane and trimethylchlorosilane in addition to the monosilane obtained by the direct synthesis method. Means a residue that boils at temperature.

In addition, the present invention requires the presence of a catalytic amount of the catalyst composition, which means an amount of catalyst composition sufficient to promote the conversion of silicon-containing compounds to monosilane in the high boiling residue.

In preparing the organochlorosilanes by direct synthesis, a mixture comprising a high boiling residue is formed and distillation is usually used to separate the monosilane from these mixtures.

Typical high boiling residues are obtained by distilling the products from the direct synthesis methods described in the patent documents of US Pat. Nos. 2,598,435, 2,681,355, 2,380,995 and 2,488,487. The residue remaining after distilling the upper layer of monosilane is a mixture containing, for example, high boiling silicon comprising compounds with silicon-silicon, silicon-oxygen-silicon and silicon-carbon-silicon bonds in the molecule, It also contains silicon fine particles and metals or compounds thereof.

U. S. Patent No. 2,709, 176 describes a process for forming organohalogen monosilanes by heating organohalogenpolysilanes comprising silicon-silicon bonds in the presence of tertiary organic amines and hydrogen halides at elevated temperatures to decompose silicon-silicon bonds. It is starting. However, the above method has a problem in that it does not convert the fern having two or less chlorine substituents into monosilane.

U. S. Patent No. 4,393, 229 describes a process for converting dialkyl-rich alkyl groups into halogen-rich polysilanes in the residue obtained in the preparation of alkylhalosilanes. This process involves treating an alkyl-rich disilane-containing residue with an alkyltrihalosilane or silicon tetrahalide at elevated temperatures in the presence of a catalyst and a hydrosilane accelerator, and aluminum trichloride is used in conjunction with a hydrosilane promoter. It is a useful catalyst if. In addition, in the separation step, the resulting halogen-rich polysilane can be decomposed to yield monosilane.

However, the above method is inefficient in process because the conversion rate of polysilane to monosilane is low and alkaltrihalosilane and sahalosilane separated by distillation must be added to the high fertilizer again.

U.S. Patent No. 2,681,355 suggests contacting hydrogen chloride at elevated temperatures with high boiling residues resulting from the direct process to form methylchlorosilanes. U. S. Patent No. 5,175, 329 also describes a process for preparing organosilanes from high boiling point residues produced by a direct synthesis method that completely consumes organotrichlorosilane. In this process, the high boiling residue is contacted with the organotrichlorosilane and hydrogen gas in the presence of a hydrogenation catalyst and a redistribution catalyst.

U.S. Patent 5,430,168 discloses a process for forming a mixture comprising organotrihalosilane and high boiling residues in the presence of hydrogen gas and catalytic amount of aluminum trichloride, in which organotrihalosilane is consumed completely. Indicating that monosilane is formed. However, according to the above-described process, there is a problem that a considerable high temperature and high pressure are required in the process.

U.S. Pat.No. 5,292,912 discloses a high boiling point residue from a direct synthesis method with a catalyst selected from the group consisting of activated carbon, platinum supported on alumina, zeolite and aluminum trichloride and aluminum trichloride supported on a support selected from the group consisting of carbon, alumina and silica. A process involving contacting with hydrogen chloride at a temperature in the range of 250-1000 ° C. in the presence thereof is shown.

In current commercial processes for performing direct synthesis, about 5% by weight of the product consists of high-boiling residues, which are converted into commercially available products to improve the use of raw materials and to reduce industrial waste. It was also necessary to reduce the costs of supplying raw materials and waste disposal, and to develop effective methods for environmental conservation.

Commonly used methods in the above-mentioned processes used distillation to convert the high-boiling residues produced by the direct synthesis into monosilane, and a catalyst and a catalyst adjuvant were used to promote this reaction.

However, there is an urgent need to develop a more practical process that improves the conversion of high-fertilizer to monosilane and solves the above problems.

Therefore, the present inventors have tried to find a method for converting the high-boiling residue obtained in performing the above-described direct synthesis into a commercially available product in an effective manner. As a result, high-boiling residues using the catalyst composition of the present invention can promote redistribution of alkyl and chlorine groups between silicon atoms, hydrochlorination and silicon-silicon bonds, or optionally silicon-carbon bonds. Knowing how to convert to commercially available monosilane has completed the present invention.

Therefore, the present invention converts the high-boiling residue produced in the current commercial process for performing the direct synthesis into monosilane, which is a commercially useful product, thereby improving the use of raw materials and reducing waste, thereby reducing the cost of the environment. It is an object to provide a catalyst composition for use in the process for the conversion of monosilane from high boiling point residues which is also effective in preservation.

In addition, the catalyst composition of the present invention comprises at least one chemical component which provides the above activity in the process claimed in the present invention, in general, any Lewis acid or its equivalent is redistributed to the catalyst composition of the present invention. Can be used to provide activity

The present invention provides a high boiling point residue produced from the reaction of organochloride and metal silicon with a catalyst composition consisting of hydrogen chloride, tertiary organic amine and aluminum trichloride, and a temperature of 150 to 500 ° C. and 0.69 to 34.5 Mpa (100 to 5000 psi). And reacting at high pressure to convert the high boiling point residue into monosilane.

The present invention will be described in more detail as follows.

Conventional methods for reacting organochlorides with metallic silicon consist of reacting the mixture at a temperature of 300-350 ° C. in the presence of a suitable catalyst composition and gaseous material. Here, the supplied raw material is continuously separated from the manufacturing process as fine powder is formed during the reaction. The distillation of the separated material to recover the organochlorosilane leaves a high boiling residue and to the mixture of high boiling residue and hydrogen chloride is added a catalyst composition effective to promote the formation of monosilane.

According to the present invention, a high boiling point residue and a hydrogen chloride mixture produced by reacting organochloride and metal silicon by direct synthesis have a temperature of 150 to 500 ° C., preferably 275 to 425 ° C., and most preferably 300 to 375 ° C. Of the amount of catalyst at a reactor gauge pressure of 0.69 to 34.5 Mpa (100 to 5000 psi), preferably 2.07 to 10.03 Mpa (300 to 1500 psi), most preferably 4.14 to 7.6 Mpa (600 to 1,100 psi) Contacting the catalyst composition. The amount of catalyst composition added depends on the chemical component comprising the catalyst composition, and the amount added is easily determined by those skilled in the art.

Preferred high-boiling residues used in the monosilane preparation process of the present invention are boiling points above 70 ° C. produced by distillation of organochlorosilanes from the reaction products of methylchloride and metalsilicon, typical of such high-boiling residues. The composition comprises 1-5 wt% ethylmethylsilane, 60-80 wt% disilane, 15-25 wt% silmethylene, 5-15 wt% other high boiling silicon containing compounds; 1 to 5% by weight of silicon-containing fine particles and a catalyst delivered from a direct process such as copper, aluminum, calcium, iron or compounds thereof.

More specifically, the disilane and silmethylene may be represented by the following Chemical Formulas 1 to 2, each containing 2 to 4 methyl substituents per molecule.

Si2Q6

Wherein Q is each independently selected from methyl or chlorine.

Q3SiCH2SiQ3

Wherein Q is each independently selected from methyl or chlorine

In the process of the invention the mixture may be formed outside the reactor and then added to the reactor or by adding each component to the reactor independently.

The content of hydrogen chloride constituting the mixture is in the range of 1 to 70% by weight, preferably 15 to 50% by weight, based on the weight of the high boiling residues supplied to the reactor.

Monosilane production process according to the present invention can be carried out in a batch process or a continuous process using a standard pressurized reactor suitable for contact with chlorosilane, the standard pressurized reactor is a stirred bed reactor, a continuous stirred tank reactor, bubble -Ball-column reactors, trickle-bed reactors or plug-flow reactors.

Preferred catalyst composition used in the present invention is composed of a tertiary organic amine represented by the following formula (4) and aluminum trichloride.

NR3

Wherein R is selected from the group consisting of alkyl having 1 to 6 carbon atoms, aryl, alkoxy having 1 to 6 carbon atoms, trimethylsilyl and trifluoropropyl, trimethylamine, triethylamine, N-dimethylaniline, pyridine, quinoline, tri n-butylamine, N, N-dimethylbenzylamine and the like, but preferred is when R is methyl.

Tertiary organic amine is added to the mixture during the manufacturing process, aluminum trichloride can be added as a compound during the manufacturing process or formed from high boiling residues during the heating or reaction process, and the catalytic amount of aluminum trichloride is added to the aluminum trichloride and the process It may be a combination of aluminum trichloride formed therein.

In the process for producing monosilane from the high boiling residues of the present invention, tertiary organic amines facilitate the hydrochlorination of silicon-silicon bonds to facilitate conversion to monosilanes and Lewis acids such as aluminum trichloride are interposed between silicon atoms. Effective in redistributing alkyl and chlorine groups. Such Lewis acids include aluminum trichloride, antimony pentachloride, zirconium tetrachloride, potassium aluminum tetrachloride, quaternary phosphonium halides, quaternary ammonium halides, ammonium halides, copper chloride, boric acid and boron halides.

The addition amount of the tertiary organic amine is usefully 0.1 to 5.0% by weight based on the combined weight of the catalyst composition and the high boiling point residue, preferably in the range of 0.5 to 2.0% by weight.

When aluminum trichloride is added to the catalyst composition, the catalyst composition is useful in the range of 0.01 to 10% by weight, preferably in the range of 0.5 to 5% by weight, based on the combined weight of the catalyst composition and the high boiling residue.

The monosilane of the following formula (5) is recovered by the method of the present invention.

RyHzSiCl4-y-z

In the above, R is selected from the group consisting of alkyl having 1 to 6 carbon atoms, aryl, alkoxy having 1 to 6 carbon atoms, trimethylsilyl and trifluoropropyl.

y is 0-4, z is 0-3, y + z is 0-4.

In general, the monosilane products of this process generally include dimethyldichlorosilane (Me ₂ SiCl ₂ ), methyldichlorosilane (MeHSiCl ₂ ) and methyltrichlorosilane (MeSiCl ₃ ), with other monosilanes being formed only in small amounts. . In particular, dimethyldichlorosilane is the most industrially useful material obtained through direct synthesis and is used as a main raw material for silicone oil and rubber production.Methyltrichlorosilane and methyldichlorosilane are also major monomers in the silicone industry. Their use is becoming increasingly important.

Hereinafter, the scope of the present invention is not limited as described in detail through the embodiments of the present invention.

Example

0.15 kg of the high-boiling residue filtered from the direct synthesis method in which methyl chloride was reacted with metal silicon to prepare methylchlorosilane was added to the reactor. The main component of the high boiling point residue is shown in Table 1 based on the weight%.

Based on 5% by weight of tertiary organic amine and 3.5% by weight of aluminum trichloride, based on the weight% of the high boiling residue, 0.03 to 0.04 kg of hydrogen chloride gas was introduced into the reactor. The reactor was heated to 325 ° C. and the gauge pressure inside the reactor was 4.8-6.9 Mpa (700-1000 psi) and stirred for 3 hours to react.

The reactor used for this reaction is a stirred-batch reactor, a Parr Bomb reactor, which is stirred by aerodynamics of 650 ml capacity.

The monosilane obtained at the end of the reaction was analyzed by gas chromatography using a thermal conductivity detector and the results obtained are shown in Table 2 below, which is a net value calculated by weight percentage of monosilane species from total monosilane present in the product. .

As shown in Table 2 above, all of the disilane was converted from the high boiling residue to monosilane by the method of the present invention, and about 50% of the silmethylene was converted to monosilane. The resulting monosilanes are also commercially valuable in the use of high boiling residues, mainly as commercially available methyltrichlorosilane, methyldichlorosilane and dimethyldichlorosilane.

Comparative example

0.15 kg of the high-boiling residue filtered from the direct synthesis method in which methyl chloride was reacted with metal silicon to prepare methylchlorosilane was added to the reactor.

Based on the weight percent of the high boiling residues, aluminum trichloride was added to the reactor with 3.5 wt% added to the reactor followed by 0.03-0.04 kg hydrogen chloride gas. The reactor was heated to 325 ° C. and the gauge pressure inside the reactor was 4.8-6.9 Mpa (700-1000 psi) and stirred for 3 hours to react.

The reactor used for this reaction is a stirred-batch reactor, a Parr Bomb reactor, which is stirred by aerodynamics of 650 ml capacity.

The monosilane obtained at the end of the reaction was analyzed by gas chromatography using a thermal conductivity detector and the results obtained are shown in Table 2 below, which is a net value calculated by weight percentage of monosilane species from total monosilane present in the product. .

As shown in Table 3 above, the conversion rate of disilane to monosilane was 100%, and in the case of silmethylene, 20 wt% was converted to monosilane, but the main products from which high-boiling residues were converted were methyltrichlorosilane and As the tetrasilane, there is a problem that the commercial utility of the monosilane produced in comparison with the embodiment of the present invention is poor.

According to the present invention, the high boiling point residue produced by the direct synthesis can be converted into a high conversion ratio into monosilane, which is easy for commercial use, by using a catalyst composition composed of tertiary organic amine, aluminum trichloride, and the like. Can be used as

Claims (5)

A high boiling point residue resulting from the reaction of organochloride and metal silicon is reacted with a catalyst composition consisting of hydrogen chloride, tertiary organic amine and aluminum trichloride to convert it into monosilane represented by the formula (5). Formula 5 RyHzSiCl4-y-z here, R is selected from the group consisting of alkyl and aryl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms, trimethylsilyl and trifluoropropyl, y is 0-4, z is 0-3, y + z is 0-4. The method according to claim 1, wherein the tertiary organic amine is used in an amount of 0.1 to 5.0% by weight based on the combined weight of the catalyst composition and the high boiling point residue. The method of converting high-boiling residue to monosilane according to claim 1, wherein the aluminum trichloride is used in an amount of 0.01 to 10% by weight based on the combined weight of the catalyst composition and the high-boiling residue. The method of claim 1, wherein the hydrogen chloride is used in an amount of 1 to 70% by weight based on the high boiling residue. According to claim 1, the high boiling point residue, tertiary organic amine, hydrogen chloride and catalytic composition of the catalyst composition is reacted at a temperature of 150 ~ 500 ℃ at a pressure of 0.69 ~ 34.5 Mpa (100 ~ 5000 psi) mono represented by the formula (5) How to convert to silane.