JPS6322096A - Production of alkylchlorosilane - Google Patents

Abstract

PURPOSE:To inexpensively obtain the titled compound having Si-H bond useful for such as a raw material for producing a H-oil, etc., from a readily available raw material, by reducing alkyltrichlorosilanes, followed by replacing hydrogen atoms of thus produced alkylsilanes with chlorine atoms by a specific method. CONSTITUTION:First, alkyltrichlorosilanes expressed by the formula RSiCl3 (R represents alkyl, alkenyl or aryl) as a starting raw material are reacted with an alkylaluminum hydride preferably in an inert atmosphere at 0-50 deg.C for 30min-5hr to carry out reduction. Then the obtained alkylsilanes expressed by the formula RSiH3 are reacted with alkyltrichlorosilanes expressed by the formula R<1>SiCl3 (R<1> is R) preferably under an inert atmosphere at 0-100 deg.C to replace hydrogen atoms with chlorine atoms and obtain the aimed compound having Si-H bond. The starting raw material is preferably CH3SiCl3 and the alkylaluminum hydride is preferably (C2H5)2AlH, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention is directed to the use of alkyltrichlorosilanes represented by the general formula R51Cl;
The present invention relates to a method for producing alkylchlorosilanes having two Si-H bonds.

[Background technology]

In recent years, the progress of the organosilicon chemical industry has been extremely steady, and except for exceptional stagnation during oil shocks and economic recessions, it has always reached 2.
This shows extremely high growth. The main product applications of organosilicon chemistry include silicones (elastomers, oils, resins), silane coupling agents, silylation agents, hard coating agents, etc., and the trend of producing a wide variety of products in small quantities, which has traditionally been seen in this field, has changed. In recent years, the development of highly functional products tailored to various uses has become more and more active.

Demand for the alkylchlorosilanes having at least one Si-)1 bond according to the present invention has recently increased significantly as high-performance products, such as CHzSiH
CIg (methyldichlorosilane) produces so-called H oil through hydrolysis and polycondensation, and is attracting attention as a fiber treatment agent, water injection agent, modification additive, etc. The hydrogen atoms of H oil are active and react with various alcohols in the presence of a basic catalyst to give a considerable amount of poly(methylalkoxy)siloxane.

These are crosslinked in the presence of A1 medium, but the methoxylated product undergoes a simple de-etherification reaction under non-catalytic heating to give a cured product. Phenoxides are stabilized due to steric hindrance. Unlike polydimethyl silicone (PD-S), it is an interesting silicone because it has high compatibility with various resin materials and is useful for imparting water repellency and heat resistance.

Also, CF3CHzC obtained by adding CF2Cl-CH2 (trifluoropropylene) to CH3SiHCh
)IzSiC)lxch (T-trifluoropropylmethyldichlorosilane) is hydrolyzed and a redistribution reaction is performed to obtain fluorosilicone.

It is chemically and thermally extremely stable, and has excellent antifoaming and lubricity properties for organic solvents, and can be used as a lubricant for chemical pumps and compressors, as a sealing material when mixed with shifufuna, as a caulking material, or as a mold release agent. Its high functionality is also utilized. In particular, elastomers are used in large quantities in aircraft-related applications. In addition, RSiHCh or RSiHz (:l
Because Si-H bonds are rich in reactivity, various silanes are used in the synthesis of organic silicon compounds.For example, as shown in the formula below, they are reacted with various olefins to produce raw materials for producing silane cuffing agents, etc. It is also used as

CHz-CM-SiR(OCH3) zCHz=CH-
SiR(OCI(3) z(jl, 0H CH=CH+RSiHzC1j CHz=C)ISil
lHCl → CL engineering C1 (SiR(OCL) 2) Furthermore, it can also be used to produce phenylsilane compounds used as festivals, oils, etc. by reacting with benzene or chlorobenzene, for example, as shown in the following formula.

-) ICI As described above, the usefulness of alkylchlorosilanes, which are the object of the present invention, has been rapidly recognized in recent years, and their uses are rapidly expanding.

On the other hand, these alkylchlorosilanes can be produced by reacting silicon containing metal with chlorinated hydrocarbons, a so-called direct method.
Although it is industrially produced together with alkylchlorosilanes that do not have an i-H bond, the production ratio of both is almost constant, and there is a limit to increasing the production amount due to the balance with alkylchlorosilanes for cough and other purposes. There is. Furthermore, if operating conditions are adopted to improve the yield of the alkylchlorosilanes, the yield of dialkyldichlorosilane, which is the main target product, will decrease, which is not preferable.

For example, the production ratio of each product in the direct reaction method of metal silicon and methyl chloride currently used by silicone manufacturers is approximately as follows, and the production ratio of CHiS+HC1z, which is the target substance of the present invention, is only a few %. It's nothing more than that.

32 2X 9χ The present inventors took the above circumstances into consideration and made earnest efforts to develop a new method for producing alkylchlorosilanes as described above, and as a result, they arrived at the present invention. That is, the present invention provides a process for producing alkylchlorosilanes having at least one Si-H bond at low cost using alkyltrichlorosilanes (RSiCh or R' Sil (CI 3), which are presently in excess and easily available, as raw materials. This is what we do.

[Summary of the invention]

That is, the present invention uses alkyltrichlorosilanes represented by the general formula R51Ch (where R is an alkyl group, an alkenyl group, or an atomyl group) as a starting material to produce an alkylchlorosilane having at least one Si-H bond. a process for producing alkylsilanes having the general formula RSiHs (wherein R is as defined above) by reducing the RSiCl 3 with an alkyl aluminum hydride, and Q) l The alkylsilanes represented by the obtained R51lh and the alkyl tris represented by R'SiC13 (wherein R' is an alkyl group, an alkenyl group, or an aryl group, and may be the same as or different from R) The gist of the present invention is a method for producing alkylchlorosilanes, which comprises at least the steps of: reacting chlorosilanes with hydrogen and chlorine to exchange hydrogen and chlorine;

[Detailed disclosure of the invention]

The present invention will be explained in detail below.

The alkyltrichlorosilanes used as starting materials in the present invention are alkyltrichlorosilanes represented by -In2R31C13, where R is an alkyl group, an alkenyl group, or an aryl group, and these are halogen or amino groups. It may also contain substituents such as.

Specifically, as the alkyl group, for example, -CHl, -C2
H4, -(CHz) zcHx,=CH(CH,) z
, -(CHI) zcL, -C)It(jl(CHz
) z, -C(CH3) x, -(CL) *CHx
, -(CJI z) 5CHx , -C)IzCHzC
Examples of the alkenyl group include -CI(=CH2, -C)I.

-CH-CHg-, -(CHz)zcH=cHt,
The following are particularly preferred.

In particular, C)13SiC13 is obtained as a by-product in the production process of (C1h)zsiclz, which is the main raw material of soricone, by the so-called direct method described above, but it currently exists in excess and its use and efficacy are limited. There is no established way to use it, and it can be obtained at an extremely low cost.

In the present invention, alkylsilanes are first obtained by reducing these alkyltrichlorosilanes with alkylaluminum hydrides, and the alkylaluminum hydrides used for the reduction have the general formula R'R''A
It is a compound that has a reducing ability indicated by IH. Here, R1 and R2 are both alkyl groups having 1 to 10 carbon atoms, such as -C2H4, -(CLLCL, -
CHzCH(CH3)z R1 and R2 may be the same or different. Among the compounds represented by the above general formula, particularly preferred examples include (CJs)
! AI) l, ((CL) xcHcH'z ) z
Al)I.

Furthermore, due to the manufacturing process, these alkyl aluminum hydrides are cheaper and easier to manufacture industrially as a mixture with trialkylaluminum, but in the present invention, this mixture is directly reduced without separating the trialkylaluminium. It can also be used as an agent.

In mixtures of alkyl aluminum hydride and trialkylaluminium, -S often contains the same -f[ alkyl group.

However, when used in the practice of the present invention, a mixture of different alkyl groups may be used.

Furthermore, the alkyl aluminum hydride and the trialkylaluminium may each be a mixture of compounds having different alkyl groups.

A mixture of alkylaluminum hydride and trialkylaluminium hydride having a weight ratio of about 3 to 8:2 is usually easily available.

+a1 The reduction reaction in the first step of the present invention is usually carried out by mixing and reacting the raw material alkyltrichlorosilane and the reducing agent alkyl aluminum hydride in a solvent, but the applicant has already reported that Showa 57
-209815, and as proposed in JP-A-58-9809, a certain amount of dialkyl aluminum monohalide is added in advance to an alkyl aluminum hydride, or a certain amount of alkyl aluminum halide is added to a mixture of an alkyl aluminum hydride and a trialkyl aluminum, It is preferable to add it prior to the reaction (this is preferable in terms of suppressing by-products of impurities of the target alkylsilanes and improving yield).

Such alkyl aluminum halide has the general formula R'
, , IAIX, -n (where n is O, 1, 1, 5 or 2). (In the formula, R3 is an alkyl group having 1 to 10 carbon atoms, such as -CJ
s, -(CHz) xcHff, or -CLCI(
(CL) 2nd grade. X is a halogen atom, such as Cl or Br. ) Preferred examples of alkyl aluminum halides include (ClH5) 1
AIcl, ((CHs)tcHc)It)zAlc
l 1C, HsAICh, (CzHs)+, 5AIC
++, s-((CH3)ZCH(412) AlC11
, ^lCh. These compounds may be used alone or in combination, and when a dialkyl aluminum monohalide is added to an alkyl aluminum hydride, the amount added is 50 mol or more of the alkyl aluminum hydride, and more preferably. It is 70 mol% or more. Also, according to the formula below, 90 mol% of the alkyl aluminum hydride and trialkyl aluminum halide
The above amount is sufficient to convert the above into dialkyl aluminum monohalide, or the amount of trialkyl aluminum is 10% of the amount of the alkyl aluminum hydride.
This is the amount that reduces the amount to less than mol%.

R3AI + RAIXz →2AIRZχ In the latter case, the amount of alkyl aluminum halide added is:
It is determined by the amount of trialkylaluminum in the mixture and the amount of halogen atoms present in the aluminum halide in the alkino to be added. The upper limit of the amount added is not particularly limited, but it is sufficient to add the minimum stoichiometric amount. Adding too much will reduce the concentration of alkyl aluminum halide and increase the total amount of alkyl aluminum compounds, resulting in increased industrial disadvantages such as a decrease in reaction rate, an increase in the volume of the reaction vessel, and an increase in the amount of heat used. So I don't like it.

The alkyl aluminum halide may be added to the alkyl aluminum hydride by directly mixing the two, or by diluting them with a solvent and mixing them.

In the reaction between the alkyltrichlorosilanes of the present invention and the above-mentioned alkyl aluminum hydride (particularly in the case of a mixture with trialkylaluminum, preferably a certain amount of alkyl aluminum halide is added), the use of a reaction solvent is of course essential. However, it is generally preferable to use a solvent because the reaction becomes graceful and the reaction can be easily controlled.

In addition, regarding the reaction solvent, in order to recover the alkyl aluminum present in the reaction system after the reduction reaction, a solvent that does not react with the alkyl aluminum and does not form a complex is preferable. Specifically, they include heptane, octane, liquid paraffin, benzene, and toluene.

On the other hand, in order to carry out the reaction faster and at a lower temperature, it is preferable to use a polar solvent such as diethyl ether or tetrahydrofuran. Simple operations such as the above have the disadvantage that aluminum alkyls cannot be separated and recovered, making the separation operation difficult.

The reaction temperature is generally preferably in the range of -30°C to 100°C, more preferably in the range of 0°C to 50°C.

Reaction time may vary depending on temperature, pressure, etc.
The time is usually from several minutes to 20 hours, preferably from 10 minutes to 10 hours, and more preferably from 30 minutes to 5 hours. Further, the reaction pressure is usually normal pressure or 2 Kg/aJ (gauge pressure), but it goes without saying that the reaction may be carried out under reduced pressure or higher pressure depending on the reaction temperature or equipment.

The raw materials and products used in the reaction are active, and most of them easily decompose or ignite when they react with oxygen and moisture, so the reaction must be carried out in an atmosphere that is inert to the raw materials and products produced. It is preferable to do this below.

For example, separation of the reaction product after completion of the six reactions, which must be carried out under an atmosphere of an inert gas such as helium argon or nitrogen or hydrogen which has been sufficiently deoxidized and dehydrated, can be carried out by a conventional method such as distillation.

(b) In the present invention, trialkylsilanes represented by RSiH3 produced by decomposition in the second step and RoS
It reacts with an alkyltrichlorosilane represented by iCh (wherein Ro has the same meaning as R defined above) to exchange hydrogen and chlorine. The reaction in this step is a so-called exchange reaction of hydrogen and chlorine in a silane compound, and is thought to be a type of equilibrium reaction as shown in the following formula. That is, as shown in the following equation.

I! SiH3+ R'5tCIs = R51) IzC
l + R'SiHCh (R and Ro may be the same or different) The alkylchlorosilanes having at least one Si-)1i bond obtained by the present invention have the general formula, R51lh
It is represented by CI, R31HCIz, R'SiHtel, or RoSiHC11 (R and Ro represent an alkyl group, an alkenyl group, or an aryl group).

This reaction is a catalytic reaction, and the catalyst used is:
Surprisingly, known chlorosilane disproportionation catalysts can be used. As such a liquid phase homogeneous catalyst, (CHx
)xN, (Czll5)J, tertiary amines such as pyridine (e.g. USP-2834648); N
cyanamides such as mcN(CH3)2, N=CH(CJs)z (e.g., nitriles such as USP-2
732282) ; etc. (e.g., JP-A-57-209816); and such solid catalysts include macrocyclic ethers attached to crosslinked polystyrene and inorganic salt catalysts (e.g., LISP-45489).
17), tertiary amine, tertiary amine hydrochloride and quaternary ammonium salt type anion exchange resins (e.g. [l5P-3
968199, 15P-3928542) or reaction products of sulfonic acid type cation exchange resins and various amines (JP-A-6O-125127). Catalysts are more preferred.

In the present invention, (alkyltrichlorosilanes to be reduced in the first step and (b) alkyltrichlorosilanes used in the reaction with the alkylsilanes in the second step are It goes without saying that the groups (alkyl groups, etc.) do not have to be the same and can be freely selected depending on the availability of alkyltrichlorosilanes and the change in yield in the reduction reaction or exchange reaction.

For example, (L)(7)I[CHiSiCI* + 3(C
zHs)tAIH-CI'1tSiHff+3(CJs
)zAIcl (However, a+c-b+ds2 is a+b+c+d=4
) The second step, the exchange reaction, can be performed in either the gas phase or the liquid phase.
(The same solvent used in step 11 can be used. Furthermore, the process can be carried out under elevated pressure, normal pressure, or reduced pressure. The raw materials and products react with oxygen and moisture. As in the first step, the reaction must be carried out in an atmosphere that is inert to the raw materials and products produced.There is no particular restriction on the reaction temperature; Although it varies depending on the temperature, it is generally in the range of 0 to 200°C, preferably 0 to 100°C.The reaction time is not particularly limited, but for example, in a gas phase reaction, it is 1 second to 2 hours, and in a liquid phase reaction, it is 1 second to 5 hours. That's about it.

In the present invention, the first step tal and the second step (bl) may be carried out sequentially or simultaneously; in the case of the former, alkyltrichlorosilanes are first added to the first reaction tank. It may be a continuous reaction operation in which a catalyst is supplied, and the produced alkylsilanes obtained by performing the first step, the catalyst, and the alkyltrichlorosilanes are supplied to a second reaction tank and then the second step is performed. In addition, the same reaction tank is first charged with a catalyst and alkyltrichlorosilanes to perform the first step, and when the alkylsilanes are generated, the alkyltrichlorosilanes and catalyst are supplied to the reaction tank and the second step is performed. It may also be a batch reaction operation.

In the latter case, the reduction reaction catalyst, the exchange reaction catalyst, and the alkyltrichlorosilanes are simultaneously charged into the same reaction tank, and the first step and the second step are carried out spatially and temporally simultaneously.

Next, an example of the present invention will be explained using a continuous process shown in FIG.

In FIG. 1, 1 is a mixing treatment tank for alkyl aluminum hydride (or a mixture of this and trialkylaluminium) and alkyl aluminum halide; The alkyltrichlorosilane V4 (RSiC13) is transferred to a similar reduction tank and used to reduce alkyltrichlorosilane V4 (RSiC13).
h) is separated from other reactants and solvent in the distillation column 5, and further mixed with alkyl) IJ dichlorosilanes in the exchange reaction tank or exchange reactor 3, and then processed in the second step (b).
), if a solid catalyst is used here, a catalyst bed filled with the solid catalyst is formed, and alkylsilanes and alkyltrichlorosilanes are continuously supplied to the catalyst bed to carry out the exchange reaction. is preferred.

In this case, 3 is not the tank wall, but rather the front type. Note that the generated target product alkylchlorosilane H (RSiHClg or RSiHiC1) is separated in the distillation column No. 6, and unreacted alkyltrichlorosilanes and alkylsilanes are recycled to the reactor No. 3 for reuse. Distillation column 4 separates high-boiling components after the reduction reaction, and can recover the solvent and various alkyl aluminum compounds.

If there is a compound that is not directly required among the obtained alkylchlorosilane [(RSiHCh or RSiHiC1, etc.), the compound is collected and re-processed in step 2 in Figure 1.
It goes without saying that it is also possible to reduce the compound to an alkylsilane by reducing it to an alkylsilane, or to use it in an exchange reaction with an alkyltrichlorosilane in 3 in FIG.

The present invention will be explained below with reference to Examples.

<Example 1> A 500n+ 1 stainless steel induction stirring autoclave was equipped with a condenser set at -50°C, and a stainless steel gas trap was attached to the end of the condenser.

Furthermore, CHzSiC1 dissolved in liquid paraffin from the outside
A 3W metering pump was connected. The charging tube was a dip tube. These entire systems were placed in a helium atmosphere before the reaction. The gas collection trap was cooled with liquid nitrogen. (C.J.s.
) 82.4 g (958 mmol) of zAIH was diluted in 80 g of liquid paraffin. Then, (CzHs)zAl
127.4 g (1056 mmol) of cl was dissolved in 100 g of liquid paraffin and added dropwise.

(CJs) against zAIH (CzHs) zAIc
The molar ratio of l is 110 mol χ.

This mixture was charged into an autoclave and heated to 21w at room temperature.
It was degassed for 20 minutes under reduced pressure of #IHg, and then the atmosphere was returned to helium.

On the other hand, C) IzSiCh 39.8g (266mno
+) was dissolved in 60 g of liquid paraffin. This was pressurized into an autoclave kept at 50°C using a metering pump for 3.0 hours. The generated C13Sil was collected in a trap. After the reaction was completed, the remaining gas in the reaction system was sent to the trap using helium and collected. After the reaction was completed, the trapped gas was analyzed by gas chromatography and found to be CH25t.
The amount of Hx generated is 4.9 N-1 (218m + monk o1)
The yield was 84%.

Next, patent application No. 60-125127 filed by the present applicant.
10 g of a reaction product of a sulfonic acid type cation exchange resin and trilobylamine prepared by a method similar to that described in Example 1, 200 g of toluene and C.
13.3 g (89 m + 5 ol) of H3SiC1z was charged in a helium atmosphere, and the C produced by the above method was charged.
H3Sibh 2N-12 (8911@01) was press-fitted. Then in a closed system at 80°C for 2 hours at 90°C.
After the exchange reaction was carried out under pressure at Kg/cm'G, the temperature was returned to room temperature, and the silicon compounds in the gas and liquid phases were analyzed and quantified by gas chromatography.

C) The production amounts of IzSiHCh and CI (jsithcl) were 48a@ol and 47s*ol, respectively.

In addition, almost no other by-products were collected, and unreacted CHtSiCh and (J13SiH3) could be recovered and reused.

<Example 2> (CJs) zAIH70wtχ, (CzHs)sAl
118.1 g of a mixture of 3omtχ was added to liquid paraffin l.
ong 7' diluted.

In this case (CJs) zAIH is 960 mmol, (
CJs) Co-Al was present in 31Q+u+ol.

Czf (sAIcIz 39.4 g (3
10m+@ol) was dissolved in 46g of liquid paraffin and added dropwise. This amount is (CJs) zAl (C2H
4) The amount of l required to change to ZAICI is 10.
0 mol χ.

The mixture of these three types of alkylaluminum compounds was placed in a container and degassed for 20 minutes at 30° C. under a reduced pressure of 2 ssHg. After that, the atmosphere was changed to helium, and Example 1
The autoclave was charged to the same 500+wl autoclave used in .

Furthermore, 39.8g of CJSiClt (266II
An experiment was carried out in the same manner as in Example 1, using 60 g of liquid paraffin dissolved in 1% of I1%of. In this case, the production amount of C1 (SiH3) is 5.6 N l (
250rarao1) and the yield was 94χ.

Next, in the same manner as in Example 1, 10 g of Amberlyst A-21 (anion exchange resin) was used instead of the reaction product of sulfone 61 cation exchange resin and toledobutylamine used in Example 1. CH3Sib and CH35tCh
An exchange reaction was carried out with

The production amounts of CHzSiHClz and CHxSil(zcl) were 46@sol and 45m5ol, respectively, and almost no by-products were observed, and unreacted CI(ss
icIs and CI (3Sil) (2 could be recovered and reused).

<Example 3> In Example 2, 56.3 g (266 + * 5 ol) of phenyltrichlorosolane Φ-SiCh (hereinafter Φ represents a phenyl group) was used instead of CIhSi (:13),
Furthermore, a reduction reaction was carried out at 60°C using tetrahydrofuran instead of liquid paraffin. After the completion of the reaction, the reaction solution was analyzed by gas chromatography, and it was found that Φ-Si
The amount of 112 produced was 22 g (205+*so+) and the yield was 77χ.

Next, 18.8g (89m+++ol) of Φ-SiC1s and 39.6g (89+u+ol) of the synthesized Φ-3iH were mixed into one volume of tetrahydrofuran to form a reaction product of a sulfonic acid type cation exchange resin and tridobutylamine in the same manner as in Example 1. After the completion of the disproportionation reaction using as a catalyst, the reaction solution was analyzed by gas chromatography and quantified.

The amount of Φ-SiHC1g and Φ-SiHzC1(7) produced was 41 m+*ol% 42+amol, respectively. In addition, almost no by-products were observed, and unreacted φ-Si
Ch and Φ-SiHx could be recovered and reused.

〔Effect of the invention〕

The present invention is a novel, industrially economical alkylchlorane M having a Si4 bond (RSiHCI g and R31HzC1) whose demand has been increasing in recent years. The present invention proposes a process in which the starting materials used in the present invention, alkyltrichloranes (
In particular, CHxSiCh), and the alkyl aluminum HytriF (9 di
Js)zAlHt(CJs)1Al (obtained by mixing t(7) mixture) is industrially inexpensive and easy to use;
), 7JL, and Kirshira 7 (CHtSi)Is), which proceed under relatively mild conditions, have the effect that their production costs are low.

[Brief explanation of drawings]

FIG. 1 is a flow sheet diagram illustrating a process suitable for carrying out the present invention. Patent Deseto Mitsui Toatsu Kagaku Co., Ltd. Sagi 1 Figure 1 Archel Aluminum Chem Hydride Processing Story 2 Uroroshira y Class J and Hair Box 3 N-*Anti-e'@ 4, 5.6 Engineering VA Difference

Claims (4)

[Claims] (1) General formula RSiCl_3 (where R is an alkyl group,
Alkenyl group or aryl group) is used as a starting material, at least one
A method for producing alkylchlorosilanes having two Si-H bonds, the method comprising: (a) reducing the RSiCl_3 with an alkyl aluminum hydride to form an alkyl compound represented by the general formula RSiH_3 (wherein R is as defined above); (b) The obtained alkylsilanes represented by RSiH_3 and R'SiCl_3 (where R' is an alkyl group, an alkenyl group, or an aryl group, and may be the same as or different from R. 1. A method for producing alkylchlorosilanes, which comprises at least the following steps: reacting the alkyltrichlorosilanes represented by the following formula to exchange hydrogen and chlorine. (2) The method according to claim 1, wherein R or R' is a methyl group or a phenyl group. (3) The method according to claim 1, wherein the alkyl aluminum hydride is diethyl aluminum hydride. (4) The method according to claim 1, which uses an alkyl aluminum hydride mixed with trialkyl aluminum.