JPH0631271B2 - Method for producing aryldihalosilane - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an aryldihalosilane.
More specifically, it provides an efficient method for producing a monohydroaryldihalosilane (hereinafter simply referred to as “aryldihalosilane”) by reacting an aromatic hydrocarbon compound (hereinafter referred to as “aryl compound”) with dihalosilane. Is.

[Prior art and its problems]

Aryl dihalosilanes formed by bonding one hydrogen atom and one aromatic group (hereinafter referred to as an aryl group) to a silicon atom and two halogen atoms of the same or different type are silicone oil, silicone rubber, silicone varnish, etc. It is regarded as important as the starting material. Conventionally, as a production method thereof, I) a Grignard method using trihalosilane and a nucleus-substituted halogenated aromatic compound as a raw material II) a reduction method using aryltrihalosilane as a raw material and lithium aluminum hydride as a reducing agent III) arylhalosilanes IV) Aryl compound (represented by ArH) and dihalosilane (represented by H ₂ SiX ₂ ) are used as raw materials and ArH + H ₂ SiX ₂ → ArSi (H) X ₂ + H ₂
A method based on the reaction represented by the formula is known.
The Grignard method of I) and the reduction method of II) are not only generally expensive processes, but also have the drawback that they are not suitable for selective and high-yield production. As the disproportionation method of III), for example, in British Patent No. 663,810, phenyldichlorosilane is synthesized by a disproportionation reaction using diphenylchlorosilane and diphenyldichlorosilane as raw materials. Although examples have been described, the production of synthetic raw materials often has difficulties in themselves, and there are many by-products due to the reaction, which is not necessarily an advantageous method. The method for producing aryldihalosilane by the reaction of IV) with an aryl compound and dihalosilane includes a method using a catalyst and a method not using a catalyst. In either case, the reaction is carried out under the condition of maintaining a liquid phase. There is a need. When no catalyst is used, for example, in US Pat. No. 2,775,606, benzene, dichlorosilane, and trichlorosilane are mentioned as a synthesis example of phenyldichlorosilane (the coexistence of trichlorosilane gives a higher yield). It is described that the reaction is carried out without a catalyst, but the reaction temperature is as high as 400 ° C., and it is presumed that the reaction pressure needs to be as high as 200 kg / cm ² or more in order to maintain the liquid phase. Such high temperature and high pressure reaction conditions are by no means an advantageous process in industrial practice. On the other hand, when a catalyst is used, a Lewis acid such as aluminum trichloride or boron trichloride is usually used as a catalyst, and the above-mentioned US Pat. No. 2,775,606 also has a synthesis example of phenyldichlorosilane. Have been described. However, although it seems that milder reaction conditions of lower temperature and lower pressure can be adopted by using the Lewis acid catalyst, the yield of the target phenyldichlorosilane as a final isolated product is uncatalyzed reaction. It is extremely low compared with the case of, and it is hard to say that it can be put to practical use.

[Means for solving problems]

In view of such a problem, the present inventors continued the earnest research on a method for producing an aryldihalosilane in a high yield using the Lewis acid catalyst of the above IV). As a result, the fact that the aryldihalosilane formed in the presence of a Lewis acid catalyst from the aryl compound and dihalosilane is modified in the process of separating it from other by-products by distillation and can be produced only in a low yield Found out. Therefore, as a result of investigating various methods for suppressing the alteration of aryldihalosilane at the stage of distillation separation, it was found that the metal atom of the Lewis acid compound used as a catalyst in the synthesis of aryldihalosilane and the acid-base It was found that the target aryldihalosilane can be produced in a high yield by distilling a specific Lewis base compound which can have an action after the reaction of the aryl compound and the dihalosilane, and thus completed the present invention. It was

That is, the present invention provides a product obtained by reacting an aryl compound and a dihalosilane in the presence of a Lewis acid catalyst, which has an interaction between a metal atom of the catalyst and an acid-base and at least a titanium element, a phosphorus atom, and a sulfur atom. A method for producing a target aryldihalosilane in a high yield, which is characterized in that a Lewis base compound containing one is coexistent and is separated by distillation.

In the present invention, for the reaction between the aryl compound and the dihalosilane in the presence of the Lewis acid catalyst, a conventionally known method can be suitably adopted as it is. That is, as an aryl compound, there is basically no problem as long as it has at least one nuclear-substituted hydrogen atom in the aromatic ring, but it is typically represented by benzene, alkylbenzene represented by toluene or ethylbenzene, chlorobenzene or fluorobenzene. Preferred are halogenated benzenes. Naphthalene, anthracene,
A compound having two or more benzene rings such as biphenyl and diphenyl ether, or an alkyl and / or halogen derivative thereof can also be used. As dihalosilane,
Most preferred is dichlorosilane, but dibromosilane,
A dihalosilane containing different halogen atoms such as difluorosilane or chlorobromosilane and chlorofluorosilane can also be used. Further, coexistence of trihalosilane is often effective, but in this case, trichlorosilane, tribromosilane, trifluorosilane and the like are preferably adopted. As the Lewis acid catalyst, conventionally known metal halide Lewis compounds are suitable, and particularly for this reaction, triboron halides such as boron trichloride and boron trifluoride, and aluminum trichloride and aluminum tribromide. Aluminum trihalides or antimony pentahalides such as antimony pentachloride and antimony pentabromide are used as effective catalysts.

As a reaction method, generally, a batch reaction method in which an aryl compound as a raw material, a dihalosilane (and trihalosilane if necessary) and a Lewis acid compound as a catalyst are charged into a pressure autoclave and heated and stirred is preferably used. It is also possible to employ a flow reaction system in which the catalyst and the catalyst are reacted independently or as a mixture while flowing through the reaction tube. The raw material composition may be 0.3 to 20 as the molar ratio of [aryl compound] / [dihalosilane], but is usually 1
-10 is preferable. Coexistence of trihalosilane is often effective, but in that case, a molar ratio of [trihalosilane] / [dihalosilane] of 0.1 to 10 can be adopted, and 1 to 5 is usually effective. The optimum concentration of the Lewis acid compound in the catalyst varies depending on the kind of the aryl compound, but 0.001 to 10% by weight is adopted, and usually 0.01 to 5% by weight is preferable with respect to the total weight of the charged raw materials. The reaction temperature may be 100 to 500 ° C., but is usually 130.
~ 300 ° C is preferred. The reaction pressure is generally between several and 100 kg / cm ² , but since it is necessary to maintain the liquid phase,
Especially in the flow reaction system, it is important to note that the gas phase reaction does not occur on the low pressure side. However, the high pressure can be preferably used even under the condition of exceeding 100 kg / cm ² , for example.

After the reaction of the above-mentioned aryl compound of the present invention with dihalosilane is completed, various by-products such as aryltrihalosilane and diaryldihalosilane are mixed in the reaction solution in addition to the intended aryldihalosilane. Moreover, when boron trichloride is used as a catalyst, in reality, most of this is mixed as a high-boiling compound that is produced by complex reaction with benzene (Journal of Organometallic Chemistr
y, 145, 307-314 (1978) describes such a boron compound), and the situation is the same for other catalyst compounds. Therefore, it becomes necessary to separate the target aryldihalosilane from the liquid after such reaction. A fractionation column method can also be adopted as this separation method, but the distillation operation is the most general and efficient. However, as described above, when the above reaction solution is simply distilled, the aryldihalosilane is deteriorated in the course of the operation of heating and pressure reduction in the distillation, and the amount thereof is significantly reduced. As a result of examining the precise mass balance of the liquid before and after the distillation by gas chromatography analysis, the present inventors found that the alteration of aryldihalosilane as described above was 2ArSi (H) X ₂ → Ar ₂
It was found that the aryldihalosilane, which was once formed, was changed into diaryldihalosilane and dihalosilane over time due to the disproportionation reaction represented by the formula of SiX ₂ + H ₂ SiX ₂ . However, aryldihalosilanes do not inherently undergo the above disproportionation reaction under the conditions of heating and reduced pressure. Therefore, it is presumed that the Lewis acid catalyst used for the reaction of the aryl compound and dihalosilane in the previous step changed into a complex high boiling point compound and then acted as a catalyst for the above disproportionation reaction. Therefore, prior to the above-mentioned distillation, a compound capable of suppressing the disproportionation action of these catalyst compounds was allowed to coexist, and if the distillation was carried out thereafter, it was expected that the intended aryldihalosilane could be produced in a high yield. . As a result of various studies as such a compound, a Lewis base compound having an interaction between a metal atom and an acid base in the catalyst compound and containing at least one of a titanium atom, a phosphorus atom and a sulfur atom was found. Proved to be effective. Among them, the compound containing a phosphorus atom was particularly effective.

What can be used as the above compound is described below. First,
As the compound containing a titanium atom, various amines can be cited as effective compounds. For example, primary amines such as ethylamine, propylamine, n-butylamine and n-amylamine, secondary amines such as diethylamine, dipropylamine, di-n-butylamine, di-n-amylamine, triethylamine and triethylamine. Propylamine, tri-n-butylamine, tri-n-amylamine, N, N-dimethylcyclohexylamine,
Tertiary amines such as N, N-dimethylaniline, N, N-dimethylbenzylamine and cyclic amines such as pyridine, 2-methylpyridine, piperidine and N-methylpiperidine, ethylenediamine, hexamethylenetetramine, imidazole, amber Polyamines having two or more amino groups, such as List A-21, can be used. In addition to these, amides such as N, N-dimethylacetamide, 2-methylpropanamide, 2-pyrrolidone, 2-piperidone, N, N-dimethylcyanamide and N- which is a Schiff base.
Substituted imines may also be used. Next, examples of compounds containing a phosphorus atom include, for example, phosphines such as methylphosphine, di-n-butylphosphine, tri-n-butylphosphine, triphenylinphosphine, and bisdiphenylphosphinobutane. Triethyl phosphine oxide, tri-n-butyl phosphine oxide, triphenyl phosphine oxide and other phosphine oxides, tripropyl phosphite, tri-n-butyl phosphite, triphenyl phosphite and other phosphite, and other three Phosphorus chloride, phosphorus oxychloride, diethylphosphinic chloride, diethylphenylphosphonite, phenylphosphonasdichloride, methylphosphonic dichloride, methyldimethylphosphinite, dimethylphosphinus chloride and the like can be used. Also, a compound containing both a phosphorus atom and a titanium atom, such as tris (2-cyanoethyl) phosphine or hexamethylphosphonic acid triamide, can be used.
Finally, a compound containing a sulfur atom is, for example, n
-Mercaptans such as butyl mercaptan, benzyl mercaptan, phenyl mercaptan, sulfides such as di-n-butyl sulfide, dibenzyl sulfide, diphenyl sulfide, di-n-butyl sulfoxide, dibenzyl sulfoxide, diphenyl Sulfoxides such as sulfoxide, diphenyldisulfide, thiobenzophenone, thiacyclobutane, S-phenylthiabenzene and the like can be used. Further, compounds such as dithiourea and thiocyanuric acid containing both a sulfur atom and a titanium atom, and compounds such as triphenylphosphine sulfide containing both a sulfur atom and a phosphorus atom may be used.

The Lewis base compound containing at least one of titanium atom, phosphorus atom and sulfur atom is preferably used as follows. The Lewis base compound used first needs to be added to the reaction product solution after the completion of the reaction between the aryl compound and dihalosilane in the previous step. This is because if the Lewis base compound is allowed to coexist with the Lewis acid catalyst before the reaction, the reaction itself in the previous step does not proceed. As these Lewis base compounds, many compounds can be used as described above, but avoid the use of a compound that makes it difficult to separate from the target aryldihalosilane during distillation, especially a compound having a small boiling point difference. Is, of course, preferable. If this point is noted, it is not necessary that the Lewis base compound to coexist is one kind, and two or more kinds of compounds can coexist at the same time. The amount of these Lewis base compounds used varies depending on the compound, but normally, the sum of titanium atom, phosphorus atom, and sulfur atom in the Lewis base compound is 0.3 to 3.0 per metal atom of the Lewis acid catalyst. Individuals are preferable, and 0.5 to 2.0 are often more effective. However, in the case where the Lewis basicity of the Lewis basic compound is present on the oxygen atom in addition to the above-mentioned titanium atom, phosphorus atom, and sulfur atom, a smaller amount of the compound can be sufficiently effective.

A conventionally known method is preferably adopted as the distillation method. Simple distillation, precision distillation, thin-film distillation, etc.
Regardless of the continuous type, any of them can be arbitrarily selected. The temperature of distillation varies depending on the kind of the target aryldihalosilane and the pressure of distillation, but is generally selected from room temperature to 350 ° C. From the standpoint of preventing the efficiency of distillation and the decrease in yield due to contact, etc., 50 ° C to 30 ° C.
Preference is given to working between 0 ° C. The distillation pressure is generally from several atm to about 10 ^-3 Torr, but usually from atmospheric pressure to about 10 ^-2 Torr is preferable.

〔The invention's effect〕

According to the present invention, as is apparent from Examples and Comparative Examples described later, it is possible to obtain the result that the yield of the target aryldihalosilane can be increased by about 10 times as the yield based on dihalosilane.

〔Example〕

Next, the present invention will be described with reference to examples and comparative examples will be given for the purpose of clarifying the effects thereof, but the present invention is not limited to these examples.

Example 1 Benzene 31 which had been dehydrated and distilled beforehand was placed in a stainless steel autoclave having an internal volume of about 1 equipped with an electromagnetic induction stirrer.
2.4 g (4.0 mol), 50.4 g (0.50 mol) of dichlorosilane, 141.9 g (1.05 mol) of trichlorosilane and 0.428 g (3.65 mmol) of boron trichloride as a catalyst were added.
The reaction was carried out at 70 ° C for 4 hours. The final pressure is 28 kg / c
When the temperature rose to m ² and was cooled to room temperature, it was 15 kg / cm ² .

497 g of the reaction product solution obtained by the above reaction was added to the internal volume 1
After transferring to a glass flask of No. 1, 1.0 g (3.81 mmol) of triphenylphosphine was added thereto, the bath temperature was kept at 80 ° C. with a packed column type rectifier equipped with a reflux controller, Distillation separation was performed by a method of gradually increasing the degree of vacuum. As a result, the content ratio of phenyldichlorosilane was 9
49.2 g of a 7% rectified liquid was obtained (53.9% as the yield based on dichlorosilane). Most of the impurities contained in this solution were phenyltrichlorosilane, and a small amount of diphenyldichlorosilane was contained in the other impurities.

Comparative Example The reaction between benzene and dichlorosilane was carried out in the same manner as in Example 1 to obtain 499 g of a reaction product liquid. This liquid was placed in a glass flask No. 1 and distilled and separated in the same manner as in Example 1 without adding any additives. As a result, 6.4 g of a liquid containing phenyldichlorosilane as a main component was obtained. According to the analysis by gas chromatography, phenyldichlorosilane contained in this distillate was 5.2 g (purity 81.3%, dichlorosilane standard). The yield was 5.9%), and the remainder was mostly phenyltoluchlorosilane. In addition, the residue in the flask of 1 is about 3
When 8 g was analyzed, the amount of phenyldichlorosilane contained therein was only 0.3 g, and most of the phenyldichlorosilane was diphenyldichlorosilane.

Example 2 Benzene and dichlorosilane were reacted in the same manner as in Example 1 to obtain 496 g of a reaction product liquid. This solution was placed in a glass flask of 1, and tri-n
After adding 0.7 g (3.78 mmol) of -butylamine, distillation separation was carried out in the same manner as in Example 1. As a result, 44.3 g of phenyldichlorosilane having a purity of 96% was obtained (yield based on dichlorosilane was 48.0%). Most of the impurities contained in this solution were phenyltrichlorosilane.

Example 3 Benzene and dichlorosilane were reacted in the same manner as in Example 1 to obtain 498 g of a reaction product liquid. This solution was placed in a glass flask No. 1, and 0.7 g (3.76 mmol) of diphenyl sulfide was added to the flask, followed by distillation separation in the same manner as in Example 1. As a result,
40.7 g of phenyldichlorosilane having a purity of 93% was obtained (42.7% as a yield based on dichlorosilane). Most of the impurities contained in this solution were phenyltrichlorosilane.

Claims (1)

[Claims] 1. A product obtained by reacting an aryl compound with a dihalosilane in the presence of a Lewis acid catalyst, which has an interaction between a metal atom of the catalyst and an acid-base and which contains a titanium atom, a phosphorus atom or a sulfur atom. A method for producing an aryldihalosilane, characterized in that a Lewis base compound containing at least one is coexistent and separated by distillation.