JP3248390B2 - Method for producing halosilane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing halosilanes, in particular, chlorosilanes, in a resource-friendly manner.

[0002]

2. Description of the Related Art
The industrial production of chlorosilanes and organochlorosilanes involves the production of metallic silicon and / or
Alternatively, the reaction is carried out at a temperature in the range of 200 to 500 ° C. by a direct reaction between a metal silicon-containing substance and hydrogen chloride or organochloride.

[0003] In the present invention, chlorosilane is
A substance in which only a chlorine atom or a chlorine atom and a hydrogen atom are bonded to a silicon atom, typically tetrachlorosilane and trichlorosilane is referred to. Organochlorosilanes are those in which a chlorine atom and an organic group such as a methyl group and a phenyl group are bonded to a silicon atom, such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, and triphenylchlorosilane. Is referred to.

[0004] Incidentally, since the direct reaction is an exothermic reaction, hot spots tend to be formed in the reaction mixture, and an increase in the reaction temperature leads to an undesirable result of lowering the selectivity of a desired product. For this reason, it is necessary to efficiently remove the heat generated by the reaction, keep the temperature in the reaction mixture constant, and control the reaction temperature. For this reason, in the production of chlorosilanes and organochlorosilanes on an industrial scale by a direct synthesis method, a fluidized bed reactor excellent in heat transfer operation is mainly used.

[0005] Further, in the reactor, it is necessary to maintain a stable fluidized state in order to perform an efficient reaction and heat transfer. For this reason, the average particle size of the contact body is 20 μm or more.
It is preferably in the range of 500 μm (here, the contact body in the present invention means a mixture of metal silicon and / or metal silicon-containing solid powder and a catalyst). When the particle size of the contact body is smaller than 20 μm, the adhesive force between the particles is so strong that stable flow becomes difficult, sintering due to heat history easily occurs, and the formation of a fluidized bed is hindered. Therefore, it is necessary to maintain the formation of the fluidized bed by applying an external force such as stirring and vibration. On the other hand, the particle size of the contact body is 500 μm
If it is larger, the surface area of the contact body becomes smaller, the reaction speed becomes slower, and disadvantages arise that the linear velocity of the fluidizing gas must be increased in order to form a fluidized bed. For these reasons, when using a fluidized bed reactor, it is important to control the particle size of the contact body.

[0006] From such a point, chlorosilane and organochlorosilane are generally produced by the following production steps. That is, a lump of metal silicon and / or a metal silicon-containing solid is pulverized by a pulverizer or the like, and the pulverized powder is classified by a classifier to adjust the powder to a target particle diameter.
Next, the prepared raw material powder and a catalyst containing copper are charged into a reactor and reacted with hydrogen chloride or an organochloride while fluidizing. The contact body in the reactor is 200-500 ° C
The catalyst and hydrogen chloride or organochloride are added so that the gas-solid reaction is continued continuously.

[0007] As the reaction continues in this manner, the contact body consumed and reduced in particle size is discharged out of the reactor together with the produced silane and fluidizing gas, and is discharged by one or more cyclones. Most recovered. The cyclone pass-through containing the ultrafine particles not collected by the cyclone is then sent to a condenser to obtain a product liquid containing solids and product silane. Next, this product liquid is heated to separate a distillable fraction, separated and sent to a distillation step as crude silane. When stopping the reaction which continues in this way, it is common to stop the supply of the contact body and the supply of hydrogen chloride or organohalide, but when the reaction is stopped, the unreacted material is left in the reactor. The touch body remains.

Conventionally, unreacted metallic silicon-containing solids generated in the above-mentioned production process (scattered contact bodies and residual contact bodies in the reactor)
Had been disposed of as waste after appropriate treatment. Therefore, it has been desired to increase the utilization rate of metallic silicon and reduce the above-mentioned unreacted metallic silicon-containing solid from the viewpoint of effective utilization of resources and reduction of waste.

[0009] Among them, in order to reduce the number of scattered contact bodies in the fluidized bed reactor, the linear velocity of the reaction gas or the inert gas as the fluidizing gas may be reduced. But,
Reducing the linear velocity causes the following problem.
(1) Industrially stable operation cannot be maintained due to sintering or the like due to poor heat transfer. (2) Reducing the linear velocity of the reactant gas results in lowering the partial pressure of the reactant gas, resulting in an adverse effect of reducing the reaction rate. It is practically impossible to do. (3) The contact body in the reactor has a particle size distribution formed by the fineness due to the reaction between the particle size of the contact body to be added and the fluidized particles, and it is inevitable that fine particles jump out of the system. (4) Furthermore,
In the reaction of organochlorosilane, it is common to remove the fine touch body containing many impurities out of the system in order to keep the impurity concentration in the system below a certain level and to increase the selectivity of useful silane among the products. It is used for

For these reasons, it is difficult to reduce the number of scattered contact bodies in a fluidized bed reactor.

On the other hand, various studies have been made to effectively use the flying contact body. For example, JP-A-54-248
No. 32 discloses a method of heating a flying contactor in air or under an inert gas to 100-350 ° C. for at least 15 hours and then returning or introducing the reaction of hydrocarbon halide and / or HCl with silicon. Has been proposed. In Japanese Patent Application Laid-Open No. 57-135710, a part of a flying contact body is analyzed for particle size distribution, classified into a relatively pure first part and a relatively impure second part, and the first part is reacted. Recirculation methods have been proposed, but these methods have not been able to make full use of the flying haptics.

Further, the scattered contact body is a fine powder having a particle size of 20 μm or less, and since the scattered contact body contains impurities, it is difficult to effectively use the silicon content thereof. .

As described above, from the conventional industrial production reaction system for chlorosilane and organochlorosilane,
There is a problem in that a large amount of unreacted metal silicon-containing contact bodies such as cyclone recovery contact bodies, crude silane distillation residues, and reactor remaining contact bodies are generated. This has been unavoidable in industrial production reaction systems for chlorosilanes.

[0014] Therefore, in the production of chlorosilanes and organochlorosilanes, it has been desired to effectively utilize unreacted metal silicon-containing solids generated from the reactor system and reduce waste.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a practical method for producing a halosilane, which can effectively utilize unreacted metal silicon-containing solid powder generated when chlorosilane and organochlorosilane are directly synthesized. Aim.

[0016]

Means for Solving the Problems and Action As a result of intensive studies to achieve the above object, the present inventors have suspended metallic silicon or a metallic silicon-containing solid in a solvent such as liquid paraffin to form a slurry. By passing a hydrogen halide such as hydrogen chloride through the slurry, metal silicon can be easily and reliably halogenated to produce halosilane,
In this method, when a metal silicon-containing solid (catalyst) generated from a fluidized-bed reactor system during chlorosilane or organochlorosilane production is used as the metal silicon source, the metal silicon source is stable irrespective of the particle size and the impurity content of the catalyst. A reaction is performed, and it is found that halosilanes such as chlorosilane can be synthesized from metal silicon contained in the contact body, the contact body can be effectively used, and waste can be reduced.
The present invention has been accomplished.

Accordingly, the present invention is characterized in that metallic silicon and / or a metallic silicon-containing solid is used as a silicon source, the silicon source is suspended in a solvent to form a slurry, and hydrogen halide is passed through the slurry. The present invention provides a method for producing a halosilane. In this case, it is effective to use, as the silicon source, an unreacted metal silicon-containing solid produced by a direct synthesis method of chlorosilane or organochlorosilane from metal silicon using a fluidized bed reactor.

Hereinafter, the present invention will be described in more detail. As the metal silicon source used in the production method of the present invention,
Any of metal silicon and metal silicon-containing solids such as industrial metal silicon and high-purity metal silicon, and in particular, unreacted metal silicon-containing solid (catalyst) powder coming out of a fluidized bed reactor during production by direct reaction of chlorosilane or organochlorosilane. Can also be used.

Here, the average particle size of the metal silicon source is appropriately selected. The smaller the particle size, the more efficiently the reaction between silicon and hydrogen halide can be performed. More preferably, those having a size of 8 μm or less are used. In this regard, since the above-mentioned contact body usually has an average particle diameter of 20 μm or less, it is possible to perform a reaction very advantageously by using the contact body without pulverization.

In the method of the present invention, the metal silicon source is reacted with hydrogen halide in the form of a slurry in which the metal silicon source is suspended in a solvent. The present invention can be applied to the production of any halosilane having a functional group corresponding to the halogen of the hydrogen halide. In this case, examples of the hydrogen halide include hydrogen chloride, hydrogen bromide, hydrogen iodide, and the like. These hydrogen halides can be used as they are without purification of general commercial products. The method of the invention is particularly effectively employed for the production of chlorosilanes using hydrogen chloride.

The solvent used in this reaction is appropriately selected, and usually has a boiling point of 250 ° C. or higher at atmospheric pressure, more preferably 300 ° C. or higher. Solvents that are substantially inert to hydrogen halide at this solvent temperature are preferred because hydrogen halide such as hydrogen is allowed to react with the silicon by aeration. As such a solvent, for example, polycyclic aromatic hydrocarbons such as alkylnaphthalene and alkylbiphenyl,
Examples thereof include alkylbenzenes such as dodecylbenzene, and alkylnaphthenes such as liquid paraffin. In addition,
These may be used alone or in combination of two or more.

The amount of the solvent is preferably such that the slurry concentration of the metal silicon source is in the range of 5 to 20% by weight, more preferably 8 to 10% by weight. If the slurry concentration is higher than this range, stirring becomes difficult, silicon powder cannot be sufficiently dispersed in the solvent, and a uniform reaction may be difficult. On the other hand, if the slurry concentration is too low, a sufficiently satisfactory reaction rate cannot be obtained, which may be disadvantageous in terms of reaction volume.

A catalyst can be used in the above reaction of the present invention. As the catalyst, copper compounds such as metallic copper, iron and copper chloride, iron compounds and the like can be used.

In this case, since a metal compound which can act as a catalyst such as copper or iron is contained in a contact body coming out of a fluidized bed reactor at the time of producing the above-mentioned chlorosilane or organochlorosilane, a catalyst is added separately. The reaction can be carried out without the use of the contact element, and the use of the above-mentioned contact body is also advantageous from this point.

The reaction temperature is preferably at least 200 ° C., more preferably from 250 to 35, from the viewpoint of efficiently promoting the reaction between metal silicon and hydrogen halide.
It is preferable that the temperature is 0 ° C. and the temperature is controlled within a certain range. If the reaction temperature is too low, the reaction rate decreases, leading to a decrease in productivity. It is recommended from the viewpoint of energy that the reaction temperature is lower than the boiling point of the solvent. That is,
The reaction can be carried out while refluxing at the boiling point of the solvent,
This does not make the reaction more efficient, and may instead cause an energy disadvantage.
If the reaction temperature is higher than the boiling point of the solvent, a desired slurry concentration may not be maintained due to evaporation of the solvent. Therefore, it is most preferable that the reaction temperature is higher than the above temperature and lower than the boiling point of the solvent.

In the production method of the present invention, when the temperature in the reactor reaches the reaction temperature, hydrogen halide is introduced,
It is preferable to start the reaction between the metal silicon and hydrogen chloride, and if a hydrogen halide such as hydrogen chloride is passed through the slurry heated to the reaction temperature, the hydrogen halide starts the reaction with the metal silicon. .

In this case, the amount of hydrogen halide, such as hydrogen chloride, is selected depending on the amount of the metal silicon source, but it is usually 1 to 3 times the theoretical equivalent to the amount of metal silicon, and more preferably 1.5 to 2 times. Double the amount. If the amount of hydrogen chloride used is large, the reaction rate will increase and the productivity will improve, but conversely, the amount of unreacted hydrogen halide will increase, so it is recommended to consider the economically balanced usage. Is done. It is economically desirable to recover and reuse the unreacted hydrogen halide.

In the reaction, stirring can be performed if necessary.

After the above reaction, the resulting reaction product is purified by distillation or the like to obtain a purified halosilane.

[0030]

According to the production method of the present invention, since a fine metal silicon source can be used as compared with the gas-solid fluidized bed reaction, the reaction can be continued with a large number of active sites. There is an advantage that can be. Furthermore, when chlorosilanes are produced in a fluidized-bed reactor, there is a danger of catching highly active reaction residues when the reaction residues are withdrawn from the reactor at the end of the reaction. is necessary. However, in the production method according to the present invention, the reaction residue can be extracted in a state of being suspended in the solvent, so that the danger of ignition can be significantly reduced.

According to the present invention, the unreacted metal silicon-containing solid produced during the production of chlorosilane and alkylchlorosilane can be effectively used, and halosilanes such as trichlorosilane can be produced very efficiently from the unreacted metal silicon. And contribute to the effective use of resources.

[0032]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples.

Example 1 A 0.5-liter cylindrical reactor equipped with a hydrogen halide introducing pipe, a nitrogen gas introducing pipe, a product distilling pipe, a thermometer, a cooler, a heater and a stirrer was averaged. After charging 50 g of industrial metal silicon powder having a particle size of 8 μm and 230 g of liquid paraffin (industrial 70), heating was performed while flowing nitrogen gas at a flow rate of 100 ml / min, and the temperature in the reactor was set to 230 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 103 ml / min to start the reaction. During the reaction, the temperature in the reactor was 230
C. was maintained.

Two hours after the start of the reaction, 10.9 g of a product was obtained, and the product was analyzed by gas chromatography. Table 1 shows the results.

Example 2 The average particle size was measured in a 1-liter cylindrical reactor equipped with a hydrogen halide inlet tube, a nitrogen gas inlet tube, a product distilling tube, a thermometer, a cooler, a heater and a stirrer. After charging 200 g of industrial metal silicon powder of 20 μm and 486 g of liquid paraffin (industrial 70), heating was performed while flowing nitrogen gas at a flow rate of 100 ml / min, and the temperature in the reactor was set to 270 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 119 ml / min to start the reaction. During the reaction, the temperature in the reactor was 270
C. was maintained.

Two hours after the start of the reaction, 23.2 g of a product was obtained, and the product was analyzed by gas chromatography. Table 1 shows the results.

Example 3 200 g of industrial metal silicon powder having an average particle size of 20 μm and 486 g of alkylbenzene were charged into the same reactor as in Example 2, and 100 g of nitrogen gas was added.
Heating was performed while flowing at a flow rate of ml / min, and the temperature in the reactor was set to 270 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 119 ml / min to start the reaction. During the reaction, the temperature in the reactor was 270
C. was maintained.

Two hours after the start of the reaction, 30.0 g of a product was obtained, and the product was analyzed by gas chromatography. Table 1 shows the results.

Example 4 A high-purity metallic silicon powder having an average particle diameter of 8 μm (silicon purity 9
After charging 190 g of 9.3%), 10 g of copper chloride and 486 g of liquid paraffin (70 for industrial use), 10 g of nitrogen gas was added.
Heating was performed while flowing at a flow rate of 0 ml / min, and the temperature inside the reactor was set to 270 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 565 ml / min to start the reaction. During the reaction, the temperature in the reactor was 270
C. was maintained.

In 2 hours after the start of the reaction, 49.9 g of a product was obtained, and the product was analyzed by gas chromatography. Table 1 shows the results.

Example 5 A reaction apparatus similar to that of Example 2 was charged with 300 g of industrial metal silicon powder having an average particle size of 8 μm, 10 g of copper chloride, and 460 g of liquid paraffin (industrial 70), and then 100 ml of nitrogen gas. The heating was performed while flowing at a flow rate of / min, and the temperature in the reactor was set to 270 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 606 ml / min to start the reaction. During the reaction, the temperature in the reactor was 270
C. was maintained.

After 2 hours from the start of the reaction, 54.0 g of a product was obtained, and this product was analyzed by gas chromatography. Table 1 shows the results.

Example 6 A reaction apparatus similar to that of Example 2 was charged with 50 g of unreacted metal silicon-containing solid powder produced in the step of synthesizing methylsilane having an average particle diameter of 8 μm and 456 g of liquid paraffin (70 for industrial use). 10 nitrogen gas
Heating was performed while flowing at a flow rate of 0 ml / min, and the temperature in the reactor was set to 270 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 565 ml / min to start the reaction. During the reaction, the temperature in the reactor was 270
C. was maintained.

Seven hours after the start of the reaction, 203.5 g of a product was obtained, and the product was analyzed by gas chromatography. Table 2 shows the results.

Example 7 A reaction apparatus similar to that of Example 1 was charged with 300 g of unreacted metal silicon-containing solid powder produced in the synthesis step of methylsilane having an average particle diameter of 8 μm and 486 g of liquid paraffin (70 for industrial use). 10 nitrogen gas
Heating was performed while flowing at a flow rate of 0 ml / min, and the temperature inside the reactor was set to 270 ° C.

Next, at the same time as the introduction of nitrogen gas was stopped, hydrogen chloride gas was introduced at a flow rate of 606 ml / min to start the reaction. During the reaction, the temperature in the reactor was 270
C. was maintained.

In 26 hours after the start of the reaction, 1016.4 g of a product was obtained, and this product was analyzed by gas chromatography. Table 2 shows the results.

[0054]

[Table 1]

[0055]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C01B 33/107

Claims (2)

(57) [Claims] 1. Production of a halosilane characterized by using metal silicon and / or a metal silicon-containing solid as a silicon source, suspending the silicon source in a solvent to form a slurry, and passing a hydrogen halide through the slurry. Method. 2. The process according to claim 1, wherein an unreacted metal silicon-containing solid produced by a direct synthesis method of chlorosilane or organochlorosilane from metal silicon using a fluidized bed reactor is used as a silicon source.