JP2001122609A - Method for manufacturing disproportionation reaction product of silane compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform the disproportionation reaction of hydrohalogenated silane by developing a catalyst having high catalytic activity. SOLUTION: The disproportionation reaction product of the silane compound is manufactured by using the catalyst composed of at least one metal or metal oxide selected from chromium, molybdenum, tungsten, nickel, platinum and fringing hydrohalogenated silane such as trichlorosilane into contact with the catalyst to cause the disproportionation reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a disproportionation reaction product of various silane compounds. More specifically, the present invention relates to a method suitable for producing a disproportionation reaction product of a silane compound such as monosilane by disproportionating a hydrogenated silane such as dichlorosilane in the presence of a specific catalyst.

[0002]

2. Description of the Related Art Silane compounds such as monosilane and dichlorosilane are important materials in the semiconductor industry such as a raw material for silicon single crystal and epitaxial growth of silicon.
In recent years, demand has rapidly increased.

[0003] Various methods for producing these compounds are known. However, many disproportionation reaction products containing a target silane compound are obtained by disproportionating a hydrogenated silane. The most economical method is to obtain a target compound from the compound by distillation or other means.

[0004] Here, the disproportionation reaction of the hydrogenated silane refers to a method in which hydrogen and halogen are exchanged between the molecules of the hydrogenated silane to form silanes different from the raw material hydrogenated silane. This is a reaction for producing a compound. Since the newly generated compound repeats the same exchange reaction, the reaction system has a mixed composition composed of several kinds of silane compounds.

The disproportionation of trichlorosilane will be described as an example. In the presence of a suitable catalyst, trichlorosilanes first exchange hydrogen and chlorine to form dichlorosilane and silicon tetrachloride, as shown below. Dichlorosilane also produces monochlorosilane and trichlorosilane. Monochlorosilane similarly produces monosilane and dichlorosilane. These reactions are repeated, and the system becomes a mixed composition comprising five components of monosilane, monochlorosilane, dichlorosilane, trichlorosilane, and silicon tetrachloride.

[0006]

Embedded image For example, when the target substance is monosilane, the mixture may be separated from the mixture by a method such as distillation. This disproportionation reaction is an equilibrium reaction, and the reaction system reaches an equilibrium composition when a sufficient reaction time (contact time) is taken. However, it is not always necessary for the system to reach equilibrium when separating and obtaining the target substance.

As to the catalyst used for the disproportionation reaction of the hydrogenated silane, many techniques are disclosed in patents and the like. For example, in Japanese Patent Publication No. 63-16328,
A method in which a quaternary ammonium salt is dissolved in a solvent and used as a liquid phase homogeneous catalyst is disclosed.
JP-A-7-12569 discloses a method using an anion exchange resin as a solid heterogeneous catalyst. Also,
JP-A-1-122914 discloses a method using metal rhodium as a catalyst.

[0008]

However, when a quaternary ammonium salt described in JP-B-63-16328 is used as a homogeneous catalyst in a liquid phase, a great deal of work is required to separate the reaction product from the catalyst. There was a problem of requiring energy.

If the anion exchange resin described in JP-A-47-12569 is used as a catalyst, the above-mentioned separation problem can be solved, but the maximum use temperature of the anion exchange resin is 100%. Since the temperature is as low as about ° C., there was a problem that a sufficient reaction rate could not be obtained and the cost was higher.

The method using a metal rhodium as a catalyst described in JP-A-1-122914 is easy in separating a reaction product and a catalyst and is excellent in heat resistance.
There was a problem that the activity of the catalyst was low.

Therefore, in the disproportionation reaction of the above-mentioned hydrogenated silane, a catalyst which can easily separate the reaction product from the catalyst, has high heat resistance, and has higher catalytic activity has been developed. The task was to perform the process efficiently.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems and found that chromium, molybdenum,
By using a catalyst comprising at least one metal or metal oxide selected from tungsten, nickel, and platinum, it has been found that the disproportionation reaction of a hydrogenated silane can be performed with high reaction activity, and the present invention has been completed. I came to.

That is, the present invention is characterized in that a hydrogenated silane is disproportionated using a catalyst comprising at least one metal or metal oxide selected from chromium, molybdenum, tungsten, nickel and platinum. This is a method for producing a disproportionation reaction product of a silane compound.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrogenated silane used in the present invention is a silane compound having at least one hydrogen atom and at least one halogen atom bonded to silicon. Such hydrogenated halogenated silanes include:
Generally, a compound represented by the following general formula (1) is used.

Y _(4-mn) SiH _n X _m (1) wherein Y represents an alkyl group or an aryl group;
Represents a halogen atom. M and n are 1 or more and 3
The following integer and m + n is 4 or less. As the alkyl group, one having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, and a butyl group are preferable, and as the aryl group, a phenyl group and the like are preferable. As a specific example,
Trichlorosilane, dichlorosilane, monochlorosilane, methyldichlorosilane, methylmonochlorosilane,
Examples thereof include dimethylmonochlorosilane, ethyldichlorosilane, ethylmonochlorosilane, diethylmonochlorosilane, phenyldichlorosilane, phenylmonochlorosilane, diphenylmonochlorosilane, and mixtures thereof.

Of these, the compound of m + n = 4;
That is, a chlorosilane compound selected from trichlorosilane, dichlorosilane and monochlorosilane represented by the following general formula (2) SiH _n X _m (2), or a mixture thereof is particularly preferable.

Incidentally, hydrogenated silanes having no halogen atom bonded to silicon atoms such as monosilane and methylsilane, and halogenated silanes having no hydrogen atom bonded to silicon atoms such as silicon tetrachloride and methyltrichlorosilane Silane alone does not cause a disproportionation reaction.
However, when co-existing with the above-mentioned hydrohalogenated silane, it participates in the disproportionation reaction and gives a corresponding mixture.

Accordingly, in the present invention, a hydrogenated silane may be used as a raw material, or these may be mixed with the above-mentioned halogenated silane or hydrogenated silane.

In the present invention, in the disproportionation reaction of the hydrogenated silane, a catalyst comprising at least one metal or metal oxide selected from chromium, molybdenum, tungsten, nickel and platinum is used.

Specific examples of the metal or metal oxide used in the present invention include chromium, chromium (II) oxide, chromium (III) oxide, chromium (VI) oxide, molybdenum, molybdenum oxide (IV), and molybdenum oxide (IV). VI), tungsten, tungsten (IV) oxide, tungsten (VI) oxide, nickel, Raney nickel, nickel (II) oxide, platinum, platinum sponge,
Examples include, but are not limited to, platinum black, platinum (II) oxide, platinum (IV) oxide, diplatinum (II), platinum (IV) oxide and non-stoichiometric compounds due to their lattice defects.

In the present invention, the above-mentioned metal or metal oxide may be used alone for the catalyst, but it is more preferable that the metal or metal oxide is supported on a carrier such as activated carbon to increase the specific surface area. The carrier used here is not particularly limited as long as it is generally used as a catalyst carrier. Specific examples include silica, alumina, activated carbon, graphite, silica-alumina, zeolite, titania, zirconia, and carborundum. In particular, the specific surface area is 10 to 2000
m ² / g, preferably it is preferable to use those 100 to 400 m ² / g. Further, the particle diameter is preferably 10 μm to 1 mm, more preferably 30 μm to 200 μm.

In the present invention, the method for preparing the catalyst is not particularly limited. Specifically, the catalyst support is immersed in an aqueous solution of a compound containing an active metal, dried, and then subjected to a heat treatment and an activation treatment.
Carbonates, hydroxides, organic acid salts and ammonium salts are thermally decomposed at high temperatures, and if necessary, activated, etc., besides the calcination method, an aqueous solution of a compound containing an active metal and sodium hydroxide, carbonate A precipitation method in which an aqueous solution of a precipitant such as sodium, sodium bicarbonate, ammonium carbonate or the like is simultaneously dropped into distilled water to prepare a precipitate such as a carbonate of an active metal, and the precipitate is subjected to heat treatment and activation treatment. , An ion exchanger typified by zeolite or an ion exchange resin is immersed in an aqueous solution of a compound containing an active metal, the sodium ions of the zeolite are exchanged for ions containing the active metal, washed sufficiently with water, dried, and then heat-treated and activated. It may be performed by an ion-exchange method or the like for performing a conversion treatment.

In the case of a supported catalyst, the amount of the active metal component supported is not particularly limited, but is usually 0.01 to the total amount of the catalyst.
It is desirably in the range of from 50 to 50% by weight, preferably from 0.1 to 20% by weight.

In the present invention, the disproportionation reaction is carried out by bringing the raw material hydrogenated silane into contact with the above catalyst. The reaction apparatus and method used are not particularly limited, and a conventionally known method may be used.

In the present invention, the reaction method is not particularly limited, and may be a batch type or a flow type, and may be a gas phase or a liquid phase. As the contact method, a fixed bed system, a fluidized bed system, a system in which a catalyst suspension is brought into contact, or the like is optionally adopted.

Among them, in order to carry out the present invention most effectively, a flow-type reaction using a fixed bed as a catalyst is desirable.
This reaction can be carried out under a wide range of reaction conditions from reduced pressure to increased pressure, but considering the efficiency and safety of the reaction, the reaction can be carried out at 0.1.
It is desirable to carry out at 5 to 100 atm, more preferably,
It is desirable to carry out at normal pressure to 60 atm. In addition, the reaction can be performed in a wide range with respect to the reaction temperature. However, the reaction temperature is preferably 0 ° C. or higher for promptly proceeding the reaction, and is preferably 400 ° C. or lower in consideration of the safety of the catalyst. . More preferably, it is desirable to carry out the reaction in the range of 40 to 300C, more preferably in the range of 100 to 300C.

The contact time is desirably set so that the reaction system almost reaches the equilibrium composition. If the contact time is too short, the disproportionation reaction does not proceed sufficiently, so that the yield of the target product decreases. If the contact time is longer than necessary, the equilibrium composition is sufficiently reached, and the yield of the target substance with respect to the raw material does not change.However, the ratio of the target substance cannot exceed the equilibrium composition, and as a result, the unit time The yield of the desired product is reduced. The appropriate contact time depends on the reaction temperature and pressure, the raw material, the catalyst, and other factors, but is generally 0.01 to 300 seconds when the raw material is a gas,
When the raw material is liquid, it is adopted from 0.05 to 60 minutes.

According to the production method of the present invention, the hydrogenated silane as the raw material gives many disproportionation reaction products by the disproportionation reaction. Therefore, from the mixture,
The necessary components are separated using common methods such as distillation,
Just get it.

Among them, at least one selected from trichlorosilane, dichlorosilane and monochlorosilane is used as a hydrogenated silane, if necessary, mixed with silicon tetrachloride. It is preferably applied to obtain a silane compound which is hydrogenated to a higher degree than a halogenated silane.

In particular, it is preferable to use trichlorosilane as the hydrogenated silane and to carry out a two-stage disproportionation reaction to obtain monosilane. An example of the process is shown in FIG.

The raw material trichlorosilane is supplied from the drum 6 to the disproportionation reactor 1, for example, a fluidized bed type or fixed bed type reactor, and brought into contact with a metal or metal oxide catalyst. Thereby, a mixed system of various chlorosilane compounds, mainly dichlorosilane, trichlorosilane and silicon tetrachloride is generated. At this point, the proportion of the target monosilane is low. The mixture generated in the disproportionation reactor 1 is sent to a distillation column 3 which is a separation device in the next step. Distillation tower 3
, Low-boiling components centering on dichlorosilane and trichlorosilane are sent from the pipeline 8 to the distillation column 4, and silicon tetrachloride is discharged from the bottom of the distillation column 3.
In the distillation column 4, low-boiling components centering on dichlorosilane are supplied from the pipeline 9 to the disproportionation reactor 2. Trichlorosilane is recovered from the bottom of the distillation column 4 to the drum 6 and subjected to a disproportionation reaction. In the disproportionation reactor 2,
Similarly, by contacting with a catalyst, various chlorosilane compounds,
A mixed system of mainly monosilane, monochlorosilane, dichlorosilane and trichlorosilane is formed. At this point, it is preferable that the target monosilane is contained in a ratio that can be sufficiently separated. This mixture is sent to the distillation column 5 and monosilane is obtained from the pipeline 10. Monochlorosilane, dichlorosilane and trichlorosilane are mainly recovered from the bottom of the distillation column 5 to the drum 7,
Further, in the distillation column 4, it is separated into a low boiling component mainly composed of monochlorosilane and dichlorosilane and a high boiling component mainly composed of trichlorosilane. The low-boiling component and the high-boiling component are sent to the disproportionation reactor 2 and the disproportionation reactor 1, respectively, and are again subjected to the disproportionation reaction. Thus, monosilane can be obtained using trichlorosilane as a raw material.

Of course, when a target compound is a silane compound other than monosilane, for example, dichlorosilane, for example, when distillation is adopted as a separation step, the distillation conditions are changed to obtain only the target compound, dichlorosilane. And the higher or lower boiling chlorosilane compound is recycled to the disproportionation reactor. In this manner, any one of the disproportionation reaction products or two or more chlorosilane compounds can be obtained as the target product.

[0033]

EXAMPLES The present invention will be described with reference to specific examples, but the present invention is not limited to these examples.

Example 1 3.2 g of ammonium molybdate was dissolved in 20 ml of water, and alumina as a catalyst carrier (Sumitomo Chemical; A
C-11, specific surface area: 120 m ² / g, pore volume: 0.3
7 ml / g, average pore size: 12 nm, particle size: 80 to 10
(0 μm) and dried at 110 ° C. Next, the mixture was calcined at 520 ° C. for 5 hours in air, and further activated in a hydrogen stream at 415 ° C. for 3 hours to obtain a molybdenum (VI) oxide / alumina catalyst.

2 having an inner diameter of 4 mm and 8 mm, respectively
The prepared molybdenum oxide (VI) /
0.5 ml of alumina catalyst in a 4 mm reaction tube, 8 mm
The reaction tubes were filled with 2.0 ml and heated to 200 ° C., respectively. Here is one of trichlorosilane and helium:
One mixed gas was passed through a 4 mm reaction tube at 60 ml / min and 30 ml / min, and an 8 mm reaction tube was supplied with 60 ml / min.
Min and at a flow rate of 24 ml / min to carry out a disproportionation reaction. The contact time at this time was 0.5 seconds and 1.0, respectively.
And 2.0 seconds and 5.0 seconds (note that the contact times of 0.5 and 1.0 seconds were 4 mm reaction tubes, and the contact times of 2.0 and 5.0 seconds were 8 mm reaction tubes). Is the value at.). The reaction was performed at normal pressure.

The gas passed through the catalyst layer was analyzed by gas chromatography to determine the conversion of trichlorosilane at each contact time, and the value was divided by the equilibrium conversion of trichlorosilane at 200 ° C. of 29.9%. . This value was defined as the equilibrium attainment rate. The results are shown in Table 1. At a contact time of 1.0 second, the equilibrium attainment rate reached a high rate of 88.6%.

The gas composition at a contact time of 5.0 seconds is as follows: monosilane; 0.1 mol% monochlorosilane; 0.9 mol% dichlorosilane; 13.0 mol% trichlorosilane; 70.1 mol% silicon tetrachloride; 15.9 mol % Met. This composition was consistent with the equilibrium composition of the disproportionation reaction of trichlorosilane at 200 ° C.

Example 2 8.0 g of ammonium tungstate was gradually added and dissolved in 100 ml of 3% aqueous ammonia heated to 90 ° C. At this temperature, concentrated nitric acid was carefully added dropwise until no yellow precipitate was formed, and the mixture was allowed to cool to room temperature. Warm water was added and the mixture was thoroughly washed by decantation until neutral.
After filtration, the resultant was dried at 100 ° C., and further dried in a hydrogen stream at 35 ° C.
Activate at 0 ° C for 3 hours, and use tungsten oxide (VI)
A catalyst was obtained.

The reaction was carried out according to Example 1, except that this catalyst was used. The results are shown in Table 1.

Example 3 6.3 g of chromium (VI) oxide was dissolved in 30 ml of water, and 30.0 g of alumina as a catalyst carrier was added thereto.
And dried. Next, it was calcined at 500 ° C. for 30 minutes in the air to obtain a chromium (VI) oxide / alumina catalyst.

The reaction was carried out according to Example 1, except that this catalyst was used. The results are shown in Table 1.

Example 4 A solution of 9.1 g of aluminum nitrate nonahydrate in 60 ml of water was added to 20 ml of a 20% aqueous sodium hydroxide solution at 5 to 10 ° C. while stirring to prepare a sodium aluminate solution. Next, 2.0 g of nickel nitrate was added for 10 m.
1 ml of water and 1.0 ml of concentrated nitric acid was added to the solution, and the sodium aluminate solution previously prepared was gradually added dropwise at 5 to 10 ° C. The resulting precipitate was thoroughly washed to neutrality by decantation and dried at 110 ° C. Further, a reduction treatment was performed at 360 ° C. in a hydrogen stream to obtain a nickel / alumina catalyst.

The reaction was carried out according to Example 1, except that this catalyst was used. The results are shown in Table 1.

Example 5 A reaction was carried out in the same manner as in Example 1 except that an Adams catalyst (platinum (IV) oxide catalyst; manufactured by Aldrich) was used. The results are shown in Table 1.

Example 6 The molybdenum (VI) oxide / alumina catalyst used in Example 1 was further reduced at 520 ° C. in a hydrogen stream to obtain a molybdenum / alumina catalyst.

The reaction was carried out according to Example 1, except that this catalyst was used. The results are shown in Table 1.

Example 7 The tungsten (VI) catalyst used in Example 2 was further reduced at 520 ° C. in a hydrogen stream to obtain a tungsten catalyst.

The reaction was carried out according to Example 1, except that this catalyst was used. The results are shown in Table 1.

Example 8 2.8 g of nickel nitrate hexahydrate was dissolved in 10 ml of water.
9.3 g of alumina as a catalyst carrier was added thereto, and
Dry at ℃. Next, the mixture was calcined at 415 ° C. for 1 hour in a nitrogen stream to obtain a nickel (II) oxide / alumina catalyst.

The reaction was carried out according to Example 1, except that this catalyst was used. The results are shown in Table 1.

Example 9 A reaction was carried out in the same manner as in Example 1 except that dichlorosilane was used instead of trichlorosilane. Here, the equilibrium attainment rate was determined by converting the conversion rate of dichlorosilane at each contact time into an equilibrium conversion rate of dichlorosilane at 200 ° C. of 62.0%.
Divided by Contact time 0.5, 1.0, 2.0, 5.0
The equilibrium arrival rates in seconds are 69.9, 90.9, and 99.
2,100%.

The gas composition at a contact time of 5.0 seconds is as follows: monosilane; 10.7 mol% monochlorosilane; 13.7 mol% dichlorosilane; 38.0 mol% trichlorosilane; 36.2 mol% silicon tetrachloride; 1.4 mol % Met. This composition was consistent with the equilibrium composition of the disproportionation reaction of dichlorosilane at 200 ° C.

Comparative Example 1 As a catalyst, a weak basic anion exchange resin Amberlyst A-21 manufactured by Rohm & Haas Co. (ion exchange capacity: 4.6)
The reaction was carried out in the same manner as in Example 1 except that the reaction was carried out at 80 ° C. using meq / g). The results are shown in Table 1. At a contact time of 2.0 seconds, the equilibrium attainment rate reached only 63.2%.

Comparative Examples 2 to 4 Silica (manufactured by Nishio Industry; ID gel, specific surface area: 310 m ²⁾
/ g, pore volume: 1.2 ml / g, average pore diameter: 15 n
m, particle size: 250-500 μm) and octylamine (O
A catalyst supporting cNH ₂ ), dioctylamine (Oc ₂ NH), and trioctylamine (Oc ₃ N) was prepared. The loading amount was 5% by weight in all cases, and was carried by the impregnation method.

The reaction was carried out in the same manner as in Example 1 except that the reaction was carried out at 80 ° C. using these catalysts. Table 1 shows the results
It was shown to. With these catalysts, the equilibrium attainment rate did not reach 80% even at a contact time of 5.0 seconds.

[0056]

[Table 1] Example 10 A disproportionation reaction of trichlorosilane was carried out using a two-stage pressurized liquid phase reactor having a reaction tower and a distillation tower shown in FIG. In the disproportionation reactor 11, the disproportionation reaction was performed at 200 ° C.-6 atm, and in the disproportionation reactor 12, the disproportionation reaction was performed at 80 ° C.-30 atm. The distillation columns 13 and 14 used had 40 theoretical plates. The disproportionation reactor 11 was charged with 300 ml of the catalyst used in Example 1 and the disproportionation reactor 12 with 30 ml, and the disproportionation reactor 11 was charged with 10 ml / ml of trichlorosilane.
The disproportionation reaction was carried out by continuously supplying the mixture in minutes (liquid). The contact time at this time was 30 minutes. Then, the distillation column 13
Then, a dichlorosilane fraction (including monochlorosilane) and a silicon tetrachloride fraction (including trichlorosilane) were separated, and the dichlorosilane fraction was continuously supplied to the disproportionation reactor 12. In the disproportionation reactor 12, the amount of dichlorosilane was 1 ml /
Per minute (liquid) and the contact time was 30 minutes. Then, in the distillation column 14, monosilane and other fractions were separated to obtain monosilane.

After continuous operation for 10 hours, monosilane was obtained from the upper part of the distillation column 14 at a rate of 40 ml / min (gas; standard state).

[0058]

According to the production method of the present invention, a silane compound can be produced in a shorter contact time than in the conventional method. That is, when the catalyst according to the present invention is used, the reaction rate is high, so that the time required to sufficiently advance the disproportionation reaction can be set shorter than that of the conventional catalyst. Therefore, if the catalyst amount is the same, compared to the conventional method,
The yield per unit time can be increased. Conversely, to obtain the same yield, less catalyst is required.

Since the disproportionation reaction of the hydrogenated silane is an equilibrium reaction, the reaction temperature can be set higher than before by making use of the heat resistance of the metal or metal oxide catalyst. Thereby, the equilibrium composition can be changed efficiently. In the above-described method for producing monosilane by a two-stage disproportionation reaction using trichlorosilane as a raw material, the reaction temperature for disproportionation of trichlorosilane, which is the first-stage reaction, is raised to increase the equilibrium of trichlorosilane. The conversion can be improved and is very useful.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a typical mode of a manufacturing process for carrying out the present invention.

FIG. 2 is a schematic diagram showing a pressurized liquid phase two-stage disproportionation reactor.

[Explanation of symbols]

 1, 2; disproportionation reactors 3, 4, 5; distillation columns 6, 7; drums 8, 9, 10; pipelines 11, 12; disproportionation reactors 13, 14;

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Claims (1)

[Claims] 1. A silane compound characterized in that a hydrogenated silane is disproportionated using a catalyst comprising at least one metal or metal oxide selected from chromium, molybdenum, tungsten, nickel and platinum. A method for producing a disproportionation reaction product.