JPS6395111A - Production of trichlorosilane - Google Patents

Abstract

PURPOSE:To economically carry out conversion of silicon tetrachloride into trichlorosilane in good yield, by converting the silicon tetrachloride into a liquid state and carrying out reaction in the presence of a specific additive in reacting the silicon tetrachloride with metallic silicone and hydrogen to produce the trichlorosilane. CONSTITUTION:Silicon tetrachloride is reacted with metallic silicone and hydrogen or hydrogen and hydrogen chloride to produce trichlorosilane. In the process, the reaction is carried out in the presence of metallic copper, a metal halide and acidic compound. The reaction is particularly preferably carried at 150-400 deg.C temperature. The metallic halide is selected from chlorides, bromides and iodides of Cu, Ti, V, Cr, Mn, Co, Zr, etc. The acidic compound is selected from chlorides, bromides of iodides of Ga, Zr, Hf, Sb, Nb, Ta, Be, etc., and acidic metal oxides or acidic metal sulfides.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing trichlorosilane from silicon tetrachloride and hydrogen.

With the development of the electronics industry in recent years, demand for polycrystalline silicon, single crystal silicon, monosilane gas, etc. has increased rapidly, and demand is expected to continue to increase in the future. Here, trichlorosilane is used in the largest quantity as a raw material for the silicon material mentioned above.For example, high-purity polycrystalline silicon is produced by thermal decomposition of trichlorosilane. Most silicon is manufactured using this method. Furthermore, recently, a method for producing monosilane by disproportionation reaction of trichlorosilane has been put into practical use, and the demand for trichlorosilane will become extremely important in the future. However, in these methods, trichlorosilane is consumed and a large amount of silicon tetrachloride is produced as a by-product. For example, in the production of high-purity polycrystalline silicon by thermal decomposition of trichlorosilane, approximately 60% of trichlorosilane is produced as silicon tetrachloride, and
In the production of monosilane by disproportionation of trichlorosilane, substantially three times the mole of silicon tetrachloride as half-nosilane is produced as a by-product. Therefore, a method is known in which the by-produced silicon tetrachloride is used as a raw material for, for example, Aerosil, thereby reducing the production cost of trichlorosilane.

A method of utilizing silicon tetrachloride, which has excellent substantially tensile properties, is to convert it back into trichlorosilane and reuse it as a raw material for the above-mentioned method. For example, by converting silicon tetrachloride to trichlorosilane, the production of monosilane by disproportionation of trichlorosilane essentially results in a process of producing monosilane with metallic silicon and hydrogen, a process that has recently been put into practical use. be.

Therefore, the technology for converting silicon tetrachloride into trichlorosilane is extremely useful, and in particular, it is extremely important from the economic point of view of the process to be able to do this at low cost, simply, and efficiently.

Conventionally, the following method is known as a method for converting silicon tetrachloride into trichlorosilane.

(1) A method for producing trichlorosilane by reacting silicon tetrachloride and hydrogen at a temperature of around 1000"C or higher.

(2) Silicon hydrogen tetrachloride and metallic silicon soo'
A method for producing trichlorosilane by reacting near c.

(3) A method of producing trichlorosilane by reacting silicon tetrachloride, hydrogen, metallic silicon, and hydrogen chloride at around 500°C.

Regarding the method (1), for example, Japanese Patent Application Laid-Open No. 57-3711
In No. 1, trichlorosilane was obtained in a yield of 60% by spraying hydrogen and silicon tetrachloride onto a heating element at 1100-1600°C. Also, JP-A-5
No. 7-156318, in the first stage, hydrogen and silicon tetrachloride were mixed at a molar ratio of H2/5tCIa・2 at a temperature of 900°C.
Trichlorosilane was obtained with a yield of 25%. Furthermore, in JP-A-59-45920, trichlorosilane is obtained by reacting silicon tetrachloride with hydrogen in plasma. In addition, in Japanese Patent Application Laid-Open No. 60-81010, 1
Silicon tetrachloride and hydrogen are reacted in a temperature range of 200-1400°C to obtain trichlorosilane with a yield of about 30%.

Method (2) can be said to be an energetically advantageous method since the reaction proceeds at a relatively low temperature compared to method (1). Naturally, method (3) in which hydrogen chloride gas is used to promote the reaction more effectively than method (2) also has similar features. Regarding methods (2) and (3), it is effective to use a catalyst, and a method using a copper compound or metallic copper as a catalyst is effective, for example, in JP-A-56-73.
No. 617 uses copper powder as a catalyst at 350 to 600°C.
A fluidized bed reaction was performed to obtain trichlorosilane. Furthermore, in JP-A-58-11042, trichlorosilane is obtained by conducting a reaction using a catalyst supported with copper or with copper and nickel supported.

One of these methods is, for example, method (1).

Trichlorosilane has been obtained with a fairly high conversion rate of silicon tetrachloride, but in order to obtain trichlorosilane with a yield of 30% or higher, the reaction must be carried out at a high temperature of 1000"C or higher, which requires energy consumption. In addition, since it is a high-temperature reaction, the reactor etc. are severely corroded by silicon chloride, and undesirable high molecular weight chlorosilanes are inevitably produced as by-products. It is still far from being put into practical use.

On the other hand, methods (2) and (3) are useful methods for producing trichlorosilane from a thermodynamic point of view, and as mentioned above, they are secondary to the method for producing monosilane by disproportionation of trichlorosilane. It can be said that converting the silicon tetrachloride produced to produce trichlorosilane is a very useful method, especially since method (2) essentially produces monosilane from silicon and hydrogen. In addition, (3
), the yield of trichlorosilane is high, but hydrogen chloride does not participate in the conversion of silicon tetrachloride to trichlorosilane, and the method essentially only synthesizes trichlorosilane from metallic silicon. Therefore, from the point of view of reusing silicon tetrachloride, it is somewhat less useful than method (2), but on the other hand, it has the advantage of increasing the yield of trichlorosilane, and the use of hydrogen chloride is It is desirable to bring out its characteristics by using a small amount.

Furthermore, a process that combines methods (2) and (3) is also known (Japanese Patent Application Laid-open No. 36318/1983).

Among the above methods, method (2) is the best from the viewpoint of effective reuse of silicon tetrachloride, and method (3) is also excellent from the viewpoint of producing matatrichlorosilane. Hard to throw away.

That is, method (2) or (3) is highly economical (method (2) in particular is currently being put into practical use as the preferred method).

However, in method (2), one reaction temperature is usually carried out at 500 to 600°C, and there is no example in which trichlorosilane is substantially produced at a reaction temperature of 300°C or lower. As in the present invention, there has been no known example of producing trichlorosilane by a heterogeneous gas-liquid-solid phase reaction using silicon tetrachloride as a liquid at a temperature below the critical temperature of silicon tetrachloride.

In the method (2), a gas-solid phase fluidized bed apparatus has conventionally been used to continuously produce trichlorosilane in large quantities. However, in this case, since a fluidized bed is used, there is a loss of active ingredients due to volatilization of silicon metal and catalyst components whose particle size has become smaller due to one reaction.
Volatilization of catalyst components due to high-temperature reactions, corrosion of equipment, decrease in selectivity of trichlorosilane due to the formation of high molecular weight chlorosilanes, and large use of energy due to high temperatures.
Such as business. It has many drawbacks that need to be further resolved in order to be industrialized.

The inventors of the present invention have made extensive studies in view of these considerations.

Not only at temperatures around 500'C, but even at low temperatures below 300'C, and even surprisingly below the critical temperature of silicon tetrachloride,
The present inventors discovered an extremely economically advantageous method for producing trichlorosilane by reacting silicon tetrachloride in a liquid state with high yield and increasing the throughput per unit volume of silicon tetrachloride, and completed the present invention. Ta.

An object of the present invention is to convert by-produced silicon tetrachloride into trichlorosilane in the production of polycrystalline silicon by thermal decomposition of trichlorosilane or the production of monosilane by disproportionation reaction of trichlorosilane. The object of the present invention is to provide an extremely economical method for converting and effectively utilizing silicon tetrachloride.

According to the present invention, in the method for producing trichlorosilane by reacting silicon tetrachloride and silicon metal with hydrogen or hydrogen and hydrogen chloride, the reaction is carried out in the presence of copper metal, a metal halide, and an acidic compound. A method for producing trichlorosilane is provided.

Light plate Gosarajo The present invention will be explained in detail below.

The conversion of silicon tetrachloride into trichlorosilane carried out in the present invention is basically expressed by the following formula % (%). This reaction is an equilibrium reaction, and the higher the temperature, the higher the pressure, and the higher the H2/5IC14 molar ratio, the more the reaction proceeds in the right direction. In addition, as will be described later, a low-temperature gas-liquid-solid phase reaction occurs when silicon tetrachloride is in a liquid state at a temperature below 233.6°C (actually 230°C or lower), which is the critical temperature of silicon tetrachloride. Until now, there has been no known example of trichlorosilane being produced using
In the present invention, by performing the above reaction in the presence of specific additives such as metal copper, metal halides, and acidic compounds, silicon tetrachloride is kept in a liquid state not only at high temperatures but also at low temperatures below 300°C. This makes it possible to produce trichlorosilane in good yield by reacting with Naturally, it is also possible to adopt a method that clearly increases the yield of trichlorosilane by adding hydrogen chloride gas into the reaction system of the present invention.

The purity of the metal silicon used in the present invention is not particularly limited, and it may be either low purity metallurgical silicon or high purity silicon.

From an economic point of view, it is preferable to use the former.Although the form of these metal silicons does not matter, from the viewpoint of reaction rate, it is recommended that they be used in the form of a powder with a large surface area. Of course, it is also possible to use it in other forms such as a single grain.

In the present invention, the above reaction is carried out in the presence of metallic copper, a metal halide, and an acidic compound; 1. The metallic copper used in the present invention is not particularly limited; 1. Usually commercially available electrolytic copper is used; Copper can also be used. There is no need to worry much about the purity, and the form of the metal copper does not matter, but from the viewpoint of reaction rate, it is recommended to use it in the form of a powder with a large surface area. Of course, it is also possible to use it in other forms such as a single grain.

In addition, the metal halides used in the present invention are Ib to VIIb and IIIa to V in the long periodic table of elements (here, according to the MERCK INDEX).
It is a chloride, bromide or iodide of metal a, and the element symbol is Cu, Ti, V, Cr, Mn, F
e, Co, Ni.

Zn, Zr, Mo, Ru, Rh,
Pd, Ag, Sn, Sb, W,
Hg.

It is a chloride, bromide or iodide such as pt, pb, etc. Specifically, it has one molecular formula of CuC1, CuC1z, T
iCl3+TlC14+VC11+VC1i+VOC1
, +CrC1g+CrC1z+MnC1z+FeC1z
+FeCl3+CoC1z, NiC1z, ZnC11,
ZrC1a, ZrOClg.

MoC15JoC15, RuC1tJuC13, RhC
l3+PdCl2. AgCl, 5nCIZ, Sn(
:1 a + 5bct3.5bC1s + WCl5
．． WCL+ HgzCl z+ HgCl Z, Pt
Metal chlorides such as CIn, PbC1z and PbC1;
CuBr.

CuBrz, TiBra+VBrz+CrBrz+Mn
Brz, FeBrg+FeBr, +CoBrx+ N1
Brt+ ZnBrz+ ZrBra, MoBr3.
PdBr*+AgBr.

5nBrz+SnBr4+5bBr2JBr5. Hgz
Br2. Metal bromides such as HgBrz+ and PbBr2:
and Cul, Ti1a, CrIz+MnIt+ Fe
I2. CoIz+ Nt I! l Zn1z+ Zr
14+ PdIz, AgI+ SnI it Snl
a, 5b1i, 5bls, Ka1a, HgzIg, Pt
These include metal iodides such as rz, Pt141 and Pb1i. Further, halides containing two or more types of halogen atoms are also effective, and these halides are used alone or in a mixture of two or more types.

Use in mixtures.

Next, the acidic compounds used in the present invention are Ga, Zr, Hf
, Sb, Nb+Ta, Mo, InJ, Re+Zn+As
, B, P, Ti+Pt or Be fluorides, chlorides, bromides or iodides, and furthermore, aprotic acidic compounds such as acidic metal oxides or acidic metal sulfides. Specifically, the molecular formula or composition formula is GaCl3. GaC
1z+GaBr3. Gal*+ZrC141HfC1a
+ HfBr 41 Hf I a + 5bFs+
SbC]s+ 5bCI3. NbFs+NbCl5+
TaF5+TaCl5+TaBrs1MoFh+MoC
l5+ InCl3+InBr! +'1n13. W.C.I.
thJeC15, ReCl5. ZnC1z, BCI:
++BBra+ BI:++ SI'lC1a + 5
nC1z + TiC14+ TiBr4+ TlCl
21 P tcIa, etc. halide-containing compound + BeO
, Cr2O5, PzOs, Ti0z+Alz(Soa)
z, AIzOz・XCrzOz, AIjOt・Fe
Js+MnO.

AIzOt Coo, Altos ・Mo0z+M
Examples include acidic metal oxides or sulfides such as O5t+Mo5z. In the present invention, one type or a mixture of two or more of these is used. However, in the present invention, the metal halide and the acidic compound are not the same compound. For example, if Ti chloride is selected for the former, Ti chloride is not selected for the latter.

Next, a method for converting silicon tetrachloride into trichlorosilane in the present invention will be described.

The conversion reaction is basically carried out according to the above formula (1)6
In the present invention, one reaction may be carried out under normal pressure, increased pressure, or reduced pressure, but from the viewpoint of one reaction equilibrium and the throughput of raw materials, it is preferable to carry out under increased pressure. In addition, pressurization is required in order to carry out the process at a predetermined temperature in a heterogeneous system of gas phase, liquid phase, and solid phase, that is, a so-called gas-liquid-surface phase. Hydrogen used in the reaction may be diluted in advance with a medium (gas) inert to the reaction, such as argon, helium, and/or nitrogen, but from the viewpoint of 1 reaction equilibrium 1 reaction rate and economics, hydrogen may be used alone. It is preferable to use it in In addition, solvents that are inert to the raw materials, products, and additives such as metal steel, metal halides, and acidic compounds under the reaction conditions may contain impurities to the extent normally expected. - It is also possible to use aliphatic hydrocarbons such as hexane and n-hebutane, alicyclic hydrocarbons such as cyclohexane and cyclooctane, and aromatic hydrocarbons such as benzene and toluene. .

Next, the most noteworthy point of the present invention, which is the advantage that silicon tetrachloride can be reacted in a liquid state, will be described.

Reacting silicon tetrachloride while keeping it in a liquid state means that liquid silicon tetrachloride and solid metal silicon, and hydrogen incorporated into the liquid silicon tetrachloride by dissolution or the like or by gas-liquid contact, reacts, and therefore the reaction field is almost essentially a liquid-solid phase.

The trichlorosilane produced there is first produced in the liquid phase and dissolved in the liquid, but then moves to the gas phase.

At this time, as a matter of course, silicon tetrachloride also transfers to the gas phase. The vapor pressure of trichlorosilane and silicon tetrachloride at the same temperature is higher for trichlorosilane, so the 5iHC1s/5iC1a concentration ratio in the gas phase is higher than the 5iHCja/SEC1g concentration ratio in the liquid phase. . Thus, if the reaction is carried out continuously, the 5iHC1i/5iC14 concentration ratio in the liquid phase will always decrease, so the reaction rate of the reaction will be increased from the viewpoint of one reaction equilibrium, and this will improve the production of trichlorosilane. The reaction will proceed in a more advantageous direction. Therefore, compared to a normal fluidized bed reaction where the product gas composition is discharged as it is, it is possible to expect the effect of making the composition of the product always work in favor of the product in terms of the reaction equilibrium. It is.

Furthermore, by using anhydrous hydrogen chloride gas in the reaction, the amount of trichlorosilane produced can be further increased.

As described above, in the present invention, the reaction temperature is 100
℃ or higher, preferably 150℃ or higher and 600℃ or lower.

More preferably, the temperature is 150"C or higher and 300"C or lower.

Substantial production of trichlorosilane cannot be expected at a temperature below 100° C. However, when carrying out this reaction, trichlorosilane may be present in an amount less than the reaction equilibrium amount in the silicon tetrachloride charged as a raw material.

This means that it is possible to use silicon tetrachloride in which trichlorosilane remains when the trichlorosilane produced by the reaction is separated by distillation, etc., but it is preferable to contain as much trichlorosilane as possible in view of the reaction equilibrium. It is desirable to use silicon tetrachloride with no trichlorosilane content or with as little trichlorosilane content as possible because this will substantially increase the amount of trichlorosilane produced.

Next, the amounts of raw materials, metal steel, and additives such as metal halides used in the present invention will be described.

The amount of silicon metal to be used is not particularly limited, but when conducting batchwise, it is preferably 1% by weight or more based on silicon tetrachloride, and if it is less than this value, silicon metal will be consumed along with the reaction and the reaction will not be effective. I can't do it (there is a risk that it will happen).

In addition, the amount of additives such as metallic copper, metal halides, and acidic compounds is not particularly limited. -at+ms), the amount of metal copper is preferably 0.5% or more, and the acidic compound and metal halide are each 0.1% or more in terms of reaction speed.

Next, specific embodiments for actually implementing the present invention will be described. As mentioned above, the reaction in the present invention can be carried out at normal pressure, increased pressure, or reduced pressure, but from the viewpoint of raw material throughput and equilibrium amount, it is preferable to carry out the reaction under pressure (hydrogen pressure is preferable). It is possible to carry out the reaction by either a formula reaction method or a batch reaction method.

Although the method of carrying out the present invention is not particularly specified, the following method may be mentioned as a method that is easy to carry out. Of course, the present invention is not limited to these methods.

(1) A predetermined amount of silicon tetrachloride in an autoclave.

A method in which metal silicon, metal copper, metal halides, and acidic compounds are added, then pressurized with hydrogen to a predetermined pressure, and then heated and stirred.

(2) A predetermined amount of silicon tetrachloride 1w4. A method of continuously introducing a metal halide and an acidic compound and continuously extracting a produced gas and/or a produced liquid to carry out a reaction.

(3) Metallic silicon 1w4. A metal halide and an acidic compound are placed in a reactor, kept at a predetermined temperature, silicon tetrachloride and hydrogen are continuously introduced under hydrogen pressure, and the reaction is carried out while continuously extracting the product gas and/or product liquid. A method of intermittently introducing metal silicon, metal copper, metal halides, and acidic compounds as necessary.

In particular, method (2) or (3) is preferable as a method for producing trichlorosilane in large quantities.In addition, by performing continuous reactions, metallic silicon is consumed by one reaction,
Copper, metal halides and acid compounds are virtually not consumed. Therefore, if the reaction is carried out at a low temperature, their volatilization can be prevented, so even if the ratio of copper, metal halides, and acidic compounds to metal silicon is high in the reactor, there is no need to add them further, so it is sufficient. This can be done as an economically viable method.

The present invention is an extremely effective method for economically converting silicon tetrachloride to trichlorosilane. By operating below the critical temperature of silicon tetrachloride, which was previously impossible, silicon tetrachloride can be introduced into the reactor in a liquid state and the reaction can be carried out in a liquid state. Therefore, it is possible to easily downsize the reaction container, which is economical. In addition, as a result of making it possible to carry out the reaction at low temperatures, it is possible to suppress corrosion of the 9 reaction equipment, etc. In addition, it is possible to produce trichlorosilane with low energy, and the economic effect is extremely high. (It is extremely useful industrially. In other words, it has become possible to significantly reduce energy consumption for conventional high-temperature reactions that required a large amount of energy.)

Liquid phase (silicon tetrachloride) reactions are now possible at low temperatures, allowing the size of one reaction vessel to be reduced, preventing corrosion of nine reaction devices, and allowing the use of low-temperature heating media such as steam, resulting in a significant reduction in equipment. becomes possible.

The present invention will be explained in more detail below using examples.

Example 1 S [l531
6 made 200m1 autoclave (inner volume 220+111
) and 6.00 g (214a+g-at+nL) of metallic silicon (99.9% purity, 200 mesh) 6.25 g (98,4+wg-at+nL) of Ichisaka's metallic copper powder B (98,4+wg-at+
), antimony pentachloride 7.48g (25.0mmol
), 2.48 g (25, Om+*ol) of cuprous chloride, and 88.3 g (520 mm+ol) of silicon tetrachloride were then pressurized into hydrogen at 40 Kg/cm"G at room temperature. Then, 3
The autoclave was heated to 260°C while stirring at 00 rpm. (Temperature rising time 20 minutes) 2.5 each at 260℃
．． 1.5.1.0.0.5. After the reaction was carried out for 0 hours (immediately after the temperature was raised), the autoclave was cooled to 5° C., the pressure was lowered to normal pressure, and the reaction solution was analyzed by gas chromatography.

As shown in Table 1, the reaction almost reached equilibrium after 1.0 hours of reaction, indicating that trichlorosilane was produced efficiently.

First table umbrella TSC! ) Lichlorosilane; STC: represents silicon tetrachloride; the same shall apply hereinafter.

Example 2 The same amounts of silicon metal, copper powder B, cupric chloride, and silicon tetrachloride as in Example 1 were placed in the same autoclave as in Example 1, and in place of antimony pentachloride, various compounds shown in Table 2 were added. Add 25 mmol of acidic compound to each 26
After reacting for 0.5 hours at 0°C, the mixture was similarly cooled and the pressure was lowered, and each reaction solution was analyzed. As shown in Table 2, the results were compared with Comparative Example C) described later, and it was confirmed that trichlorosilane was produced in a good yield no matter which acidic compound was used in combination.

Table 2 24 Mo5211.6 88.4 Example 3 No. 1 of Example 2 Using the same amounts of metallic silicon, metallic copper powder, antimony trichloride and silicon tetrachloride, and further replacing cuprous chloride. The reaction conditions were the same as in Example 2 (260" c, o, s time) by adding 25.0 m+wol of various metal halides as shown in Table 3.
After the reaction was carried out, one reaction solution was similarly analyzed after cooling and reducing the pressure. As shown in Table 3, the results were compared with Comparative Example B) described below, and it was found that each metal halide had good reaction activity.

Table 3 Example 4 A reaction was carried out under exactly the same reaction conditions as in Example 3, except that only metallic silicon was replaced with 6.00 g of 150 mesh with a purity of 98%. After the reaction was completed, the reaction solution was prepared in the same manner. Analysis revealed that trichlorosilane was 20.0% and silicon tetrachloride was 80.0%. Therefore, this result corresponds to the No.
, 2, and it became clear that commercially available silicon metal with a purity of 98.0% can be used.

Comparative Example (Blank Test) A blank test was carried out under the same reaction conditions as in Example 4, with A) not adding nickel chloride and antimony trichloride, B) not adding only nickel chloride, and C) not adding only antimony trichloride. went. As shown in Table 4, the results revealed that this was due to the synergistic effect of nickel chloride and antimony trichloride.

Table 4 Example 5 9.00 g of metallic silicon (purity 9969%, 200 mesh) was placed in the same autoclave as Examples 1 to 4.
(320mg-atm), metallic copper powder B7. OOg
(110 mg-atm), nickel chloride 4.86 g
(37,5a+mol), antimony trichloride 8.5
5 g (37,5 wmol) and 176 silicon tetrachloride
．． Add 7g (1.04mol) and hydrogen at room temperature at 110K.
g/cm"G and reacted for 5 hours at 230°C, 215°C, and 200°C, respectively, and then cooled and lowered the pressure in the same manner and analyzed the reaction solution. The results are as shown in Table 5. It was confirmed that trichlorosilane was produced in good yield even when the reaction was carried out using silicon chloride in a liquid state.

Table 5 Example 6 A 5US316 reaction tube with an inner diameter of 25 m++ and a length of 700 n+m was filled with 150 g of metallic silicon (purity 98%) and copper powder 8
10g, nickel chloride Log and chromium oxide (Crz
(h) Fill 10 g and increase the internal pressure to 10 Kg/ca+”G
A mixed gas of silicon tetrachloride and hydrogen (Hz/5iC14-2 molar ratio) was introduced at a spatial linear velocity of 2.1 cm/sec at the following reaction temperatures, and the reactions were carried out in a fluidized state.The reaction gases were as follows: The reactor was taken out from the outlet, and after lowering the pressure to atmospheric pressure, it was analyzed in its gas state by gas chromatography while keeping the temperature at 70°C. Table 6 shows the composition of trichlorosilane and silicon tetrachloride in steady state. This result shows that trichlorosilane was produced extremely efficiently.

Table 6

Claims (8)

[Claims] (1) A method for producing trichlorosilane by reacting silicon tetrachloride and silicon metal with hydrogen or hydrogen and hydrogen chloride, characterized in that the reaction is carried out in the presence of copper metal, a metal halide, and an acidic compound. A method for producing trichlorosilane. (2) The method according to claim 1, wherein the reaction temperature is 100°C or higher. (3) The method according to claim 1, wherein the reaction temperature is 150°C to 600°C. (4) The method according to claim 1, wherein the reaction temperature is 150°C to 400°C. (5) Metal halides are I b in the long periodic table of elements.
A method according to claim 1, wherein the chloride, bromide or iodide of a metal of group VIIb and IIIa to Va. (6) Metal halide is Cu, Ti, V, Cr, Mn
, Fe, Co, Ni, Zn, Zr, Mo, Ru, Rh,
6. The method according to claim 5, wherein the metal halide is selected from the group consisting of chlorides, bromides, and iodides of Pd, Ag, Sn, Sb, W, Hg, Pt, and Pb. (7) Acidic compound is Ga, Zr, Hf, Sb, Nb, T
a, Mo, In, W, Re, Zn, As, B, P, Ti
, Pt, or Be fluoride, chloride, bromide, or iodide. (8) The method according to claim 1, wherein the acidic compound is an acidic metal oxide or an acidic metal sulfide.