JPH09328492A - Production of tetraarylphosphonium halide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain the subject compound useful as a catalyst for various kinds of reactions without carrying out a troublesome operation by reacting a triarylphosphine with an aryl halide in the presence of a metal halide catalyst in a water-soluble high boiling point solvent. SOLUTION: A triarylphosphine of formula I (Ar<1> -Ar<3> are each an aryl such as phenyl or naphthyl which may have a substituent such as an alkyl group, an alkoxy group or a halogen atom) (e.g. triphenylphosphine) is reacted with an aryl halide of formula II (Ar<4> is the same as Ar<1> ; X is a halogen such as Cl, Br or I) (e.g. bromobenzen) in the presence of a metal halide catalyst (e.g. nickel chloride hexahydrate) in a water-soluble high boiling point solvent (e.g. ethylene glycol) at a temperature of >=160 deg.C to easily obtain the objective tetraarylphosphonium halide useful as a catalyst for various kinds of reactions, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a tetraarylphosphonium halide from a triarylphosphine and an aryl halide. Tetraarylphosphonium halides are compounds useful as catalysts for various reactions (phase transfer catalysts, polymerization catalysts, halogen exchange reaction catalysts for halides, etc.).

[0002]

2. Description of the Related Art A method for producing a tetraarylphosphonium halide from a triarylphosphine and an aryl halide is a reaction of a triarylphosphine with an aryl halide at high temperature and high pressure using methanol as a solvent in the presence of a metal halide. Method [Bul
l. Chem. Soc. Jpn. , 30, 667 (19
57), Nippon Kagaku Journal, 86, 112 (1965)] are known. However, this method not only requires a pressure-resistant reactor, but also has a problem that when methanol is distilled off after the reaction, the reaction product solidifies and its handling and separation of the target product become complicated. That is, the solidified reaction product itself is not only complicated to handle, but in order to separate the target tetraarylphosphonium halide and the metal halide of the catalyst from the solidified reaction product, for example, recrystallization from water is performed. Such an operation is further required, but in this case, there arises a problem that a large amount of waste liquid containing the metal halide of the catalyst is produced and the treatment thereof is also required.

In addition, a method of reacting a triarylphosphine with an aryl halide under atmospheric pressure using benzonitrile as a solvent in the presence of a metal halide [Ch
em. Ber. , 99, 2782 (1966)] is also known. However, in this method, it is necessary to use a large amount of metal halide (50 mol% of triarylphosphine), and further separation of the target product requires complicated operations such as steam distillation and solvent extraction. There's a problem. There is also a problem that a large amount of chlorine-containing organic solvent such as chloroform and methylene chloride is required for solvent extraction. Further, even if the benzonitrile is distilled off without performing steam distillation, there arises a problem that the reaction product is solidified and the handling and separation of the target product are complicated as in the case described above.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a method for producing a tetraarylphosphonium halide from a triarylphosphine and an aryl halide, which includes known reactions such as reaction under high pressure, steam distillation and solvent extraction. An object of the present invention is to produce a tetraarylphosphonium halide by solving the problems of complicated separation operation, handling of solid matter, and generation of waste liquid containing metal halide. That is, the present invention is a method for producing a tetraarylphosphonium halide from a triarylphosphine and an aryl halide, which is capable of producing a target product with a high yield under mild reaction conditions,
An object of the present invention is to provide a method for producing a tetraarylphosphonium halide in which a target product can be easily separated.

[0005]

The object of the present invention is to provide a tetraarylphosphonium halide characterized by reacting a triarylphosphine with an aryl halide in the presence of a metal halide catalyst and a water-soluble high-boiling solvent. It is achieved by the manufacturing method.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The triarylphosphine used in the present invention is a compound represented by the chemical structural formula (I).

[0007]

Embedded image (In the formula, Ar ¹ , Ar ² and Ar ³ represent an aryl group such as a phenyl group and a naphthyl group and may have a substituent such as an alkyl group, an alkoxy group and a halogen atom.)

Examples of the aryl group include (1) phenyl group, (2) (a) alkyl group having 1 to 12 carbon atoms such as methyl group and ethyl group, (b) methoxy group, ethoxy group and the like. Examples thereof include an alkoxy group having 1 to 12 carbon atoms, (c) a substituted phenyl group having a substituent such as a halogen atom such as a fluorine atom and a chlorine atom, and (3) a naphthyl group. In addition, these aryl groups may be the same as or different from each other, and may be bonded to each other or may be crosslinked.

The substituted phenyl group includes various isomers.
Examples of these isomers include (a) 2- (or 3
-, 4-) methylphenyl group, 2- (or 3-, 4-)
Ethylphenyl group, 2,3- (or 3,4-) dimethylphenyl group, 2,4,6-trimethylphenyl group, 4-
An alkylphenyl group in which an alkyl group having 1 to 12 carbon atoms such as a trifluoromethyl group and a 3,5-bistrifluoromethyl group is bonded to a phenyl group, (b) 3-methoxyphenyl group, 2,4,6- An alkoxyphenyl group in which an alkoxy group having 1 to 12 carbon atoms such as a trimethoxyphenyl group is bonded to a phenyl group, (c) a 3- (or 4-) chlorophenyl group, a halogen atom such as a 3-fluorophenyl group is phenyl. A halophenyl group attached to the group.

Specific examples of the triarylphosphine corresponding to the above aryl group include (1) triphenylphosphine, (2) (a) tris (2-methylphenyl) phosphine and tris (3-methylphenyl). Phosphine, tris (4-methylphenyl) phosphine, tris (2-ethylphenyl) phosphine, tris (3-ethylphenyl) phosphine, tris (4-ethylphenyl) phosphine, tris (2,3-dimethylphenyl) phosphine, tris (3,4-dimethylphenyl) phosphine,
Tris (2,4,6-trimethylphenyl) phosphine, diphenyl (2-methylphenyl) phosphine, diphenyl (3-methylphenyl) phosphine, diphenyl (4-methylphenyl) phosphine, tris (4-
Trifluoromethylphenyl) phosphine, tris (3,5-bistrifluoromethylphenyl) phosphine, (2) (b) tris (3-methoxyphenyl) phosphine, tris (2,4,6-trimethoxyphenyl) phosphine, (2) (c) tris (3-chlorophenyl) phosphine, tris (4-chlorophenyl) phosphine, tris (3-fluorophenyl) phosphine, (3) tri (1-naphthyl) phosphine, tri (2-naphthyl) phosphine, And so on.

The aryl halide used in the present invention is a compound represented by the chemical structural formula (II).

Embedded image (In the formula, Ar ⁴ represents an aryl group such as a phenyl group and a naphthyl group, and may have a substituent such as an alkyl group, an alkoxy group, an aryloxy group and a halogen atom.
X represents a halogen atom such as a chlorine atom, a bromine atom and an iodine atom. )

Specific examples of the aryl halide include:
Bromobenzene, iodobenzene, 1-chloronaphthalene, 1-bromonaphthalene, 1-iodonaphthalene, 2
-Aryl halide having no substituent such as chloronaphthalene, 2-bromonaphthalene, and 2-iodonaphthalene, 2-bromotoluene, 3-bromotoluene, 4-bromotoluene, 2-iodotoluene, 3-iodotoluene, 4-iodotoluene, 2-bromoethylbenzene,
4-bromoethylbenzene, 2-iodoethylbenzene, 4-iodoethylbenzene, 2,3-dimethylchlorobenzene, 2,4-dimethylchlorobenzene, 3,4
1 to 6 carbon atoms such as dimethylchlorobenzene, 2,5-dimethylchlorobenzene, 2,3-dimethylbromobenzene, 2,4-dimethylbromobenzene, 3,4-dimethylbromobenzene and 2,5-dimethylbromobenzene
An aryl halide having an alkyl group of 3 as a substituent, 3-chloroanisole, 3-bromoanisole, 3
-Aryl halide having an alkoxy group having 1 to 6 carbon atoms such as iodoanisole as a substituent, 2-bromobiphenyl, 4-bromobiphenyl, 2-iodobiphenyl, 4-iodobiphenyl, 4,4'-dibromobiphenyl, etc. An aryl halide having an aryl group having 6 to 12 carbon atoms as a substituent, an aryl halide having an aryloxy group having 6 to 12 carbon atoms such as 4-bromodiphenyl ether as a substituent, 1,2-di Halogen atom such as chlorobenzene, 1,4-dichlorobenzene, 1,2-dibromobenzene, 1,4-dibromobenzene, 1,4-diiodobenzene, 4-chlorobromobenzene, 4-chloroiodobenzene as a substituent And the like.

In the present invention, the above triarylphosphine can be reacted with an aryl halide to form the corresponding tetraarylphosphonium halide. Tetraarylphosphonium halide is a chemical structural formula
(III).

Embedded image (In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ and X are the same as above.)

In the above reaction, the aryl halide is usually 0.8 to 2 relative to the triarylphosphine.
The molar amount is preferably 0.9 to 1.5 times, more preferably 1.0 to 1.3 times.

Further, in the above reaction, at least one known metal halide catalyst is used. Examples of metal halide catalysts include groups 7, 8 and 9 of the periodic table.
Halides of metals belonging to group 10, group 10, group 11 or group 12 are used. As the halide of the Group 7 metal,
Examples include manganese halides such as manganese chloride, manganese bromide, and manganese iodide. Examples of Group 8 metal halides include iron halides such as iron chloride, iron bromide, and iron iodide. Examples of the Group 9 metal halides include cobalt halides such as cobalt chloride, cobalt bromide, and cobalt iodide. Examples of Group 10 metal halides include nickel halides such as nickel chloride, nickel bromide, and nickel iodide. Examples of the Group 11 metal halides include copper halides such as copper chloride, copper bromide, and copper iodide. Examples of Group 12 metal halides include zinc halides such as zinc chloride, zinc bromide, and zinc iodide.

Among the metal halides, 9 of the periodic table
Halides of metals belonging to Group 10, 10, 11 or 12 are preferable, and among them, chloride and bromide are preferable. Among these, nickel halides (nickel chloride, nickel bromide, etc.), cobalt halides (cobalt chloride, cobalt bromide, etc.), copper halides (copper chloride, copper bromide, etc.), zinc halogens. Compounds (zinc chloride, zinc bromide, etc.) are particularly preferable, and nickel halides (nickel chloride, nickel bromide, etc.) are most preferable. The metal halide may be an anhydride or a hydrate. When using a hydrate, the hydrate may be dissolved in a water-soluble high-boiling point solvent in advance and water may be removed by distillation before the reaction to carry out the reaction. The reaction may be carried out at. Further, the metal halide may have the above-mentioned triarylphosphine or aryl halide as a ligand. The amount of the metal halide used is usually 0.1 to 0.1 with respect to the triarylphosphine.
It is 40 mol%, preferably 1 to 30 mol%.

In the present invention, in the above reaction,
As the solvent, a water-soluble high boiling point solvent inert to the reaction is used. As such a water-soluble high-boiling point solvent, a water-soluble solvent having at least one hydroxyl group in the molecule and having a boiling point of 150 ° C. or higher, particularly 150 to 314 ° C. and inert to the reaction is preferable. By using the above-mentioned water-soluble high-boiling point solvent, the catalyst and the product can be dissolved during the reaction, and the reaction product and the distillation residue are not solidified during the separation of the product. Furthermore, the resulting product from the separation residue after separation, a solution containing a metal halide catalyst and a water-soluble high-boiling solvent can be reused in the reaction. When a water-soluble solvent having a boiling point of less than 150 ° C. is used, the reaction temperature becomes lower under normal pressure and the reaction rate becomes slower, so that it is necessary to carry out the reaction under high pressure.

Examples of the water-soluble high boiling point solvent include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerin, 1,
2-butanediol, 1,3-butanediol, 2,3
-Butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, etc. having 2 carbon atoms
To 12 aliphatic polyhydric alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, etc., monoether of aliphatic polyhydric alcohol having 5 to 14 carbon atoms, carbon such as phenol, o-cresol, m-cresol, p-cresol Examples thereof include aromatic alcohols having 6 to 7 carbon atoms, aliphatic carboxylic acids having 5 to 6 carbon atoms such as n-valeric acid, i-valeric acid and pivalic acid.

Among the water-soluble high boiling point solvents, the above-mentioned aliphatic polyhydric alcohols and aromatic alcohols are preferable, and particularly ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, glycerin, 1,
2-butanediol, 1,3-butanediol, 2,3
-Butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol and phenol are preferred. These solvents may be used alone,
Also, two or more may be mixed and used. The amount of the water-soluble high boiling point solvent used is usually 0.2 to 8 ml, preferably 0.3 to 5 ml, per 1 g of triarylphosphine.

In the above-mentioned reaction, the reaction temperature varies depending on the raw material compound and the solvent, but it is preferably not higher than the temperature at which the reaction mixture is refluxed at 150 ° C. or higher, particularly preferably 160 ° C. or higher and the temperature at which the reaction mixture is refluxed or lower. The reaction time varies depending on the starting compound, solvent and reaction temperature, but is usually 0.5
It is about 30 hours. The reaction pressure is preferably normal pressure.

In the present invention, by using the water-soluble high-boiling point solvent, the product (tetraarylphosphonium halide) can be easily separated without performing a complicated operation after the reaction. That is, in the present invention, the product can be separated by a simple operation in which water is added to the obtained reaction liquid or the distillation residue thereof to precipitate and separate the tetraarylphosphonium halide. When the reaction solution is distilled, the distillation is performed such that 0.1 ml or more of the water-soluble high-boiling point solvent remains per 1 g of the triarylphosphine charged in the distillation residue, and the water-soluble high-boiling point solvent or aryl halide is used. (When the boiling point of the aryl halide is lower than the boiling point of the water-soluble high-boiling solvent). The obtained distillation residue is in the form of a uniform slurry which is easily stirred. And to this distillation residue, 0.5 to 30 ml, preferably 1 to 1 g of triarylphosphine charged.
By adding 20 ml of water, the tetraarylphosphonium halide is separated from the aqueous solution of the distillation residue as crystals having good filterability or an oily substance which can be easily separated.

Thus, by using the water-soluble high-boiling point solvent and leaving the water-soluble high-boiling point solvent in the distillation residue,
A uniform slurry-like distillation residue that can be easily stirred can be obtained without causing solidification of the tetraarylphosphonium halide, and the tetraarylphosphonium halide can be easily separated by filtration or fractionation. When the residual amount of the water-soluble high-boiling point solvent is small, the whole distillation residue is solidified and stirring becomes very difficult.
The recovered water-soluble high-boiling point solvent and aryl halide are reused in the reaction.

When the reaction solution is not distilled, the reaction solution is added in an amount of 0.5 to 30 with respect to 1 g of charged triarylphosphine.
By adding ml, preferably 1 to 20 ml of water, the tetraarylphosphonium halide is separated from the reaction solution as a crystal having good filterability or an oily substance which can be easily separated. By thus allowing the reaction liquid to contain a water-soluble high-boiling point solvent, the tetraarylphosphonium halide can be easily separated by filtration or fractionation.

The tetraarylphosphonium halide separated as described above is washed with water in the case of crystals or, if necessary, washed with an organic solvent after washing with water. In the case of an oily substance, the oily substance is dropped into the organic solvent under stirring, or the organic solvent is dropped into the oily substance to crystallize and then washed with the organic solvent. The organic solvent used here may be one having a low solubility of tetraarylphosphonium halide. For example, aromatic hydrocarbons (benzene, toluene, xylene, chlorobenzene, etc.), aliphatic carboxylic acid esters (ethyl acetate, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethers (diethyl ether, diisopropyl ether) , Dibutyl ether, etc.) can be used.

The separation residue obtained by separating the tetraarylphosphonium halide from the aqueous solution of the distillation residue or the reaction solution as described above contains the metal halide catalyst, the water-soluble high-boiling point solvent and water. By removing water, a solution containing the metal halide catalyst and the water-soluble high-boiling point solvent can be easily obtained. In the present invention, the solution containing the metal halide catalyst and the water-soluble high-boiling solvent, which is obtained by removing water from the separation residue, is obtained by adding only the raw materials (triarylphosphine, aryl halide) and the water-soluble high-boiling solvent. And can be reused as a catalyst in the above reaction. At this time, if necessary, a metal halide is added. Further, in the present invention,
Since the separation residue contains a water-soluble high-boiling point solvent, the metal halide remains dissolved even when water is distilled off, and the complicated operation of recovering the metal halide as a solid is unnecessary.

[0026]

Next, the present invention will be described specifically with reference to examples. The yield (mol%) of tetraarylphosphonium halide was calculated for triarylphosphine. Example 1 A 500 ml glass three-necked flask was charged with ethylene glycol (180 ml) and nickel chloride hexahydrate (0.
0342 mol) and put it under reduced pressure (2
Water was removed by distillation at 0 mmHg). At this time, the total amount of water and ethylene glycol distilled was 4.5 ml. The pressure in the flask was returned to normal pressure, and triphenylphosphine (0.3431 mol) and bromobenzene (0.401) were added to a solution of ethylene glycol and nickel chloride.
2 mol) was added, and the mixture was heated under reflux at 176 to 190 ° C. for 6 hours with stirring.

After completion of the reaction, 120 to 145 ° C./95 to 2
The reaction solution was distilled under reduced pressure at 3 mmHg to collect 157 ml of bromobenzene and ethylene glycol. Next, the temperature of the reaction liquid (distillation residue) was set to 115 ° C., and 240 ml of water was added dropwise to the distillation residue over 0.5 hours with stirring.
The aqueous solution of the distillation residue was stirred at 90 ° C. to form a uniform solution, cooled to room temperature, and the precipitated crystals were collected by suction filtration. After washing the obtained crystals with 170 ml of water, 1
Dry under reduced pressure at 00 ° C for 3 hours, then at 150 ° C for 2 hours,
The yield of tetraphenylphosphonium bromide is 95.2.
%.

Example 2 The aqueous solution of the distillation residue (filtrate) after separating the tetraphenylphosphonium bromide of Example 1 and the washing solution after washing the crystals with water were combined and concentrated to give a solution (23) containing nickel chloride. .19 g) was obtained. In Example 1, except that the amount of ethylene glycol was changed to 150 ml, this solution was used as a catalyst, and the operation of removing water by distillation was not performed, the reaction and the separation of the product were performed in the same manner as in Example 1. , Tetraphenylphosphonium bromide yield 9
It was obtained at 8.5% (however, the yield in this case was obtained with respect to the triphenylphosphine added in Example 2). In addition,
The total amount of bromobenzene and ethylene glycol recovered was 131 ml.

Example 3 In a 50 ml glass three-necked flask, 1,3-butanediol (6 ml) and nickel chloride hexahydrate (29 m
mol), triphenylphosphine (19.1 mmo
1) and 4-bromobiphenyl (19.1 mmol) were added, and the mixture was heated under reflux at 180 to 188 ° C. for 3 hours with stirring. After the reaction was completed, the reaction solution was cooled to 130 ° C., and 40 ml of water was added dropwise with stirring. Then, the reaction solution was stirred at 100 ° C. to form a uniform solution, cooled to room temperature, and the precipitated crystals were collected by suction filtration. The crystals obtained are 10 m of water
It was washed twice with 1 l and further twice with 7 ml of toluene, and then dried at 90 to 100 ° C. under normal pressure to obtain 4-biphenyltriphenylphosphonium bromide with a yield of 96%.

EXAMPLE 4 Phenol (3.0 g) and anhydrous cobalt chloride (0.965 mmo) were placed in a 50 ml glass three-necked flask.
l), triphenylphosphine (19.1 mmol) and 4-iodotoluene (19.1 mmol),
It heated at 195-202 degreeC for 3 hours, stirring. After completion of the reaction, phenol was removed by an evaporator to obtain an oily residue (10 g). 50 m of water was added to this oily residue at 90 ° C.
1 was added and stirred, and the oily substance in the lower layer was separated. Then
20 ml of butyl acetate was added dropwise to this oily substance under stirring, and the precipitated crystals were collected by suction filtration. The obtained crystals were washed twice with 5 ml of butyl acetate and then dried under reduced pressure at 100 ° C. to obtain 4-methylphenyltriphenylphosphonium iodide with a yield of 49%.

Example 5 A 50 ml glass three-necked flask was charged with diethylene glycol (6 ml) and nickel chloride hexahydrate (1.9 m).
mol), triphenylphosphine (19.1 mmo
1) and bromobenzene (22.0 mmol) were added, and the mixture was heated with stirring at 182-195 ° C. for 4 hours. After completion of the reaction, the reaction liquid was distilled under reduced pressure at 100 to 150 ° C./90 to 20 mmHg to collect 3.8 g of bromobenzene and diethylene glycol together. Next, the temperature of the reaction liquid (distillation residue) is set to 100 ° C., and the distillation residue is mixed with water 2 under stirring.
3 ml was added dropwise. This aqueous solution of distillation residue was cooled to room temperature with stirring, and the precipitated crystals were collected by suction filtration. The obtained crystals were washed twice with 8 ml of water, then 100
After drying under reduced pressure at ℃ for 3 hours, tetraphenylphosphonium bromide was obtained with a yield of 90%.

Example 6 In a 30 ml glass three-necked flask, ethylene glycol (3 ml) and nickel chloride hexahydrate (0.336) were added.
mmol), tris (4-methylphenyl) phosphine (3.283 mmol) and 4-iodotoluene (3.
308 mmol) and stirred at 205 ° C. for 5.5.
Heated for hours. After completion of the reaction, the reaction solution was cooled to 110 ° C., and 10 ml of water was added dropwise with stirring. Then, the reaction solution was heated under reflux for 0.5 hours with stirring, cooled to room temperature, and the precipitated crystals were collected by suction filtration. The crystals obtained were washed twice with 2 ml of water and further washed with 2 ml of toluene.
After washing twice, it was dried under reduced pressure at 100 ° C. for 2 hours to obtain tetrakis (4-methylphenylphosphonium) iodide with a yield of 93%.

[0033]

INDUSTRIAL APPLICABILITY According to the present invention, a known production method for producing a tetraarylphosphonium halide from a triarylphosphine and an aryl halide has a reaction under high pressure, a complicated separation operation such as steam distillation or solvent extraction, and a solid substance. It is possible to easily produce a tetraarylphosphonium halide with a high yield by solving all the problems of the above (3) and the problem of forming a metal halide-containing waste liquid.
Furthermore, the present invention allows a solution containing a metal halide and a water-soluble high-boiling solvent to be reused as a catalyst as it is, and the metal halide-containing waste liquid can be significantly reduced. It is possible to provide an excellent method for producing a tetraarylphosphonium halide.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Doi 5 1978, Koujigushi, Ube City, Yamaguchi Prefecture 5 Ube Ube Laboratory Ltd.

Claims (6)

[Claims] 1. A process for producing a tetraarylphosphonium halide, which comprises reacting a triarylphosphine with an aryl halide in the presence of a metal halide catalyst and a water-soluble high-boiling solvent. 2. A triarylphosphine and an aryl halide are reacted in the presence of a metal halide catalyst and a water-soluble high boiling point solvent, and water is added to the resulting reaction solution or a distillation residue thereof to precipitate a tetraarylphosphonium halide. A method for producing a tetraarylphosphonium halide, which comprises separating by separation. 3. A triarylphosphine and an aryl halide are reacted in the presence of a metal halide catalyst and a water-soluble high boiling point solvent, and water is added to the resulting reaction solution or distillation residue to precipitate a tetraarylphosphonium halide. Characterized in that a solution containing a metal halide catalyst and a water-soluble high-boiling solvent, obtained by separating and then removing water from the separation residue, is reused to react a triarylphosphine with an aryl halide. Method for producing tetraarylphosphonium halide. 4. The tetraarylphosphonium according to claim 1, wherein the water-soluble high-boiling point solvent is a water-soluble solvent having at least one hydroxyl group in the molecule and having a boiling point of 150 ° C. or higher. Halide manufacturing method. 5. The tetraketone according to claim 1, 2 or 3, wherein the water-soluble high-boiling point solvent is an aliphatic polyhydric alcohol having 2 to 12 carbon atoms or an aromatic alcohol having 6 to 7 carbon atoms. Method for producing arylphosphonium halide. 6. The metal halide catalyst according to claim 7 of the periodic table.
3. A halide of a metal belonging to Group 8, Group 8, Group 9, Group 10, Group 11 or Group 12.
Alternatively, the method for producing the tetraarylphosphonium halide according to Item 3.