WO2003042148A2

WO2003042148A2 - Process for producing bisbenzil compounds

Info

Publication number: WO2003042148A2
Application number: PCT/JP2002/011682
Authority: WO
Inventors: Hiroshi Yasuda
Original assignee: Showa Denko K. K.
Priority date: 2001-11-12
Filing date: 2002-11-08
Publication date: 2003-05-22
Also published as: AU2002344645A1; WO2003042148A3

Abstract

A bis(phenylacetyl)benzene compound is reacted with a sulfoxide compound and a halide in the presence of an acid and an organic solvent. Also, a bis((-ketonitrile) compound is reacted in an acidic environment in the presence of water, a halide and a sulfoxide compound. It is thereby possible to produce bisbenzil compounds at a high yield and with high productivity.

Description

DESCRIPTION

PROCESS FOR PRODUCING BISBENZIL COMPOUNDS

Technical Field

The present invention relates to a process for producing bisbenzil compounds. Bisbenzil compounds are important intermediates for electronic materials, functional polymer monomers, and the like.

Background Art

Processes for producing bisbenzil compounds using bis (phenylacetyl)benzene compounds as starting materials are known. According to U.S. Patent No. 4,082,806, synthesis of bisbenzil compounds is carried out by oxidation of bis (phenyace^'tyl )benzene compounds in the presence of copper (II) halides or in the presence of copper (II) halides and hydrogen bromide, in a dimethyl sulfoxide solvent. According to J. Org. Chem. USSR, 22 p.753 (1989), bisbenzils are synthesized in dimethyl sulfoxide in the presence of hydrogen bromide without using copper (II) halides. The produced bisbenzil compounds are purified by adding the reaction solution to a large amount of water, filtering out the precipitated bisbenzil compounds and using an alcohol-based solvent for recrystallization. The solubility of the bisbenzils in alcohols is low, with a solid content of about 5%.

Disclosure of the Invention It is an object of the present invention, which has been accomplished in light of these circumstances, to provide a strategy for solving the problems associated with industrialized production of bisbenzil compounds. Specifically, the following problems are encountered with the processes described in the aforementioned U.S. patent and Russian documents when they are applied industrially. That is, the processes require prolonged reaction under highly diluted conditions using high boiling point dimethyl sulfoxide as the solvent, and the complexity of isolating and purifying the product and the low productivity have become significant issues requiring improvement. Another issue is how to deal with the malodorous dimethyl sulfide by-product of the reaction.

The present inventors have completed the invention upon finding that the aforementioned objects can be achieved by reacting a bis (phenyacetyl)benzene compound with a sulfoxide compound and a halide in the presence of an organic solvent.

Specifically, the invention provides a process wherein a bis (phenylacetyl)benzene compound represented by the following formula (1) or a bis (phenacyl )benzene compound represented by the following formula (2):

wherein Ri-R₄ each independently represents hydrogen, a halogen atom, C^^ alkoxy, C₁-C₄ alkyl, monocyclic aryl, dialkylamino with C^C^ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro, and R₅-R₁₄ each independently represents hydrogen, a halogen atom, C^C^ alkoxy, C^C^ alkyl, monocyclic aryl, dialkylamino with C_x-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro; is reacted with a sulfoxide compound and a hydrogen halide in the presence of an organic solvent, to produce a bisbenzil compound represented by the following formula (3):

Best Mode for Carrying Out the Invention Preferred embodiments of the present invention will now be explained in detail, with the understanding that the invention is not limited to these embodiments.

According to the invention, the compounds represented by the above formulas (1), (2) and (3) are all preferably compounds wherein R_j-R^ each independently represents hydrogen or a halogen atom.

The reaction according to the process of the invention is conducted by mixing the bis (phenylacetyl )benzene compound or the bis (phenacyl) benzene compound and the hydrogen halide and sulfoxide compound in an organic solvent, and stirring for a prescribed time at a prescribed temperature. After completion of the stirring, the produced bisbenzil compound is recovered.

The charging and reaction of the reaction starting materials may be carried out at atmospheric pressure. A glass vessel is suitable as the reaction vessel.

The reaction mechanism of the process of the invention is not fully understood but, based on experimental results and the known literature (J. Org. Chem., 40 p.1990 (1975) , J. Org. Chem. , 50 p5022 ( 1985 ) ) , it is conjectured to proceed in the manner described below. The following explanation is based on an example of a reaction which produces 1 , 4-bisbenzil from 1,4- bis (phenylacetyl)benzene in an organic solvent in the presence of hydrogen bromide as the hydrogen halide and dimethyl sulfoxide as the sulfoxide compound

(corresponding to a compound wherein R_x-R₁₄ in formula (3) are all hydrogen atoms, and the benzoylcarbonyl groups on both ends are in the para configuration with respect to the central benzene ring). First, an oxidation-reduction reaction occurs between the dimethyl sulfoxide and the hydrogen bromide. The dimethyl sulfoxide is reduced to dimethyl sulfide, and the hydrogen bromide is oxidized to bromine (formula (4)). 2HBr + Me₂SO → Br₂ + Me₂S + H₂0 (4)

The bromine reacts with the bis (phenylacetyl)benzene to produce an α-dibromo compound (formula (5) below). For simplicity and in order to highlight the essential reaction, it will be conveniently explained in terms of production of the dibromo compound.

Here, hydrogen bromide is released and is again oxidized by dimethyl sulfoxide to bromine.

The α-dibromo compound reacts with the dimethyl sulfoxide to form 1 , 4-bisbenzil (formula (6) below). This is assumed to occur by the same reaction mechanism as ordinary oxidation of α-haloketones by dimethyl sulfoxide.

Here, dimethyl sulfoxide and hydrogen bromide are released. The hydrogen bromide is again oxidized by dimethyl sulfoxide to bromine. It is therefore believed that, in this reaction, dimethyl sulfide is produced as a by-product while hydrogen bromide acts as a catalyst.

The actual procedure for the process of the invention will now be explained. The reaction temperature is 40-180°C, and preferably 60-120°C. The reaction time is preferably 0.5-20 hours.

An organic solvent is used for the reaction. Suitable organic solvents are those which are inert to halogen molecules such as bromine and iodine which are generated during the reaction. Specifically there may be mentioned aliphatic carboxylic acids such as acetic acid and propionic acid, polar amide-based solvents such as formamide and dimethylformamide, sulfolane compounds such as sulfolane, imidazolidones such as 1 , 3-dimethyl-2- imidazolidone, and ethers such as dioxane, 1,2- dimethoxyethane and diglyme. Aliphatic lower carboxylic acids are preferred among these, with acetic acid being particularly preferred. These organic solvents may be used alone, or in combinations of two or more. Such solvents are used in an amount of preferably 2-20 parts by weight, and more preferably 4-8 parts by weight, to one part by weight of the bis (phenylacetyl)benzene compound or the bis (phenacyl )benzene compound.

The presence of the hydrogen halide is essential in the reaction according to the process of the invention. As hydrogen halides there may be suitably used hydrogen bromide and hydrogen iodide. The hydrogen halide is preferably used at 0.1-2.0 moles and more preferably at 0.5-1.5 moles to one mole of the bis (phenylacetyl)benzene compound or the bis (phenacyl )benzene compound. The hydrogen halide may be used in the form of an aqueous or other solution, or as a gas. It may be added all at once, or dropwise if necessary, during charging of the reaction agents.

The presence of the sulfoxide compound is also essential in the reaction according to the process of the invention. As sulfoxide compounds there may be mentioned aliphatic sulfoxide compounds such as dimethyl sulfoxide, and aromatic sulfoxides such as diphenyl sulfoxide, among which dialkyl sulfoxides with C^C^ alkyl groups and tetramethylene sulfoxide having a cyclic structure are preferred, with dimethyl sulfoxide being particularly preferred. The sulfoxide compound is preferably used at 4-20 moles and more preferably at 6-10 moles to one mole of the bis (phenylacetyl)benzene compound or the bis (phenacyl)benzene compound. When dimethyl sulfoxide is used as the sulfoxide compound, dimethyl sulfide is produced as a by-product as the reaction progresses. Although the reaction may be carried out without distilling off the dimethyl sulfide, in this case the reaction rate will be slower than if the dimethyl sulfide is distilled off during the reaction, and therefore the reaction is preferably conducted while distilling off the dimethyl sulfide. The dimethyl sulfide distilled off from the reaction vessel may be recovered, oxidized to dimethyl sulfoxide by an oxidizing agent such as hydrogen peroxide, and reused for the reaction. Isolation and purification of the product will now be explained. The example used will be a reaction which produces 1 , 4-bisbenzil from 1 , 4-bis (phenylacetyl )benzene in an acetic acid solvent in the presence of hydrogen bromide and dimethyl sulfoxide. Upon completion of the reaction, the reaction solution is generally homogeneous under heating at 70 °C or higher. Acetic acid is added until the 1 , 4-bisbenzil concentration is about 5%, and subsequent cooling results in precipitation of 1,4- bisbenzil crystals. The 1 , 4-bisbenzil is isolated by filtration and water washing. While this method is convenient, there is considerable loss due to residue of the product in the mother liquor. In order to increase the yield, the reaction solution is kept at 90-100°C and water is gradually added to the same weight as the charged acetic acid to precipitate the 1 , 4-bisbenzil . Upon cooling after addition of the water, the 1,4- bisbenzil is almost completely precipitated. The 1,4- bisbenzil is filtered, washed with water, dried and collected. The 1 , 4-bisbenzil obtained in this manner is of sufficient purity as a starting material for an electronic material or functional polymer monomer.

A useful compound of formula (1) for the process of the invention may be obtained by reacting a bis(β- ketonitrile) compound represented by the following formula ( 7 ) :

wherein R_x-R₁₄ are as defined above, in the presence of sulfuric acid. A compound of formula (2) may be obtained in the same manner from the corresponding compound. The compound of formula (7) is preferably one in which Ri- ₁₄ each independently represents hydrogen or a halogen atom.

The reaction is conducted by stirring the bis(β- ketonitrile) compound for a prescribed time at a prescribed temperature in a prescribed amount of an aqueous sulfuric acid solution with a specific concentration. After completion of the stirring, the mixture is cooled and the precipitated bis (phenylacetyl)benzene compound is separated by centrifugation and then separated out by filtration and collected.

The charging and reaction of the reaction starting materials may be carried out at atmospheric pressure. A glass vessel is preferred as the reaction vessel, because of the strongly acidic conditions.

The reaction temperature is preferably 50-200°C, more preferably 100-170°C and even more preferably 120- 150°C.

There are no particular restrictions on the reaction time, but a time of 0.5-20 hours is preferred.

Sulfuric acid is used for the reaction. The sulfuric acid concentration and amount is important for improving the reaction rate and bis (phenylacetyl)benzene compound selectivity. If the sulfuric acid concentration is low (less than 55 wt%), the reaction rate is drastically lowered, while if the sulfuric acid concentration is high (greater than 85 wt%), the bis (phenyacetyl ) benzene product decomposes, thereby reducing the yield. The sulfuric acid amount also affects the yield. A sulfuric acid concentration of 60- 80 wt% is preferred, with 65-70 wt% being more preferable. The absolute amount of sulfuric acid is preferably 3-12 moles and more preferably 6-10 moles to one mole of the bis(β-ketonitrile) compound.

Sulfuric acid may be used alone in the reaction, but using it together with an organic solvent will improve the reaction rate and give a high purity bis (phenylacetyl) benzene compound without isolation and purification. Such an organic solvent is preferably an optionally branched lower aliphatic carboxylic acid of 1- 5 carbons, and especially acetic acid. The amount of the organic solvent is preferably 2-12 parts by weight and more preferably 4-8 parts by weight to one part by weight of the bis(β-ketonitrile) compound.

Isolation of the product of the reaction will now be described. As mentioned above, cooling after the reaction in the aqueous sulfuric acid/acetic acid solvent system results in precipitation of the reaction product. Appropriate dilution with acetic acid after completion of the reaction will facilitate removal of the solid. The solid is separated by filtration or the like, washed with an organic solvent and then with water, and finally dried to obtain the bis (phenylacetyl ) benzene compound.

The obtained bis (phenylacetyl)benzene compound may be directly used as the starting material for the bisbenzil compound of formula (3) above. It may also be used as the starting material for an electronic material or functional polymer monomer, since it is of sufficient purity for use as such starting materials.

The bis (β-ketonitrile) compound used as the starting material for the reaction described above may be synthesized by a publicly known method (U.S. Patent No. 4,046,814), and it may be produced by reacting an aromatic dicarboxylic diester compound with no active hydrogen at the α-position and a benzyl cyanide compound, in an inert atmosphere using a strong base (for example, sodium hydride, sodium amide, triphenylmethyl sodium, etc.) as the condensing agent in an anhydrous solvent (for example, liquid ammonia, a hydrocarbon-based solvent, a halogen-based solvent, an ether-based solvent, or the like). As a more simple method, an alkali metal alkoxide may be used as the condensing agent base and an alcohol may be used as the solvent. In the latter method, neutralization with an acid after completion of the reaction may be followed simply by alcohol washing and water washing and the product may be used directly for production of the bisbenzil compound of formula (3) above, or alternatively, a bis (β-ketonitrile) compound may be obtained with sufficient purity as a starting material for an electronic material or functional polymer. The positional relationship between the two ketonitrile groups will correspond to, and be determined by, whether the positional relationship of the carboxyl groups of the dicarboxylic diester starting material are in the ortho, meta or para position.

The bis (β-ketonitrile) compound for the starting material preferably has its phenyl groups unsubstituted or substituted with halogen atoms. As examples there may be mentioned 1 , 4-bis (2-phenyl-2-cyanoacetyl )benzene (hereinafter to be referred to as 1, 4-bis (β- ketonitrile) ) , l,3-bis(2-phenyl-2-cyanoacetyl)benzene, 1 ,2-bis ( 2-phenyl-2-cyanoacetyl)benzene, 1 , 4-bis (2- (4- methylphenyl)-2-cyanoacetyl)benzene, 1 , 3-bis (2-( 4- methylphenyl ) -2-cyanoacetyl )benzene, 1 , 4-bis ( 2- ( 4- chlorophenyl ) -2-cyanoacetyl )benzene, 1 , 3-bis ( 2- ( 4- chlorophenyl ) -2-cyanoacetyl)benzene, 1 , 4-bis ( 2-( 3 , 4- dichlorophenyl ) -2-cyanoacetyl )benzene, 1 , 3-bis ( 2- ( 3 , 4- dichlorophenyl) -2-cyanoacetyl )benzene, 1 , 4-bis ( 2-phenyl- 2-cyanoacetyl) -2 ,3,5, 6-tetrachlorobenzene, 1, 3-bis (2- phenyl-2-cyanoacetyl)-2 ,4,5, 6-tetrachlorobenzene, 1,2- bis ( 2-pheny1-2-cyanoacetyl) -3, 4 ,5, 6-tetrachlorobenzene, 1 , 4-bis ( 2- ( 4-methylphenyl ) -2-cyanoacetyl ) -2 , 3 , 5 , 6- benzene, 1, 3-bis (2- ( 4-methylphenyl) -2-cyanoacetyl )- 2,4,5, 6-benzene, 1 , 4-bis (2-( 4-chlorophenyl )-2- cyanoacetyl) -2 ,3 , 5, 6-benzene, 1 , 3-bis (2-(4-chlorophenyl)- 2-cyanoacetyl)-2 ,4,5, 6-benzene, 1 , 4-bis (2- (3 , 4- dichlorophenyl) -2-cyanoacetyl) -2 ,3,5, 6-benzene, 1,3- bis(2-( 3 , 4-dichlorophenyl) -2-cyanoacetyl) -2 ,4,5,6- benzene, 1 , 4-bis ( 2-phenyl-2-cyanoacetyl )-2 , 3 , 5 , 6- tetrafluorobenzene, 1 , 3-bis ( 2-phenyl-2-cyanoacetyl )- 2,4,5, 6-tetrafluorobenzene, 1 , 2-bis ( 2-phenyl-2- cyanoacetyl)-3 ,4,5, 6- etrafluorobenzene, l,4-bis(2-( 4- methylphenyl ) -2-cyanoacetyl ) -2 , 3 , 5 , 6-benzene , 1 , 3-bis ( 2- ( 4-methylphenyl) -2-cyanoacetyl) -2, 4 ,5, 6-benzene, 1,4- bis (2-( 4-fluorophenyl ) -2-cyanoacetyl) -2 ,3,5, 6-benzene, 1 , 3-bis (2- (4-fluorophenyl) -2-cyanoacetyl) -2, 4,5,6- benzene , 1 , 4-bis ( 2- ( 3 , 4-difluorophenyl ) -2-cyanoacetyl- 2 , 3, 5, 6-benzene and 1 , 3-bis ( 2- ( 3 , 4-difluorophenyl) -2- cyanoacetyl ) -2 , 4 , 5 , 6-benzene.

The present inventors have found that the bisbenzil compounds of formula ( 3 ) above can be produced by reacting a bis (β-ketonitrile) compound of formula (7) above in an acidic environment in the presence of water, a halide and a sulfoxide compound. The present invention therefore provides a process for producing bisbenzil compounds represented by formula (3) above, whereby a bis (β-ketonitrile) compound of formula (7) above is reacted in an acidic environment in the presence of water, a halide and a sulfoxide compound.

The aforementioned reaction is conducted by mixing a bis (β-ketonitrile) compound with a halide compound and a sulfoxide compound in an acidic environment in the presence of water, and stirring the mixture at a prescribed temperature for a prescribed period of time. After completion of the stirring, the produced bisbenzil compound is recovered.

The reaction may be conducted by first mixing the bis (β-ketonitrile) compound with a halide compound and a sulfoxide compound in an acidic environment in the presence of water but, alternatively, the bis(β- ketonitrile) compound may be reacted in the presence of water and acid to produce a bis (phenylacetyl )benzene compound and, then, this intermediate is mixed with the halide compound and sulfoxide compound without isolation. The charging and reaction of the reaction starting materials may be carried out at atmospheric pressure. A glass vessel is suitable as the reaction vessel.

The reaction temperature is preferably from 40°C to the boiling point of the solution, and more preferably from 60°C to the boiling point of the solution. The reaction time is preferably from 0.5-24 hours.

The reaction is carried out under acidic conditions according to the invention. An acid must be used to render the reaction system acidic, and it must be an acid strong enough to release hydrogen bromide or hydrogen iodide from the salt of hydrogen bromide or hydrogen iodide as the halide described later. Particularly preferred is a proton acid with a pKa of 1 or greater. Sulfuric acid, nitric acid, hydrochloric acid or the like is preferably used, with sulfuric acid being especially preferred. The acid is preferably used in an amount of 2 moles or greater and more preferably 4-10 moles to 1 mole of the bis (β-ketonitrile) compound.

Water is also necessary for the reaction. The water is preferably used in an amount of 0.01-10 parts by weight and more preferably 0.1-4 parts by weight to one part by weight of the bis (β-ketonitrile) compound.

The reaction may be carried out using an organic solvent with the water. As organic solvents there may be used aliphatic carboxylic acids such as acetic acid and propionic acid, sulfolane compounds such as sulfolane, or ethers such as dioxane, 1 ,2-dimethoxyethane and diglyme. Aliphatic lower carboxylic acids are preferred among these, with acetic acid being especially preferred. These organic solvents may be used alone or in combinations of two or more. The solvent is preferably used in an amount of 2-20 parts by weight and more preferably 4-10 parts by weight to one part by weight of the bis (β-ketonitrile) compound.

A halide is also essential for the reaction and, as examples of halides, there may be mentioned hydrogen halides and their salts. Hydrogen bromide and hydrogen iodide are especially preferred for use. Any inorganic or organic salts may be used as hydrogen halide salts. As inorganic salts there may be mentioned alkali metal salts such as sodium bromide, sodium iodide, potassium bromide and potassium iodide, or alkaline earth metal salts such as calcium bromide, calcium iodide, barium bromide and barium iodide. As organic salts there may be mentioned ammonium salts such as ammonium bromide and ammonium iodide.

The amount of halide used is preferably 0.1-2.0 moles and more preferably 0.5-1.5 moles to one mole of the bis ( β-ketonitrile ) . The halide may be added from the start of the reaction, but the bisbenzil compound yield can be improved by adding it between 4 hours and 16 hours after the start of the reaction.

The sulfoxide compound is essential for the reaction. As sulfoxide compounds there may be used aliphatic sulfoxide compounds such as dimethyl sulfoxide, or aromatic sulfoxide compounds such as diphenyl sulfoxide, with dimethyl sulfoxide being particularly preferred. The sulfoxide compound is preferably used at 4-20 moles and more preferably 6-10 moles to one mole of the bis (β-ketonitrile) compound. The sulfoxide compound may be added from the start of the reaction, or it may be added simultaneously with addition of the halide.

Gradual cooling after completion of the reaction causes precipitation of the bisbenzil compound in a crystalline state or as an amorphous solid. After the reaction is complete, the internal temperature may be kept at around 100 °C and water added to precipitate the bisbenzil compound. The precipitated bisbenzil compound may be filtered, water washed and dried for isolation. The bisbenzil compound obtained in this manner is of sufficient purity as a starting material for an electronic material or functional polymer monomer.

The bis (β-ketonitrile) compound used as the starting material for this reaction is the same as described above .

The bis (β-ketonitrile) compound as the starting material for the process of the invention may be produced by reacting a benzyl cyanide compound represented by the following formula (8):

wherein R₁₅-R₁₉ each independently represents hydrogen, a halogen atom, C_!-C₄ alkoxy, Ci-C,, alkyl, monocyclic aryl, dialkylamino with C_!-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro; with an aromatic dicarboxylic diester compound represented by the following formula (9):

wherein R₂₀-R₂₃ each independently represents hydrogen, a halogen atom, C₁-C₄ alkoxy, C₁-C₄ alkyl, monocyclic aryl, dialkylamino with C_α-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro, and R₂₄ independently represents C_!-C₄ alkyl or monocyclic aryl; in the presence of a metal alkoxide. The bis (β-ketonitrile) compound obtained by this reaction may be represented by the following formula (10):

wherein R₁₅-R₂₄ are as defined above.

In the compounds represented by formulas (9) and (10) above, ₂₀-R₂₃ each, preferably independently, represents hydrogen or a halogen atom. In the compounds represented by formulas (8) and (10), R₁₅-R₁₉ each, preferably independently, represents hydrogen, a halogen atom, methyl, methoxy, allyl, phenyl or dimethylamino, more preferably hydrogen or a halogen atom.

The reaction is preferably carried out by combining the benzyl cyanide compound with the aromatic dicarboxylic diester compound and the metal alkoxide in an organic solvent such as an alcohol, and stirring at a prescribed temperature for a prescribed period of time. After completion of the stirring, the reaction mixture is neutralized with an acid, and the precipitated bis(β- ketonitrile) compound is centrifuged and filtered for separation and recovered.

The charging and reaction of the reaction starting materials may be carried out at atmospheric pressure. A metal vessel is preferred as the reaction vessel because the metal alkoxide is alkali.

There are no particular restrictions on the reaction temperature for the reaction, but it is preferably 0-

200°C, more preferably from room temperature (25°C) to 180°C and even more preferably 60-150°C, or the reflux temperature of the organic solvent such as alcohol which is used .

The reaction time is not particularly restricted but is preferably from 0.5-20 hours.

The condensation reaction between the benzyl cyanide compound and the aromatic dicarboxylic diester compound is conducted in the presence of the metal alkoxide as a base. The metal alkoxide must be used in an amount of at least 2 molar equivalents to one molar equivalent of the aromatic dicarboxylic diester compound starting material. Although the optimum amount of metal alkoxide to be used will differ depending on the type of metal alkoxide, it is usually preferred to be 2-4 molar equivalents, more preferably 2-3 molar equivalents and most preferably 2- 2.2 molar equivalents to one mole of the aromatic dicarboxylic diester compound.

The metal alkoxide used may generally be an alkali metal alkoxide or alkaline earth metal alkoxide. An alkali metal alkoxide or alkaline earth metal alkoxide is somewhat hygroscopic but has low ignitability, and can therefore be handled in air for most operations.

A lower alcohol of 4 carbons or less is preferred as the alcohol of the metal alkoxide. As examples of such alkali metal alkoxides and alkaline earth metal alkoxides there may be mentioned lithium methoxide, sodium methoxide, potassium methoxide, magnesium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, magnesium ethoxide, lithium 1-propoxide, sodium 1- propoxide, potassium 1-propoxide, lithium isopropoxide, sodium isopropoxide, potassium isopropoxide, lithium 1- butoxide, sodium 1-butoxide, potassium 1-butoxide, lithium 2-butoxide, sodium 2-butoxide, potassium 2- butoxide, lithium isobutoxide, sodium isobutoxide, potassium isobutoxide, lithium tert-butyl oxide, sodium tert-butyl oxide and potassium tert-butyl oxide. Preferred among these are sodium methoxide (hereunder also abbreviated as MeONa), potassium methoxide (hereunder also abbreviated as MeOK), sodium ethoxide (hereunder also abbreviated as EtONa), potassium ethoxide (hereunder also abbreviated as EtOK), sodium tert-butyl oxide (hereunder also abbreviated as tBuONa) and potassium tert-butyl oxide (hereunder also abbreviated as tBuOK), with sodium tert-butyl oxide (tBuONa) and potassium tert-butyl oxide (tBuOK) being particularly preferred. These metal alkoxides may be used alone or in combinations of two or more.

The benzyl cyanide compound may be used in an amount of at least 2 molar equivalents, preferably 2-3 molar equivalents and more preferably 2-2.5 molar equivalents to 1 molar equivalent of the aromatic dicarboxylic diester compound.

In order to inhibit dimerization of the benzyl cyanide compound, it is preferred to combine the aromatic dicarboxylic diester compound with the base beforehand and then add the benzyl cyanide compound dropwise.

Examples of benzyl cyanide compounds represented by formula (8) which may be used for the reaction include benzyl cyanide, p-methylbenzyl cyanide, p-ethylbenzyl cyanide, p-phenylbenzyl cyanide, p-allylbenzyl cyanide, p-fluorobenzyl cyanide, p-chlorobenzyl cyanide, p- bromobenzyl cyanide, p-iodobenzyl cyanide, p- methoxybenzyl cyanide, p-ethoxybenzyl cyanide, p- allyloxybenzyl cyanide, p-phenyloxybenzyl cyanide, p- dimethylaminobenzyl cyanide, p-nitrobenzyl cyanide, m- methylbenzyl cyanide, m-ethylbenzyl cyanide, m- phenylbenzyl cyanide, m-allylbenzyl cyanide, m- fluorobenzyl cyanide, -chlorobenzyl cyanide, m- bromobenzyl cyanide, m-iodobenzyl cyanide, m- methoxybenzyl cyanide, m-ethoxybenzyl cyanide, m- allyloxybenzyl cyanide, -phenyloxybenzyl cyanide, m- dimethylaminobenzyl cyanide, m-nitrobenzyl cyanide, 3,4- dimethylbenzyl cyanide, 3,5-dimethylbenzyl cyanide, 3,4- difluorobenzyl cyanide, 3 , 4-dichlorobenzyl cyanide, 3,4- dibromobenzyl cyanide, 3 , 4-dimethoxybenzyl cyanide, 3,5- di ethoxybenzyl cyanide, 3-methyl-4-chlorobenzyl cyanide, 3-methyl-4-bromobenzyl cyanide and 3-methyl-4- methoxybenzyl cyanide. Particularly preferred among these are benzyl cyanide, p-methylbenzyl cyanide, p- phenylbenzyl cyanide, p-allylbenzyl cyanide, p- fluorobenzyl cyanide, p-chlorobenzyl cyanide, p- bromobenzyl cyanide, p-iodobenzyl cyanide, p- methoxybenzyl cyanide, p-dimethylaminobenzyl cyanide, m- methylbenzyl cyanide, m-phenylbenzyl cyanide, m- allylbenzyl cyanide, m-fluorobenzyl cyanide, m- chlorobenzyl cyanide, m-bromobenzyl cyanide, m-iodobenzyl cyanide, m-methoxybenzyl cyanide and m- dimethylaminobenzyl cyanide.

Examples of aromatic dicarboxylic diester compounds represented by formula (9) to be used for the reaction include dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, dioctyl terephthalate, diphenyl terephthalate, dimethyl isophthalate, diethyl isophthalate, dipropyl isophthalate, dibutyl isophthalate, diphenyl isophthalate, dimethyl tetrachloroterephthalate, diethyl tetrachloroterephthalate , dimethyl tetrafluoroterephthalate , diethyl tetrafluoroterephthalate , dimethyl tetrachloroisophthalate, diethyl tetrachloroisophthalate, dimethyl tetrafluoroisophthalate and diethyl tetrafluoroisophthalate .

A polar organic solvent may be used as the solvent for the reaction. As suitable polar organic solvents there may be mentioned polar amide solvents such as formamide and dimethylformamide, sulfur-containing compounds such as dimethyl sulfoxide and sulfolane, imidazolidones such as 1 , 3-dimethyl-2-imidazolidone, ethers such as dioxane, 1,2-dimethoxyethane and diglyme, and alcohols such as methanol, ethanol, 1-propanol, 2- propanol, 1-butanol, 2-butanol, isobutanol, tert-butyl alcohol, heptanol, hexanol, amyl alcohol and octanol. Alcohols are preferred among these, with tert-butyl alcohol being especially preferred. These organic solvents may be used alone or in combinations of two or more. The amount of the solvent used is preferably at least 4 parts by weight and no greater than 30 parts by weight, and more preferably 5-20 parts by weight, to one part by weight of the aromatic dicarboxylic diester. The solvent may be added all at once at the moment of charging for the reaction, or it may be added gradually during the reaction. It sometimes occurs in this reaction that the intermediates and products have low solubility such that the solid content increases as the reaction progresses, thereby hampering the stirring action; in such cases additional solvent may be added to evenly disperse the reaction system. The starting materials, i.e. the benzyl cyanide compound, aromatic dicarboxylic diester compound and metal alkoxide, are highly soluble in the solvent, i.e. alcohol or the like, and therefore the reaction can be brought to completion without any significant precipitation of intermediate products. The bis(β- ketonitrile) compound which is produced is precipitated by acidifying the reaction solution, and after separating it by a filtration or centrifugation procedure, washing with an alcohol can separate out the unreacted starting materials and intermediates, to reduce the load for purification and to easily provide a highly pure product. The salt by-products can be removed by washing with hot water at 40-100°C.

The present invention will now be further explained through the following examples which are in no way intended to be limitative on the invention.

In the examples, the products were analyzed under the following high performance liquid chromatography conditions . High performance liquid chromatography conditions

Column: RP-18 (ODS) endcap treatment, product of Kanto Chemical Eluent: Water/acetonitrile = 35/65 (volume)

Conditions: Flow rate = 1.5 ml/min (UV 265 nm)

Column oven: 40 °C

Example 1 After combining 31.4 g of 1,4- bis (phenylacetyl )benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 17.21 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95- 105°C and a reaction was conducted for 3 hours while distilling off the dimethyl sulfide.

Next, 157 g of acetic acid was added and the mixture was cooled to room temperature over a period of 8 hours. The precipitated crystals were filtered, washed with water and dried to obtain 24.1 g of 1 , 4-bisbenzil

(isolation yield: 70%). The purity of the 1 , 4-bisbenzil obtained by high performance liquid chromatography analysis was ≥99%. Example 2 After combining 31.4 g of 1,4- bis(phenylacetyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 17.21 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95- 105 °C and a reaction was conducted for 3 hours while distilling off the dimethyl sulfide.

Next, 157 g of water was added over a period of 3 hours while keeping the internal temperature at 90-100 °C, and then the mixture was cooled to room temperature over a period of 8 hours. The precipitated solid was filtered, washed with water and dried to obtain 33.9 g of 1, 4-bisbenzil (isolation yield: 99%). The purity of the 1 , 4-bisbenzil obtained by high performance liquid chromatography analysis was ≥99%. Example 3

After combining 31.4 g of 1,4- bis (phenylacetyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 27.0 g of a 30% HBr/acetic acid solution was added at room temperature. The temperature in the reaction vessel was kept at 55-60 °C and the reaction was conducted for 8 hours without distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 84%. Example 4

After combining 31.4 g of 1,4- bis (phenylacetyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 27.0 g of a 30% HBr/acetic acid solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105 °C and the reaction was conducted for 3 hours while distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 101% (quantitative error).

Example 5

There were combined at room temperature 31.4 g of 1, 4-bis (phenylacetyl) benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid. HBr gas was introduced in an amount of 8.3 g at from room temperature to no higher than 50°C. After introducing the HBr gas, the temperature in the reaction vessel was kept at 95- 105 °C and the reaction was conducted for 3 hours while distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 99%.

Example 6 (Large-scale production)

After combining 80 kg of 1,4- bis (phenylacetyl )benzene, 160 kg of dimethyl sulfoxide and 400 kg of acetic acid in a 1 m³ glass reaction boiler at room temperature, 44 kg of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction boiler was kept at 95-105°C and reaction was conducted for 6 hours while distilling off the dimethyl sulfide. The mixture was kept at an internal temperature of 90-100°C while adding 400 kg of water over a period of 6 hours, after which it was cooled to room temperature over a period of 12 hours. The liquid was removed from the precipitated solid by centrifugal separation, washing was performed with 200 kg of water, and then washing was again performed with 200 kg of methanol. This was followed by drying under reduced pressure to obtain 84 kg of 1, 4-bisbenzil (98% purity, 96% yield).

Example 7 (Recovery and reutilization of dimethyl sulfide) After combining 31.4 g of 1,4- bis (phenylacetyl )benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 17.21 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95- 105°C and the reaction was conducted for 4 hours while distilling off the dimethyl sulfide. Isolation in the same manner as in Example 2 produced 33.5 g of 1,4- bisbenzil (yield: 98%).

A 48 g portion of the dimethyl sulfide produced by the reaction was recovered (theoretical yield: 49.7 g). To 100 g of 30% aqueous hydrogen peroxide cooled on ice there was added dropwise 48 g of dimethyl sulfide without the internal temperature exceeding 40 °C. A 5% aqueous solution of sodium bisulfite was then added until iodine starch test paper no longer exhibited color. The water was distilled off under reduced pressure and, then, fractionation was performed under reduced pressure (theoretical number of plates: 5, 83°C/17 mmHg) to obtain 45 g of dimethyl sulfoxide (yield: 75%). After next combining 22.6 g of 1 , 4-bis (phenylacetyl) benzene, 45 g of the previously recovered dimethyl sulfoxide and 110 g of acetic acid at room temperature, 12.4 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105°C and the reaction was conducted for 4 hours while distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 99%. Example 8 After combining 31.4 g of 1 , 4-bis(phenacyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 17.21 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105°C and the reaction was conducted for 3 hours while distilling off the dimethyl sulfide.

Next, 157 g of acetic acid was added and the mixture was cooled to room temperature over a period of 8 hours. The precipitated crystals were filtered, washed with water and dried to obtain 24.1 g of 1 , 4-bisbenzil (isolation yield: 68%). The purity of the 1 , 4-bisbenzil obtained by high performance liquid chromatography analysis was ≥99%. Example 9 After combining 31.4 g of 1 ,4-bis(phenacyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 17.21 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105 °C and the reaction was conducted for 3 hours while distilling off the dimethyl sulfide.

Next, 157 g of water was added over a period of 3 hours while keeping the internal temperature at 90-100°C, and then the mixture was cooled to room temperature over a period of 8 hours. The precipitated solid was filtered, washed with water and dried to obtain 33.9 g of 1, 4-bisbenzil (isolation yield: 99%). The purity of the 1, 4-bisbenzil obtained by high performance liquid chromatography analysis was ≥99%.

Example 10

After combining 31.4 g of 1 , 4-bis (phenacyl )benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 27.0 g of a 30% HBr/acetic acid solution was added at room temperature. The temperature in the reaction vessel was kept at 55-60 °C and reaction was conducted for 3 hours without distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography analysis, the 1 , 4-bisbenzil yield was found to be 85%.

Example 11

After combining 31.4 g of 1 , 4-bis (phenacyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 27.0 g of a 30% HBr/acetic acid solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105°C and the reaction was conducted for 3 hours while distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography analysis, the 1 , 4-bisbenzil yield was found to be 99%.

Example 12

There were combined at room temperature 31.4 g of 1 , 4-bis (phenacyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid. HBr gas was introduced in an amount of 8.3 g at room temperature to no higher than 50 °C. After introducing the HBr gas, the temperature in the reaction vessel was kept at 95-105°C and the reaction was conducted for 3 hours while distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography analysis, the 1, 4-bisbenzil yield was found to be 100%.

Example 13 (Recovery and reutilization of dimethyl sulfide)

After combining 31.4 g of 1 , 4-bis (phenacyl)benzene, 62.5 g of dimethyl sulfoxide and 157 g of acetic acid at room temperature, 17.21 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105 °C and the reaction was conducted for 4 hours while distilling off the dimethyl sulfide. Isolation in the same manner as in Example 2 produced 33.5 g of 1 , 4-bisbenzil (yield: 98%).

A 46 g portion of the dimethyl sulfide produced by the reaction was recovered (theoretical yield: 49.7 g). To 98 g of 30% aqueous hydrogen peroxide cooled on ice there was added dropwise 46 g of the dimethyl sulfide without the internal temperature exceeding 40 °C. A 5% aqueous solution of sodium bisulfide was then added until iodine starch test paper no longer exhibited color. The water was distilled off under reduced pressure, and then fractionation was performed under reduced pressure

(number of theoretical plates: 5, 83°C/17 mmHg) to obtain 43 g of dimethyl sulfoxide (yield: 75%).

After next combining 43 g of the previously recovered dimethyl sulfoxide, 21.7 g of 1,4 bis(phenacyl)benzene and 105 g of acetic acid at room temperature, 11.8 g of a 47% HBr aqueous solution was added at room temperature. The temperature in the reaction vessel was kept at 95-105 °C and the reaction was conducted for 4 hours while distilling off the dimethyl sulfide. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 99%. Example 14 After combining and stirring 36 g of 80 wt% concentration sulfuric acid and 3.64 g of l,4-bis(β- ketonitrile) at room temperature, the reaction was conducted at 140°C for 2 hours. The product was filtered, washed with water and dried, and then recrystallized from dichloroethane . The crystals were filtered and dried to obtain 2.46 g of 1,4- bis(phenylacetyl) benzene (yield: 72%). The purity of the 1 , 4-bis (phenylacetyl) benzene obtained by high performance liquid chromatography analysis was ≥99 % .

Example 15

After combining and stirring 180 g of acetic acid, 120 g of 65 wt% concentration sulfuric acid and 36.4 g of 1, 4-bis (β-ketonitrile) at room temperature, the mixture was circulated for 8 hours. Next, 180 g of acetic acid was added and the mixture was slowly cooled. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 30.5 g of 1 , 4-bis (phenylacetyl )benzene (yield: 89%). The purity of the 1 , 4-bis (phenylacetyl )benzene obtained by high performance liquid chromatography analysis was ≥99%.

Example 16

After combining and stirring 180 g of acetic acid, 120 g of 65 wt% concentration sulfuric acid and 36.4 g of 1 , 4-bis (β-ketonitrile) at room temperature, the mixture was circulated for 12 hours. Next, 180 g of acetic acid was added and the mixture was slowly cooled. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 31.5 g of 1 , 4-bis (phenylacetyl )benzene (yield: 92%). The purity of the 1 , 4-bis (phenylacetyl )benzene obtained by high performance liquid chromatography analysis was ≥99%. Example 17 After combining and stirring 180 g of propionic acid, 120 g of 65 wt% concentration sulfuric acid and 36.4 g of 1 , 4-bis (β-ketonitrile ) at room temperature, the mixture was circulated for 8 hours. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bis (phenylacetyl)benzene yield was found to be 88%. Example 18

After combining 36.4 g of 1 , 4-bis (β-ketonitrile) , 180 g of acetic acid and 105.6 g of 65 wt% concentration sulfuric acid at room temperature, the mixture was circulated for 12 hours. it was then cooled until the internal temperature reached 80 °C, after which 62.5 g of dimethyl sulfoxide and 9.8 g of ammonium bromide were added and the reaction was conducted at 100 °C for 3 hours. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 88%. Example 19 After combining 36.4 g of 1 , 4-bis (β-ketonitrile) , 180 g of acetic acid and 105.6 g of 65 wt% concentration sulfuric acid at room temperature, the mixture was circulated for 8 hours. It was then cooled until the internal temperature reached 80 °C, after which 62.5 g of dimethyl sulfoxide and 15 g of a 48% HBr aqueous solution were added and the reaction was conducted at 100 °C for 3 hours. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 83%. Example 20 After combining 36.4 g of 1 , 4-bis (β-ketonitrile) ,

180 g of acetic acid and 105.6 g of 65 wt% concentration sulfuric acid at room temperature, the mixture was circulated for 8 hours. It was then cooled until the internal temperature reached 80 °C, after which 62.5 g of dimethyl sulfoxide and 10.3 g of sodium bromide were added and the reaction was conducted at 100 °C for 3 hours. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 86%. Example 21

After combining 36.4 g of 1 , 4-bis (β-ketonitrile) , 120 g of acetic acid, 62.5 g of dimethyl sulfoxide and 105.6 g of 65 wt% concentration sulfuric acid at room temperature, the mixture was circulated for 12 hours. It was then cooled until the internal temperature reached

80 °C, after which 9.8 g of ammonium bromide was added and the reaction was conducted at 100 °C for 3 hours. When the reaction solution was sampled and analyzed by high performance liquid chromatography, the 1 , 4-bisbenzil yield was found to be 87%. Example 22

After combining 36.4 g of 1 , 4-bis (β-ketonitrile) , 180 g of acetic acid and 105.6 g of 65 wt% concentration sulfuric acid at room temperature, the mixture was circulated for 8 hours. It was then cooled until the internal temperature reached 80 °C, after which 62.5 g of dimethyl sulfoxide and 10.3 g of sodium bromide were added and the reaction was conducted at 100 °C for 3 hours. After slowly cooling to room temperature, the precipitated crystals were filtered, collected, washed with water and dried to obtain 21.8 g of 1 , 4-bisbenzil (isolation yield: 64%). Example 23

After combining 36.4 g of 1 , 4-bis (β-ketonitrile) , 180 g of acetic acid and 105.6 g of 65 wt% concentration sulfuric acid at room temperature, the mixture was circulated for 8 hours. It was then cooled until the internal temperature reached 80 °C, after which 62.5 g of dimethyl sulfoxide and 9.8 g of ammonium bromide were added and the reaction was conducted at 100 °C for 3 hours. After then adding 180 g of water while keeping the internal temperature at 95-100°C, the mixture was slowly cooled. The precipitated crystals were filtered, washed with water and dried to obtain 24.5 g of 1,4- bisbenzil (isolation yield: 73%). Example 24

There were combined and stirred at room temperature 20 ml of tert-butanol (tBuOH), 1.95 g of dimethyl terephthalate and 2.47 g of tBuOK. Next, 2.56 g of benzyl cyanide was added dropwise over a period of 2 hours while circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3-4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 3.35 g of 1 , 4-bis ( 2-cyano-2- phenylacetyl)benzene as the corresponding bis(β- ketonitrile) compound. The purity of the l,4-bis(2- cyano-2-phenylacetyl) benzene obtained by high performance liquid chromatography analysis was ≥99%.

Example 25 There were combined and stirred at room temperature 20 ml of tBuOH, 1.95 g of dimethyl terephthalate and 2.11 g of tBuONa. Next, 2.56 g of benzyl cyanide was added dropwise over a period of 2 hours which circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3-4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 3.28 g of 1 , 4-bis (2-cyano- 2-phenylacetyl) benzene. The purity of the 1 , 4-bis (2- cyano-2-phenylacetyl)benzene obtained by high performance liquid chromatography analysis was ≥99%. Example 26

There were combined and stirred a room temperature 20 ml of 1-butanol, 1.95 g of dimethyl terephthalate and 1.70 g of EtONa. Next, 2.56 g of benzyl cyanide was added dropwise over a period of 2 hours while circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3-4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 2.91 g of 1 , 4-bis (2-cyano-2-phenylacetyl )benzene . The purity of the 1, 4-bis ( 2-cyano-2-phenylacetyl)benzene obtained by high performance liquid chromatography analysis was ≥99%. Example 27

There were combined and stirred at room temperature 20 ml of 2-propanol, 1.95 g of dimethyl terephthalate and 1.35 g of MeONa. Next, 2.56 g of benzyl cyanide was added dropwise over a period of 2 hours while circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3-4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 2.55 g of 1 , 4-bis ( 2-cyano-2-phenylacetyl)benzene. The purity of the 1 , 4-bis (2-cyano-2-phenylacetyl)benzene obtained by high performance liquid chromatography analysis was ≥99%. Example 28 (Large-scale production) After loading 380 kg of tBuOH, 76 kg of dimethyl terephthalate and 96 kg of tBuOK into a 1.5 m³ SUS reaction boiler at room temperature in a nitrogen atmosphere, the mixture was stirred. This was heated and circulated while adding 100 kg of benzyl cyanide dropwise over a period of 6 hours. After one hour, 340 kg of tBuOH was loaded in at room temperature. After a further reaction for 4 hours, cooling was effected to an internal temperature of 50°C. Next, 440 kg of a 10% aqueous sulfuric acid solution was added to adjust the pH of the solution to 3-4. The precipitated solid was subjected to centrifugal separation to remove the liquid, washed with 300 kg of methanol and then washed again with 100 kg of water. The wet body was repulped with 1200 kg of water at 80 °C, and the liquid was removed with a centrifugal separator. This was followed by heat drying under reduced pressure to obtain 139 kg of 1, -bis (2-cyano-2- phenylacetyl )benzene. (98% purity, 90% yield). Example 29

There were combined and stirred at room temperature 20 ml of tBuOH, 1.95 g of dimethyl isophthalate and 2.47 g of tBuOK. Next, 2.56 g of benzyl cyanide was added dropwise over a period of 2 hours while circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3-4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 3.35 g of 1 , 3-bis ( 2-cyano- 2-phenylacetyl)benzene. The purity of the 1, 3-bis (2- cyano-2-phenylacetyl) benzene obtained by high performance liquid chromatography analysis was ≥99%. Example 30

There were combined and stirred at room temperature 25 ml of tBuOH, 1.95 g of dimethyl terephthalate and 2.47 g of tBuOK. Next, 2.88 g of p-methylbenzyl cyanide was added dropwise over a period of 2 hours while circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3-4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 3.52 g of 1 , 4-bis (2-cyano-2-phenylacetyl) benzene as the corresponding bis(β-ketonitrile) compound. The purity of the 1 , 4-bis ( 2-cyano-2-phenylacetyl)benzene obtained by high performance liquid chromatography analysis was ≥99%. Example 31

There were combined and stirred at room temperature 30 ml of tBuOH, 1.95 g of dimethyl terephthalate and 2.47 g of tBuOK. Next, 3.63 g of 3-chloro-4-methylbenzyl cyanide was added dropwise over a period of 2 hours while circulating the mixture. After cooling to room temperature, 22 g of a 10% aqueous sulfuric acid solution was added dropwise to adjust the pH of the solution to 3- 4. The precipitated crystals were filtered, washed with methanol, washed with water and then dried to obtain 3.92 g of 1 , 4-bis (2-cyano-2-phenylacetyl) benzene as the corresponding bis (β-ketonitrile) compound. The purity of the 1, 4-bis (2-cyano-2-phenylacetyl)benzene obtained by high performance liquid chromatography analysis was ≥99%. Industrial Applicability

According to the present invention it is possible to produce bisbenzil compounds conveniently and at high purity, as important intermediates for electronic materials, functional polymer monomers, and the like.

Claims

CLAIMS 1. A process wherein a bis (phenylacetyl )benzene compound represented by the following formula (1) or a bis (phenacyl) benzene compound represented by the following formula (2):

wherein R-R₄ each independently represents hydrogen, a halogen atom, C₁-C₄ alkoxy, C_x-C₄ alkyl, monocyclic aryl, dialkylamino with Ci-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro, and R₅-R₁₄ each independently represents hydrogen, a halogen atom, C_x-C₄ alkoxy, C_j-C,, alkyl, monocyclic aryl, dialkylamino with Ci-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro; is reacted with a sulfoxide compound and a hydrogen halide in the presence of an organic solvent, to produce a bisbenzil compound represented by the following formula (3):

wherein Ri- ₁₄ are as defined above.

2. A process according to claim 1, wherein Ri-R₁₄ each independently represents hydrogen or a halogen atom.

3. A process according to claim 2, wherein the bis (phenylacetyl )benzene compound is 1,4- bis (phenylacetyl ) benzene, and the bisbenzil compound is the corresponding 1 , 4-bisbenzil.

4. A process according to any one of claims 1 to 3, wherein the organic solvent is an aliphatic carboxylic acid.

5. A process according to claim 4, wherein the organic solvent is acetic acid.

6. A process according to any one of claims 1 to 5, wherein the sulfoxide compound is at least one selected from among dialkyl sulfoxides with C^^ alkyl groups and tetramethylene sulfoxide.

7. A process according to claim 6, wherein the sulfoxide compound is dimethyl sulfoxide.

8. A process according to claim 7, wherein the dimethyl sulfide by-product of the reaction is oxidized to dimethyl sulfoxide and reutilized as a dimethyl sulfoxide starting material.

9. A process according to claim 8, wherein the oxidation of the dimethyl sulfide is accomplished using oxygen.

10. A process according to any one of claims 1 to 9, wherein the hydrogen halide is hydrogen bromide and/or hydrogen iodide.

11. A process according to claim 1, wherein the bis (phenylacetyl ) benzene compound represented by formula (1) is produced by reacting a bis (β-ketonitrile) compound represented by the following formula (7):

wherein Ri-R₁₄ are as defined above, in the presence of sulfuric acid.

12. A process according to claim 11, wherein the sulfuric acid is used in an amount of 3-12 moles with respect to 1 mole of the bis (β-ketonitrile) compound.

13. A process according to claim 11 or 12, wherein the sulfuric acid is used as a 60-80 wt% aqueous solution.

14. A process according to any one of claims 11 to 13, wherein the reaction is conducted in the presence of an organic solvent.

15. A process according to claim 14, wherein the organic solvent is an optionally branched C-_L-C_S aliphatic carboxylic acid.

16. A process according to any one of claims 11 to 15, wherein Ri~R₁₄ each independently represents hydrogen or a halogen atom.

17. A process wherein a bis (β-ketonitrile) compound represented by the following formula (7):

wherein Ri~R₄ each independently represents hydrogen, a halogen atom, C^^ alkoxy, C_!-C₄ alkyl, monocyclic aryl, dialkylamino with C₁-C₁ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro, and R₅-R₁₄ each independently represents hydrogen, a halogen atom, C_!-C₄ alkoxy, C₁-C₄ alkyl, monocyclic aryl, dialkylamino with C₁-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro; i is reacted in an acidic environment in the presence of water, a halide and a sulfoxide compound, to produce a bisbenzil compound represented by the following formula (3):

wherein Ri-R₁₄ are as defined above.

18. A process according to claim 17, wherein the bis (β-ketonitrile) compound is reacted in an acidic environment in the presence of water, and then the halide and sulfoxide compound are added for reaction.

19. A process according to claim 17 or 18, wherein the reaction is conducted in the presence of a solvent.

20. A process according to claim 19, wherein the organic solvent is acetic acid.

21. A process according to any one of claims 17 to

20, wherein the reaction system is rendered acidic using a proton acid with a pKa of 1 or greater.

22. A process according to claim 21, wherein the proton acid is sulfuric acid.

23. A process according to any one of claims 17 to

22, wherein the halide is at least one selected from among hydrogen bromide, hydrogen bromide salts, hydrogen iodide and hydrogen iodide salts.

24. A process according to any one of claims 17 to 23, wherein the sulfoxide compound is dimethyl sulfoxide.

25. A process according to any one of. claims 17 to 24, wherein

each independently represents hydrogen or a halogen atom.

26. A process according to any one of claims 11 to 17, wherein the bis (β-ketonitrile) compound is a bis(β- ketonitrile) compound represented by the following formula ( 10 ) :

wherein R₂₀-R₂₃ ^{are as} defined below, obtained by reacting a benzyl cyanide compound represented by the following formula (8):

wherein R₁₅-R₁₉ each independently represents hydrogen, a halogen atom, C_!-C₄ alkoxy, C^C,, alkyl, monocyclic aryl, dialkylamino with C_x-C₄ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro; with an aromatic dicarboxylic diester compound represented by the following formula (9):

wherein ₂₀-R₂₃ each independently represents hydrogen, a halogen atom, C_x-C₄ alkoxy, Ci-C₄ alkyl, monocyclic aryl, dialkylamino with C^C^ alkyl as the alkyl group, C₂-C₈ alkenyl or nitro, and R₂₁ independently represents Ci-C₄ alkyl or monocyclic aryl; in the presence of a metal alkoxide.

27. A process according to claim 26, wherein R₂₀-R₂₃ each independently represents hydrogen or a halogen atom.

28. A process according to claim 26 or 27, wherein Ri_s-R_.g each independently represents hydrogen, a halogen atom, methyl, methoxy, allyl, phenyl or dimethylamino.

29. A process according to claim 28, wherein the benzyl cyanide compound is benzyl cyanide, and the aromatic dicarboxylic diester compound is dimethyl terephthalate.

30. A process according to any one of claims 26 to 29, wherein the metal alkoxide is an alkali metal alkoxide or an alkaline earth metal alkoxide.

31. A process according to claim 30, wherein the metal alkoxide is an alkali metal alkoxide.

32. A process according to claim 31, wherein the metal alkoxide is a metal alkoxide of a C_!-C₄ alcohol.

33. A process according to claim 32, wherein the metal alkoxide is one selected from among alkali metal ethoxides, alkali metal ethoxides and alkali metal tert- butyl oxides.

34. A process according to claim 33, wherein the metal alkoxide is sodium tert-butyl oxide or potassium tert-butyl oxide.

35. A process according to any one of claims 26 to 34, wherein the reaction is conducted in the presence of an alcohol in addition to the metal alkoxide.

36. A process according to claim 35, wherein the alcohol is a C^C^ alcohol.