JPH10109962A - Production of diaryl carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a diaryl carbonate in a high selectivity by the decarbonylation reaction of a diaryl oxalate in the presence of especially an organic phosphorus compound catalyst while keeping high activity and selectivity of the catalyst even after the repeated use of the catalyst. SOLUTION: A diaryl oxalate is subjected to decarbonylation reaction in the presence of an organic phosphorus compound catalyst to obtain a diaryl carbonate. The residue obtained by recovering the produced diaryl carbonate from the reaction liquid and containing the organic phosphorus compound catalyst is incorporated with a halogen compound and repeatedly used as the catalyst for the decarbonylation reaction of diaryl oxalate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a diaryl carbonate useful as a raw material for producing a polycarbonate.

[0002]

2. Description of the Related Art As a method for producing a diaryl carbonate, a method of reacting phosgene with an aromatic hydroxy compound in the presence of an alkali (Japanese Patent Laid-Open No. 62-190146).
And a method of subjecting a dialkyl carbonate and an aromatic hydroxy compound to a transesterification reaction in the presence of a catalyst (JP-B-56-42577, JP-B-1-558).
No. 8 is well known. However, the former method using phosgene is not necessarily industrially excellent because phosgene itself is a highly toxic compound and a large amount of alkali is used. In addition, the latter transesterification method, as described in many patents relating to this method, does not have a sufficient reaction rate despite the use of a highly active catalyst. There is a problem that a device is required.

As another method, a method of producing a diaryl carbonate by decarbonylating a diaryl oxalate is known, but this method has a low selectivity and a yield of the diaryl carbonate and a high reaction temperature. Therefore, there is a problem that it is very disadvantageous industrially. For example, a method for producing diphenyl carbonate by boiling diphenyl oxalate in a distillation flask without a catalyst [Journal of the Society of Organic Synthesis, 5, 47 (1)
948) and 70], because no catalyst and a high reaction temperature, phenol and carbon dioxide are by-produced, and the selectivity and the yield of diphenyl carbonate are remarkably reduced. There is a problem that it cannot be obtained.

Further, a method for producing a dialkyl carbonate by heating a dialkyl oxalate or the like in the liquid phase at 50 to 150 ° C. in the presence of an alcoholate catalyst (US Pat.
According to the examples described in this publication, even when diphenyl oxalate is heated in the presence of a potassium phenoxide catalyst, the main product obtained is diphenyl oxalate as a raw material. It is. As described above, a highly active and highly selective catalyst capable of producing a diaryl carbonate from a diaryl oxalate is not known, and further, the catalyst is maintained at a high activity and a high selectivity for a long period of time so that the diaryl carbonate can be produced with a high activity. There is no known method for continuous production with selectivity.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for industrially and continuously producing diaryl carbonate without using phosgene which is a highly toxic compound and using a catalyst having high activity, high selectivity and long life. The task is to provide That is, a method for producing a diaryl carbonate from a diaryl oxalate, particularly a method for producing a diaryl carbonate by subjecting a diaryl oxalate to a decarbonylation reaction in the presence of an organic phosphorus compound catalyst,
An object of the present invention is to provide a method capable of continuously producing a diaryl carbonate with a high selectivity by repeatedly using the catalyst while maintaining high activity and high selectivity over a long period of time.

[0006]

The object of the present invention is to provide (1)
The diaryl oxalate is subjected to a decarbonylation reaction in the presence of an organophosphorus compound catalyst to form a diaryl carbonate, (2) recovering the diaryl carbonate from the reaction solution, and then (3) removing the residue containing the organophosphorus compound catalyst. In the presence, a halogen compound is added, a diaryl oxalate is subjected to a decarbonyl reaction to produce a diaryl carbonate, and a method for producing a diaryl carbonate, and the diaryl oxalate is decarbonylated in the presence of an organic phosphorus compound catalyst. A halogen compound is added to a residue containing an organic phosphorus compound catalyst, which is obtained by recovering the diaryl carbonate from the reaction solution in which the diaryl carbonate is produced by the reaction, and the residue is subjected to a decarbonylation reaction of the diaryl oxalate. Roll as a catalyst Is achieved by the method for producing a diaryl carbonate, characterized by using.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A diaryl carbonate is produced by a decarbonylation reaction of a diaryl oxalate represented by the following formula.

[0008]

Embedded image (In the formula, Ar represents an aryl group.)

In the present invention, an organic phosphorus compound is repeatedly used as a catalyst in the decarbonylation reaction of diaryl oxalate. That is, in the present invention, a residue containing an organic phosphorus compound, which is obtained by recovering a diaryl carbonate from a reaction solution of a decarbonylation reaction of a diaryl oxalate in the presence of an organic phosphorus compound catalyst, is repeatedly used as a catalyst. Then, at this time, the decarbonylation reaction of the diaryl oxalate is performed by adding a halogen compound. Hereinafter, the present invention will be described in detail.

As the diaryl oxalate used in the present invention, the aryl group includes (1) a phenyl group, (2) (a) an alkyl group having 1 to 12 carbon atoms such as a methyl group and an ethyl group, and (b) A alkoxy group having 1 to 12 carbon atoms such as a methoxy group and an ethoxy group, (c) a halogen atom such as a fluorine atom and a chlorine atom, or (d) a substituted phenyl group having a substituent such as a nitro group, or (3) naphthyl And the like. Among these aryl groups, a phenyl group is preferred.

The above substituted phenyl group includes various isomers. These isomers include (a) 2- (or 3-, 4-
-) A carbon number of 1 to 2 (or 3- or 4-) such as a methylphenyl group or a 2- (or 3- or 4-) ethylphenyl group;
An alkyl-substituted phenyl group having 12 alkyl groups,
(B) 2- (or 3-, 4-) methoxyphenyl group, 2
An alkoxy-substituted phenyl group having an alkoxy group having 1 to 12 carbon atoms at the 2- (or 3- or 4-) position such as-(or 3- or 4-) ethoxyphenyl group, (c) 2- (or 3
-, 4-) fluorophenyl group, 2- (or 3-, 4)
-) A halogen-substituted phenyl group having a halogen atom at the 2- (or 3- or 4-) position such as a chlorophenyl group, (d)
2- (or 3-, 4-) nitrophenyl group and the like.

Examples of the diaryl oxalate include diphenyl oxalate, bis (2-methylphenyl) oxalate, bis (3-methylphenyl) oxalate, bis (4-methylphenyl) oxalate, bis (2-chlorophenyl) oxalate, bis ( Specific examples include 3-chlorophenyl) oxalate, bis (4-chlorophenyl) oxalate, bis (2-nitrophenyl) oxalate, bis (3-nitrophenyl) oxalate, and bis (4-nitrophenyl) oxalate. Other diaryl oxalates are synthesized based on a known method. Among these diaryl oxalates, diphenyl oxalate is preferred.

The organic phosphorus compound catalyst used in the present invention includes an organic phosphorus compound having a trivalent or pentavalent phosphorus atom. The valence of the phosphorus atom is trivalent or 5
Organic phosphorus compounds that are monovalent have at least one carbon-
An organic phosphorus compound having a phosphorus (CP) bond is preferable, and an organic phosphorus compound having three or more carbon-phosphorus (CP) bonds is particularly preferable.

Preferred examples of the organic phosphorus compound include phosphonium salts, phosphines, phosphine dihalides, and phosphine oxides represented by the following general formula.

Embedded image (Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ ,
R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ^{13 each} have 6 to 14 carbon atoms.
Aryl group, alkyl group having 1 to 16 carbon atoms, 7 carbon atoms
To 22 aralkyl group, heterocyclic group having 4 to 16 carbon atoms, or an aryloxy group having 6 to 14 carbon atoms, X represents an atom or an atomic group capable of forming counterions phosphonium salt, Y ^1, Y ² represents a halogen atom. )

As the phosphonium salt represented by the general formula (A), R ¹ , R ² , R ³ and R ⁴ are the above-mentioned aryl group,
Those which are an alkyl group, an aralkyl group, a heterocyclic group or an aryloxy group are exemplified. Further, these groups may be the same or different from each other, and may be cross-linked between the two groups to form a ring containing a phosphorus atom.

The aryl, alkyl, aralkyl, heterocyclic and aryloxy groups represented by R ¹ , R ² , R ³ and R ⁴ include the following. That is, examples of the aryl group include an aryl group having 6 to 14 carbon atoms such as a phenyl group and a naphthyl group which may have a substituent, and the alkyl group may have a substituent. , A methyl group, an ethyl group, an n- (or i-) propyl group, an n- (or i-, sec-, tert-) butyl group and other alkyl groups having 1 to 16 carbon atoms. A benzyl group, a phenethyl group, a naphthylmethyl group or the like, which may have a substituent, having 7 to 2 carbon atoms.
2 aralkyl groups, and examples of the heterocyclic group include an optionally substituted heterocyclic group having 4 to 16 carbon atoms such as a thienyl group, a furyl group and a pyridyl group, and an aryloxy group Examples thereof include an aryloxy group having 6 to 14 carbon atoms such as a phenoxy group and a naphthoxy group which may have a substituent.

The above-mentioned aryl group, aralkyl group, heterocyclic group and aryloxy group have, on the aromatic ring or the heterocyclic ring, an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, and 2 carbon atoms. An amino group such as an alkoxycarbonyl group having 12 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an N, N-dialkyl-substituted amino group having 2 to 16 carbon atoms, a cyano group, a nitro group, and a halogen atom such as fluorine, chlorine and bromine. May have one or more substituents (including various isomers such as o, m, and p). The alkyl group is an alkoxy group having 1 to 15 carbon atoms, 2 carbon atoms.
At least one of various substituents such as an alkoxycarbonyl group having from 12 to 12, an amino group having 2 to 16 carbon atoms such as an N, N-dialkyl-substituted amino group, a cyano group, a nitro group, and a halogen atom such as fluorine, chlorine and bromine. You can have it.

Examples of the above phosphonium salts include, for example,
R ¹ , R ² , R ³ and R ⁴ in which all are aryl groups (tetraarylphosphonium salts), R ¹ , R ² and R 4
³ or R ⁴ is an aryl group and one is another group, or ^{two of} R ¹ , R ² , R ³ and R ⁴
One is an aryl group and two are different groups,
One of R ¹ , R ² , R ³ , and R ⁴ is an aryl group and three are other groups, and R ¹ , R ² , R ³ ,
R ⁴ is not an aryl group. Among these phosphonium salts, R ¹ , R ² , R ³ , R
All ⁴ are aryl groups, R ¹ , R ² ,
It is preferable that ^{three of} R ³ and R ⁴ are aryl groups and one of them is a heterocyclic group, and among them, R ¹ , R ² , R ³ and R
Those in which all ⁴ are aryl groups are preferred.

[0019] The pair of phosphonium salt ion X ^- as is,
Halogen ions (chlorine ions, bromine ions, iodine ions, etc.), hydrogen dihalide ions (hydrogen dichloride ion, hydrogen dibromide ion, hydrogen diiodide ion, hydrogen bromide chloride ion, etc.), and halogen acids Ion (chlorate ion, bromate ion, iodate ion, etc.), perhalate ion (perchlorate ion, perbromate ion, periodate ion, etc.), and aliphatic carboxylate ion (acetate ion, triacetate ion). Fluoroacetate ion, propionate ion, etc.), aromatic carboxylate ion (benzoate ion, α- (or β-) naphthalenecarboxylic acid ion, etc.), aromatic hydroxy ion (phenoxide ion, etc.), inorganic acid Ion (sulfate ion, hydrogen sulfate ion, phosphate ion , Hydrogen phosphate ion, borate ion,
Hydrogen borate ion, cyanate ion, thiocyanate ion, fluoroborate ion, etc.) and tetraalkyl borate ion (having an alkyl group having 1 to 10 carbon atoms such as tetramethyl borate ion, tetraethyl borate ion)
And tetraarylborate ions (having an aryl group having 6 to 14 carbon atoms such as tetraphenylborate ion and tetrakis-p-fluorophenylborate ion), and alkylsulfonic acid or alkylsulfinate ions (methyl group, ethyl group, an alkyl group having 1 to 16 carbon atoms such as an n- (or i-) propyl group, or an arylsulfonic acid or an arylsulfinate ion (phenyl group, p-
Having an aryl group such as a toluyl group and a p-nitrophenyl group). These counter-ions by X ^- Among halogen ions, hydrogen dihalide ion are preferred, among them chlorine ions, hydrogen dichloride ion is particularly preferred.

Specific examples of the phosphonium salt include the following compounds. R ¹ , R ² , R ³ ,
Examples of the phosphonium salt wherein all of R ⁴ are aryl groups and X ⁻ is a halogen ion include tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, tetraphenylphosphonium iodide, tetrakis (p-chlorophenyl) phosphonium chloride, Tetrakis (p-fluorophenyl) phosphonium chloride, tetrakis (p-tolyl) phosphonium chloride, p-chlorophenyltriphenylphosphonium chloride, p-chlorophenyltriphenylphosphonium bromide, p-chlorophenyltriphenylphosphonium iodide, p-tolyltolide Phenylphosphonium chloride, p-tolyltriphenylphosphonium bromide, p-tolyltriphenylphosphonium iodide M-trifluoromethylphenyltriphenylphosphonium chloride, p-biphenyltriphenylphosphonium chloride, m-methoxyphenyltriphenylphosphonium chloride, p-
Methoxyphenyltriphenylphosphonium chloride, p-ethoxyphenyltriphenylphosphonium chloride, p-ethoxyphenyltriphenylphosphonium bromide, p-ethoxyphenyltriphenylphosphonium iodide, p-dimethylaminophenyltriphenylphosphonium chloride, p-ethoxy Examples include carbonylphenyltriphenylphosphonium chloride, m-cyanophenyltriphenylphosphonium chloride, 1-naphthyltriphenylphosphonium chloride, and 2-thiophenetriphenylphosphonium chloride. Among these phosphonium salts, tetraphenylphosphonium chloride is particularly preferred.

Examples of the phosphonium salt wherein R ¹ , R ² , R ³ and R ⁴ are all aryl groups and X ⁻ is a hydrogendihalide ion include, for example, tetraphenylphosphonium hydrogendichloride, tetraphenylphosphonium Hydrogen dibromide, tetraphenyl phosphonium hydrogen diiodide, tetraphenyl phosphonium hydrogen bromide chloride are exemplified. Among these phosphonium salts, tetraphenylphosphonium hydrogen dichloride is particularly preferred.

Examples of the phosphonium salt in which ^{three of} R ¹ , R ² , R ³ and R ⁴ are an aryl group, one is a heterocyclic group, and X ⁻ is a halogen ion include 2-thiophenetriene. Phenylphosphonium chloride.

Examples of the phosphonium salt in which ^{three of} R ¹ , R ² , R ³ and R ⁴ are an aryl group, one is an aryloxy group and X ⁻ is a halogen ion include:
Phenoxytriphenylphosphonium chloride is exemplified.

Among the phosphonium salts, those not commercially available can be obtained by a known method [Bull. Chem. Soc. Jp
n. , 56, 2869 (1983); Am. Che
m. Soc. , 70, 737 (1948)]. For example, tetraarylphosphonium chloride is a triarylphosphine and a corresponding aryl halide (iodo or bromo compound)
Is reacted in the presence of a palladium acetate catalyst, and the resulting tetraarylphosphonium iodide or tetraarylphosphonium bromide is converted to tetraarylphosphonium chloride using an ion exchange resin (chlor type). The obtained tetraarylphosphonium chloride is dried at 80 to 200 ° C. for 0.5 to 5 hours under a flow of a dry inert gas such as dry argon gas, and then at a temperature in this range of 0.5 to 5 hours under a flow of hydrogen chloride gas. Treated for 2 hours. It is preferable to use a commercially available tetraarylphosphonium chloride after performing the same treatment.

The tetraarylphosphonium salt having a counter ion other than a halogen ion can be obtained by converting the tetraarylphosphonium chloride obtained as described above into an alkali metal salt (sodium salt, potassium salt, etc.) having a corresponding counter ion or ammonium. Reaction with salt (ion exchange)
And synthesized. Other phosphonium salts other than tetraarylphosphonium salts are synthesized by the same method.

The phosphine represented by the general formula (B) includes an aryl group, an alkyl group, an aralkyl group or a heterocyclic group in which R ⁵ , R ⁶ and R ⁷ are the same as R ¹ , R ² , R ³ and R ^4. Is included. These groups may be the same or different from each other, and may be bridged between the two groups to form a ring containing a phosphorus atom.

As the phosphine, for example,
R ⁵ , R ⁶ , and R ⁷ in which all are aryl groups (triarylphosphine); and R ⁵ , R ⁶ , and R ⁷
One is an aryl group and one is another group,
One of R ⁵ , R ⁶ and R ⁷ is an aryl group;
Examples include those in which two are different groups, and those in which none of R ⁵ , R ⁶ , and R ⁷ is an aryl group. Among these phosphines, those in which all of R ⁵ , R ⁶ and R ⁷ are aryl groups are preferred.

Specific examples of the phosphine include the following compounds. Examples of the case where all of R ⁵ , R ⁶ and R ⁷ are aryl groups (triarylphosphine) include, for example, triphenylphosphine and tris (p
-Chlorophenyl) phosphine, tris (p-tolyl)
Phosphine and α-naphthyl (phenyl) -p-methoxyphenylphosphine.

As the phosphine dihalide represented by the general formula (C), R ⁸ , R ⁹ , and R ¹⁰ are R ¹ , R ² , R ³ ,
The same aryl group, alkyl group, aralkyl group or heterocyclic group as R ⁴ , wherein Y ¹ and Y ² are a halogen atom such as a chlorine atom, a bromine atom and an iodine atom. These groups may be the same or different from each other, and may be bridged between the two groups to form a ring containing a phosphorus atom. Also, Y ¹ and Y ² may be the same or different.

Examples of the phosphine dihalide include those in which all of R ⁸ , R ⁹ and R ¹⁰ are aryl groups (triaryl phosphine dihalide), R ⁸ ,
Two of R ⁹ and R ¹⁰ are aryl groups and one is another group, or one of R ⁸ , R ⁹ and R ¹⁰ is an aryl group and two are different groups Or
Any of R ⁸ , R ⁹ , and R ¹⁰ is not an aryl group. Among these phosphine dihalides,
Preferably, all of R ⁸ , R ⁹ and R ¹⁰ are aryl groups.

Specific examples of the phosphine dihalide include the following compounds. R ⁸ , R ⁹ ,
Examples in which all of R ¹⁰ are aryl groups (triarylphosphine dihalide) include triphenylphosphine dichloride, triphenylphosphine diglomide, and triphenylphosphine diiodide.

As the phosphine oxide represented by the general formula (D), R ¹¹ , R ¹² , and R ¹³ represent R ¹ , R ² , R ³ ,
The same aryl group, alkyl group, aralkyl group or heterocyclic group as R ⁴ can be mentioned. These groups may be the same or different from each other, and may be bridged between the two groups to form a ring containing a phosphorus atom.

Examples of the phosphine oxide include those in which all of R ¹¹ , R ¹² and R ¹³ are aryl groups (triaryl phosphine oxide), R ¹¹ ,
One in which two of R ¹² and R ¹³ are aryl groups and one is another group, and one in which one of R ¹¹ , R ¹² and R ¹³ is an aryl group and two are Or
Any of R ¹¹ , R ¹² , and R ¹³ is not an aryl group. Among these phosphine oxides,
Preferably, all of R ¹¹ , R ¹² and R ¹³ are aryl groups.

Specific examples of the phosphine oxide include the following compounds in which the phosphorus atom of the phosphine is oxidized. Examples of the compound in which all of R ¹¹ , R ¹² and R ¹³ are aryl groups (triarylphosphine oxide) include triphenylphosphine oxide, tris (p-chlorophenyl) phosphine oxide, tris (p-tolyl) phosphine oxide, α-naphthyl (phenyl) -p-methoxyphenylphosphine oxide.

Among the organic phosphorus compounds used in the present invention, tetraarylphosphonium halides, tetraarylphosphonium hydrogendihalides and triarylphosphine dihalides are preferable, and particularly, tetraarylphosphonium chloride and tetraarylphosphonium hydrogendichloride are preferred. , Triarylphosphine dichloride is preferred.

The halogen compounds used in the present invention include the following inorganic halogen compounds and / or organic halogen compounds. Among these halogen compounds, chlorine compounds and bromine compounds are preferable, and among them, chlorine compounds are particularly preferable.

Examples of the inorganic halogen compounds include phosphorus halides such as phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, phosphorus tribromide, phosphorus pentabromide and phosphorus oxybromide, thionyl chloride, sulfuryl chloride, Sulfur halides such as sulfur chloride and disulfur dichloride, hydrogen halides such as hydrogen chloride and hydrogen bromide, and simple halogens such as chlorine and bromine are used. Among these inorganic halogen compounds, the above-mentioned inorganic chlorine compounds are preferable, and hydrogen chloride is particularly preferable.

As the organic halogen compound, for example, a structure in which a halogen atom is bonded to a saturated carbon (C-Ha)
l) or an organic halogen compound having a structure in which a halogen atom is bonded to a carbonyl carbon (-CO-Hal) is preferably used. Here, Hal represents a halogen atom such as a chlorine atom and a bromine atom. These structures, for example,
It is represented as general formulas (a) and (b).

[0039]

Embedded image (In the formula, Hal represents a halogen atom such as a chlorine atom or a bromine atom, and n represents an integer of 1 to 4.)

As such an organic halogen compound,
For example, the following compounds are specifically mentioned. Examples of the organic halogen compound having a structure in which a halogen atom is bonded to a saturated carbon as represented by the general formula (a) include chloroform, carbon tetrachloride, 1,2-dichloroethane, butyl chloride, hexyl chloride, and chloride. Alkyl halides such as dodecyl and 3-chloro-1-propene; aralkyl halides such as benzyl chloride, benzotrichloride, triphenylmethyl chloride and α-bromo-o-xylene; β-chloropropionitrile; γ -Halogen-substituted aliphatic nitriles such as chlorobutyronitrile, and halogen-substituted aliphatic carboxylic acids such as chloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid, and chloropropionic acid;
And aryl esters of halogen-substituted aliphatic carboxylic acids such as phenyl chloroacetate and phenyl trichloroacetate.

Examples of the organic halogen compound having a structure in which a halogen atom is bonded to a carbonyl carbon as represented by the general formula (b) include acetyl chloride, oxalyl chloride, propionyl chloride, stearoyl chloride, benzoyl chloride, Acid halides such as -naphthalenecarboxylic acid chloride, 2-thiophenecarboxylic acid chloride,
Examples include aryl halogenoglyoxylates such as phenyl chloroglyoxylate, and aryl halogenoformates such as phenyl chloroformate. Among these organic halogen compounds, the above-mentioned organic chlorine compounds in which the halogen atom is a chlorine atom are preferred.

In the decarbonylation reaction of the diaryl oxalate of the present invention, (1) a diaryl oxalate is subjected to a decarbonylation reaction in the presence of an organic phosphorus compound catalyst to form a diaryl carbonate (first reaction step), (2)
The diaryl carbonate is recovered from the reaction solution (recovery step), and (3) a halogen compound is added in the presence of the residue containing the organophosphorus compound catalyst to cause the diaryl oxalate to undergo a decarbonylation reaction to form a diaryl carbonate. (Re-reaction step). Then, the decarbonylation reaction of the diaryl oxalate of the present invention is performed by repeating the recovery step and the re-reaction step. That is, in the present invention, a diaryl oxalate is subjected to a decarbonylation reaction in the presence of an organophosphorus compound catalyst to obtain a diaryl carbonate, and the resulting diaryl carbonate is recovered to obtain a diaryl carbonate. , A halogen compound is added and the diaryl oxalate is decarbonylated by repeated use as a catalyst.

In the decarbonylation reaction of the diaryl oxalate (first reaction step), the diaryl oxalate and the organic phosphorus compound catalyst are charged into a reactor, and if necessary, the above-mentioned halogen compound is charged.
° C, preferably 160-400 ° C, more preferably 18
By heating at 0 to 350 ° C., the reaction is performed in a batch or continuous liquid phase reaction. At this time, a diaryl carbonate is generated from the diaryl oxalate according to the above reaction formula, and carbon monoxide is generated. The reaction pressure is not particularly limited, and the reaction may be performed under any of pressurized, normal and reduced pressure conditions. The residence time of the reaction solution is usually 0.5 to 10 hours, preferably 1 to 5 hours. At that time, the conversion of the diaryl oxalate is 3
0 to 100%.

In the present invention, the halogen compound may be added as needed in the first reaction step. In particular, as the organic phosphorus compound, when phosphine or phosphine oxide is used, when a phosphonium salt other than halide and hydrogendihalide is used, or when low-concentration phosphonium halide or phosphonium hydrogendihalide is used In this case, it is preferable to add a halogen compound. When a diaryl carbonate is produced by a continuous process as described below, it is preferable to add a halogen compound from the first reaction step.

In the first reaction step, the organic phosphorus compound is generally used in an amount of 0.001 to 50 mol%, preferably 0.01 to 20 mol%, based on the diaryl oxalate. The organic phosphorus compound may be used alone or in combination of two or more, or may be used after being dissolved and / or suspended in a reaction solution. When a halogen compound is added,
The molar ratio of the halogen compound to the organic phosphorus compound (halogen compound / organic phosphorus compound) is usually 0.01 to 30.
0, preferably 0.1 to 100. The halogen compound may be used alone or in combination.

A solvent is not particularly required for the decarbonylation reaction of the diaryl oxalate, but if necessary, diphenyl ether, sulfolane, N-methylpyrrolidone,
Dimethylimidazolidone, 1,3-dimethyl-3,4,
A solvent such as 5,6-tetrahydro-2 (1H) -pyrimidinone can be used as appropriate. The material of the reactor is not particularly limited, and for example, a reactor made of glass or stainless steel (SUS) can be used.
In addition, the reactor may be a single tank or multiple tanks.

After the reaction, the resulting diaryl carbonate is recovered, for example, by distillation from the reaction solution completely or partially withdrawn from the reactor (recovery step). To recover the diaryl carbonate, after separating the residue containing the organic phosphorus compound catalyst by an evaporator, a thin film evaporator, and the like,
A general method of distilling the evaporated portion (including diaryl carbonate and unreacted diaryl oxalate) using a packed column or a distillation column having a certain number of theoretical plates (particularly, 5 to 50 plates) is preferably used. . Further, a method is also used in which the reaction solution is distilled in the above-mentioned packed column or distillation column to extract the diaryl carbonate from the top of the column and the residue containing the organic phosphorus compound catalyst from the bottom of the column. The distillation is performed, for example, under a reduced pressure of 2 to 100 mmHg at a column bottom temperature of 150 to 250 ° C, a column top temperature of 80 to 200 ° C, preferably 100 to 180 ° C. By such a method, the diaryl carbonate contained in the reaction liquid extracted from the reactor is recovered.

The amount of the residue containing the organophosphorus compound catalyst obtained by recovering the diaryl carbonate is usually 1 to 20% by weight, preferably 1 to 10% by weight of the reaction solution. Almost 100% of the organic phosphorus compound catalyst contained in the reaction liquid extracted from the vessel was contained, and in addition, unreacted diaryl oxalate, unrecovered diaryl carbonate, and the like were included. The residue containing the organophosphorus compound catalyst is circulated to the reactor and reused in the decarbonylation reaction of the diaryloxalate (re-reaction step). Further, in addition to being circulated and supplied to the reactor, a part or all of the residue is continuously or batchwise extracted to prevent the accumulation of high-boiling substances and the like outside the reaction system.

Next, the diaryl oxalate is subjected to a decarbonylation reaction using the residue containing the organophosphorus compound catalyst as a catalyst (re-reaction step). In this re-reaction step, the diaryl oxalate and the residue containing the organophosphorus compound catalyst are put into a reactor, a halogen compound is further added, and the decarbonylation reaction is carried out under the same reaction conditions as in the first reaction step. Done. At this time, the residue containing the organophosphorus compound catalyst contains almost the entire amount of the organophosphorus compound catalyst used when the reaction solution is completely withdrawn from the reactor in the recovery step, and thus is used as a catalyst in the re-reaction step as it is. used. On the other hand, when a part of the reaction liquid is withdrawn from the reactor in the recovery step, this residue contains only a part of the used organic phosphorus compound catalyst, and thus is based on the amount of the reaction liquid withdrawn. In order to replenish the shortage and keep the concentration of the organic phosphorus compound within a certain range, a necessary amount of an organic phosphorus compound catalyst is newly added in the re-reaction step. The diaryl oxalate has a high conversion in the first reaction step and is separated as an evaporant in the recovery step, and is contained only in a small amount in the residue containing the organic phosphorus compound catalyst. It is added as in one reaction step. The halogen compound is added in the re-reaction step at the same ratio as when the halogen compound is added in the first reaction step. In the present invention, diaryl carbonate can be continuously produced at a high selectivity by repeating the recovery step and the re-reaction step. At this time, the amount of the organic phosphorus compound catalyst and the halogen compound used, the reaction conditions and the like are the same as described above.

In the case where the diaryl carbonate is continuously produced industrially, a halogen compound is added and the first compound is added.
The reaction step, the recovery step, and the re-reaction step are performed successively, and the recovery step and the re-reaction step are repeated. This process will be described according to a flow showing one embodiment of the present invention.
Diaryl oxalate through conduit 1, and the organic phosphorus compound catalyst and a halogen compound is supplied to the reactor 1 through conduit 2. In the reactor 1 , a decarbonylation reaction of the diaryl oxalate is performed, and diaryl carbonate is generated with the generation of carbon monoxide. The generated carbon monoxide is withdrawn from the gas phase of the reactor 1 through the conduit 3. Then, the reaction liquid containing the diaryl carbonate is withdrawn from the bottom of the reactor 1 through the conduit 4 and supplied to the evaporator 2 .

In the evaporator 2 , the residue containing the organophosphorus compound catalyst is separated, extracted from the bottom of the evaporator 2 through the conduit 6, and circulated to the reactor 1 . A part of the residue is drawn out of the system through the conduit 7. On the other hand, the distillate containing diaryl carbonate is withdrawn from the top of the evaporator 2 through the conduit 5 and supplied to the distillation column 3 . Then, in the distillation column 3 , the diaryl carbonate is recovered by distillation through the conduit 8. The distillation still residue is drawn out of the system through a conduit 9.

In the reactor 1 , the residue containing the organophosphorus compound catalyst and the diaryl oxalate, which are circulated through the conduit 6, are supplied through the conduit 1, and the concentration of the organophosphorus compound catalyst and the halogen compound in the reactor. Is maintained within a certain range, the organophosphorus compound catalyst and the halogen compound are replenished through the conduit 2 to continuously carry out the decarbonylation reaction of the diaryl oxalate. The reaction conditions and the like in this re-reaction step are the same as in the first reaction step.

As described above, according to the present invention, an organophosphorus compound catalyst obtained by recovering a diaryl carbonate from a reaction solution in which a diaryloxalate is subjected to a decarbonylation reaction in the presence of an organophosphorus compound catalyst to produce a diaryl carbonate. Is repeatedly used as a catalyst in the presence of a halogen compound to carry out a decarbonylation reaction of the diaryl oxalate.

[0054]

Next, the present invention will be described specifically with reference to examples and comparative examples. The conversion of diaryl oxalate (the ratio of consumed diaryl oxalate to charged diaryl oxalate) and the selectivity of diaryl carbonate (the ratio of generated diaryl carbonate to consumed diaryl oxalate) are on a molar basis (mol%). ).

Example 1 A 100 ml glass flask equipped with a thermometer and a reflux condenser was charged with diphenyloxalate (41.32 mmol).
l), tetraphenylphosphonium chloride (0.825 mmol: 2.0 mol% based on diphenyloxalate) is added as a catalyst, and chloroform is added as a halogen compound in an amount of 0.2 mol per 1 mol of tetraphenylphosphonium chloride. 230 ° C under stirring
After the temperature was raised to room temperature, a decarbonylation reaction was performed for 2 hours at this temperature while removing generated carbon monoxide to the outside of the system under normal pressure (first reaction). In addition, tetraphenylphosphonium chloride is heated at 120 ° C. under a dry argon gas flow.
Heat treatment was performed at 150 ° C. for 1 hour and at 180 ° C. for 1 hour, and then cooled to room temperature under argon gas flow before use. After completion of the reaction, the reaction solution was cooled to room temperature and analyzed by gas chromatography. As a result, the conversion of diphenyl oxalate was 95.4%, and the selectivity of diphenyl carbonate was 99.0%.

The diphenyl carbonate produced and unreacted diphenyl oxalate were recovered from the reaction solution by distillation under reduced pressure (2 to 3 mmHg / 185 ° C.).
A portion corresponding to 0% by weight was distilled off. The same amount of diphenyl oxalate and chloroform as above was added to the residue containing the organic phosphorus compound obtained by recovering diphenyl carbonate from this reaction solution, and the reaction was carried out in the same manner as above (first re-reaction). . As a result, the conversion of diphenyl oxalate was 97.0%, and the selectivity for diphenyl carbonate was 99.0%.

Hereinafter, the same procedure is repeated, and the residue containing the organic phosphorus compound obtained by recovering diphenyl carbonate from the reaction solution of the decarbonylation reaction of diphenyl oxalate in the presence of the organic phosphorus compound is used as a catalyst. Thus, a total of six reactions were performed. As a result, re-reaction 2
In the second run, the conversion of diphenyl oxalate was 95.8.
%, The selectivity of diphenyl carbonate is 99.0%,
In the third re-reaction, the conversion of diphenyl oxalate was 93.4% and the selectivity of diphenyl carbonate was 99.
At 0%, the conversion of diphenyl oxalate was 95.0%, the selectivity of diphenyl carbonate was 99.0% at the fourth re-reaction, and the conversion of diphenyl oxalate was 96.1% at the fifth re-reaction. And the selectivity of diphenyl carbonate was 99.0%. Table 1 shows the results.

[0058]

[Table 1]

Example 2 Diphenyloxalate (20.83 mmol) was placed in a 50 ml glass flask equipped with a thermometer and a reflux condenser.
l), tetraphenylphosphonium chloride (0.10 mmol: 0.5 mol% based on diphenyl oxalate) is added as a catalyst, and oxalyl chloride is used as a halogen compound in an amount of 0.6 mol per mol of tetraphenylphosphonium chloride. In addition, 2
After the temperature was raised to 55 ° C., a decarbonylation reaction (first reaction) was performed at this temperature for one hour while removing generated carbon monoxide from the system under normal pressure, and analysis was performed in the same manner as in Example 1. Was. As a result, the conversion of diphenyl oxalate was 8
At 5.0%, the selectivity for diphenyl carbonate is 99.
It was 0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of 29 reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of oxalyl chloride added were the same as in the case of the first reaction.
The results are shown in Tables 2 and 3.

[0060]

[Table 2]

[0061]

[Table 3]

Example 3 In Example 2, diphenyl oxalate was added at 20.5%.
Example 2 was repeated except that 8 mmol was used, 0.092 mmol of tetraphenylphosphonium hydrogen dichloride (0.45 mol% based on diphenyl oxalate) was used, the reaction temperature was changed to 260 ° C., and oxalyl chloride was not added. The reaction (first reaction) and analysis were performed in the same manner as described above. Incidentally, tetraphenylphosphonium hydrogen dichloride can be obtained by a known method [Z. anorg.
allg. Chem. , 551 (1987), 179].
Was synthesized according to the following procedure. As a result, the conversion of diphenyl oxalate was 89.7%, and the selectivity for diphenyl carbonate was 99.0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of six reactions and analysis. However,
In each re-reaction, 1.4 moles of chloroform were added to 1 mole of tetraphenylphosphonium hydrogen dichloride, and the reaction conditions such as the amount of diphenyl oxalate added were the same as in the first reaction. Table 4 shows the results.

[0063]

[Table 4]

Example 4 In Example 2, diphenyl oxalate was added at 7.88.
mmol, 0.039 mmol of tetraphenylphosphonium chloride (0.5 mol% based on diphenyloxalate), and 2.0 mol of chloroacetic acid per mol of tetraphenylphosphonium chloride instead of chloroform. Then, a reaction (first reaction) was carried out in the same manner as in Example 2 except that the reaction temperature was changed to 260 ° C. As a result, the conversion of diphenyl oxalate was 8
At 1.4%, the selectivity for diphenyl carbonate is 99.
It was 0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of chloroacetic acid added were the same as in the case of the first reaction. Table 5 shows the results.

Example 5 In Example 2, diphenyl oxalate was replaced with 7.97
mmol, and tetraphenylphosphonium chloride was used in an amount of 0.040 mmol (0.5 mol% based on diphenyl oxalate).
The reaction was performed in the same manner as in Example 2 except that chloro-1-propene was used in an amount of 2.6 mol per mol of tetraphenylphosphonium chloride, and the reaction temperature was changed to 260 ° C.
Reaction). As a result, the conversion of diphenyl oxalate was 82.6%, and the selectivity for diphenyl carbonate was 99.0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the amount of added diphenyl oxalate, 3-chloro-1-
The reaction conditions such as the amount of propene added were the same as in the case of the first reaction. Table 5 shows the results.

Example 6 In Example 2, the diphenyl oxalate was replaced with 12.3.
9 mmol, 0.061 mmol of tetraphenylphosphonium chloride (0.5 mol% based on diphenyl oxalate), and 1 instead of chloroform.
A reaction (first reaction) was carried out in the same manner as in Example 2 except that -chlorohexane was used in an equimolar amount to tetraphenylphosphonium chloride and the reaction temperature was changed to 260 ° C. As a result, the conversion of diphenyl oxalate was 9
At 0.8%, the selectivity for diphenyl carbonate is 99.
It was 0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of 1-chlorohexane added were the same as in the case of the first reaction. Table 6 shows the results.

Example 7 In Example 2, diphenyl oxalate was replaced with 8.23.
mmol, tetraphenylphosphonium chloride is used in an amount of 0.041 mmol (0.5 mol% based on diphenyloxalate), and benzoyl chloride is replaced with tetraphenylphosphonium chloride in place of chloroform.
A reaction (first reaction) was carried out in the same manner as in Example 2 except that 3.6 mol was used per mol and the reaction temperature was changed to 260 ° C. As a result, the conversion of diphenyl oxalate was 8
At 9.8%, the selectivity for diphenyl carbonate is 99.
It was 0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of benzoyl chloride added were the same as in the first reaction. Table 5 shows the results.

Example 8 In Example 2, diphenyl oxalate was added in an amount of 41.2%.
9 mmol, 0.826 mmol of tetraphenylphosphonium chloride (2.0 mol% based on diphenyl oxalate), and hydrogen chloride gas instead of chloroform.
The reaction was carried out in the same manner as in Example 2 except that 3.0 mol was used per mol (diluted to 1% by volume with nitrogen gas and supplied in 30 minutes from the start of the reaction), and the reaction temperature was changed to 230 ° C. First
Reaction). As a result, the conversion of diphenyl oxalate was 80.1%, and the selectivity for diphenyl carbonate was 99.0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of hydrogen chloride gas added were the same as in the case of the first reaction.
Table 5 shows the results.

Comparative Example 1 A total of three reactions were carried out in the same manner as in Example 1 except that the reaction was repeated without adding chloroform. As a result, in the first reaction, the conversion of diphenyl oxalate was 93.4%, and the selectivity of diphenyl carbonate was 9%.
In the first re-reaction, the conversion of diphenyl oxalate was 55.4%, the selectivity of diphenyl carbonate was 90.0%, and in the second re-reaction, the conversion of diphenyl oxalate was 36. 0.8% and the selectivity for diphenyl carbonate was 53.2%.

[0070]

[Table 5]

Example 9 In Example 2, diphenyl oxalate was added at 18.8.
1 mmol was used, and instead of tetraphenylphosphonium chloride, 0.376 mmol of tetraphenylphosphonium bromide (2.0 mol% based on diphenyl oxalate) was used, and chloroform was 3.3 mol per 1 mol of tetraphenylphosphonium bromide. A reaction (first reaction) was carried out in the same manner as in Example 2 except that the reaction temperature was changed to 230 ° C. and the reaction time was changed to 2 hours. As a result, the conversion of diphenyl oxalate was 76.8%, and the selectivity of diphenyl carbonate was 9%.
It was 7.6%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of chloroform added were the same as in the case of the first reaction. Table 6 shows the results.

Example 10 In Example 2, diphenyl oxalate was added at 21.2%.
7 mmol, and using triphenylphosphine instead of tetraphenylphosphonium chloride for 1.504 mm
ol (7.0 mol% based on diphenyl oxalate)
The reaction (first reaction) was carried out in the same manner as in Example 2 except that the reaction temperature was changed to 250 ° C. and the reaction time was changed to 2 hours, using chloroform in an equimolar amount to triphenylphosphine. Was. As a result, the conversion of diphenyl oxalate was 58.5%, and the selectivity for diphenyl carbonate was 91.4%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of chloroform added were the same as in the case of the first reaction. Table 6 shows the results.

Example 11 In Example 2, diphenyl oxalate was added at 20.7%.
5 mmol was used, and triphenylphosphine oxide was used instead of tetraphenylphosphonium chloride.
038 mmol (5.
0 mol%) and chloroform was used in an equimolar amount to triphenylphosphine oxide, and the reaction temperature was 2 mol%.
The reaction (first reaction) was carried out in the same manner as in Example 2 except that the temperature was changed to 50 ° C. and the reaction time was changed to 2 hours. as a result,
The conversion of diphenyl oxalate was 34.6%, and the selectivity for diphenyl carbonate was 77.8%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added, the amount of chloroform added, etc.
The same as in the case of the reaction. Table 6 shows the results.

Example 12 In Example 2, diphenyl oxalate was added at 20.8%.
1.0 mmol of triphenylphosphine dichloride (5.1 mol% based on diphenyl oxalate) was used instead of tetraphenylphosphonium chloride, and chloroform was used at 0.9 mol per mol of triphenylphosphine dichloride. The reaction (first reaction) was carried out in the same manner as in Example 2 except that the reaction temperature was changed to 250 ° C. and the reaction time was changed to 2 hours using moles. As a result, the conversion of diphenyl oxalate was 99.0%, and the selectivity of diphenyl carbonate was 9%.
It was 9.0%. Thereafter, the same procedure as in Example 1 was repeated to perform a total of two reactions. However, in the re-reaction, the reaction conditions such as the amount of diphenyl oxalate added and the amount of chloroform added were the same as in the case of the first reaction. Table 6 shows the results.

[0075]

[Table 6]

[0076]

According to the present invention, in a method for producing a diaryl carbonate by subjecting a diaryl oxalate to a decarbonylation reaction in the presence of an organophosphorus compound catalyst, the organophosphorus compound used as a catalyst can have high activity and high selectivity for a long period of time. It can be used repeatedly while maintaining the properties. That is, in the present invention, diaryl carbonate can be continuously produced at a low reaction temperature which is industrially suitable and at a high selectivity as compared with a known method of boiling a diaryl oxalate to carry out a decarbonylation reaction. According to the present invention, a diaryl carbonate useful as a raw material for polycarbonate can be industrially continuously produced without using phosgene which is a highly toxic compound.
The present invention is the first method capable of industrial continuous production of diaryl carbonate from diaryl oxalate,
Very useful.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing one embodiment of the present invention, in which 1 is a reactor, 2 is an evaporator, 3 is a distillation column,
9 indicates a conduit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoichi Inbe 5-1978 Kogushi, Ube City, Yamaguchi Prefecture 5 Ube Industries, Ltd. Ube Research Laboratories

Claims (9)

[Claims] 1. A diaryl oxalate is decarbonylated in the presence of an organic phosphorus compound catalyst to produce a diaryl carbonate, (2) a diaryl carbonate is recovered from the reaction solution, and (3) an organic phosphorus compound A method for producing a diaryl carbonate, comprising adding a halogen compound in the presence of a residue containing a compound catalyst and subjecting the diaryl oxalate to a decarbonylation reaction to produce a diaryl carbonate. 2. A residue containing an organophosphorus compound catalyst, which is obtained by recovering a diarylcarbonate from a reaction solution in which a diaryloxalate is subjected to a decarbonylation reaction in the presence of an organophosphorus compound catalyst to produce a diarylcarbonate. , A halogen compound is added thereto, and the residue is repeatedly used as a catalyst in a decarbonylation reaction of diaryl oxalate, thereby producing a diaryl carbonate. 3. An organophosphorus compound catalyst wherein the valence of a phosphorus atom is trivalent or pentavalent and at least one carbon-phosphorus (C-
3. The method for producing a diaryl carbonate according to claim 1, wherein the organic phosphorus compound has a P) bond. 4. An organophosphorus compound catalyst comprising a phosphonium salt,
The method for producing a diaryl carbonate according to claim 1 or 2, wherein the method is phosphine, phosphine dihalide, or phosphine oxide. 5. The method for producing a diaryl carbonate according to claim 1, wherein the organophosphorus compound catalyst is a tetraarylphosphonium salt, a triarylphosphine, a triarylphosphine dihalide or a triarylphosphine oxide. 6. The method for producing a diaryl carbonate according to claim 1, wherein the organophosphorus compound catalyst is a tetraarylphosphonium halide or a tetraarylphosphonium hydrogendihalide. 7. A structure in which a halogen compound has a structure in which a halogen atom is bonded to a saturated carbon (C-Hal) or a structure in which a halogen atom is bonded to a carbonyl carbon (-CO-Ha).
3. The method for producing a diaryl carbonate according to claim 1 or 2, wherein Hal represents a halogen atom. 8. The method according to claim 1, wherein the halogen compound is a halide of phosphorus.
The method for producing a diaryl carbonate according to claim 1 or 2, wherein the method is at least one kind of an inorganic halogen compound selected from a halide of sulfur, a hydrogen halide, and a simple halogen. 9. The method for producing a diaryl carbonate according to claim 1, wherein the halogen compound is a chlorine compound.