JPH11152252A - Production of diaryl carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially suitable process for the production of a diaryl carbonate by the decarbonylation reaction of a diaryl oxalate in the presence of a decarbonylation catalyst, especially an industrial process for producing a diaryl carbonate in high conversion and selectivity by using the diaryl oxalate and the decarbonylation catalyst in a state free from influence on the decarbonylation reaction. SOLUTION: A diaryl carbonate is produced by the decarbonylation reaction of a diaryl oxalate in the presence of a decarbonylation catalyst. A diaryl oxalate having controlled contents of aromatic hydroxy compounds, alkyl aryl oxalates, water and the like is used as the raw material. As an alternative, a diaryl oxalate having controlled water content and contained in a raw material mixture containing the diaryl oxalate and the decarbonylation catalyst is used as the raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for industrially producing a diaryl carbonate by subjecting a diaryl oxalate to a CO removal reaction. Diaryl carbonate is a compound useful as a raw material for producing polycarbonate and the like.

[0002]

2. Description of the Related Art As a method for producing a carbonic acid ester by removing CO from an oxalic acid diester, there is known a method for producing a diaryl carbonate by boiling diphenyl oxalate in a distillation flask without using a catalyst ( Journal of the Society of Organic Synthesis,
5, Report 47 (1948), 70). However, this method has low selectivity and yield of diphenyl oxalate,
In addition, there is a problem that it is industrially very disadvantageous because the reaction temperature is high.

[0003] Further, oxalic acid diesters such as dialkyl oxalate are reacted at 50 to 150 ° C in the presence of an alcoholate catalyst.
A method for producing a carbonate such as dialkyl carbonate by heating in a liquid phase has also been reported (US Pat. No. 454,450).
No. 7), according to the examples described in the publication, this method gives diphenyl oxalate as a main product even if diphenyl oxalate is heated in the presence of a potassium phenoxide catalyst, and gives diaryl carbonate as a main product. It is hard to say that it is an industrially advantageous method for manufacturing.

On the other hand, as a method capable of solving the above-mentioned problem, there is disclosed a method of producing diaryl carbonate by heating diaryl oxalate in the presence of a CO removal catalyst (Japanese Patent Application Laid-Open No. 8-333307). This method is very superior to the above-mentioned method because the diaryl carbonate can be produced at a high conversion and a high selectivity, but there is still a problem to be solved for industrial implementation. ing. That is, the raw material diaryl oxalate is produced by various methods, and the diaryl oxalate is decarbonized in the presence of a CO removal catalyst.
In producing the diaryl carbonate by the O-reaction, the diaryl oxalate and the de-CO catalyst are used in a suitable form that does not affect the de-CO reaction, and the diaryl carbonate is industrially produced at a high conversion and a high selectivity. There is no known production method.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to an industrially suitable method for producing a diaryl carbonate in producing a diaryl carbonate by subjecting a diaryl oxalate to a CO removal reaction in the presence of a CO removal catalyst. It is an object of the present invention to provide a method for industrially producing a diaryl carbonate with a high conversion and a high selectivity by using a diaryl oxalate or a CO removal catalyst in a suitable form that does not affect the CO removal reaction. And

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to produce a diaryl carbonate by subjecting a diaryl oxalate to a deCO reaction in the presence of a deCO catalyst to reduce the aromatic hydroxy compound contained in the diaryl oxalate to one. A method for producing a diaryl carbonate, characterized by using a diaryl oxalate in an amount of not more than 1% by weight, and a diaryl carbonate using a diaryl oxalate in which the alkylaryl oxalate contained in the diaryl oxalate is not more than 1% by weight. For removing water contained in diaryl oxalate
A method for producing a diaryl carbonate, comprising using a diaryl oxalate having an equimolar amount or less with respect to the O catalyst, and removing water contained in a raw material mixture containing the diaryl oxalate and the de-CO catalyst with respect to the de-CO catalyst. This is achieved by a method for producing a diaryl carbonate, characterized by using a raw material mixture having an equimolar amount or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, diaryl carbonate is produced by a CO removal reaction of a diaryl oxalate represented by the following formula.

[0008]

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

Examples of the diaryl oxalate include those in which the aryl group represented by Ar is a phenyl group, a substituted phenyl group, a naphthyl group, or a substituted naphthyl group. Examples of the substituent include a methyl group,
An alkyl group having 1 to 12 carbon atoms such as an ethyl group, a methoxy group, an alkoxy group having 1 to 12 carbon atoms such as an ethoxy group,
Examples include a halogen atom such as a fluorine atom and a chlorine atom, and a nitro group.

The above substituted phenyl group and substituted naphthyl group include various isomers. For example, the isomers of the substituted phenyl group include o- (or m-, p-) methylphenyl group, o
An alkyl-substituted phenyl group having an alkyl group having 1 to 12 carbon atoms at the o- (or m-, p-) position of a phenyl group such as-(or m-, p-) ethylphenyl group, or o- (or m-
-, P-) methoxyphenyl group, o- (or m-, p
-) O- (or m) of a phenyl group such as an ethoxyphenyl group;
An alkoxy-substituted phenyl group having an alkoxy group having 1 to 12 carbon atoms at the-and p-) positions, o- (or m-, p-)
A halogen-substituted phenyl group having a halogen atom such as a fluorine atom or a chlorine atom at the o- (or m-, p-) position of a phenyl group such as a fluorophenyl group, an o- (or m-, p-) chlorophenyl group, o- (or m-, p-) nitrophenyl group and the like.

The above diaryl oxalate can be prepared by various methods, for example, by subjecting oxalic acid and an aromatic hydroxy compound to an esterification reaction in the presence of a catalyst (JP-B-52-43).
No. 826) or a method in which a dialkyl oxalate and an aromatic hydroxy compound are subjected to a transesterification reaction in the presence of a catalyst. The aromatic hydroxy compound and aryl carboxylate are compounds having an aryl group corresponding to the above-described aryl group represented by Ar. Any of the diaryl oxalates produced by these methods can be used in the CO removal reaction of the present invention, but in the present invention, it is produced by a method of transesterifying a dialkyl oxalate with an aromatic hydroxy compound. It is preferred to use diaryl oxalate.

In the present invention, the removal of CO from the diaryl oxalate is carried out.
In the reaction, it is preferable to use a diaryl oxalate having a purity of 97.0% by weight or more, particularly 99.0% by weight or more, and further, the aromatic hydroxy compound contained in the diaryl oxalate is 1% by weight or less, particularly It is preferable to use a diaryl oxalate of 0.5% by weight or less. Further, in the present invention, in the CO removal reaction of diaryl oxalate, 97.0% by weight or more, particularly 99.0% by weight
It is preferable to use a diaryl oxalate having the above purity, and it is more preferable to use a diaryl oxalate having an alkylaryl oxalate contained in the diaryl oxalate of 1% by weight or less, particularly 0.1% by weight or less. . Further, in the present invention, it is preferable to use a diaryl oxalate having a purity of 97.0% by weight or more, particularly 99.0% by weight or more in the deCO reaction of the diaryl oxalate in the CO removal reaction of the diaryl oxalate. May further reduce the amount of water contained in the diaryl oxalate (diaryl oxalate in a molten state) to not more than an equimolar amount, particularly to not more than 0.5 mol, relative to the de-CO catalyst used in the de-CO reaction.
Further, it is preferable to use a diaryl oxalate of 0.3 mol or less.

Further, in the present invention, in the CO removal reaction of the diaryl oxalate, 97.0% by weight or more, particularly 99.
Having a purity of 0% by weight or more, and an aromatic hydroxy compound contained in the diaryl oxalate of 1% by weight or less;
In particular, the content is 0.5% by weight or less, the alkylaryl oxalate contained in the diaryl oxalate is 1% by weight or less, particularly 0.1% by weight or less, and the water contained in the diaryl oxalate is removed from CO 2 used in the CO removal reaction. It is particularly preferable to use a diaryl oxalate in an amount of not more than equimolar, particularly not more than 0.5 mol, and more preferably not more than 0.3 mol based on the catalyst.

Such a diaryl oxalate can be obtained by a reaction solution obtained by the above-mentioned method, in particular, a method of subjecting a dialkyl oxalate and an aromatic hydroxy compound to a transesterification reaction (ester exchange reaction solution; diaryl oxalate, alkylaryl oxalate, Contains unreacted raw materials and catalyst)
Can be obtained by distilling and purifying a diaryl oxalate. This distillation purification can be repeated as needed, whereby the desired diaryl oxalate can be obtained.

Further, in the present invention, in the CO removal reaction of the diaryl oxalate, the water contained in the raw material mixture containing the diaryl oxalate and the CO removal catalyst (the raw material mixture in a molten state) is added to the CO removal catalyst. It is preferable to use a raw material mixture having an equimolar or less, particularly 0.5 or less, and further preferably 0.3 or less. At this time, the diaryl oxalate has a purity of 97.0% by weight or more, particularly 99.0% by weight or more, and the aromatic hydroxy compound contained in the raw material mixture contains 1% by weight or less, particularly 0.5% by weight or less. And the alkylaryl oxalate contained in the raw material mixture is 1% by weight or less, particularly 0.1% by weight.
It is preferable to set the following.

[0016] Such a raw material mixture is obtained by distilling and purifying diaryl oxalate with a CO removal catalyst heat-treated under a flow of a dry inert gas (nitrogen gas, argon gas, etc.).
It is prepared by mixing under a dry inert gas in a raw material mixing tank. The heat treatment of the CO removal catalyst is performed at 100 to 300 ° C., particularly 150 to 20 ° C. under a flow of a dry inert gas.
It is preferable to carry out the reaction at 0 ° C., and it is preferable that the heat-treated CO removal catalyst be recovered under a dry inert gas and supplied to the raw material mixing tank. Further, the diaryl oxalate purified by distillation is preferably recovered as it is under a dry inert gas and supplied to a raw material mixing tank, and further, such as a molecular sieve (4A, 5A, etc.) under a dry inert gas. It may be treated with a dehydrating agent and supplied to the raw material mixing tank.

In the distillation purification of diaryl oxalate, for example, as shown in FIG. 1, most of the transesterification reaction liquid containing the diaryl oxalate and the like is evaporated in an evaporator A, and the reaction liquid is added to the reaction liquid. The catalyst contained is separated, and then the evaporated fraction is fed to the first distillation column B, and light (alkylaryl oxalate, unreacted aromatic hydroxy compound) is mainly collected from the top of the first distillation column B. A vapor as a component is withdrawn and separated, and a bottom liquid containing diaryl oxalate as a main component is withdrawn from the bottom of the first distillation column B and supplied to a second distillation column C. Alternatively, it can be carried out by extracting a diaryl oxalate fraction from the side.

As the evaporator, any evaporator capable of evaporating most of the transesterification reaction solution containing diaryl oxalate and the like to separate the catalyst contained in the reaction solution can be used.
Any type of evaporator may be used. For example, a thin film evaporator and a falling film evaporator can be suitably used. Further, the first distillation column and the second distillation column may, for example, be able to separate a diaryl oxalate fraction by distilling the evaporation supplied from an evaporator, and to obtain a diaryl oxalate due to a high-temperature heat history. Any type of distillation column may be used as long as the decomposition of the distillation column can be suppressed. As such a distillation column, for example, a continuous multi-stage distillation column is mentioned, and a distillation column (packed column or tray column) having 5 or more theoretical plates is particularly preferable.

The evaporating operation in the evaporator A may be performed under any of reduced pressure, normal pressure and pressurized conditions. However, the transesterification reaction solution containing diaryl oxalate and the like is mostly evaporated to form the reaction solution. It is preferable to carry out at a pressure at which the catalyst contained in the catalyst can be separated. For example, if the temperature of the evaporator is 160 to 350 ° C.
Is in the range of 0.1 mmHg to 1 kg / cm
² , particularly preferably about 1 mmHg to 0.5 kg / cm ² . A vapor mixture obtained by evaporating most of the transesterification reaction solution containing diaryl oxalate and the like (supplied from the line 1) by the evaporation operation is withdrawn from the top of the evaporator A from the line 3 to the first mixture. Distillation tower B
Is supplied to the middle stage. The bottom containing the catalyst is withdrawn from a withdrawal line 2 provided at the bottom of the evaporator A. In the evaporator A, the transesterification reaction solution is heated by a heater provided outside the evaporator.
The temperature is preferably 0 ° C, particularly about 180 to 250 ° C.

The distillation operation in the first distillation column B may be carried out under any of reduced pressure, normal pressure and pressurized conditions, but at a pressure at which the main component is alkylaryl oxalate and which can be evaporated from the top. It is preferred to do so. For example, if the temperature of the can solution is 50 to 350 ° C., the pressure is 0.1 mmH
g to ² kg / cm ² , especially 1 mmHg to 1 kg / cm ²
It is preferred that it is about. The can solution is heated by a heater provided in the circulation line while circulating the can solution in the circulation line. The temperature of the can solution is preferably from 50 to 350C, particularly preferably from about 80 to 250C.

By the distillation operation, a vapor containing alkylaryl oxalate as a main component is withdrawn from the top of the first distillation column B through a withdrawal line 5, and a part of the vapor is cooled and condensed by a cooler to form the first distillation column B. Circulated to On the other hand, from the bottom of the first distillation column B, a liquid in which diaryl oxalate is concentrated at a high concentration is withdrawn from the line 4 and supplied to the middle stage of the second distillation column C.

The distillation operation in the second distillation column C may be performed under any of reduced pressure, normal pressure and pressurized conditions, but it is possible to evaporate diaryl oxalate as a main component from the top or side. It is preferred to carry out at pressure. For example, if the temperature of the can solution is in the range of 150 to 300 ° C., the pressure is 0.1 mmHg to 1 kg / cm ² , particularly 1 mmHg to 1 mmHg.
It is preferably about 0.21 kg / cm ² . The can solution is heated by a heater provided in the circulation line while circulating the can solution in the circulation line. The temperature of the can solution is preferably from 150 to 300 ° C, particularly preferably from about 160 to 250 ° C.

By the distillation operation, a vapor containing a high concentration of diaryl oxalate is withdrawn from the top or side of the second distillation column C from the line 7, and cooled and condensed by a cooler to convert the diaryl oxalate into 97%. A condensate containing at a concentration of at least 98% by weight, more preferably at least 98% by weight, more preferably at least 99% by weight is obtained. Part of this condensate is second
Circulated to distillation column C. From the bottom of the second distillation column C, the bottom is withdrawn from the line 6. In the distillation purification in the second distillation column C, the objective diaryl oxalate, that is, the diaryl oxalate is 97% by weight or more by selecting the conditions of the distillation operation and / or repeating the distillation purification.
Preferably, it is contained at a concentration of 99% by weight or more, and the aromatic hydroxy compound contained in the diaryl oxalate is 1% by weight or less, preferably 0.5% by weight or less, and the alkylaryl oxalate is 1% by weight or less, preferably Is 0.
It is possible to obtain a diaryl oxalate condensate having a content of 1% by weight or less and a water content of 500 ppm or less, preferably 100 ppm or less.

The dialkyl oxalate used for the production of the diaryl oxalate includes a dialkyl oxalate having two ester groups based on an alkyl group having 1 to 10, particularly 1 to 6, and more preferably 1 to 4 carbon atoms. Is used.
Such dialkyl oxalates include, for example, dimethyl oxalate, diethyl oxalate, dipropyl oxalate, dibutyl oxalate and the like. Examples of the aromatic hydroxy compound include phenol, methylphenol, ethylphenol, methoxyphenol, ethoxyphenol, fluorophenol, chlorophenol, nitrophenol, and naphthol. However, these are o- (or m-, p-), α-
Includes isomers such as (β-).

The alkylaryl oxalate has one ester group based on an alkyl group having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms, and has an ester group based on the aryl group. An alkylaryl oxalate having one ester group is used. Examples of such an alkylaryl oxalate include methylphenyl oxalate, ethylphenyl oxalate, propylphenyl oxalate, butylphenyl oxalate and the like.

The CO removal reaction of diaryl oxalate is carried out by CO removal
It is performed in the presence of a catalyst. As the CO removal catalyst, an organic phosphorus compound, particularly an organic phosphorus compound having a trivalent or pentavalent phosphorus atom and having at least one carbon-phosphorus (CP) bond is preferably used. Examples of such an organic phosphorus compound include (1) an organic phosphonium salt, (2) phosphine, represented by general formulas (1) to (4).
Preferable examples include (3) phosphine oxide and (4) phosphine dihalide.

[0027]

Embedded image (Wherein, R ^{1 to} R ¹³ represent at least one group selected from an alkyl group having ^{1 to} 16 carbon atoms, an aryl group having 6 to 16 carbon atoms and an aralkyl group having 7 to 22 carbon atoms, and X represents a counter ion. indicates an atom or atomic group capable of forming a, Y ¹ and Y
² represents a halogen atom such as a chlorine atom, a bromine atom and an iodine atom. )

The aryl group or aralkyl group represented by R ^{1 to} R ¹³ is an alkyl group having 1 to 16 carbon atoms,
It may have 16 alkoxy groups, halogen atoms, nitro groups, or the like as substituents on the aromatic ring. Also,
R ^{1 to} R ⁴ are R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ ,
Or R ⁴ and no problem can be crosslinked or coupled between R ^1. R ^{5 to} R ⁷ , R ^{8 to} R ⁹ , and R ^{10 to} R ¹³ may be similarly crosslinked or connected between two groups.

Examples of the alkyl group represented by R ^{1 to} R ¹³ include an alkyl group having ¹ to 16 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group.
Examples of the aryl group represented by R ¹³ include phenyl, methylphenyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, chlorophenyl, fluorophenyl, nitrophenyl, and naphthyl, and the like. And aryl groups such as R ^{1 to} R ^13.
Examples of the aralkyl group represented by are aralkyl groups having 7 to 22 carbon atoms, such as a benzyl group, a phenethyl group, a p-methylbenzyl group, a p-methoxybenzyl group, and a p-methylphenethyl group.

As the organic phosphonium salt represented by the general formula (1), those in which R ^{1 to} R ⁴ are all aryl groups and the counter ion X ⁻ is a halogen ion or a hydrogen dihalide ion are preferable. R ^{1 to} R ⁴ are all aryl groups and the counter ion X ⁻ is a carboxylate ion or the like; or ^one to three of R ^{1 to} R ⁴ are aryl groups and the rest are the above-mentioned alkyl groups. Or an aralkyl group in which the counter ion X ^- is a halogen ion, a hydrogendihalide ion, a carboxylate ion, or the like.

Examples of the organic phosphonium salt in which R ^{1 to} R ⁴ are all aryl groups and the counter ion X ⁻ is a halogen ion include, for example, tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, 4-chlorophenyltriphenylphosphonium chloride , 4
- chlorophenyl triphenylphosphonium bromide, 4-methylphenyl triphenyl phosphonium chloride, 4-methylphenyl triphenylphosphonium bromide, 4-methoxyphenyl triphenyl phosphonium chloride, 4-methoxyphenyl triphenylphosphonium bromide are exemplified, R ¹ ~ Examples of the organic phosphonium salt in which R ⁴ is all an aryl group and the counter ion X ⁻ is a hydrogendihalide ion include, for example, tetraphenylphosphonium hydrogendichloride, tetraphenylphosphonium hydrogendibromide, tetraphenylphosphonium hydrogen And bromide chloride.

Examples of the organic phosphonium salts wherein R ^{1 to} R ⁴ are all aryl groups and the counter ion X ⁻ is a carboxylate ion include, for example, tetraphenylphosphonium acetate, 4-chlorophenyltriphenylphosphonium acetate, -Methylphenyltriphenylphosphonium acetate, 4-methoxyphenyltriphenylphosphonium acetate and the like.

As the phosphine represented by the general formula (2), those in which R ^{5 to} R ⁷ are all aryl groups are preferred, and one or two of R ^{5 to} R ⁷ are aryl groups. And the remainder may be the above-mentioned alkyl group or aralkyl group. Examples of the phosphine in which R ^{5 to} R ⁷ are all aryl groups include triphenylphosphine, tris (4-chlorophenyl) phosphine, and tris (4-tolyl) phosphine.

As the phosphine oxide represented by the general formula (3), those in which R ^{8 to} R ¹⁰ are all aryl groups are preferable, but one or two of R ^{8 to} R ¹⁰ are aryl groups. The remainder may be the above-mentioned alkyl group or aralkyl group. Examples of the phosphine in which R ^{8 to} R ¹⁰ are all aryl groups include triphenylphosphine oxide, tris (4-chlorophenyl) phosphine oxide, and tris (4-tolyl) phosphine oxide.

As the phosphine dihalide represented by the general formula (4), R ^{11 to} R ¹³ are all aryl groups,
Preferred are those in which Y ¹ and Y ² are halogen atoms,
One or two of R ^{11 to} R ¹³ may be an aryl group, the remainder may be the above-described alkyl group or aralkyl group, and Y ¹ and Y ² may be halogen atoms. Examples of the halogen atom include a chlorine atom, a bromine atom and an iodine atom,
These may be the same or different from each other. R
Examples of the phosphine dihalide in which ^{11 to} R ¹³ are all aryl groups include triphenylphosphine dichloride, triphenylphosphine dibromide and the like.

As the CO removal catalyst, an organic phosphorus compound is preferably used, and among them, an organic phosphonium salt and a phosphine dihalide are preferable, and a tetraarylphosphonium halide, a tetraarylphosphonium hydrogendihalide and a triarylphosphine dihalide are particularly preferable. Further, tetraarylphosphonium chloride, tetraarylphosphonium hydrogen dichloride, and triarylphosphine dichloride are preferred. The CO removal catalyst may be an organic phosphorus compound alone or a mixture thereof. Further, the CO removal catalyst may be uniformly dissolved and / or suspended in the reaction solution. The CO removal catalyst is preferably used in an amount of about 0.001 to 50 mol%, particularly about 0.01 to 20 mol%, based on diaryl oxalate.

In the present invention, the dephosphorization of an organic phosphorus compound
At least one halogen compound selected from inorganic halogen compounds and organic halogen compounds may be used in combination with the O catalyst. In particular, when phosphine or phosphine oxide is used as the CO removal catalyst, it is preferable to use a halogen compound in combination. This halogen compound is used in an amount of 0.01 to 150 times the molar amount of the organic phosphorus compound,
In particular, it is preferably used in a molar amount of 0.1 to 100 times.

Examples of the inorganic halogen compounds include aluminum halides (aluminum chloride, aluminum bromide, etc.), platinum group metal halides (palladium chloride, platinum chloride, ruthenium chloride, etc.), and phosphorus halides (phosphorus trichloride, Phosphorus pentachloride, phosphorus tribromide, phosphorus pentabromide, etc.),
Examples thereof include halides of sulfur (thionyl chloride, sulfuryl chloride, etc.), hydrogen halides (hydrogen chloride, hydrogen bromide, etc.), and simple halogens (chlorine, bromine, etc.). Among the inorganic halogen compounds, these inorganic chlorine compounds are particularly preferred.

Examples of the organic halogen compound include a structure in which at least one halogen atom is bonded to a saturated carbon,
A structure in which a halogen atom is bonded to the carbonyl carbon,
An organic halogen compound having at least one structure in which a halogen atom is bonded to a silicon atom, a structure in which a halogen atom is bonded to a sulfur atom, or the like is given.

Examples of the organic halogen compound having at least one structure in which at least one halogen atom is bonded to a saturated carbon include alkyl halides (chloroform, carbon tetrachloride, 1,2-dichloroethane, butyl chloride, dodecyl chloride, etc.). ), Aralkyl halides (benzyl chloride, benzotrichloride, etc.), halogen-substituted aliphatic nitriles (β-chloropropionitrile, γ-chlorobutyronitrile, etc.), halogen-substituted aliphatic carboxylic acids (chloroacetic acid, bromoacetic acid, Chloropropionic acid).

Examples of the organic halogen compound having at least one structure in which a halogen atom is bonded to a carbonyl carbon include acid halides (acetyl chloride, oxalyl chloride, propionyl chloride, benzoyl chloride, 2-naphthalene carboxylic acid chloride, Thiophene carboxylic acid chloride), aryl haloformate (phenyl chloroformate) and the like.

Examples of the organic halogen compound having at least one structure in which a halogen atom is bonded to a silicon atom include halogenated silanes (such as diphenyldichlorosilane and triphenylchlorosilane).

Examples of the organic halogen compound having at least one structure in which a halogen atom is bonded to a sulfur atom include sulfonyl halide (p-toluenesulfonic acid chloride, 2-naphthalenesulfonic acid chloride) and the like.

In the CO removal reaction of the diaryl oxalate, the diaryl oxalate distilled and purified is heated to remove the C
The O catalyst is fed (preferably as a raw material mixture) to the reactor (preferably a dried reactor) under a dry inert gas, and the reaction temperature is 100 to 450 ° C, especially 160 to 400 ° C.
It is preferred that the diaryl oxalate is subjected to a CO removal reaction at a temperature of 180 ° C., more preferably 180 ° C. to 350 ° C. while removing the generated CO gas to produce a diaryl carbonate. in this case,
The reaction pressure is not particularly limited.
The reaction can be performed within a range of 10 kg / cm ² G.

As the CO removal catalyst, the above-mentioned organic phosphorus compounds are suitably used, and if necessary, the above-mentioned halogen compounds are used in combination. Catalyst for removing CO (preferably organic phosphorus compound)
Is preferably used after being heat-treated as described above. Regarding the halogen compound, the inorganic halogen compound is also preferably used after being heat-treated under the flow of dry inert gas, and the organic halogen compound is preferably dried and inert. It is preferably used after being treated with a molecular sieve (4A, 5A or the like) under a gas.

The deCO reaction of the diaryl oxalate is carried out, for example, according to the flow shown in FIG. That is, as described above, the diaryl oxalate obtained by the distillation operation in the second distillation column C is supplied via the line 7 to the de-CO reactor E
Supplied to Then, the heat-treated CO removal catalyst is supplied to the raw material mixing tank D from the line 9 under a dry inert gas, and mixed with the diaryl oxalate supplied from the line 8. The obtained raw material mixture is supplied to the reactor E via the lines 10 and 7. In the de-CO reactor E, the de-CO reaction of the diaryl oxalate is performed as described above,
The generated CO is withdrawn from line 12 and the generated diaryl carbonate is withdrawn from line 11. The halogen compound used together with the organic phosphorus compound is supplied to the raw material mixing tank D from the line 9 together with the organic phosphorus compound.

The unreacted diaryl oxalate or the de-CO 2 is added to the reaction solution obtained by the de-CO reaction of the diaryl oxalate.
Although the catalyst is included, diaryl carbonate is obtained by, for example, separating and recovering the catalyst in an evaporator or a thin film evaporator, and distilling the evaporated fraction using a packed tower or a tray column having a certain number of stages. And high purity diaryl carbonate.

[0048]

Next, the present invention will be described specifically with reference to examples and comparative examples. REFERENCE EXAMPLE 1 [Production of methylphenyl oxalate] At the twelfth stage from the top of an Older show equipped with a 1 L bottom flask and having an inner diameter of 32 mm and 50 stages, 61.2% by weight of phenol and 38.5% by weight of dimethyl oxalate % And a solution having a composition of 0.3% by weight of tetraphenoxytitanium were supplied at a flow rate of 300 ml / hr. Bottom flask with mantle heater 19
The mixture was heated to 0 ° C., and the reaction was carried out while condensing the vapor from the top of the tower with a condenser and extracting the vapor at a reflux ratio of 2. During this time, the bottom liquid was continuously withdrawn so as to maintain 500 ml.
When the composition of the bottom liquid (reaction liquid) at the time when the state of the column (temperature, liquid composition) was stabilized (after 5 hours from the start of supply) was analyzed by gas chromatography, dimethyl oxalate was 23.45% by weight, Methylphenyl oxalate was 26.7% by weight, diphenyl oxalate was 6.74% by weight, and phenol was 42.62% by weight. Note that the amount of the bottom liquid withdrawn was about 306 g / hr. A liquid having a composition of 99.7% by weight of methanol and 0.3% by weight of dimethyl oxalate was withdrawn from the top of the column at about 24 g / hr.

Reference Example 2 [Production of diphenyl oxalate] The same Older show as in Reference Example 1 was used.
At the bottom, the reaction solution obtained in Reference Example 1 was added at 300 ml / hr.
Supplied with Bottom flask with mantle heater 23
The mixture was heated to 0 ° C., and the reaction was carried out while condensing the vapor from the top of the tower with a condenser and extracting the vapor without reflux. During this time, the bottom liquid was continuously withdrawn so as to maintain 500 ml. When the composition of the bottom liquid (reaction liquid) at the time when the state of the column (temperature, liquid composition) was stabilized (5 hours after the start of the supply) was analyzed by gas chromatography, 2.82% by weight of dimethyl oxalate was obtained. Methylphenyl oxalate 2
7.81% by weight, diphenyl oxalate 54.74% by weight, and phenol 13.64% by weight. The amount of the bottom liquid withdrawn was about 126 g / hr. From the top, 2.32% by weight of methanol and 45.
23% by weight, 5.37% by weight of methylphenyl oxalate,
0.13% by weight of diphenyl oxalate, phenol 46.
A liquid having a composition of 95% by weight was withdrawn at about 189 g / hr.

Example 1 [Distillation and Purification of Diphenyl Oxalate] Helipack (5 × 5
mm), the reaction liquid obtained in Reference Example 2 was supplied at a rate of 100 ml / hr to a position 80 cm from the top of the column using a glass distillation column having an inner diameter of 20 mm and a height of 2 m.
Continuous distillation was performed at a bottom temperature of 135 ° C., a top pressure of 10 mmHg, and a reflux ratio of 2, and dimethyl oxalate 5.6 from the top.
3% by weight, methylphenyl oxalate 61.48% by weight,
2.46% by weight of diphenyl oxalate, 30.
A liquid having a composition of 43% by weight was withdrawn at about 47 g / hr.
A liquid having a composition of 97.9% by weight of diphenyl oxalate was withdrawn from the bottom of the column at a rate of about 58 g / hr.

The extracted bottom liquid was supplied to the same glass distillation column as described above, and continuous distillation was performed as described above.
Then, a liquid having a composition of 99.9% by weight of diphenyl oxalate, 150% by weight of methyl oxalate, 80% by weight of phenol, and 20% by weight of water was withdrawn at a rate of about 90 g / hr from the top of the column under dry nitrogen gas. Collected in container. From the bottom, about 1
A liquid containing 5% by weight was withdrawn at about 15 g / hr.

[Production of diphenyl carbonate] A 500 ml four-necked flask equipped with a thermometer, a stirrer, and a condenser was thoroughly dried, and while blowing dry nitrogen gas into the flask, the slurry obtained in Example 1 was blown. 300 g (about 1.24 mol) of diphenyl acid and 5.1 g (0.01 mol) of tetraphenylphosphonium hydrogen dichloride heat-treated at 180 ° C. for 2 hours under flowing dry nitrogen gas.
2 mol). Next, the flask was heated in an oil bath to dissolve diphenyl oxalate, and the reaction was carried out for 2 hours with stirring while adjusting the heating temperature so that the temperature of the reaction solution was 230 ° C. During the reaction, the nitrogen gas and the generated CO gas were discharged from the upper part of the condenser. When the reaction solution was analyzed by gas chromatography after the reaction, the conversion of diphenyl oxalate was 93%.
The selectivity for diphenyl carbonate was 99.6%.

Comparative Example 1 [Production of diphenyl carbonate] In the production of diphenyl carbonate of Example 1, 300 g (about 1.24 mol) of the diphenyl oxalate obtained in Example 1 was placed in a flask under air.
And unheated tetraphenylphosphonium hydrogen dichloride 5.1 g (0.012 mol)
Reaction was carried out in the same manner as in Example 1 except that
As a result, the conversion of diphenyl oxalate was 82%, and the selectivity for diphenyl carbonate was 98.1%. The water content of the raw material mixture when the raw materials were charged and dissolved was 850.
It was ppm by weight.

Comparative Example 2 In the production of diphenyl carbonate of Example 1, diphenyl oxalate containing 150% by weight of methylphenyl oxalate, 1.2% by weight of phenol, and 20% by weight of water was added while blowing dry nitrogen gas into the flask. 300g
(About 1.24 mol) and 180 ° C under a flow of dry nitrogen gas.
The reaction was carried out in the same manner as in Example 1 except that 5.1 g (0.012 mol) of tetraphenylphosphonium hydrogen dichloride heat-treated for 2 hours was charged. As a result, the conversion of diphenyl oxalate was 31%, and the selectivity for diphenyl carbonate was 97.0%.

Comparative Example 3 In the production of diphenyl carbonate of Example 1, diphenyl oxalate containing 1.2% by weight of methyl oxalate, 80% by weight of phenol, and 20% by weight of water was added while blowing dry nitrogen gas into the flask. 300 g (approximately 1.24 mol) at 180 ° C. under dry nitrogen gas flow.
The reaction was carried out in the same manner as in Example 1 except that 5.1 g (0.012 mol) of tetraphenylphosphonium hydrogen dichloride which had been subjected to heat treatment for an hour was charged. As a result, the conversion of diphenyl oxalate was 57%, and the selectivity for diphenyl carbonate was 97.0%.

Example 2 [Production of diphenyl carbonate] A 300 ml round bottom flask equipped with a thermometer and a stirrer was thoroughly dried, and obtained in Example 1 while blowing dry nitrogen gas into the flask. 200 g (about 0.826 mol) of diphenyl oxalate and 6.2 g of tetraphenylphosphonium chloride heat-treated at 180 ° C. for 2 hours under a flow of dry nitrogen gas.
(0.0165 mol) and 0.5 g of chloroform (0.0
04 mol). Next, the flask was heated in an oil bath and reacted at 230 ° C. for 2 hours with stirring. During the reaction, the nitrogen gas and the generated CO gas were exhausted from an exhaust pipe connected to the reactor. When the composition of the reaction solution was analyzed after the reaction, diphenyl carbonate was found to be 96.2% by weight.
The content of diphenyl oxalate was 3.6% by weight.

Subsequently, the temperature of the reaction solution was 230 ° C.
The raw material mixture in which diphenyl oxalate, tetraphenylphosphonium chloride and chloroform were dissolved was stirred at a rate of 50 ml / min from a nitrogen-sealed glass vessel with a capacity of 1000 ml while stirring and adjusting the heating temperature so that The reaction solution was supplied to the flask and continuously withdrawn so that the amount of the reaction solution was maintained at 200 ml. As the raw material mixture, 2.0 mol% of tetraphenylphosphonium chloride and 0.5 mol% of chloroform dissolved in diphenyl oxalate obtained in Example 1 were used. Was. When the composition of the reaction solution was stabilized (about 15 hours after the start of the continuous reaction), the composition of the extracted reaction solution was analyzed. As a result, diphenyl carbonate was 88.5% by weight and diphenyl oxalate was 11.1%. It was 2% by weight.

[0058]

According to the present invention, when a diaryl oxalate is subjected to a de-CO reaction in the presence of a de-CO catalyst to produce a diaryl carbonate, the starting material diaryl oxalate or de-CO is removed.
Using the catalyst in a suitable form that does not affect the de-CO reaction (i.e., controlling the minor components that affect the de-CO reaction of the diaryl oxalate), high conversion and high selectivity, Diaryls can be produced. INDUSTRIAL APPLICABILITY The present invention is a method capable of industrially continuously producing a diaryl carbonate by subjecting a diaryl oxalate to a CO removal reaction, and is very useful.

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating one embodiment of the present invention.

[Explanation of symbols]

 A: Evaporator B: First distillation column C: Second distillation column D: Raw material mixing tank E: De-CO reactor 1 to 9: Conduit (line) is shown.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Yoshida 1010, 1978 Kogushi, Oji, Ube City, Yamaguchi Prefecture Inside Ube Chemical Plant Ube Chemical Plant (72) Inventor Yutaka Asada 1010, 1978 Kogushi, Oji, Ube City, Yamaguchi Prefecture In the Ube Chemical Plant of Ube Industries, Ltd.

Claims (8)

[Claims] In producing a diaryl carbonate by subjecting a diaryl oxalate to a deCO reaction in the presence of a decocatalyst, a diaryl oxalate having an aromatic hydroxy compound contained in the diaryl oxalate of 1% by weight or less is used. A method for producing a diaryl carbonate. 2. In producing a diaryl carbonate by subjecting a diaryl oxalate to a CO removal reaction in the presence of a CO removal catalyst, a diaryl oxalate containing 1% by weight or less of an alkylaryl oxalate contained in the diaryl oxalate is used. A method for producing a diaryl carbonate. 3. A process for producing a diaryl carbonate by reacting a diaryl oxalate in the presence of a CO removal catalyst to produce a diaryl carbonate, wherein the water contained in the diaryl oxalate is adjusted to an equimolar amount or less with respect to the CO removal catalyst. A method for producing a diaryl carbonate, comprising using 4. In producing a diaryl carbonate by subjecting a diaryl oxalate to a deCO reaction in the presence of a deCO catalyst, water contained in a raw material mixture containing the diaryl oxalate and the deCO catalyst is converted to a deCO catalyst. A method for producing a diaryl carbonate, comprising using a raw material mixture having an equimolar amount or less. 5. An aromatic hydroxy compound having a purity of 97.0% by weight or more and contained in the diaryl oxalate when the diaryl oxalate is subjected to a CO removal reaction in the presence of a CO removal catalyst to produce a diaryl carbonate. To 1% by weight or less, the alkylaryl oxalate contained in the diaryl oxalate to 1% by weight or less, and the water content in the diaryl oxalate to the equimolar amount or less with respect to the CO removal catalyst. A method for producing a diaryl carbonate. 6. The method for producing a diaryl carbonate according to claim 1, wherein the CO removal catalyst is an organic phosphorus compound. 7. The method for producing a diaryl carbonate according to claim 1, wherein the catalyst for removing CO is an organic phosphonium salt, phosphine, phosphine oxide, or phosphine dihalide. 8. The method for producing a diaryl carbonate according to claim 1, wherein the CO removal catalyst is a tetraarylphosphonium halide, a tetraarylphosphonium hydrogendihalide, or a triarylphosphine dihalide.