JPH10101621A - Production of diaryl carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a diaryl carbonate useful as a raw material for producing polycarbonate in good yield by heating a diaryl oxalate in the presence of a specific catalyst in decarbonylation reaction of the diaryl oxalate. SOLUTION: A lead compound, a tin metal or a tin compound is used as a catalyst in decarbonylation reaction and a diaryl carbonate is heated normally at 100-450 deg.C, especially 180-350 deg.C in the presence of the catalyst. A halide, an inorganic acid salt, an alcoholate, an organic acid salt, etc., is preferably used as the lead compound. A halide, an inorganic acid salt, an alcoholate, an organic acid salt, etc., of tin is used as the tin compound. An cyanate or an organic acid salt of lead, a tin metal or an organic acid salt of tin is preferably used among these compounds. The lead or tin compound may be supported on a support such as alumina and the supported amount of the compound is preferably about 0.1-50wt.% based on the support. The catalyst is used in an amount of about 0.001-50mol% as the metal, based on diaryl oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD 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, there is known a method for producing a diaryl carbonate by decarbonylating a diaryl oxalate. However, this method has a problem that the yield of a target diaryl carbonate is extremely low. have. For example, a method of producing diphenyl carbonate (diphenyl carbonate) by boiling diphenyl oxalate (diphenyl oxalate) in a distillation flask [Journal of the Society of Organic Synthesis, 5, pp. 47]
(1948), 70], the phenol is produced as a by-product as isolated as a by-product, and carbon dioxide is also produced as a by-product as isolated as a by-product. Yield is significantly lower.

Further, a method has been proposed in which an oxalate diester is heated in the liquid phase at 50 to 150 ° C. in the presence of an alcoholate catalyst to produce a carbonate diester (US Pat. No. 4,544,507). However, in this method, even when diphenyl oxalate is heated in the presence of a potassium phenolate catalyst, the main product obtained is not the target diphenyl carbonate but the starting material, as shown in the described example. Of diphenyl oxalate. As described above, a method capable of producing a diaryl carbonate with a high yield by a decarbonylation reaction of the diaryl oxalate has not been known.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a diaryl carbonate by subjecting a diaryl oxalate to a decarbonyl reaction to provide a method for producing a diaryl carbonate with a high yield.

[0005]

An object of the present invention is to provide a method for producing a diaryl carbonate, which comprises subjecting a diaryl oxalate to a decarbonylation reaction by heating in the presence of a lead compound, a tin metal or a tin compound. Achieved.

[0006]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a diaryl carbonate is formed by a decarbonylation reaction of a diaryl oxalate represented by the following formula.

[0007]

Embedded image (Wherein, Ar represents an aryl group)

The aryl group includes (1) a phenyl group, (2) a substituent, (a) an alkyl group having 1 to 12 carbon atoms such as a methyl group and an ethyl group, (b) a methoxy group and an ethoxy group. And (c) a nitro group, (d) a substituted phenyl group having a halogen atom such as a fluorine atom and a chlorine atom, and (3) a naphthyl group. Of these aryl groups, a phenyl group is preferred.

The substituted phenyl group includes various isomers.
These isomers include (a) 2- (or 3-, 4-)
2- having an alkyl group having 1 to 12 carbon atoms such as a methylphenyl group and a 2- (or 3-, 4-) ethylphenyl group;
(Or 3-, 4-) alkylphenyl group, (b) 2-
(Or 3-, 4-) methoxyphenyl group, 2- (or 3)
-, 4-) ethoxyphenyl group or other 2- (or 3-, 4-) alkoxyphenyl group having an alkoxy group having 1 to 12 carbon atoms, (c) 2- (or 3-, 4-) nitrophenyl group , (D) 2- (or 3-, 4-) fluorophenyl group, 2- (or 3-, 4-) halophenyl group having a halogen atom such as 2- (or 3-, 4-) chlorophenyl group, etc. Is mentioned.

As the diaryl oxalate, 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), 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.

In the present invention, a lead compound, tin metal or tin compound is used as a catalyst in the above decarbonylation reaction. Examples of the lead compound include halides of lead, inorganic acid salts (cyanate, sulfate, nitrate, phosphate, etc.),
Alcoholates, organic acid salts and the like are used. As the tin compound, tin halides, inorganic acid salts (such as cyanate, sulfate, nitrate, and phosphate), alcoholates, and organic acid salts are used.

Examples of the halide of lead include lead chloride and lead bromide. Examples of the lead inorganic acid salt include lead cyanate, lead sulfate, lead nitrate, lead phosphate, and other lead cyanate, sulfate, nitrate, phosphate, and the like. Examples of the lead alcoholate include lead phenoxide and lead butoxide. Examples of the organic acid salt of lead include salts of lead with an aliphatic carboxylic acid having 1 to 15 carbon atoms such as lead acetate, lead propionate, lead 2-ethylhexanoate, and lead oxalate (lead aliphatic carboxylate). ) And salts of lead with an aromatic carboxylic acid having 7 to 15 carbon atoms such as lead benzoate and lead methyl benzoate (aromatic carboxylate of lead). Among the lead compounds, an inorganic acid salt and an organic acid salt of lead are preferred, and a cyanate salt of lead (lead cyanate) and an organic acid salt are particularly preferred.

[0013] Tin halides include tin chloride,
And tin bromide. As inorganic salts of tin,
Examples include tin cyanate, tin sulfate, tin nitrate, tin phosphate, and other tin cyanates, sulfates, nitrates, and phosphates. Examples of tin alcoholates include tin phenoxide, tin butoxide and the like. As organic salts of tin, tin acetate, tin 2-ethylhexanoate,
Salts of tin with aliphatic carboxylic acids having 1 to 15 carbon atoms such as tin oxalate (aliphatic carboxylate of tin), and aromatic carboxylic acids having 7 to 15 carbon atoms such as tin benzoate and tin methylbenzoate Salt of acid and tin (tin aromatic carboxylate)
Is mentioned. Examples of the tin metal include metal tin powder. Among tin metals or tin compounds, tin metal and organic acid salts of tin are preferred.

The above-mentioned lead or tin compound can be used as it is, but can also be used by being supported on a carrier such as alumina, silica, silica-alumina, zeolite, diatomaceous earth, pumice and activated carbon. At this time, the loading amount of the lead or tin compound is usually 0.1 to 50% by weight, preferably 0.5 to 30% by weight of the metal based on the carrier.
% By weight.

The method for preparing the above-mentioned supported catalyst does not need to be a special one. For example, it is usually carried out by an impregnation method, a kneading method, a deposition method, a coprecipitation method, an evaporation to dryness method, an ion exchange method and the like. According to the method, it can be prepared by a method in which the above-mentioned lead or tin compound is supported on a carrier, dried and calcined. Drying is usually performed in air at 50 to 100 ° C, and baking is usually performed in air at 150 to 500 ° C.

The above-mentioned supported catalyst is used in the form of a powder, granules or molded. The size is not particularly limited, but usually 20 to 100 μmφ in powder,
Granular particles having a length of 4 to 200 mesh and molded articles having a length of 0.5 to 10 mm are preferably used.

In the decarbonylation reaction of the diaryl oxalate, a diaryl oxalate and a lead compound, a tin metal or a tin compound are charged into a reactor, and the diaryl oxalate is usually heated at 100 to 450 ° C., particularly preferably at 160 to 400 ° C.
C., more preferably by heating in the liquid phase at 180 to 350.degree. At this time, according to the above reaction formula, diaryl carbonate is generated from diaryl oxalate and carbon monoxide is generated. The reaction pressure is usually normal pressure, but is not particularly limited. The catalyst may be used alone or as a mixture of two or more kinds. The amount of the catalyst to be used is usually 0.001 to 50 mol%, preferably 0.01 to 20 mol% as the metal based on the diaryl oxalate. is there. The catalyst is usually used by dissolving it in the reaction solution, but may be used by suspending it.

A solvent is not particularly required in the decarbonylation reaction, but an aprotic polar solvent such as sulfolane, N-methylpyrrolidone and dimethylimidazolidone can be used as appropriate. The material of the reactor is not particularly limited. For example, glass, stainless steel (SU
A reactor from S) can be used. After the reaction, the produced diaryl carbonate is separated and purified by distillation or the like.

[0019]

Next, the present invention will be described specifically with reference to examples and comparative examples. The yield (mol%) of diphenyl carbonate was determined for diphenyl oxalate. Example 1 A 100 ml glass flask equipped with a thermometer and a reflux condenser was charged with diphenyloxalate (24.8 mmol).
l) and lead cyanate [Pb (OCN) ₂ ] (1.24 mm
ol), and the mixture was heated to 245 ° C. with stirring, and then heated in a liquid phase under normal pressure at this temperature for 3 hours to carry out a decarbonylation reaction. After completion of the reaction, the reaction solution was cooled to room temperature and subjected to gas chromatography (column temperature: 130 to 170).
And the inlet temperature: 180 ° C.). As a result, the yield of diphenyl carbonate was 24.5%. In addition, generation of diphenyl carbonate from diphenyl oxalate by the analysis operation was not recognized.

[0020] Lead acetate Example 2 Cyan lead _{[Pb (OAc) 2 · 3H 2} O) ]
(1.24 mmol) and the reaction and analysis were carried out in the same manner as in Example 1 except that the reaction temperature was changed to 255 ° C. As a result, the yield of diphenyl carbonate was 15.2%.

Example 3 Diphenyl oxalate (10.0 mmol) was placed in a 50 ml glass flask equipped with a thermometer and a reflux condenser.
l) and tin acetate [Sn (OAc) ₂ ] (2.0 mmol)
After l) was added and the temperature was raised to 255 ° C. with stirring, the mixture was heated in a liquid phase at normal pressure and at this temperature for 3 hours to carry out a decarbonylation reaction. After the completion of the reaction, when analysis was performed in the same manner as in Example 1, the yield of diphenyl carbonate was 8.5%.

Example 4 A reaction and analysis were carried out in the same manner as in Example 3, except that tin acetate was replaced with tin powder [Sn] (2.0 mmol). As a result, the yield of diphenyl carbonate was 13.9%.

Comparative Example 1 The reaction and analysis were carried out in the same manner as in Example 1 except that the reaction temperature was changed to 250 ° C. and no lead cyanate was added. As a result, generation of diphenyl carbonate was not recognized.

Comparative Example 2 In the same reactor as in Example 1, diphenyloxalate (2
0.7 mmol), the space in the container was replaced with argon gas, and the temperature was raised to 330 ° C. with stirring.
Heating (boiling) in the liquid phase at this temperature for 3 hours was performed to carry out a decarbonylation reaction. After completion of the reaction, the same analysis as in Example 1 was carried out. As a result, the yield of diphenyl carbonate was 4.1%.
Met.

Comparative Example 3 Diphenyloxalate (20.7 mmol) was placed in a 90 ml stainless steel closed reactor equipped with a thermometer.
l), potassium phenolate [PhOK] (3.8 mm)
ol) and tetrahydrofuran (5.0 g), and the space in the vessel was replaced with argon gas.
The temperature was raised to 0 ° C. Then, the mixture was heated in the liquid phase at this temperature for 3 hours to perform a decarbonylation reaction. After completion of the reaction, the analysis was carried out in the same manner as in Example 1, but no formation of diphenyl carbonate was observed. Table 1 shows the results of Examples and Comparative Examples.

[0026]

[Table 1]

[0027]

According to the present invention, in a method for producing a diaryl carbonate by decarbonylating a diaryl oxalate, the diaryl carbonate can be produced with a high yield.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01J 27/26 B01J 27/26 X 31/02 101 31/02 101X 31/04 31/04 X C07C 68/00 C07C 68/00 Z // C07B 61/00 300 C07B 61/00 300 (72) Inventor, Sadao Niida, 5, 1978 Kogushi, Ube City, Yamaguchi Prefecture Ube Industries, Ltd. Ube Research Laboratory (72) Inventor Toshio Kurato Ube City, Yamaguchi Prefecture 5 Ube Kosan Co., Ltd., Ube Laboratory, 1978 Kogushi

Claims (4)

[Claims] 1. A process for producing a diaryl carbonate, comprising heating a diaryl oxalate in the presence of a lead compound to cause a decarbonylation reaction. 2. The method for producing a diaryl carbonate according to claim 1, wherein the lead compound is an inorganic acid salt or an organic acid salt of lead. 3. A process for producing a diaryl carbonate, comprising heating a diaryl oxalate in the presence of a tin metal or tin compound to cause a decarbonylation reaction. 4. The process for producing a diaryl carbonate according to claim 3, wherein the tin compound is an organic acid salt of tin.