JP3509416B2 - Method for producing diaryl carbonate - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a diaryl carbonate useful as a raw material for producing a polycarbonate. [0002] As a method for producing a diaryl carbonate, a method is known in which a diaryl oxalate is decarbonylated to produce a diaryl carbonate. However, this method has a remarkable yield of the objective diaryl carbonate. It has the problem of being low. For example, a method for 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], as shown in the reaction formula described in this document, phenol is by-produced as isolated as a by-product, and carbon dioxide is also by-produced to produce the desired diphenyl carbonate. Yield is significantly lower. Further, there has been proposed a method of producing a carbonate diester by heating an oxalate diester in the liquid phase at 50 to 150 ° C. in the presence of an alcoholate catalyst (US Pat. No. 4,544,507). However, in this method, even if diphenyl oxalate is heated in the presence of a potassium phenolate catalyst, as shown in the described example, the main product obtained is not the target diphenyl carbonate but the starting material. 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. 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 decarbonylation to provide a method for producing the diaryl carbonate with a high yield. . SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a diaryl oxalate, which comprises subjecting a diaryl oxalate to a decarbonylation reaction by heating in the presence of a lead compound, tin metal or a tin compound. Achieved by manufacturing methods. 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] (In the formula, Ar represents an aryl group.) The aryl group includes (1) a phenyl group, and (2) as a substituent, (a) a methyl group or an ethyl group having 1 to 12 carbon atoms. An alkyl group, (b) an alkoxy group having 1 to 12 carbon atoms such as a methoxy group and an ethoxy group, (c) a nitro group, or (d) a substituted phenyl group having a halogen atom such as a fluorine atom and a chlorine atom; 3) a naphthyl group and the like. 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)
A 2- (or 3-, 4-) alkoxyphenyl group having an alkoxy group having 1 to 12 carbon atoms, such as an-, 4-) ethoxyphenyl group, and (c) a 2- (or 3-, 4-) nitrophenyl group , (D) 2- (or 3-, 4-) halophenyl group having a halogen atom such as 2- (or 3-, 4-) fluorophenyl group, 2- (or 3-, 4-) chlorophenyl group, etc. Is mentioned. The diaryl oxalate includes 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, in the decarbonylation reaction, a lead compound, a tin metal or a tin compound is used as a catalyst. Lead compounds include lead halides, inorganic acid salts (cyanate, sulfate, nitrate, phosphate, etc.),
Alcoholates, organic acid salts and the like are used. Examples of the tin compound include tin halides, inorganic acid salts (such as cyanate, sulfate, nitrate, and phosphate), alcoholates, and organic acid salts. Examples of the lead halide include lead chloride and lead bromide. Examples of the inorganic acid salt of lead include lead cyanate, lead sulfate, lead nitrate, lead phosphate, and other lead cyanate, sulfate, nitrate, and phosphate. Examples of the lead alcoholate include lead phenoxide and lead butoxide. As an organic acid salt of lead, a salt of an aliphatic carboxylic acid having 1 to 15 carbon atoms such as lead acetate, lead propionate, lead 2-ethylhexanoate, lead oxalate and the like (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 (lead cyanate) and an organic acid salt of lead 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. Tin alcoholates include tin phenoxide, tin butoxide and the like. As organic salts of tin, tin acetate, tin 2-ethylhexanoate,
Salts of tin with an aliphatic carboxylic acid 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 methyl benzoate Salt of acid and tin (tin aromatic carboxylate)
Is mentioned. Examples of the tin metal include metal tin powder. Among tin metals and 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 amount of the lead or tin compound to be supported 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, the support can be prepared by a method in which the above-described lead or tin compound is supported on a carrier, and then dried and fired. Drying is usually performed at 50 to 100 ° C in air, and baking is usually performed at 150 to 500 ° C in air. The above-mentioned supported catalyst is used in the form of powder, granules or molded products. 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 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 subjected to a temperature of 100 to 450 ° C., especially 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 diaryloxalate. is there. The catalyst is usually used after being dissolved in the reaction solution, but may be used after being suspended. 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. Next, the present invention will be specifically described 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. under 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%. The production of diphenyl carbonate from diphenyl oxalate by the analytical 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 A 50 ml glass flask equipped with a thermometer and a reflux condenser was charged with diphenyl oxalate (10.0 mmol).
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 under normal pressure at this temperature for 3 hours to carry out a decarbonylation reaction. After completion of the reaction, the same analysis as in Example 1 was carried out, and 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 that 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, diphenyl oxalate (2
0.7 mmol), the space in the container was replaced with argon gas, and the temperature was raised to 330 ° C. with stirring.
The mixture was heated (boiled) at this temperature for 3 hours in the liquid phase to carry out a decarbonylation reaction. After completion of the reaction, the yield was analyzed in the same manner as in Example 1. The yield of diphenyl carbonate was 4.1%.
Met. Comparative Example 3 Diphenyl oxalate (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. [Table 1] 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.

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl. ⁷ identification mark FI C07B 61/00 300 C07B 61/00 300 ( 72) inventor Zofuji Toshio 5 Ube Kosan shares of Ube City, Yamaguchi Prefecture, Oaza Kogushi 1978 address (56) References JP 8-325207 (JP, A) JP 8-333307 (JP, A) JP 9-255628 (JP, A) JP 9-295959 (JP) JP-A-10-53563 (JP, A) JP-A-10-101620 (JP, A) JP-A-10-101622 (JP, A) Patent 3206425 (JP, B2) Patent 3206451 (JP, B2) Patent 3206452 (JP, B2) US Patent 4,544,507 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 68/00-68/08 C07C 69/96 CA (STN) REGISTRY (STN ) CASREACT (STN)

Claims (1)

(57) [Claim 1] Diaryl oxalate is converted to an inorganic acid of lead
A method for producing a diaryl carbonate, comprising subjecting a decarbonylation reaction by heating in the presence of a salt, an organic acid salt of lead, tin metal, or an organic acid salt of tin .