JPH07145107A - Production of aromatic carbonate - Google Patents

Abstract

PURPOSE:To enable efficient production of an aromatic carbonate by reaction of an aromatic hydroxy compound with CO and O2 in the presence of a catalyst comprising Pd, Pd compound, Mn salt and specific inorganic halide. CONSTITUTION:The reaction of an aromatic hydroxy compound such as phenol, carbon monoxide and oxygen gives an aromatic carbonate such as diphenyl carbonate. In this case, a catalyst comprising at least one selected from palladium and palladium compounds, at least one of manganese salts, and at least one of inorganic halides selected from alkali metal halides and alkaline earth metal halides is used. The inorganic halide is preferably a chloride such as cesium chloride, at a bromide such as, sodium bromide, potassium bromide, rubidium bromide, cesium bromide or barium bromide. As the aromatic carbonate, particularly diphenyl carbonate is useful as a starting substance for polycarbonates, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aromatic carbonic acid ester using a specific catalyst system. Aromatic carbonic acid esters, especially diphenyl carbonate, are useful as raw materials for polycarbonate and the like.

[0002]

2. Description of the Related Art Conventionally, a method of reacting an aromatic hydroxy compound with phosgene has been used as a method for producing an aromatic carbonic acid ester. However, since phosgene is highly toxic and produces a large amount of inorganic salt as a by-product, it has many problems as an industrial production method. Therefore, as a method that does not use phosgene, some methods of producing an aromatic carbonic acid ester from an aromatic hydroxy compound and carbon monoxide and oxygen have been proposed.

As a catalyst in this method, Japanese Examined Patent Publication No. 56-3
8144 discloses palladium compounds and III of the periodic table.
A, IVA, VA, VIA, IB, IIB, VIB or VIIB
Method using a compound containing a group metal and a base;
-38145 discloses a method using a palladium compound, a manganese complex or a cobalt complex, a base and a desiccant, and JP-A 1-165551 discloses a method using a palladium compound, iodine and zeolites; JP-A-2-142754 discloses a method using a palladium compound, a divalent or trivalent manganese compound, a tetraalkylammonium halide and a quinone; JP-A-2-142754 discloses a palladium compound, a cobalt compound, a tetraalkylammonium halide and a quinone. Method using a compound; JP-A-5-25095 discloses a method using palladium or a palladium compound, a cobalt compound, a halogen compound and a basic compound; JP-A-5-97775 (US Pat. No. 5,142,086) describes , Palladium compounds, quaternary ammonium salts, cobalt, iron, cerium, manganese, molybdenum A method using down, samarium, vanadium, chromium, metal promoter selected from copper, aromatic ketones, aliphatic ketones, a catalyst comprising selected organic cocatalyst aromatic polycyclic hydrocarbons;
Japanese Patent Application Laid-Open No. 5-58961 describes a method using palladium or a palladium compound, a cobalt compound and an alkali metal halide.

However, these methods have major problems that the activity of the catalyst is not sufficiently high and the yield of aromatic carbonic acid ester per aromatic hydroxy compound is low, which is satisfactory as an industrial production method. Was not. It is speculated that this is due to the fact that the hydrolysis reaction of aromatic carbonates is promoted in the case of the conventional catalyst system in addition to the reduction of the activity of the catalyst due to the water generated in the reaction. A method of coexisting a large amount of dehydrating agent (JP-A-54-135744) and a method of distilling off by reactive distillation (JP-A-4-261142) have been proposed to remove the slag, but the effect is not sufficient. I couldn't say that.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention According to the results of studies conducted by the inventors of the prior art using phenol as a substrate, the reaction proceeds at a satisfactory rate in the initial stage when a manganese compound is used as a cocatalyst. However, it was revealed that the reaction stopped in the middle and the hydrolysis reaction of the aromatic carbonate with water as a by-product proceeded further, and the reaction rate was generally slow when a cobalt compound was used as a cocatalyst. . SUMMARY OF THE INVENTION The present invention is to solve the problems of conventionally proposed catalyst systems and to provide a method for efficiently producing an aromatic carbonate ester.

[0006]

Means for Solving the Problems That is, the present invention is a method for producing an aromatic carbonic acid ester by reacting an aromatic hydroxy compound with carbon monoxide and oxygen, wherein the reaction system comprises (A) palladium and a palladium compound. The reaction is carried out in the presence of at least one selected from the group consisting of (B) one or more manganese salts and (C) one or more inorganic halides selected from alkali metal halides and alkaline earth metal halides. A method for producing an aromatic carbonate ester is provided.

1. Reaction Raw Materials (1) Aromatic Hydroxy Compound The aromatic hydroxy compound used in the present invention is an aromatic mono- or polyhydroxy compound, for example, phenol; p-cresol, 2,6-xylenol, 2,4,6-trimethyl. Substituted phenols such as phenol, 2,3,4,5-tetramethylphenol, ethylphenol, propylphenol, methoxyphenol, ethoxyphenol, chlorophenol, 2,4-dichlorophenol, bromophenol, 2,4-dibromophenol And their positional isomers; substituted naphthols such as naphthol, 2-methylnaphthol, 2-ethylnaphthol, 2-chloronaphthol, 2-bromonaphthol and their positional isomers; 2,2-
Various bisphenols such as bis (4-hydroxyphenyl) propane and their positional isomers; Various biphenols such as 4,4′-biphenol and their positional isomers; Various heteroaromatic hydroxy compounds such as 4-hydroxypyridine And their positional isomers; and their substitutions with alkyl, halogen and the like. Of these, phenol is particularly preferred.

(2) Carbon monoxide Carbon monoxide used in the present invention is not only high-purity but also diluted with other gases such as nitrogen, argon, carbon dioxide, and hydrogen that do not adversely affect the reaction. You can use it even if there is.

(3) Oxygen The oxygen used in the present invention is not only high-purity oxygen,
It is also possible to use one diluted with air or another gas that does not adversely influence the reaction, such as nitrogen, argon, carbon dioxide, or hydrogen.

2. Catalyst (A) Palladium or palladium compound Palladium or palladium compound used in the present invention
Is palladium black; palladium / carbon, palladium
/ Supports porous carriers such as alumina and palladium / silica
Palladium held; palladium chloride, palladium bromide,
Palladium iodide, palladium sulfate, palladium nitrate
Which inorganic salts of palladium; palladium acetate, oxalic acid
Examples thereof include organic acid salts of palladium such as palladium. Well
Palladium (II) acetylacetonate and paradium
Carbon monoxide, nitriles, amines, phosphines
Complexation of palladium coordinated with compounds and olefins
Thing, eg PdCl₂(PhCN)₂, PdCl₂(PPh
₃)₂, Pd (CO) (PPh₃) ₃, [Pd (NH₃)_Four]
Cl₂, Pd (C₂H_Four) (PPh₃)₂Or
Compounds in which these complex compounds are formed in the reaction system
It is also possible to use mixtures of palladium with palladium. reaction
The amount of palladium component used in
No problem, but molar ratio to aromatic hydroxy compound
So 1 to 10^-FiveIt is preferably in the range of 10 and particularly 10^-1
-10^-FourIt is preferably in the range of.

(B) Manganese Salt The manganese salt used in the present invention is preferably a divalent or trivalent manganese salt, such as manganese fluoride (II), manganese chloride (II), manganese bromide (II) and iodide. Manganese (I
I), manganese (II) sulfate, manganese (II) carbonate, manganese (II) nitrate and other inorganic salts; manganese formate (II), manganese acetate (II) or (III), manganese butyrate (II) and other organic acids Salts; acetylacetonatomanganese (II) or (I
II), complex compounds in which carbon monoxide, nitriles, amines, phosphines, olefins, etc. are coordinated with their salts; compounds with which these complex compounds are formed in the reaction system and manganese salts May be a mixture of. The amount of the manganese component used in the reaction is not particularly limited, but the molar ratio to the palladium component (A) is preferably in the range of 10 ⁻³ to 10 ² , and particularly in the range of 10 ⁻² to 10. It is preferable.

(C) Inorganic Halide The inorganic halide used in the present invention is an alkali metal
Alternatively, it is a halide of an alkaline earth metal. Halogen
As the chloride, chloride and bromide are preferable, and particularly
Cesium chloride, sodium bromide, potassium bromide, rubromide
Bidium, cesium bromide and barium bromide are preferred. Anti
There is no particular limitation on the amount of inorganic halide used.
However, the molar ratio to the palladium component (A) is 10^-2~ 1
0³It is preferably in the range of 10 and particularly 10 ^-1-10²
It is particularly preferable that the range is. Also, aromatic hydroxy
Molar ratio to 10 compounds^-FourBe in the range of ~ 1
Is preferred, especially 10^-3-10^-1Is preferably in the range
Good

3. Reaction method / reaction conditions The reaction is carried out with the aromatic hydroxy compound and the above-mentioned components (A) to
A catalyst comprising (C) is charged into a reactor, pressurized with carbon monoxide and oxygen, and sufficiently stirred under heating. The reaction pressure is 1 to 500 atm in total pressure,
It is preferably in the range of 1 to 250 atm, and the oxygen partial pressure is in the range of 0.1 to 6 atm, preferably 0.5 to 2 atm. If the oxygen partial pressure is too high, the halogenation reaction of the aromatic hydroxy compound will occur simultaneously, which is not preferable.

The composition ratio of carbon monoxide and oxygen can be any ratio, but from the viewpoint of safety, it is preferable that the composition ratio is out of the combustion range, which further affects the reaction. Diluting with no inert gas is also effective. If the amount of the diluent gas is too large, the partial pressure of carbon monoxide and oxygen will decrease, which is not preferable. The reaction gas composition cannot be uniquely determined because the combustion range changes depending on the temperature, pressure, dilution gas, etc., but usually carbon monoxide is excessive, and oxygen is 1 to 10% with respect to the total pressure. The diluent gas is used at 0 to 50%. When any of the gas components becomes insufficient as the reaction progresses, pressure may be replenished each time, or a mixed gas having a constant composition may be continuously supplied to the reactor under pressure. The reaction temperature is in the range of 70 to 150 ° C. The reaction time varies depending on the reaction conditions, but is usually several minutes to several hours.

In the reaction, as a solvent, an inert solvent such as hexane, heptane, cyclohexane, benzene, toluene, xylene, methylene chloride, chloroform, chlorobenzene, diethyl ether, diphenyl ether, tetrahydrofuran, dioxane, ethyl acetate, methyl formate, acetonitrile, etc. Can be used. When the raw material aromatic hydroxy compound is used as the reaction solvent, it is not necessary to use any other solvent. After completion of the reaction, it is possible to purify and isolate the high-purity aromatic carbonate by a purification method such as distillation purification or crystallization after separating the reaction mixture as it is or by separating the solid matter by filtration. Further, the catalyst component obtained from the filtration or the distillation residue can be directly recovered and reused in the next reaction.

[0016]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. Example 1 In a Hastelloy autoclave having an internal volume of 40 ml, 1.88 g (20 mmol) of phenol, 21.4 mg (10 microgram atom Pd) of 5% palladium / carbon, manganese (II) acetate tetrahydrate 2.5 mg (10 μm) mol) and 35.7 mg (0.30 mmol) of potassium bromide, and after replacing the system with carbon monoxide, carbon monoxide 60 atm, dry air 5
Atmospheric pressure was introduced (oxygen partial pressure 1 atm), and 12
The mixture was stirred at 0 ° C. for 3 hours. The gas phase and the liquid phase after completion of the reaction were analyzed by gas chromatography. As a result, diphenyl carbonate was obtained in a yield of 3.9 with respect to phenol.
Obtained in 2% (0.40 mmol). Carbon dioxide was produced as a by-product in an amount of 0.55 mmol, but o-, p-bromophenol was not produced as a by-product.

Comparative Example 1 Example 1 was repeated except that potassium bromide was not used. As a result, by-products of o- and p-bromophenol were not found, but the yield of diphenyl carbonate was 0.2%.

Comparative Example 2 As in Example 1 except that 2.5 mg (10 μmol) of cobalt (II) acetate tetrahydrate was used instead of 2.5 mg of manganese (II) acetate tetrahydrate. went. As a result, o-,
Although no by-product of p-bromophenol was found, the yield of diphenyl carbonate was 1.01%.

Examples 2 to 6 The procedure of Example 1 was repeated, except that various manganese salts shown in Table 1 were used instead of manganese (II) acetate tetrahydrate. Table 1 shows the yield of the obtained diphenyl carbonate with respect to phenol and the amount of carbon dioxide as a by-product. In addition, by-products of o- and p-bromophenol were not found in any of the examples.

[0020]

[Table 1]

Examples 7 to 11 The same procedure as in Example 1 was repeated except that various inorganic halides shown in Table 2 were used instead of potassium bromide. Table 2 shows the yield of the obtained diphenyl carbonate with respect to phenol and the amount of carbon dioxide as a by-product. In addition, by-products of o- and p-bromophenol were not found in any of the examples.

[0022]

[Table 2]

Example 12 Example 12 was repeated except that the reaction temperature was 100 ° C. As a result, diphenyl carbonate was obtained with a yield of 2.33%. Carbon dioxide was produced as a byproduct of 0.17 mmol, but o-, p-
No bromophenol by-product was found.

EXAMPLE 13 Palladium (II) acetate 2.2 mg (10 microgram atom P) instead of 5% palladium / carbon 21.4 mg
Example 1 was repeated except that d) was used. As a result, diphenyl carbonate was obtained with a yield of 2.41%. Although 0.67 mmol of carbon dioxide was by-produced, o- and p-bromophenol by-products were not found.

Example 14 3 carbon monoxide was introduced in place of carbon monoxide at 60 atm.
The same procedure as in Example 1 was carried out except that the pressure was 0 atm. As a result, diphenyl carbonate was obtained with a yield of 2.22%. Although 0.36 mmol of carbon dioxide was by-produced, no by-product of o- and p-bromophenol was observed.

Example 15 In Example 1, after the reaction was started, the gas phase was withdrawn every hour, the system was replaced with carbon monoxide, and then carbon monoxide (60 atm) and dry air (5 atm) were introduced. The same procedure as in Example 1 was carried out except that As a result, diphenyl carbonate was obtained in a yield of 6.10%. Carbon dioxide was produced as 1.28 mmol, but o- and p-bromophenol were not produced as by-products.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hidekazu Miyagi 8-3-1 Chuo, Ami-machi, Inashiki-gun, Ibaraki Mitsubishi Petrochemical Co., Ltd. Tsukuba Research Institute

Claims (4)

[Claims] 1. A method for producing an aromatic carbonic acid ester by reacting an aromatic hydroxy compound with carbon monoxide and oxygen, wherein in the reaction system, one or more selected from (A) palladium and a palladium compound, and (B) manganese. A process for producing an aromatic carbonic acid ester, characterized in that the reaction is carried out in the presence of at least one salt, and at least one inorganic halide selected from (C) alkali metal halides and alkaline earth metal halides. 2. The method according to claim 1, wherein the inorganic halide is selected from chloride and bromide. 3. The method according to claim 2, wherein the chloride is cesium chloride. 4. The method according to claim 2, wherein the bromide is selected from sodium bromide, potassium bromide, rubidium bromide, cesium bromide and barium bromide.