JP2000256269A - Production of aromatic carbonate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain the subject compound simply, economically in an improved conversion without impairing selectivity of reaction by reacting an aromatic hydroxy compound with carbon monoxide and oxygen in the presence of a platinum group metal, etc., a redox agent, an ammonium salt, etc. SOLUTION: An aromatic hydroxy compound is reacted with carbon monoxide and oxygen in the presence of a platinum group metal or a platinum group compound, a redox agent (preferably manganese, cobalt, copper or cerium) and a quaternary ammonium salt or phosphonium salt preferably at 50-150 deg.C to give the objective compound. The reaction is carried out by substantially constantly maintaining pressure in a reactor and a gas flow ratio of carbon monoxide and oxygen circulating in the reactor in the presence of an organic solvent azeotropic with water. The organic solvent is preferably a compound containing no active hydrogen (preferably benzene, toluene or xylene).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an aromatic carbonate by reacting an aromatic hydroxy compound with carbon monoxide and oxygen.

[0002]

2. Description of the Related Art Aromatic carbonates represented by diphenyl carbonate are compounds useful as raw materials for polycarbonates. Conventionally, as a method for producing an aromatic carbonate, a method of reacting an aromatic hydroxy compound with phosgene has been used. However, the above method has many problems as an industrial production method because phosgene is highly toxic and further produces a large amount of inorganic salts as a by-product. Therefore, several methods have been proposed as a method for producing an aromatic carbonate without using phosgene.

[0003] For example, Japanese Patent Publication No. 56-38144 discloses that the periodic table IIIA, IVA, V
A, VIA, IB, IIB, IVB, VB, VIB, VIIB and VII
A compound containing a Group IB metal and a method of reacting phenol with carbon monoxide using a base are described.
JP-B-56-38145 discloses a method using a palladium compound and a manganese complex or a cobalt complex, a base and a drying agent; JP-A-1-165551 discloses a method using a palladium compound, an iodine compound and zeolite; Japanese Patent Application Laid-Open No. 2-104564 proposes a method using a palladium compound, a manganese compound, a tetraalkylammonium salt and a quinone as an additive. No., JP-A-6-4102
0, JP-A-6-172268, JP-A-6-172268
No. 172269 discloses a method using various additives and a special ligand in addition to a palladium compound, a redox metal and a quaternary ammonium salt. More recently, JP-A-8-89810 discloses a method using a palladium compound, a redox agent, an alkali metal halide and activated carbon;
JP-A-8-281108 discloses a method using a palladium compound, a lead compound, a quaternary ammonium halide and a copper compound;
V, Mn, Cr, Fe, Co, Ni, Cu, La, N
b, Mo, Pb, a catalyst comprising a platinum group metal compound supported on a support containing oxides of rare earth metals and actinides, a cocatalyst such as a manganese or cobalt salt, a quaternary ammonium or phosphonium salt and a base Japanese Unexamined Patent Publication No. 8-281114 discloses a method of reacting in the presence of a quaternary ammonium or quaternary ammonium using a known catalyst and a supported catalyst supporting a platinum group metal compound and a metal compound acting as a cocatalyst. A method of reacting in the presence of a phosphonium salt and a base is disclosed in JP-A-8-28320.
No. 6 discloses, in addition to a platinum group metal compound, a cocatalyst such as a manganese or cobalt salt, a quaternary salt and a base, a heterogeneous cocatalyst such as a metal oxide, a carbide, a nitride or a boride. Methods to be used have been proposed.

[0004]

However, a common problem in any of the methods is that the reaction proceeds relatively slowly and the conversion of the reaction does not increase. Therefore, in addition to raising the reaction temperature and the reaction pressure, it is considered necessary to devise a method of continuously extracting water generated by the reaction to the outside of the reaction system. When the reaction temperature is increased, undesired side reactions often increase, and although the conversion increases, the selectivity of the reaction decreases, and the catalytic activity may decrease rapidly, so that the optimum temperature is limited.

[0005] In some cases, increasing the reaction pressure or the partial pressure of oxygen increases the load on the equipment in spite of its effect, and impairs economic efficiency. Undesirable side reactions may also occur, which are also limited to a particular range. On the other hand, it is considered that it is effective to continuously remove generated water from the reaction system, and a method of coexisting a dehydrating agent such as molecular sieves in the reaction system is often adopted as seen in the above-described example. ing. (Sho 56
However, when these dehydrating agents are used, a considerably large amount of the dehydrating agent is required for the reactant in order to obtain a sufficient effect, and considering the recycle use thereof. The operation is complicated and not economical.

In consideration of these points, the present inventors have conducted a reaction while keeping the pressure in the reactor and the gas flow ratio of carbon monoxide and oxygen flowing through the reactor substantially constant. A method has been adopted in which the generated water is continuously removed along with a flowing gas and some reactants (aromatic hydroxy compound) to remove the water continuously to promote the progress of the reaction. It has been found that by using an organic solvent, water is more efficiently and continuously taken out of the reaction system. By this method, the conversion of the reaction can be improved by a simple and economical method without impairing the selectivity of the reaction, and the diaryl carbonate can be produced more efficiently, thereby completing the present invention. That is, the present invention relates to an aromatic hydroxy compound, carbon monoxide and oxygen, one or more compounds of a platinum group metal or a platinum group metal compound, a metal compound selected from manganese, cobalt or cerium, and a quaternary ammonium salt. Alternatively, when the reaction is carried out in the presence of a phosphonium salt to produce an aromatic carbonate, the reaction is carried out while keeping the pressure in the reactor, and the gas flow ratio of carbon monoxide and oxygen flowing through the reactor substantially constant. At the same time, this is a process for producing a diaryl carbonate carbonate in which the reaction is carried out in the presence of an organic solvent azeotropic with water. Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst used in the present invention comprises a platinum group metal and / or a platinum group metal compound as a main catalyst and one or more compounds of a metal selected from manganese, cobalt or cerium. Redox co-catalyst containing and fourth
And a co-catalyst comprising a quaternary ammonium salt or a quaternary phosphonium salt. The catalyst system may further contain an inorganic or organic promoter.

The platinum group metal and / or platinum group metal compound of the main catalyst includes Pd, Pt, Ru, Rh, Ir or O
and metal and / or compounds such as s.
d, Pt, and Ru are preferred, and Pd and Pd compounds are particularly preferred. For example, Pd and Pd compounds include finely powdered metals such as palladium black; supported palladium catalysts such as palladium / carbon, palladium / silica, palladium / alumina, palladium / silica alumina, palladium / titania; palladium chloride; Inorganic salts such as palladium, palladium iodide, palladium nitrate or palladium sulfate; organic acid salts such as palladium acetate, palladium benzoate and palladium oxalate; For example, Pd (CO) Cl, PdC
l ₂ (PhCN) ₂ , PdCl ₂ (PPh ₃ ) ₂ , PdCO
(PPh ₃ ) ₃ , [Pd (NH ₄ ) ₄ ] Cl ₂ , [Pd (en) ₂ ]
Cl ₂ (en = ethylenediamine), Pd (C ₂ H ₄ )
(PPh ₃ ) _{2 and the} like, or those in which such complex compounds are formed in a reaction system.

Further, a catalyst in which palladium metal or an oxide thereof or the above compound is supported on a metal oxide or a metal composite oxide by a composite oxide is also mentioned as a suitable catalyst. Examples of such metal oxides include the above-mentioned silica, alumina, titania, zirconia, vanadia and chromium,
Oxides of transition metals such as manganese and iron, yttrium,
Oxides of rare earth metals such as lanthanum and cerium are exemplified. Examples of the composite oxide include a composite oxide having a spinel-type or perovskite-type structure. Among them, a perovskite-type composite oxide represented by ABO ₃ is preferable, and further, a part of the A-site metal is replaced with another metal. Oxygen-deficient perovskite-type composite oxides produced as a result are mentioned as particularly preferred carriers.

[0010] These palladium or palladium compounds may be used alone or in combination of two or more. In the present invention, the amount of the palladium component used in the reaction as the main catalyst is preferably in the range of 1 to 10 ^-5 in terms of the molar ratio of the palladium atom to the aromatic hydroxy compound, particularly 10 ^-2 to 10 ^-4. Is preferable.

The aromatic carbonate production reaction of the present invention is carried out in the presence of a redox agent. Such redox agents include IIIA, IVA, VA, VIA, IB, IIB, VI of the periodic table.
B, VIIB, compounds of the iron group (VIII) and rare earth metals (IIIB). Compounds of these metals can be used in various oxidation states, for example, halides, oxides, hydroxides, carbonates, organic carboxylate salts, diketone salts, oxalate salts, and complex salts such as salicylates. And carbon monoxide,
It can be used as a complex in which olefins, amines, phosphines and the like are coordinated. Among these metal compounds having a redox ability, preferred are manganese, cobalt, copper and compounds of rare earth metals such as lanthanum and cerium, and particularly preferred are compounds of manganese, cobalt, copper and cerium metal. . The amount of these redox agents to be used is not particularly limited, but is preferably in the range of 0.1 to 1000, more preferably 0.1 to 100, in terms of molar ratio with respect to the palladium compound.

Quaternary ammonium salt used in the present invention
And phosphonium salts of the formula R₁R_TwoR _ThreeR_FourNX and R₁
R_TwoR_ThreeR_FourR in the formula represented by PX₁~ R_FourIs carbon
Alkyl having 1 to 8 carbon atoms or aryl having 6 to 12 carbon atoms
The groups may be the same or different. X is an anion
Hydroxyl group, alkoxy group, phenoxy group, chloride,
Halogen such as romide and iodide are often used
You. Among them, especially tetra-n-butylammonium
Salts and tetraphenylphosphonium salts are preferred. Anti
Quaternary ammonium salts or quaternary phos
The amount of honium salt is palladium or palladium compound
In a molar ratio of 0.1 to 1000, especially 1
It is preferably in the range of 100.

In the present invention, the aromatic hydroxy compound is further reacted with carbon monoxide and oxygen in the presence of the above-mentioned catalyst and redox agent, in the presence of a quaternary ammonium salt or a phosphonium salt, and in the presence or absence of a base. To obtain the desired aromatic carbonate.

The aromatic carbonate obtained in the present invention is represented by the following formula (1). RO-CO-OR '(1) (wherein R and R' are the same or different and are substituted or unsubstituted aryl having 6 to 10 carbon atoms, preferably substituted
Or unsubstituted phenyl, particularly preferably unsubstituted phenyl. )

The aromatic hydroxy compound which can be used in the present reaction is an aromatic monohydroxy compound or a polyhydroxy compound, for example, phenol, cresol, xylenol, trimethylphenol, tetramethylphenol, ethylphenol, propylphenolmethoxyphenol. , Ethoxyphenol, chlorophenol, substituted phenols such as bromophenol and their isomers, naphthol, methylnaphthol,
There are substituted naphthols such as chloronaphthol and bromonaphthol and isomers thereof, and bisphenols such as bisphenol A, among which phenol is particularly preferred.

This reaction is carried out in the presence or absence of a base. The presence of a base may increase the reaction rate and sustainability and bring about an increase in yield, and is used as necessary.
Depending on the type and amount of base used or its form, it may ultimately react with the quaternary salt and cannot be recycled, so it is not always necessary to use it. When used, the base is used as an alkali metal or alkaline earth metal hydroxide, carbonate, bicarbonate, acetate or other organic acid salt, alkoxide or phenoxide. Organic tertiary amines or pyridines can also be used as another type of base to be used. Examples of such organic bases are triethylamine, tripropylamine, tributylamine, trioctylamine, benzyldimethylamine, pyridine, picoline, bipyridine and the like. When a base is used, the amount used is in the range of 0.01 to 500 in molar ratio to palladium.

The production reaction of the aromatic polycarbonate in the present invention is carried out by charging the above-mentioned aromatic hydroxy compound, the above-mentioned catalyst and the above-mentioned co-catalyst component into a reactor, and pressurizing and heating carbon monoxide and oxygen. Further, at that time, the reaction is carried out while keeping the pressure in the reactor and the gas flow ratio of carbon monoxide and oxygen flowing through the reactor substantially constant, and simultaneously with the presence of an organic solvent azeotropic with water. The reaction is performed. Thus, the reaction can be effectively performed by simultaneously removing excess water and the generated water outside the reaction system by azeotropic distillation of the organic solvent.

In the present invention, the gas components carbon monoxide and oxygen which are circulated during the reaction can be used in a state diluted with another gas which does not adversely influence the reaction, such as nitrogen, argon, carbon dioxide, etc. Air can also be used as oxygen. It is necessary to keep the total pressure in the reactor and the gas flow ratio of carbon monoxide and oxygen flowing through the reactor constant. The pressure inside the reactor is 1 to 30 in total pressure.
The range is 0 atm, preferably 1 to 150 atm, and more preferably 2 to 100 atm. The gas flow ratio between carbon monoxide and oxygen is kept constant, but it is preferable that the flow ratio has a composition outside the explosion range from the viewpoint of safety. The flow ratio of carbon monoxide to oxygen varies depending on the total pressure and the ratio of the contained inert gas component, but is usually selected from the range of 5: 1 to 30: 1. In this way, the flow rate ratio of the gas circulated during the reaction is kept constant to maintain the optimum gas composition for the reaction, and at the same time, the water generated by the reaction is continuously removed together with the organic solvent azeotropic with water, accompanying the water. The reaction can be carried out while performing the reaction.

Examples of the organic solvent azeotropic with water used in the present invention include organic solvents which have been recognized to be azeotropic, and are directly involved in the reaction, react with the raw materials, and react with the product. It is of course unsuitable for a substance having a higher-order reaction to be azeotropic with water. Therefore, aliphatic alcohols such as ethanol and those having active hydrogen such as primary and secondary amines may be involved in the reaction and are not suitable. In addition, since the azeotropic composition is generally affected not only by the coexisting reactants but also by the temperature and pressure, it is desirable that the azeotropic temperature of the organic solvent with water under the reaction condition pressure be not significantly higher than the reaction temperature. . Since the reaction temperature of the reaction of the present invention is in the range of 30 to 200 ° C., preferably 50 to 150 ° C., the azeotropic temperature under the reaction pressure is preferably close to the temperature range.

Specific examples of the organic solvent satisfying the above conditions include methyl acetate, ethyl acetate, ethyl acrylate,
Esters such as methyl methacrylate, methyl butyrate or ethyl benzoate, ethers such as anisole and 1,4-dioxane, cyclohexanone, 3-heptanone,
Ketones such as 4-heptanone and acetylacetone; halides such as chlorobenzene, chloroform and carbon tetrachloride; nitroethane; acrylonitrile; pyridine;
-Nitrogen-containing compounds such as -methylpyridine, 3-methylpyridine, and 4-methylpyridine; aliphatic hydrocarbons such as cyclohexane, hexane, octane, and didecane; aromatic hydrocarbons such as benzene, toluene, xylene, and naphthalene And the like.

In addition, a mixture of two kinds of organic solvents which forms an azeotropic mixture of water and water may be used. There are many such combinations including unknown ones. For example, a combination of acetonitrile and benzene, methyl ethyl ketone and hexane, nitromethane and octane, t-butyl alcohol and benzene can be used. Among these, an organic solvent that does not mix with water is particularly preferable in consideration of separation from separated water and circulating reuse. Also, considering that the chemical reactivity is small, the influence on the reaction system is small, and the separation from the catalyst components and products, etc., volatile aromatic hydrocarbons such as benzene, toluene, and xylene are most preferable. is there.

The amount of the above-mentioned organic solvent which forms an azeotrope with water may be 1 to 1 parts by weight based on the amount of the aromatic hydroxy compound as a raw material in the reaction.
It is in the range of 0.01, preferably 0.5 to 0.02.
And, as a method of use, the above-mentioned organic solvent azeotropic with water may be mixed with the raw material aromatic hydroxy compound in a liquid state and supplied to the reaction phase, or may be supplied together with the gaseous raw material in a partially vaporized state. It may be supplied to the reaction phase. After the organic solvent azeotropic with water stays in the reaction phase, a part or most of the organic solvent is discharged from the reaction phase as a gas together with the water azeotropically used with a gaseous reactant usually used in excess. Thus, by separating and removing water from the discharged gaseous mixture and returning to the reaction phase again, water generated by the reaction is continuously removed from the reaction phase without substantially losing the organic solvent and the reaction gas. It is possible. The reaction time varies depending on the reaction conditions, but is usually several minutes to several hours.

[0023]

According to the present invention, an aromatic hydroxy compound, carbon monoxide and oxygen are reacted in the presence of a quaternary ammonium salt or a phosphonium salt in the presence or absence of a base to convert an aromatic carbonate. In manufacturing,
By removing the generated water continuously and efficiently out of the reaction system and improving the reaction yield, it is possible to provide a more economical industrial production method of aromatic carbonate.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[Example 1] [Production of diphenyl carbonate using toluene as azeotropic solvent] Content 1 equipped with a gas injection pipe and a stirring blade
Using a 00 ml reactor, 50.0 g of phenol and 15 ml of toluene, 40 mg of palladium acetylacetonate: Pd (acac) ₂ , 70 mg of manganese (II) acetylacetonate: Mn (acac) ₂ , tetra-n-butylammonium bromide 1000 mg and sodium phenolate 220 mg were charged and the reactor was replaced with carbon monoxide. At the same time as the temperature of the reactor was raised to 80 ° C., the pressure was increased to 10 bar with carbon monoxide, and when a predetermined temperature and pressure was reached, the flow rate of carbon monoxide was 500 m.
1 / min (standard condition) and pure oxygen flow rate of 25 ml /
The reaction was carried out for 3 hours while maintaining the pressure in the reactor at 10 bar and the reaction temperature at 80 ° C. by flowing a gas (min. standard). After completion of the reaction, the reaction product in the reactor was taken out and analyzed by gas chromatography to obtain 9.75 g (yield 10.1%) of diphenyl carbonate (DPC). Almost no by-products were detected and the reaction selectivity was 99.
% Or more.

[0026] Example 2: 2.5% using a Pd-supported catalyst, toluene] [perovskite oxide; Preparation of La _0.4 Pb _0.6 MnO _3] lanthanum nitrate _{hexahydrate; La (NO 3) 3 ·} 6H _Two
O5.20G, lead _{nitrate; Pb (NO 3) 2 5.96g} , manganese nitrate _{hexahydrate; Mn (NO 3) 2 ·} 6H 2 O8.7
Dissolve 0 g in a small amount of water and heat the homogeneous solution obtained by combining with an aqueous solution of 12.3 g of citric acid to evaporate the water. The foamed solid obtained by evaporating to dryness is thermally decomposed and further calcined at 550 ° C. for 3 hours. The obtained solid powder is fired again in an electric furnace at 700 ° C. for 6 hours. The X-ray diffraction pattern of the obtained sintered body has a diffraction angle of 2 as shown in FIG.
θ = 22.76 °, 32.56 °, 40.2 °, 46.
74 °, 52.76 °, 58.26 °, 68.44 °,
A strong peak is observed at 78.12 ° or the like, confirming that the compound has a perovskite structure.

[Perovskite oxide; La _0.4 Pb
_0.6 Palladium on MnO ₃ ] Disodium tetrachloroparadate in 50 ml of water; Na ₂ PdCl ₄ 276 m
g, and 4.0 g of the perovskite oxide obtained above is suspended. While stirring, the mixture was neutralized slowly with a 5% aqueous sodium hydroxide solution to pH = 9. After standing for a while, the mixture was filtered and washed with water, and the obtained supported catalyst was dried at 110 ° C. overnight. This catalyst reacts with perovskite oxide
It contained about 2.5% by weight of palladium as a metal.

[Production of diphenyl carbonate using the above supported catalyst] Using the same reactor of Example 1 equipped with a gas injection pipe and a stirring blade with a content of 100 ml, 50.0 g of phenol and 15 ml of toluene and the above Pd were used. 800 mg of a supported catalyst, 70 mg of manganese (II) acetylacetonate: Mn (acac) ₂ , and 1000 mg of tetra-n-butylammonium bromide are charged, and the reactor is replaced with carbon monoxide. At the same time as the temperature of the reactor was raised to 80 ° C., the pressure was increased to 10 bar with carbon monoxide, and when a predetermined temperature and pressure were reached, the flow rate of carbon monoxide was increased to 50 bar.
0 ml / min (standard condition) and the flow rate of pure oxygen is 30 m
A gas of 1 / min (standard state) is passed, and the reaction is carried out for 3 hours while maintaining the pressure in the reactor at 10 bar and the reaction temperature at 80 ° C. After completion of the reaction, the reactant in the reactor was taken out and analyzed by gas chromatography to find 12.9 g.
(Yield 22.7%) of diphenyl carbonate (DP
C) was obtained. Almost no by-product was detected, and the reaction selectivity was 99% or more.

Example 3 In the same apparatus and under the same reaction conditions as in Example 2, benzene 1 was used instead of toluene 15 ml.
The reaction was carried out using 5 ml under the same gas flow conditions.
As a result, 13.6 g (yield 23.9%) of DPC was obtained. The DPC selectivity was 99% or more.

Comparative Example 1 Production of Aromatic Carbonate Using the Supported Catalyst The phenol was prepared in the same manner as in Example 1 using a 100 ml reactor equipped with a gas injection pipe and stirring blades. 0g and the above catalyst 1000m
g, manganese acetylacetonate dihydrate; Mn (a
cac) ₂ · 2H ₂ O80mg, tetra n- butylammonium bromide 1000mg through the charged reactor is replaced with carbon monoxide. At the same time as the temperature of the reactor was raised to 80 ° C., the pressure was increased to 10 bar with carbon monoxide, and when a predetermined temperature and pressure were reached, the flow rate of carbon monoxide was increased to 500 bar.
ml / min (standard condition) and the flow rate of pure oxygen is 30 ml
Per minute (standard state), and the reaction is carried out for 3 hours while maintaining the pressure in the reactor at 10 bar and the reaction temperature at 80 ° C. After completion of the reaction, the reaction product in the reactor was taken out and analyzed by gas chromatography to obtain 10.9 g (yield: 19.1%) of diphenyl carbonate (DPC).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H006 AA02 AC48 BA08 BA10 BA14 BA16 BA19 BA20 BA22 BA25 BA30 BA34 BA36 BA37 BA45 BA46 BA48 BB11 BB12 BB14 BB16 BB17 BB18 BB24 BB61 BC35 BD20 BE30 BE40 BT40 4H039 CA66 CC20

Claims (4)

[Claims] 1. An aromatic carbonate is produced by reacting an aromatic hydroxy compound, carbon monoxide and oxygen in the presence of a platinum group metal or a platinum group compound, a redox agent, and a quaternary ammonium salt or a phosphonium salt. In the method, the reaction is carried out while keeping the pressure in the reactor and the gas flow ratio of carbon monoxide and oxygen flowing in the reactor substantially constant, and at the same time, the reaction is carried out in the presence of an organic solvent azeotropic with water. A process for producing an aromatic carbonate. 2. The method according to claim 1, wherein one or more compounds selected from the group consisting of metals selected from manganese, cobalt, copper and cerium are used as the redox agent.
A process for producing the aromatic carbonate according to the above. 3. The method for producing an aromatic carbonate according to claim 1, wherein the organic solvent is a compound containing no active hydrogen. 4. The method for producing an aromatic carbonate according to claim 3, wherein the organic solvent is benzene, toluene or xylene.