JP3139108B2 - Method for producing carbonate ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an industrially useful carbonate as an intermediate for producing polycarbonate, an intermediate for medical and agricultural chemicals and a solvent.

[0002]

2. Description of the Related Art As a method for producing a carbonate ester, there is a method in which an alcohol is reacted with phosgene. However, the toxicity of phosgene is high, the electrolytic chlorine required for producing phosgene is expensive, and There is a problem that highly corrosive hydrochloric acid is by-produced due to the reaction of phosgene with phosgene. As a production method that does not use phosgene, there is a method in which an alcohol is reacted with carbon monoxide and oxygen in the presence of a copper salt catalyst (Japanese Patent Publication No. 60-58739). There are problems such as a low reaction rate. Also, a method of reacting an alcohol with carbon monoxide and oxygen in the presence of a catalyst system comprising palladium, a copper salt and an amine in place of a copper catalyst (JP-B-61-8816, JP-B-61-43)
338) is known, but there are problems such as a large combustion loss of carbon monoxide. Further, a method is also known in which an alcohol is reacted with carbon monoxide and an oxidizing agent in the presence of a catalyst system comprising palladium, a copper salt and pyridine (JP-A-2-4737). Is not sufficiently effective against the loss caused by the In addition, the production method using these liquid phases has problems such as difficulty in separating the catalyst and the product. As an attempt to solve this problem, a nitrate ester and carbon monoxide are reacted in a gas phase in the presence of a solid catalyst in which a second metal such as iron, copper, bismuth, etc. is added to a platinum group metal to form a carbonate ester. A production method (Japanese Patent Application Laid-Open No. 3-141243) is also known, but the production process is complicated, for example, a sufficient reaction rate cannot be obtained, and a step of recovering and regenerating nitrite is required.

[0003]

SUMMARY OF THE INVENTION The present invention relates to alcohols,
In a method for producing a carbonate ester from carbon monoxide and oxygen, a decrease in the selectivity of carbon monoxide due to combustion loss or the like is reduced, and a carbonate ester is produced at a high reaction rate that can be industrially used. It is intended to provide a process by a gas phase method which is advantageous in terms of process and does not require a step of separating product and product.

[0004]

SUMMARY OF THE INVENTION The present inventors have developed a process for obtaining a carbonate ester from alcohol, carbon monoxide and oxygen using a platinum group metal-copper catalyst for a gas phase method which is advantageous in terms of process. Upon intensive investigation, (1) selected from the group consisting of platinum group metals or salts thereof, metallic copper or copper salts, trialkylamines, hetero-bridged cyclic tertiary amines, disubstituted carbodiimides, alkali metal salts and alkali metal alkoxides (2) a complex compound comprising a platinum group metal or a salt thereof and a 2-hydroxypyridine, metal copper or a copper salt, and Alkylamines, hetero-bridged cyclic tertiary amines, disubstituted carbodiimides, alkali metal salts and alkali metal alkoxides By using a solid catalyst in which at least one member selected from the group consisting of a carrier is supported, the decrease in selectivity due to the combustion loss of carbon monoxide is significantly reduced, and the rate of carbonate ester generation is also improved. The inventors have found that effects can be obtained, and arrived at the present invention. The mechanism of action of 2-hydroxypyridines has not been elucidated so far, but the strength of the acid / base possessed by 2-hydroxypyridines and the steric distance between the acid and the base combine to make such a mechanism. It can be considered that it shows an excellent addition effect. That is, the first invention of the present application is a platinum group metal or a salt thereof, metal copper or a copper salt,
In the presence of a solid catalyst comprising at least one selected from the group consisting of trialkylamines, hetero-bridged cyclic tertiary amines, disubstituted carbodiimides, alkali metal salts and alkali metal alkoxides, and 2-hydroxypyridines supported on a carrier In addition, the present invention provides a method for producing a carbonate ester, which comprises reacting an aliphatic alcohol with carbon monoxide and oxygen in a gas phase. A complex compound composed of hydroxypyridines, metallic copper or a copper salt, and at least one selected from the group consisting of trialkylamines, hetero-bridged cyclic tertiary amines, disubstituted carbodiimides, alkali metal salts and alkali metal alkoxides are supported on a carrier. Aliphatic alcohol with carbon monoxide and oxygen in the presence of a solid catalyst There is provided a method for producing carbonic acid esters which comprises reacting a phase.

Hereinafter, the present invention will be described in detail. As the platinum group metal used in the present invention, ruthenium, rhodium, palladium, iridium, platinum and the like are used, and among them, palladium is preferable. These metals can be used alone as halides, nitrates, sulfates, phosphates,
It can also be used as a salt such as acetate. More specifically, ruthenium chloride, ruthenium iodide, ruthenium tris (acetylacetonato), rhodium chloride, rhodium bromide, rhodium iodide, rhodium nitrate, rhodium sulfate, rhodium acetate, palladium chloride, palladium bromide, palladium iodide , Palladium acetate, palladium propionate,
Examples include palladium nitrate, palladium sulfate, palladium phosphate, bis (acetylacetonato) palladium, palladium oxalate, iridium chloride, chloroplatinic acid, and potassium tetrachloroplatinate. The amount of the platinum group metal or salt thereof carried on the carrier is usually 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, as the metal of the platinum group metal.

Among the copper metal or copper salts used in the present invention, copper salts include halides such as cupric chloride and cuprous chloride, as well as nitrates, sulfates, copper acetate, copper propionate and the like. Aliphatic carboxylate, aromatic carboxylate such as copper benzoate, phosphate and the like are used. The amount of metal copper or copper salt used is usually 1 to 1 per mole of platinum group metal atom.
It is used in the range of 00 mol, preferably 1 to 20 mol.

The alkyl group of the trialkylamine preferably has 1 to 5 carbon atoms, and specific examples include tolmethylamine, triethylamine, tripropylamine and tributylamine. Examples of the hetero-bridged cyclic tertiary amine include bicyclic amidines such as 1,5-diazabicyclo [4.3.0] nonene-5 and 1,8-diazabicyclo [5.4.0] undecene-7. 1,8-diazabicyclo [2.2.2] octane and the like are used, and as the disubstituted carbodiimide, dicyclohexylcarbodiimide and the like are used.

Examples of the alkali metal salts include aliphatic carboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid and caproic acid, and alkali metal salts such as lithium, sodium and potassium of inorganic acids such as carbonic acid, nitric acid, sulfuric acid and phosphoric acid. Alternatively, potassium chloride, lithium chloride, alkali metal halides such as cesium chloride and the like are used, and as the alkali metal alkoxide, sodium methoxide, sodium ethoxide,
Potassium methoxide or the like is used. The amount of these basic substances to be used is usually 1 to 1 mol per platinum group metal atom.
It is used in a range of 10 ³ mol, preferably 1 to 200 mol.

The 2-hydroxypyridines may have a substituent such as an alkyl group, an alkoxy group, or a halogen atom on the 2-hydroxypyridine skeleton which does not inhibit the present reaction. 2-hydroxy-4-methylpyridine, 2-hydroxy-6-methylpyridine, 2-hydroxy-4-ethylpyridine,
2-hydroxy-4-methoxypyridine, 2-hydroxy-6-methoxypyridine, 4,6-dimethyl-2-hydroxypyridine, 2-hydroxy-4-chloropyridine, 2-hydroxy-6-chloropyridine and the like are used. You. Preferably, a 2-hydroxy-alkyl-pyridine such as 2-hydroxypyridine or 2-hydroxy-6-methylpyridine is used. The amount of the 2-hydroxypyridines used is as follows:
Usually, 1 to 10 ³ mol, preferably used in the range of 1 to 100 moles.

As a complex compound comprising a platinum group metal or a salt thereof and 2-hydroxypyridines, there are 2
Complex compounds coordinated with nitrogen atoms of -hydroxypyridines, for example, bis (2-hydroxypyridine) palladium dichloride, bis (2-hydroxypyridine)
Palladium dibromide, bis (2-hydroxypyridine) palladium diacetate and the like can be mentioned. As a general method for synthesizing this complex compound, for example, bis (2-hydroxypyridine) palladium dichloride can be synthesized by dissolving palladium chloride and sodium chloride in methanol and then adding 2-hydroxypyridine. The amount of the complex compound comprising a platinum group metal or a salt thereof and 2-hydroxypyridines supported on the carrier is usually
The platinum group metal is used in the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight.

The carrier used in the present invention includes activated carbon, graphite, alumina, silica, silica-alumina, diatomaceous earth, asbestos, ion exchange resin, calcium silicate, aluminosilicate, polyvinylpyridine, magnesia, titania, zirconia and the like. Can be A platinum group metal or a salt thereof (hereinafter, referred to as a first component),
At least one selected from the group consisting of metal copper or copper salt (hereinafter, referred to as a second component), trialkylamine, hetero-bridged cyclic tertiary amine, disubstituted carbodiimide, alkali metal salt and alkali metal alkoxide (hereinafter, referred to as Carrier of a third compound) and a 2-hydroxypyridine (hereinafter referred to as a fourth component), or a complex compound comprising a platinum group metal or a salt thereof and a 2-hydroxypyridine (hereinafter referred to as a fifth component) The supporting method may be a conventional method, for example, a method of dissolving the first, second, and fourth components in an organic solvent, adding a carrier thereto, impregnating, drying, and then supporting the third component in the same manner. Alternatively, a method in which the first and second components are first supported on a carrier, and then the fourth and third components are sequentially supported is employed. Also, when the fifth component is employed, it can be carried in the same manner.

As the aliphatic alcohol, saturated aliphatic alcohols, particularly methanol, ethanol, butanol,
Ethylene glycol, propylene glycol, 1,4-
Butanediol or the like is used. In carrying out the method of the present invention, the reaction is carried out under normal pressure or under pressure,
0.001-20 kg / c as carbon monoxide partial pressure
m ^2, preferably in the range of 0.01 to 10 / cm ^2, the oxygen partial pressure 0.001~10kg / cm ^2, preferably 0.01~5kg / cm ^2, the alcohol partial pressure 0.
001 to 20 kg / cm ² , preferably 0.01 to 10
It is performed within the range of kg / cm ² . Pure carbon monoxide and oxygen can be used, but nitrogen,
It may be used after being diluted with a gas inert to the reaction such as argon. In particular, it is desirable to adjust the oxygen partial pressure so that the gas composition in the reaction system is out of the explosion range.

The reaction of the present invention is carried out at a temperature of 30 to 200 ° C., preferably 60 to 150 ° C., for 30 minutes to 20 hours. The reaction can be carried out in a batch system or a continuous system, but a continuous system in which carbon monoxide, oxygen and alcohol are continuously supplied to a fixed bed or a fluidized bed in which a solid catalyst is present has a high carbonic acid ester. A production rate is obtained and is preferred. At this time, the contact time between the carbon monoxide, oxygen and alcohol and the solid catalyst is 0.04 to 72.
This is performed in seconds, more preferably in the range of 0.4 to 7.2 seconds. Carbonic acid ester can be produced and obtained from the reaction product liquid by operations such as distillation and extraction, and a complicated operation such as catalyst separation is not required.

[0014]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. The meanings of the abbreviations in the examples are as follows. STY: g number of carbonate ester formed per liter of catalyst and 1 hour of reaction time (g / l / h) CO selectivity: carbonate ester (mmol) × 100 / [carbonate ester (mmol) + carbon dioxide (mmol) +2
× oxalate (mmol) + acetate (mm
ol) + formate (mmol)] (%)

Example 1 -Preparation of Catalyst- 2.0 g (11.0 mmol) of cupric acetic anhydride was added to 75 parts of water.
Then, 50 ml (23.5 g) of activated carbon was added thereto, impregnated for 7 hours, and evaporated to dryness. Further, it was dried under nitrogen at 100 ° C. for 1 hour and at 200 ° C. for 1 hour. 0.39 g (2.2 mmol) of palladium chloride and 0.29 g (4.9 mmol) of sodium chloride were added to 65 ml of methanol.
And the insolubles were separated by filtration. Activated carbon carrying cupric acetate was added to the filtrate, impregnated overnight, and then evaporated to dryness. The obtained solid was treated with 0.63 g (6.6 mmol) of 2-hydroxypyridine in 70 m of methanol.
and soaked overnight. Next, the solid was separated by filtration, washed with methanol and water, and dried under reduced pressure. Finally, the catalyst was added to a solution of 1.65 g of potassium chloride and 70 ml of water, impregnated for 1 hour, evaporated to dryness, and dried under nitrogen at 100 ° C. for 1 hour and 150 ° C. for 1 hour.

-Production of carbonate ester-A Pyrex reactor having an inner diameter of 18 mm and a length of 400 mm
1.0 palladium as the palladium metal prepared by the above method
%, 3.0% by weight as copper metal, 2-hydroxypyri
1.8% by weight of gin and 7.0% by weight of potassium chloride
10 ml of the filled catalyst, and a glass bead
(Particle size ２2 mm). This glass bee
Layer was used as an alcohol vaporizer. This reactor
Is fixed vertically in an electric furnace, and the temperature of the catalyst layer is maintained at 100 ° C.
Chi, CO 35 vol%, O _Two3.9 vol%, N_Two
61.1vol% mixed gas was touched at 10 liter / hour.
The medium is continuously supplied, and methanol is
It was fed in the same way by a header at 10 ml / hour. Reaction student
The product is collected by a gas-liquid separator, and the collected liquid is subjected to gas chromatography.
It was analyzed by fee and quantified. For exhaust gas,
Analysis by gas chromatography and determination of carbon dioxide
Done the amount. When the reaction was carried out for 2 hours,
19.2 mmol of dimethyl (hereinafter referred to as DMC)
0.2 mmol of methyl acetate (hereinafter referred to as MF)
Chill (hereinafter referred to as MA) 0.5 mmol, carbon dioxide
1.7 mmol was produced. That is, STY86.5
g / l / h and CO selectivity was 88.9%.

Comparative Example 1 A reaction was carried out in the same manner as in Example 1 except that a catalyst not supporting 2-hydroxypyridine was used. DMC
7.5 mmol, MF 0.4 mmol, MA 0.5 mm
ol and 5.8 mmol of CO ₂ . That is, S
TY was 33.8 g / l / h and CO selectivity was 52.4%. Examples 2 to 3 The reaction was carried out in the same manner as in Example 1 except that the reaction temperature was changed as shown in Table 1. The results are shown in Table 1 together with those of Example 1. (Note that a small amount of M
F and MA are produced. )

[0018]

[Table 1]

Example 4 A reaction was carried out using the same catalyst as in Example 1 except that 5.9% by weight of copper metal was supported.
27.5 mmol, CO ₂ 6.4 mmol, MF 0.7
mmol, 1.1 mmol of MA were produced. That is,
The STY was 123.9 g / l / h and the CO selectivity was 77.1%.

Example-5 Example-1 except that 3.5% by weight of potassium chloride was supported.
When the reaction was carried out using the same catalyst as described above, DM
C17.7mmol, CO ₂ 0.9mmol, MF0.
1 mmol and 0.6 mmol of MA were produced. That is, STY 79.9 g / l / h, CO selectivity 91.6%
Met.

Example -6 The composition of the mixed gas was CO / O ₂ / N ₂ = 11% / 5.3% / 8
The reaction was carried out in the same manner as in Example 1 except that the concentration was changed to 3.7%. DMC 11.6 mmol, CO ₂ 0.8 m
mol, MF 0.2 mmol, and MA 0.3 mmol. That is, STY was 52 g / l / h and CO selectivity was 89.5%.

Example -7 When the same reaction as in Example 1 was carried out using ethanol instead of methanol as the alcohol, 2.2 mmol of diethyl carbonate and 0.4 mmol of CO ₂ were produced. That is, the STY was 25.5 g / l / h and the CO selectivity was 85.7%.

Example-8-Preparation of catalyst-0.8 g (4.4 mmol) of cupric acetic anhydride was added to 30 m of water.
Activated carbon (20 ml, 9.4 g) was added thereto, impregnated overnight, and evaporated to dryness. 100 under nitrogen
It dried at 200 degreeC for 1 hour and 200 degreeC for 1 hour. PdCl ₂ (2
0.32 g (0.88 mmol) of -PyOH) ₂ is suspended in 40 ml of methanol, and activated carbon supporting cupric acetate is added thereto. The mixture is impregnated with stirring overnight, and then evaporated to dryness. The catalyst was washed with 0.66 g (8.8 g) of potassium chloride.
mmol) was dissolved in 30 ml of an aqueous solution, and the mixture was impregnated for 1 hour, evaporated to dryness, and heated at 100 ° C. for 1 hour under nitrogen.
Dry at 50 ° C. for 1 hour.

-Production of Carbonic Ester- The reaction was carried out in the same manner as in Example 1 except that the reaction time was changed to 1 hour using the catalyst prepared by the above method. DMC 6.25 mmol, CO ₂ 4.1 mmol ,
0.3 mmol of MF and 0.5 mmol of MA were produced.
That is, STY 56.3 g / l / h, CO selectivity 6
It was 3.4%.

Example-9 The reaction was carried out in the same manner as in Example-8 except that the support was changed to silica, and only 0.7 mmol of DMC was produced. That is, STY 6.1 g / l / h, CO selectivity 1
00%.

[0026]

Industrial Applicability The present invention provides a method for efficiently producing a carbonate ester, and the obtained carbonate ester can be used in various applications as a raw material for a resin or a medicinal and agricultural chemical. According to the method of the present invention, the combustion loss of carbon monoxide can be significantly reduced, the rate of carbonate ester generation can be improved, and a step of separating a product and a catalyst is not required. It is extremely important industrially.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-356446 (JP, A) JP-A-2-4737 (JP, A) JP-A-62-81356 (JP, A) JP-A-55-1981 130939 (JP, A) JP-A-55-45655 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 69/96 C07C 68/00

Claims (2)

(57) [Claims] 1. At least one selected from the group consisting of platinum group metals or salts thereof, metal copper or copper salts, trialkylamines, hetero-bridged cyclic tertiary amines, disubstituted carbodiimides, alkali metal salts and alkali metal alkoxides. And a process for producing a carbonate ester comprising reacting an aliphatic alcohol with carbon monoxide and oxygen in the gas phase in the presence of a solid catalyst comprising 2-hydroxypyridines supported on a carrier. 2. A complex compound comprising a platinum group metal or a salt thereof and a 2-hydroxypyridine, copper metal or copper salt, trialkylamine, hetero-bridged cyclic tertiary amine, disubstituted carbodiimide, alkali metal salt and alkali A method for producing a carbonate ester, comprising reacting an aliphatic alcohol with carbon monoxide and oxygen in the gas phase in the presence of a solid catalyst comprising at least one member selected from the group consisting of metal alkoxides supported on a carrier.