JPH0813788B2 - Method for producing carbonate ester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a carbonic acid ester.

Carbonic acid ester is an industrially important compound as a polymer, a raw material for producing agricultural chemicals, and a solvent.

(Prior Art) There is a method of reacting phosgene with alcohol as a method for producing a carbonic acid ester (Japanese Patent Publication No. 58-50977, Japanese Patent Publication No. 59-492, etc.), but in this method, highly toxic phosgene is used, Chlorine ions are mixed in the carbonic acid ester, which makes it difficult to remove.

As a method for producing carbonic acid ester without using phosgene, a method of reacting alcohol with carbon monoxide and oxygen in a liquid phase in the presence of a catalyst containing cupric chloride (Japanese Patent Publication No. 58-33).
857) are known. In this method, corrosion of the reactor material due to the halide compound poses a problem, and no industrial material other than the glass lining is found. In addition, there are problems such as catalyst slurry and reduced catalyst activity.

Even in the reaction under the gas phase condition (US4625044, WO87-107601), the corrosion of the reactor material due to the halogen in the catalyst still poses a problem, and an expensive special metal such as Hastelloy C is required. Further, there is a problem that halogen may be mixed in the carbonic acid ester. Further, the halogen content is reduced during the reaction, and the catalytic activity is inevitably reduced.

(Problems to be Solved by the Invention) The present invention is a method for producing a carbonic acid ester by reacting alcohol with carbon monoxide and oxygen, and there is no highly toxic phosgene or halogen and a halogen derivative that cause device corrosion. It is an object to provide a new method for producing a carbonic acid ester in a reaction system.

(Means for Solving the Problem) As a result of intensive studies, the present inventors have surprisingly found that carbonate ester can be produced by reacting alcohol with carbon monoxide and oxygen in the presence of metallic copper. They have found the present invention.

The copper used here may be a simple substance of copper or may be supported on a carrier. When loaded on a carrier, the loading amount is usually 0.05.
Used in the range of ~ 50wt%. The amount of copper used is, for example, 0.1 mmol / (methanol) to 5000 mmol / in the liquid phase method.
(Methanol).

As the solid carrier, silica, alumina, silica-alumina, zeolite, diatomaceous earth, titania, zirconia, magnesia, activated carbon, graphite, resin or the like may be used as long as it has a function as a catalyst carrier.

The solid-supported catalyst can be obtained by dissolving a copper metal salt in water or an organic solvent, adding the solid carrier to this solution to support the solution, and then performing reduction and heat treatment.

As the copper metal salt, halides, carboxylates, nitrates, sulfates, oxides, hydroxides and the like are used.

As the alcohol which is a reaction substrate in the present invention,
Saturated aliphatic alcohols such as methanol and ethanol, unsaturated aliphatic alcohols such as allyl alcohol, cyclic aliphatic alcohols such as cyclohexanol, and alcohols having 1 to 10 carbon atoms such as ethylene glycol and benzyl alcohol are used. To be

Carbon monoxide and oxygen may be used in a pure state, diluted with a gas inert to the reaction such as nitrogen, helium, argon, carbon dioxide, or air may be used as an oxygen source. . The reaction is carried out under normal pressure or under pressure,
The carbon monoxide partial pressure in the reaction system is 0.1 to 56 atm, and the oxygen partial pressure is
The range of 0.05 to 4 atm and the alcohol partial pressure of 0.1 to 40 atm are preferred.

The reaction of the present invention is carried out in the temperature range of 50 to 200 ° C., preferably 90 to 150 ° C., and usually at a reaction pressure of 100 atm or less.

(Catalyst preparation method) Dissolve 2.5 g of cupric chloride dihydrate in 22 ml of pure water.
Add 20 g of activated carbon with a particle size of 12 to 16 mesh and soak for 16 hours,
Then, the water was evaporated with a hot air dryer at 80 ° C. for 16 hours with occasional stirring. After that, heat treatment was carried out in a hydrogen atmosphere at 400 ° C. for 2 hours to prepare a catalyst.

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

Example 1 15 ml of catalyst prepared by the above-mentioned preparation method (6.5 g, 4.8 (Cu))
mmol) into a U-shaped reaction tube for high pressure gas phase, and at 150 ℃, 2
0.4 atm, and reacted for 2 hours at a space velocity of _{^{10700h -1 (CO / O 2 /}} N 2 / methanol (molar ratio) = 37/3/57/3). The product was quantified by gas chromatography. The result is 0.
77 g of dimethyl carbonate was obtained.

(0.07 g of methyl formate was detected as a by-product from methanol.) Example 2 2.5 g (1.85 (Cu) mmol) of the same catalyst as in Example 1 was crushed into powder, and 320 ml of autoclave was mixed with 38 ml of methanol. I put it in. Further, CO of 20 atm, O _{2 of} 1 atm and Ar of 4 atm were added, and the reaction was carried out at 130 ° C. for 70 minutes. As a result, 0.80 g of dimethyl carbonate was obtained. (0.003 g of methylal was detected as a by-product from methanol.) Example 3 1 g (15.7 mmol) of copper powder together with 38 ml of methanol at 320 m
I put it in the autoclave. Furthermore, CO of 7.2 atm, 0.
9 atm of O ₂ and 4 atm of N ₂ were charged and reacted at 130 ° C. for 70 minutes. As a result, 0.014 g of dimethyl carbonate was obtained. (0.002 g of methylal was detected as a by-product from methanol.) Comparative Example The reaction was carried out under the same conditions as in Example 3 using 2.5 g of activated carbon, but no formation of dimethyl carbonate was observed.

(Effect of the invention) Carbonic acid ester can be obtained in the presence of metallic copper under mild conditions of alcohol, carbon monoxide and oxygen without corroding the reaction apparatus. Since there is no corrosion, it is possible to use inexpensive general-purpose materials such as SUS-316L for the reactor. Further, it became possible to obtain a high-purity carbonate ester without fear of inclusion of impurities.

Claims (1)

[Claims] 1. A method for producing a carbonate ester, which comprises reacting alcohol with carbon monoxide and oxygen in the presence of metallic copper.