JPH0123466B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing alkylene carbonate, and particularly to a method for producing alkylene carbonate in high yield from alkylene oxide and carbon dioxide in the presence of a catalyst. Alkylene carbonates such as ethylene carbonate and propylene carbonate are used in a wide range of applications as raw materials for organic solvents, synthetic fiber processing agents, pharmaceuticals, alkylene glycols, and the like. Conventionally, various catalysts have been proposed for use in producing alkylene carbonate from alkylene oxide and carbon dioxide. For example, (1) Bromides or iodides of alkali metals (Japanese Patent Publication No. 38-23175) (2) Halides of alkaline earth metals (US Pat. No. 2,667,497) (3) Alkylamines, quaternary ammonium salts, chlorides Ammonium (US Patent No. 2773070) (4) Amines such as pyridine and piperidine (British Patent No. 760966) (5) Rhodanammonium or thermal decomposition products of Rhodanammonium (Japanese Patent Publication No. 38-5833) (6) Lead halide or zinc halide (Japanese Patent Publication No. 45-38534) (7) Halides of iron, cobalt or nickel (Japanese Patent Publication No. 45-35311) (8) Hydroxylamine, urea, hydrazine and hydrochlorides of these compounds , hydrobromide, hydroiodide, phosphate and oxalate (Special Publication No. 47-1625) (9) Zinc, cadmium, chromium, manganese, iron,
At least one compound selected from the group consisting of inorganic weak acid salts and organic carboxylates of cobalt and nickel, and an organic halide
No. 15951) (10) Chromium, manganese, ruthenium, rhodium,
One or more metal halides selected from the group consisting of chloride, bromide, and iodide of cadmium and organic tertiary phosphine (Special Publication No. 26786/1986) (11) Iron, cobalt, nickel, zinc One or more metal halides selected from the group consisting of chlorides, bromides, and iodides, and organic tertiary phosphine (Japanese Patent Publication No. 1983-27223) (12) Phosphonium halide salt or sulfonium halide Salt (Japanese Patent Publication No. 47-27223) (13) Composite catalyst consisting of isic acid and nitrogen-containing organic base (Japanese Patent Publication No. 27314-1988) (14) Traethylammonium bromide, tetramethylammonium bromide, penzyltriethylammonium bromide, Tetrabutylammonium bromide (JP-A-54-98765
(15) Grignard reagent (Special Publication No. 54-29495). However, the conditions under which these catalysts are used require the reaction to occur at high temperature and pressure;
Rapid polymerization of alkylene oxide, low yield of alkylene carbonate based on raw material alkylene oxide, difficulty in separating the target alkylene carbonate in the separation process after the completion of the reaction, and products of the obtained alkylene carbonate. Each has its own drawbacks, such as remaining quality problems such as coloration and odor. Accordingly, an object of the present invention is to provide a method for producing high-yield, high-quality alkylene carbonate by reacting alkylene oxide and carbon dioxide under mild conditions at relatively low temperature and low pressure. Another object of the present invention is to provide a method for producing high quality alkylene carbonate. These objects are achieved by a method for producing alkylene carbonate, which comprises reacting an alkylene oxide with carbon dioxide in the presence of a crown ether alkali metal halide complex catalyst comprising a crown compound and an alkali metal halide. Alkylene oxide is reacted with carbon dioxide in the presence of a crown ether alkali metal halide complex catalyst comprising a crown compound and an alkali metal halide according to the following formula to produce alkylene carbonate. The outline of the manufacturing method of the present invention is as follows. The alkylene oxide and catalyst are placed in a reactor, carbon dioxide is supplied, and the reaction is started by heating while mixing by stirring or the like. As the reaction progresses, carbon dioxide gas is continuously supplied to complete the reaction. After the reaction is completed and excess carbon dioxide gas is released, the reaction product is taken out and rectified under reduced pressure to obtain a highly pure colorless alkylene carbonate. The catalyst recovered as a distillation residue can be subjected to the reaction again. The alkylene oxide used in the method of the present invention mainly has the general formula () (However, in the formula, R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen alkyl group, an aryl group, an alkenyl group or a cycloalkyl group.) Typical examples are ethylene oxide, propylene oxide, isobutylene oxide, 1,2-butylene oxide, 2,3
-butylene oxide, pentylene oxide, styrene oxide, etc., preferably ethylene oxide and propylene oxide, especially ethylene oxide. As the alkylene oxide as a reaction raw material, alkylene oxide obtained by any method can be used. For example, as raw material ethylene oxide, ethylene and a molecular oxygen-containing gas such as air, oxygen-enriched air, or pure oxygen are mixed in the gas phase over a silver catalyst at 180%
Ethylene oxide obtained by the direct oxidation method by reaction at temperatures of ~300°C can be used. Particularly preferred is ethylene oxide purified to substantially 100%, but impure ethylene oxide obtained before the ethylene oxide purification step can also be used. The alkylene carbonate of the general formula () corresponding to the alkylene oxide used is (However, in the formula, R ₁ , R ₂ , R ₃ and R ₄ represent hydrogen, an alkyl group, an aryl group, an alkenyl group or a cycloalkyl group.) A typical example is ethylene carbonate. , propylene carbonate, etc. Carbon dioxide as a reaction raw material is usually supplied in gaseous form and is used in an amount of 1 to 5 times, particularly 1 to 3 times, by mole relative to the alkylene oxide. The catalyst used in the process of the invention is a compound of a crown compound and an alkali metal halide. These are compounds in which a halogen anion is coordinated to a stable multidentate macrocyclic polyether alkali metal complex, and are, for example, compounds represented by the following general formula (). (However _, in the formula, M represents sodium, potassium, _rubidium , cesium, and lithium. represents.A represents oxygen.n represents 4-
8) Alkali metal halides include salts, iodides, and bromides of sodium, potassium, rubidium, cesium, and lithium. The crown compound is a macrocyclic polyether whose basic skeleton is a cyclic oligomer of alkylene oxide whose chemical structure is mainly ethylene oxide, and into which one or several benzene nuclei, cyclohexane rings, etc. are incorporated. For example, aliphatic crown ethers, aromatic crown ethers, alicyclic crown ethers, heterocyclic crown ethers, cyclic polyether esters, specifically dibenzo-18-crown-6 (2,3,11,
12-dibenzo-1,4,7,10,13,16-hexaoxanecroocta-2,11-diene), dicyclohexyl-18-crown-6, dibenzo-24-
Crown-8, 12-Crown-4, 15-Crown-5, 18-Crown-6 (1, 4, 7, 10, 13,
16-hexaoxacycloocta-2,11-diene) and the like are preferred. The catalyst comprising an alkali metal halide and a crown compound according to the present invention may be prepared by supplying the alkali metal halide and the crown compound separately to the reaction zone, or by reacting the alkali metal halide and the crown compound in advance. For example, it may be supplied in the form of a crown ether alkali metal halide complex.
Catalysts consisting of alkali metal halides and crown compounds react against alkylene oxides.
It is used in a range of 0.001 to 10 mol%, preferably 0.1 to 5 mol%. The reaction temperature varies depending on the type of raw material alkylene oxide, the type of catalyst, the composition of the reaction liquid at the beginning of the reaction, etc., but is 80 to 250°C, preferably 80 to 180°C. The reaction pressure is 1~300Kg/ ^cm2G , preferably 3~300Kg/cm2G.
It is 50Kg/cm ² G. The reaction format may be batch, semi-batch or continuous. By manufacturing according to the method of the present invention, a colorless and odorless alkylene carbonate of high quality can be obtained. The method of the present invention will be specifically explained below with reference to examples, but it goes without saying that these are merely illustrative examples and the present invention is not limited in any way by these examples. Of course, various implementations are possible. Example 1 33.0 g of ethylene oxide and 18
-crown-6-potassium iodide complex (1,4,
7,10,13,16-hexaoxacycloocta-
A complex of 2,11-diene and potassium iodide) was charged at 4.9% by weight based on ethylene oxide, carbon dioxide gas was injected to a maximum of 6 kg/cm ² G, and the mixture was immersed in an oil bath maintained at a temperature of 140°C for 90 minutes. Made me react. The pressure rose to 17 kg/cm ² G in 5 minutes and then began to fall. The reaction temperature at this time was 92°C.
After confirming the pressure drop, increase the pressure to 20-25Kg/cm ² G
Carbon dioxide gas was continuously supplied for 60 minutes to maintain the temperature. After no pressure drop was observed, the reaction was allowed to stand for 25 minutes to complete the reaction. After the reaction was completed, the contents were analyzed and found to be 99.9% for ethylene oxide.
Ethylene carbonate was obtained with a yield of mol%. Moreover, the obtained contents were colorless and odorless. Examples 2 to 4 Example 1 was carried out in the same manner as in Example 1 except for the catalyst and reaction conditions shown in Table 1. The results were as shown in Table 1. Comparative Example 1 A stainless steel autoclave with a capacity of 200 ml and equipped with a stirrer was charged with 33 g of ethylene oxide and potassium iodide in an amount of 4.9% by weight based on ethylene oxide, and reacted in the same manner as in Example 1 for 60 minutes.
The results were as shown in Table 1. Example 5 The same autoclave as in Example 1 was used, except that the raw material was changed to propylene oxide. The results were as shown in Table 1. 【table】

Claims (1)

[Claims] 1 Alkylene oxide and carbon dioxide are represented by the general formula () (However _, in the formula, M represents sodium, potassium, _rubidium , cesium, and lithium. represents.A represents oxygen.n represents 4-
8) A method for producing alkylene carbonate, which comprises reacting in the presence of the crown compound shown in item 8).