KR100354454B1 - Process for the preparation of alkylenecarbonate using lithium halide as catalyst - Google Patents

Abstract

The present invention relates to a method for producing alkylene carbonate by reacting alkylene oxide and carbon dioxide in the presence of a lithium halogen compound [LiX (X = Cl, Br, I)] catalyst.

Description

PROCESS FOR THE PREPARATION OF ALKYLENECARBONATE USING LITHIUM HALIDE AS CATALYST}

The present invention relates to a method for producing alkylene carbonate by reacting alkylene oxide with carbon dioxide. More specifically, the present invention relates to a method for preparing alkylene carbonate by reacting an alkylene oxide with carbon dioxide in the presence of a LiX (X = Cl, Br, I) catalyst.

Alkylene carbonates are used for the synthesis of polymers such as polycarbonate, intermediates in pharmaceutical processes, oxyalkylatin agents in dyestuff synthesis, process equipment protection agents, and solvents in fiber production processes. As the method for producing the alkylene carbonate, a method of reacting carbon dioxide and alkylene oxide in the presence of a catalyst is usually used, and this reaction can be represented by Scheme 1.

However, in the above reactions, many restrictions on the installation are followed because high temperatures and pressures are required to obtain industrially useful reaction rates.

In order to improve this, various kinds of materials have been developed as catalysts.

As a method of using inorganic salts, phosphonium halides and ammonium halide-based compounds as catalysts, JP-A-9-67365, JP-A-59-13776, JP-A-9-235252 and US Patent No. 2,773,070 and the like. Japanese Laid-Open Patent Publication No. 9-67365 discloses a method of using Kl as a catalyst, and Japanese Laid-Open Patent Publication No. 59-13776 discloses a tetraalkyl phosphonium such as tributyl methyl phosphonium iodide. A method of using tetraalkyl phosphnium halides is disclosed. In addition, Japanese Patent Laid-Open No. Hei 9-235252 discloses a method of using a polystyrene copolymer having a 4 ° phosphonium halide attached to a terminal group. U.S. Patent No. 2,773,070 also discloses the use of several types of ammonium halides. These patents state that the yield is 50-95% when the reaction temperature is reacted at 100-170 ° C. for 1-5 hours. However, in order to obtain high yield, high temperature and long reaction time are required. There is a problem in that the water content of the alkylene oxide to be adjusted to several hundred ppm or less.

As a method of using an ion exchange resin, Japanese Patent Laid-Open No. Hei 7-206846 discloses a method using a catalyst in which CsOH, RbOH, and ammonium halide are substituted in an ion exchange resin, and US Patent No. 4,233,221 discloses DOWEX and Amberlite series Although a method of using an exchange resin is proposed, a low yield of about 30-80% can be obtained at 80-100 ° C.

In addition to the above-mentioned materials, U.S. Patent No. 5,283,356 discloses a method using phthalocyanin including Co, Cr, Fe, Mn, Ni, Ti, V, Zr, etc. as a catalyst. 206547 discloses a method using a catalyst system in which rubidium (Rb) or cesium (Cs) ions are substituted for hydrogen ions of heteropoly acid, both of which require expensive catalysts, and the reaction temperature is 120-180. Not only was it high, but the yield was 30-90%.

As mentioned above, the prior art has a problem that the reaction conditions such as high temperature, water removal of raw materials, etc. are difficult to select industrially to produce alkylene carbonate, low selectivity and yield, and a long reaction time.

Accordingly, an object of the present invention is to solve the problems of the prior art to provide a method for producing an alkylene carbonate with a high yield in a quick time under easy reaction conditions. More specifically, to provide a method for producing an alkylene carbonate in a high yield under easy reaction conditions using a lithium halogen compound catalyst.

The present invention is characterized in that alkylene carbonate is prepared by reacting alkylene oxide and carbon dioxide in the presence of a lithium halogen compound catalyst. In the reaction of producing an alkylene carbonate by reacting alkylene oxide with carbon dioxide, the present inventors use a lithium halogen compound as a catalyst, as shown in the following Scheme 2, at a faster time at a lower pressure and temperature than when using a conventional catalyst system. It was found that high yields can be obtained.

That is, in the method for producing an alkylene carbonate having the following Chemical Formula 1 by reacting an alkylene oxide with carbon dioxide, in the case of using a lithium halogen compound [LiX (X = Cl, Br, I)] as a catalyst, It has been found that it can be produced in high yield at a faster time at low pressure and temperature conditions.

In Formula 1, R ₁ and R ₂ are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms.

In more detail, the lithium halogen compound (LiX) used as a catalyst may be LiCl, LiBr, or LiI. The amount of catalyst to be used is preferably 0.005-3 mol% based on the raw material alkylene oxide. If the amount used is less than 0.005 mol%, the reaction rate becomes too slow, and if it is 3 mol% or more, the reaction efficiency and selectivity do not improve any more, so the economic efficiency of using the catalyst becomes worse.

The reaction pressure of the reaction is preferably 10-100 atm. When the reaction pressure is less than 10 atm, the reaction rate is slowed down, and if the reaction pressure is more than 100 atm, the effect of improving the reaction rate is lost.

The reaction temperature is preferably 80-170 ° C. If the reaction temperature is low, the reaction rate is slow. If the reaction temperature is high, the alkylene oxide is not good because it causes self-polymerization or poor reaction selectivity.

The reaction proceeds quickly even in the absence of a solvent, but a solvent may be used to prevent rapid exotherm. When using a solvent, it is preferable to use a material such as alkylene carbonate produced from the raw alkylene oxide, but is not necessarily limited thereto. For example, when synthesizing ethylene carbonate from ethylene oxide, it is preferable to use ethylene carbonate as a solvent when synthesizing propylene carbonate from propylene oxide, but propylene carbonate may be used for ethylene carbonate synthesis. See Example 21-24). As a production method, it is possible to use both a batch process using a reactor equipped with a stirrer and a continuous process using a bubble column. After completion of the reaction, the alkylene oxide was completely removed, weighed, and yield was calculated using gas-liquid chromatography. The present invention will be described in more detail with reference to the following Examples, but the scope of the present invention is not limited to these Examples.

Example 1

Ethylene oxide (16.80 g, 380 mmol) and LiBr (149 mg, 1.72 mmol) were added to a 200 ml high pressure reactor, and 10 atm of carbon dioxide was charged. After raising the temperature to 100 ℃ was added to the carbon dioxide again was adjusted to 30 atm. While the reaction was in progress, the amount of carbon dioxide consumed was continuously supplied to maintain the pressure of the reactor at 30 atmospheres. After the reaction at 100 ° C. for 1 hour, the reactor was cooled to room temperature to remove volatile components using nitrogen, and the solid product was separated and weighed. The yield was 32.6 g, and the yield was 97%. It was.

Yield was calculated as follows.

Example 2-3

Table 1 shows the results of reaction experiments using other lithium halogen compounds as catalysts under the same conditions as in Example 1. The amount of catalyst was fixed at 1.72 mmol.

Example catalyst Product mass (g) Shoo rate (%) 2 LiCl 28.5 85 3 LiI 33.2 99

Comparative Example 1-5

In order to compare the reaction characteristics with the conventional catalyst under the same conditions as in Example 1, the results of the experiment while varying the catalyst type, reaction time and temperature are shown in Table 2.

Comparative example catalyst Reaction time Product mass (g) Yield (%) One KI 2 hours 16.1 48 2 NaI 2 hours (120 ° C) 31.2 93 3 NaI 2 hours (100 ° C) 7.7 23 4 KBr 2 hours To 0 To 0 5 ZnI ₂ 2 hours To 0 To 0

Example 4-8

Table 3 shows the results of the experiment while changing the reaction temperature under the same conditions as in Example 1.

Example Temperature (℃) Product mass (g) Yield (%) 4 70 11.8 35 5 80 27.9 83 6 90 31.2 93 7 120 33.2 99 8 170 31.9 95

Example 9-13

Table 4 shows the results of the reaction experiments under varying pressure under the same conditions as in Example 1.

Example Pressure (atm) Product mass (g) Yield (%) 9 10 21.8 65 10 20 32.6 97 11 40 33.2 99 12 80 33.2 99 13 100 33.2 99

Example 14-17

Table 5 shows the results of the reaction experiments under varying catalyst / ethylene oxide ratios under the same conditions as in Example 1.

Example Catalyst / ethylene oxide (mol%) Product mass (g) Yield (%) 14 0.005 11.8 35 15 0.01 27.5 82 16 0.5 32.9 98 17 3 33.2 99

Example 18-20

Table 6 shows the results of the reaction experiments while changing the type of alkylene oxide under the same conditions as in Example 1.

Example Reactant / product Product mass (g) Yield (%) 18 Propylene oxide / propylene carbonate 34.9 90 19 2-methyl-1,2-epoxypropane / 1,1-dimethylethylene carbonate 31.7 72 20 2,3-epoxybutane / 1,2-dimethylethylene carbonate 33.5 76

Example 21-24

Table 7 shows reaction experiments using ethylene carbonate or propylene carbonate as a solvent under the same conditions as in Example 1. The amount using solvent was varied to 50-200% by weight relative to ethylene oxide.

Example menstruum Solvent / Ethylene Oxide (wt%) Product mass (g) Yield (%) 21 Ethylene carbonate 50 33.2 99 22 Propylene carbonate 100 32.9 98 23 Ethylene carbonate 150 30.6 91 24 Propylene carbonate 200 29.9 89

Example 25-26

Table 8 shows the results of reaction experiments using two or more catalysts mixed under the same conditions as in Example 1.

Example catalyst Catalyst ratio Product mass (g) Shoo rate (%) 25 LiCl / LiCl 1: 1 33.2 99 26 LiI / LiCl 1: 1 33.2 99

When the lithium halogen compound is used as a new catalyst according to the present invention, it is possible to synthesize alkylene carbonate in high yield at high speed under easier reaction conditions using various types of alkylene oxide and carbon dioxide. In addition, since the catalyst has a high catalytic activity and is made of a single material, it is easy to separate from the product and easily reprocessed, and thus has a great advantage in terms of economics.

Claims (7)

In a method of preparing an alkylene carbonate having the following Chemical Formula 1 by reacting an alkylene oxide with carbon dioxide, a compound selected from lithium halogen compounds represented by LiX (X = Cl, Br or I) is used as a catalyst. Method for preparing alkylene carbonate by: [Formula 1] In Formula 1, R ₁ and R ₂ are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms. The production method according to claim 1, wherein the amount of the catalyst used is 0.005 to 3 mol% based on the raw material alkylene oxide. The production method according to claim 1, wherein the reaction temperature is 80 ° C to 170 ° C. The production method according to claim 1, wherein the reaction pressure is 10 to 100 atmospheres. The process according to claim 1, wherein no solvent is used. The process according to claim 1, wherein the same material as the alkylene carbonate produced is used as a solvent. The method of claim 6, wherein the solvent is ethylene carbonate or propylene carbonate.