JP2814005B2 - Method for producing alkylene glycol ether - Google Patents

Description

The present invention relates to a process for producing an alkylene glycol ether which is important as a water-soluble organic solvent and is widely used in the industrial field. And a method for selectively producing the alkylene glycol ether via a reaction between a carbonate ester and a lower alkylene oxide.

[Prior Art] Conventionally, a method of producing an alkylene glycol ether (hereinafter abbreviated as AGE) by adding an alkylene oxide to an alcohol in the presence of an acid or a base as a catalyst has been known. However, when sodium hydroxide or potassium hydroxide is used as the base catalyst, a dialkylene glycol ether (hereinafter abbreviated as DAGE) to which a predetermined amount or more of alkylene oxide is added in addition to the target AGE, a trialkylene glycol ether (hereinafter TAGE) Abbreviated as). To suppress the formation of these by-products, increase the molar ratio of alcohol / alkylene oxide,
It must react in the presence of a large excess of alcohol.
Therefore, the circulation amount of alcohol is enormous, the utility cost is increased, and a large-capacity reaction tank and distillation apparatus are required, which is not industrially advantageous.

On the other hand, when an acid catalyst such as sulfuric acid is used, by-products such as dialkyl ether and dioxane are generated by dehydration condensation of alcohol in addition to the above-mentioned by-products.
There are drawbacks in that the yield of AGE is reduced and that multiple stages of distillation purification are required.

Various catalysts have been studied to solve these problems.
For example, when a solid acid catalyst such as γ-alumina and phosphotungstic acid disclosed in JP-A-52-51307 is used, there is an advantage that separation of the catalyst and the reaction product can be easily performed by filtration, but the like. The selectivity of the desired AGE generation was a problem. Furthermore, in JP-A-55-49332, montmorillonite exchanged with aluminum or the like is disclosed in JP-A-55-1496.
No. 49 discloses silica alumina supporting an iron group metal or the like, and JP-A-62-289537 proposes a montmorillonite exchanged with a group I or group II metal of the periodic table as a solid acid catalyst. Although improvement in the selectivity of AGE formation was observed, DAGE and TAGE were not sufficiently suppressed industrially because they did not minimize the side effects.

"Problems to be solved by the invention" In view of the above points, the present inventors have conducted intensive studies and found that AGE
Found a revolutionary method for highly selective production of Heretofore, the reaction between a dialkyl carbonate and an alkylene oxide has not been known.However, the present inventors have studied the reaction, and when a specific catalyst is used, the alkylene oxide insertion reaction occurs with high activity, and the reaction product It has been found that AGE can be produced with high selectivity by hydrolyzing, and the present invention has been completed.

"Means for Solving the Problem" That is, the present invention relates to a carbonate represented by the following general formula (1) and a carbonate represented by the following general formula (1) in the presence of a Lewis acid comprising an Al, Zn or Ti compound and a tertiary amine compound Reacting the lower alkylene oxide represented by (2), “Here, R ¹ represents an alkyl group having 1 to 10 carbon atoms or a substituted alkyl group, and R ² and R ³ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.” Then, the following general formula (3) )) “R ¹ , R ² and R ³ represent the same substituents as described above.” This is a process for producing an alkylene glycol ether represented by the following general formula (4), characterized by reacting with water or a lower alcohol.

"R ¹ , R ² and R ³ represent the same substituents as described above." As the alkylene oxide used in the present invention, lower alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide and isobutylene oxide are generally mentioned. Can be.

Examples of the carbonate used in the present invention include dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, and di-n-carbonate.
Butyl, di-2-chloroethyl carbonate and the like can be mentioned. These may be produced by any method.

Al, one of the components used as a catalyst in the present invention,
Examples of the Lewis acid composed of Zn or Ti compounds include Al
Examples thereof include halides of these metal elements such as Cl ₃ , ZnCl ₂ , TiCl ₄ , AlBr ₃ , and ZnBr ₂ .

On the other hand, tertiary amine compounds which are other components used as the catalyst of the present invention include aliphatic amine compounds such as triethylamine and triethanolamine, pyridine,
Examples thereof include aromatic amine compounds such as quinoline.

The method of the present invention comprises a reaction of inserting an alkylene oxide into a carbonate ester, followed by a decomposition reaction of the reaction product with a hydroxyl-containing compound.

In the former insertion reaction, when the number of moles of the alkylene oxide used per mole of the carbonic ester is large, the production rate of the target alkylene glycol monoalkyl ether decreases, and for example, the insertion alkylene oxide such as dialkylene glycol monoalkyl ether is used. Is not preferable in view of the object of the present invention since the amount of by-products in which 1 mol or more is inserted increases, and the molar ratio of alkylene oxide to carbonate ester is preferably 1 / 0.2 to 1/2.

However, it is also possible to apply the method of the present invention to the production of a compound such as DAGE described above, and in such a case, the molar ratio may be increased.

The molar ratio of the Lewis acid used as the catalyst to the tertiary amine compound is usually in the range of 1/1 to 3/1. The total amount of the catalyst is preferably 0.02 to 6 mol% based on the starting carbonic acid ester.

The reaction temperature is 50 to 200 ° C, more preferably 100 to 18
Performed in the range of 0 ° C. The reaction system is generally carried out in a semi-continuous system in which alkylene oxide is successively added, but it can also be carried out in a batch system or a continuous system, and furthermore, in an open system or a closed system.

Next, the decomposition reaction in the latter half of the method of the present invention will be described. Examples of the lower alcohol used in this reaction include methanol, ether, propanol, butanol and the like. The amount of water or the alcohol is preferably 1 to 10 times the hydroxyl group equivalent per ester group. The reaction temperature is
Performed at 50-150 ° C.

For example, when hydrolyzed using water, glycol ether and carbon dioxide are generated, and the carbon dioxide is easily removed. Further, when decomposed using, for example, methanol, it becomes dimethyl carbonate, which can be easily separated and recovered by distillation.

Thus, the reaction product obtained according to the method of the present invention can be purified by distillation to obtain the desired AGE in high yield.

"Examples" Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In the following description, "parts" indicates parts by weight unless otherwise specified, and the conversion and selectivity are defined as follows.

Conversion = [moles of added alkylene oxide-mols of unreacted alkylene oxide] ÷ [moles of added alkylene oxide] x 100 AGE selectivity = [moles of AGE generated] ÷ [molecules of reacted alkylene oxide] Number of moles × 100 Selectivity of DAGE = [Number of moles of generated DAGE] × 2 ÷ [Number of moles of reacted alkylene oxide] × 100 Selectivity of TAGE = [Number of moles of generated TAGE] × 3 ÷ [Reaction Number of moles of alkylene oxide prepared] × 100 Example 1 50 with an ethylene oxide (hereinafter abbreviated as EO) supply tube
In a 0 volume part autoclave, 187.1 parts of di-2-chloroethyl carbonate, 3.8 parts of titanium tetrachloride and triethylamine 1.
0 parts were charged, and the inside of the system was replaced with nitrogen gas. After setting the internal temperature of the autoclave to 150 ° C, start supplying EO and set the internal temperature to 160 ° C.
40.9 parts of EO was supplied continuously for 30 minutes so as to maintain. Further, an aging reaction was performed for 15 minutes while maintaining the internal temperature at 160 ° C. Thereafter, the autoclave was cooled and opened, and the reaction mixture was taken out.

Next, the reaction mixture and 256.3 parts of methanol were charged into a 1,000-volume flask equipped with a stirrer, a thermometer and a reflux condenser, and refluxed for 180 minutes.

When the reaction solution was analyzed by gas chromatography, EO
100%, 2- (2-chloroethoxy) ethanol selectivity 83.7%, 2- [2- (2-chloroethoxy) ethanol
Ethoxy] ethanol selectivity 16.3%, 2- ｛2- [2
-(2-Chloroethoxy) ethoxy] ethoxy} ethanol was not produced.

Example 2 In the same autoclave as in Example 1, 348.4 parts of di-n-butyl carbonate and 7.6 parts of titanium tetrachloride were added to triethylamine.
2.0 parts were charged, and the inside of the system was replaced with nitrogen gas. After heating until the internal temperature of the autoclave reaches 155 ° C, start supplying EO, and intermittently maintain EO3 over 120 minutes while maintaining the internal temperature at 160 ° C.
0.8 parts were supplied. Further, an aging reaction was performed at 160 ° C. for 30 minutes. Thereafter, the autoclave was cooled, 144.0 parts of water was added, and a hydrolysis reaction was performed at 60 ° C. for 150 minutes. When the reaction solution was analyzed by gas chromatography, the conversion rate of EO was 10
0%, selectivity of 2-n-butoxyethanol 76.9%, 2
-(2-n-butoxy) ethoxyethanol selectivity 2
2.8%, 2- [2- (2-n-butoxy) ethoxy] ethoxyethanol was not produced.

Comparative Example 1 The same autoclave as in Example 1 was charged with 241.6 parts of 2-chloroethanol and 2.9 parts of zinc chloride, and the inside of the system was replaced with nitrogen gas. After heating the internal temperature of the autoclave to 110 ° C, start supplying EO and maintain the internal temperature at 110 ° C.
43.0 parts of EO were supplied intermittently over 0 minutes. 30 at 110 ° C
The ripening reaction was performed for minutes.

The reaction was analyzed by gas chromatography.
EO conversion 99.9%, 2- (2-chloroethyl) ethanol selectivity 58.0%, 2- [2- (2-chloroethyl) ethoxy] ethanol selectivity 28.7%, 2- {2- [2-
The selectivity for (2-chloroethyl) ethoxy] ethoxydiethanol was 13.2%.

Therefore, it is clear that the selectivity of 2- (2-chloroethyl) ethanol is higher in Example 1.

Comparative Example 2 In the same autoclave as in Example 1, n-butanol was added.
222.4 parts and 0.4 part of potassium hydroxide were charged, and the inside of the system was replaced with nitrogen gas. While maintaining the internal temperature of the autoclave at 120 ° C., 44.0 parts of EO were supplied intermittently over 40 minutes. In addition, 12
An aging reaction was performed at 0 ° C. for 40 minutes.

The reaction was analyzed by gas chromatography.
EO conversion 99.9%, selectivity of 2-n-butoxyethanol 49.6%, selectivity of 2- (2-n-butoxyethoxy) ethanol 32.8%, 2- [2- (2-n-butoxyethoxy) ethoxy ] The selectivity of ethanol was 17.5%.

Examples 3 to 10 Example 1 and Example 2 were repeated under the reaction conditions shown in Table 1, and the results are shown in Table 2.

[Effect of the Invention] By inserting a lower alkylene oxide into a specific carbonate ester and then subjecting the reaction product to a decomposition reaction with a hydroxyl group-containing compound, the alkylene glycol monoalkyl ether is obtained in a higher yield as compared with a conventionally known method. Can be obtained with high selectivity.

Claims (1)

(57) [Claims] 1. A carbonate ester represented by the following general formula (1) and a lower alkylene represented by the following general formula (2) in the presence of a Lewis acid composed of an Al, Zn or Ti compound and a tertiary amine compound. React the oxide, “Here, R ¹ represents an alkyl group having 1 to 10 carbon atoms or a substituted alkyl group, and R ² and R ³ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.” Then, the following general formula (3) )) "R ¹ , R ² and R ³ represent the same substituents as described above." A process for producing an alkylene glycol ether represented by the following general formula (4), characterized by reacting with water or a lower alcohol. "R ¹ , R ² and R ³ represent the same substituents as described above."