JPH01242541A - Production of glycol ethers - Google Patents

Abstract

PURPOSE:To obtain the present substances useful as a solvent, refrigerant, absorber, plasticizer, etc., in high yield at a low cost, by reacting glycol esters with hydrogen in the presence of a catalyst capable of hydrogenating ester bonds into ether bonds. CONSTITUTION:Glycol esters (e.g., propylene glycol monoacetate) are reacted with hydrogen in the presence of a catalyst containing Fe, Co, Ni, Ru, Rh, Pd, Pt, etc., and supported by alumina, etc., at 50-350 deg.C under 10-300kg/cm<2>G for 0.1-50hr to afford the present substances. The molar ratio of the glycol esters to the hydrogen used is preferably 1:0.1-50 and the weight ratio of the glycol esters to the catalyst is preferably 0.1-1000. The reaction can be carried out in any of the liquid, vapor and vapor-liquid phases.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing glycol ethers from glycol esters.

[Prior art and problems to be solved by the invention] Glycol ethers include glycol monoethers, glycol ether esters, and glycol diethers, and they can be used in various solvents, refrigerants, absorbents, plasticizers, penetrants, It is an industrially useful compound that can be used for a wide range of purposes, including as a softening agent.

Conventionally, as a method for producing glycol ethers, there is a method of reacting an epoxy compound with an alcohol or a carboxylic acid ester (JP-A-61-204141, JP-A-60-78938). However, since this method uses an epoxy compound and alcohol or carboxylic acid ester as raw materials, variable processing costs are relatively high, and when used mainly as a solvent, there is a problem in that it is disadvantageous in terms of cost.

On the other hand, as another conventional production method, there is a method of reacting glycols with olefins (Japanese Patent Application Laid-Open No. 163831/1983)
Publication No.). However, this method has the disadvantage that since the raw material glycols are obtained from epoxy compounds, the production process is one step longer than in the above method.

Furthermore, as another conventional production method, a method of reacting aldehydes with synthesis gas (Japanese Patent Application Laid-Open No. 60-246334
Publication No.). However, this method has the drawback that the yield of glycol ethers obtained is low.

The object of the present invention is to provide a method for producing glycol ethers with high yield, which solves the above-mentioned drawbacks.

[Means to Solve the Problem 1] Therefore, the present inventors have conducted extensive research to produce glycol ethers at a higher yield and at a lower cost than conventional techniques, and as a result, the present inventors have developed a method for producing glycol ethers that can be obtained industrially at a low cost. Focusing on glycol esters, which can be easily obtained in high yields by reacting olefins, carboxylic acids, and oxygen, we discovered that the ester bonds of these glycol esters could be converted to ether bonds by hydrogenation. This finding led to the completion of the present invention.

That is, the present invention is a method for producing glycol ethers, which is characterized by reacting glycol esters with hydrogen in the presence of a catalyst capable of hydrogenating ester bonds to ether bonds.

Glycol esters used as raw materials in the present invention include glycol monoesters and glycol diesters, and specifically, examples include ethylene glycol monoformate, ethylene glycol diacetate, and ethylene glycol monoacetate.・, ethylene glycol diacetate, ethylene glycol monoprobionate, ethylene glycol diacetate, propylene glycol monoformate, propylene glycol monoacetate, propylene glycol diacetate,
Propylene glycol monopropionate, propylene glycol diacetate, 1.2-butylene glycol monoacetate, 1.2-butylene glycol diacetate, 2.3-butylene glycol monoacetate, 2
．． Examples thereof include 3-butylene glycol diacetate, 2,3-butylene glycol dibropiopropionate, 2,3-butylene gelicol monobutyrate, and those having substituents that do not inhibit the reaction. Examples of substituents that do not inhibit the reaction include alkyl groups, aryl groups,
Examples include aralkyl groups, amino groups, and halogen atoms.

The glycol esters used in the present invention are:
One type may be used alone, or two or more types may be used. - The hydrogen used in the present invention is not only pure hydrogen, but may also contain impurities. Impurities include carbon oxide, carbon dioxide, hydrocarbons such as methane, and ethane.

Specifically, hydrogen obtained by, for example, electrolysis of water, modification of water gas, gasification of petroleum, etc. can be used.

In the present invention, the glycol esters and hydrogen are reacted in the presence of a specific catalyst. Catalysts that can be used in the present invention are catalysts that can hydrogenate ester bonds to ether bonds, and specifically include t; Catalyst containing one or more elements of group ■ of the periodic table, such as chromium, molybdenum, tungsten, etc. Catalyst containing one or more elements of group ■ of the periodic table, such as manganese, rhenium, etc. There are catalysts containing one or more types of elements, preferably catalysts containing one or more elements of group Ⅰ of the periodic table, such as iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum.

Note that these elements may be used alone or in combination of two
You may use a combination of two or more species.

The state of the elements contained in the catalyst is not particularly limited, and includes, for example, simple metals, alloys, intermetallic compounds, oxides, sulfides, carbides, nitrides, hydrides, chlorides, and hydroxides. It may exist in the form of inorganic compounds such as carbonates, oxyno-10 compounds, carboxylates, sulfates, phosphates, silicates, cyanides, oxylates, cyano complexes, etc. complex, arene complex, hydride complex, phosphine complex, alkyl complex, acetylacetonato complex, olefin complex, diene complex, acetylene complex,
It may be present in the form of an organometallic complex or organometallic compound such as a carbene complex. These components may be used alone or in combination of two or more.

The catalyst of the present invention can be used in various forms as described above, but it is preferable to use a catalyst in which a component containing the above-mentioned elements is supported on a carrier. The carrier is not particularly limited, and carriers commonly used for supported hydrogenation catalysts can be used. Specifically, such carriers include, for example, alumina such as γ-alumina, l-alumina, α-alumina, silica gel, silica, silica alumina, diatomaceous earth, carbon, zeolite, titania, zirconia, or heteropolyacid. Examples include acidic carriers.

When the catalyst used in the present invention is a solid catalyst, its shape is not particularly limited, and examples include powder, granules, columns,
It can be used in the form of spheres, pellets, fibers, etc.

In the present invention, the corresponding glycol ethers are produced by reacting the glycol esters with the hydrogen in the presence of the catalyst.

The reaction temperature is usually in the range of room temperature to 450°C,
Preferably, the temperature is in the range of 50 to 350°C.

The reaction pressure is usually in the range of normal pressure - 500 kg/cm'G, but preferably in the range of lO to 300 kg/cm'G.
is within the range of

The reaction time usually ranges from 0.05 to 100 hours, preferably from 0.001 to 50 hours.

The molar ratio of hydrogen to glycol esters in carrying out the reaction is usually preferably in the range of 0.01 to 10, particularly in the range of 0.1 to 50. Or preferable.

The ratio of the glycol esters to the catalyst is such that the Mfk ratio of the glycol esters to the catalyst is usually 0.
．． A range of 0.01-10000 is preferred, particularly 0.1-1
The range is preferably 000.

In addition, the said reaction can be performed in any state of liquid phase, gas phase, or gas-liquid phase. In the liquid phase reaction, various solvents can be used, preferably those that do not react in the hydrogenation reaction atmosphere. Specific examples of these solvents include ether, dioxane, cyclic ethers such as tetrahydrofuran, carboxylic acids, and alcohols. In the gas phase reaction, various diluents may be used, preferably those that do not react in the hydrogenation reaction atmosphere. Examples of these diluents include inert gases such as nitrogen, helium, and neon.

The reaction can be carried out in any state, such as gas phase or liquid phase, by a reaction method such as a batch method, a continuous flow method, or a semi-batch method.

By the method described above, glycol esters can be reacted with hydrogen and corresponding glycol ethers can be obtained in good yield. The corresponding glycol ethers herein refer to compounds in which the ester bonds of glycol esters are converted to ether bonds.

Incidentally, the obtained glycol ethers are separated and recovered, and if necessary, purified by a known method.

Furthermore, in the present invention, glycol ethers can be produced in high yield by recycling unreacted materials and reacting them.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the scope of the present invention is not limited in any way by these Examples.

Example 1 In a 1150 cc autoclave, 1 as a solvent was added.
．． 60.0 g of 4-dioxane and 5.9 g of propylene glycol monoacetate (PGMA) were charged. As a catalyst, 1.09 of 5% Ru supported on carbon (manufactured by Engelhard Japan) was added and sealed.

After purging the inside of the autoclave twice with nitrogen gas and twice with hydrogen gas, at room temperature, replace hydrogen gas at 100 kg/c.
The autoclave was heated to 150°C, and stirring was continued at that temperature for 6 hours to carry out the reaction.

Thereafter, the autoclave was cooled to room temperature, and the liquid inside was quantitatively analyzed using a gas chromatograph.

As a result, the conversion rate of PGMA was 53.6%, and the selectivity of propylene glycol monoethyl ether (PGMEE) was 70.0%.

Example 2 In Example 1, the reaction temperature and reaction time were changed to 150°.
The reaction was carried out in the same manner as in Example 1, except that stirring was continued at C for 6 hours and then at 130°C for 1.5 hours.

As a result, the conversion rate of PGMA was 69.1%, and the selectivity of PGMEE was 65.1%.

Example 3 The same operation as in Example 1 was performed except that the catalyst was replaced with 1.09% Pd supported on carbon.

As a result, the conversion rate of PGMA was 19.7%, PGME
The selectivity of E was 72.0%.

Example 4 The same operation as in Example 1 was carried out except that the catalyst was replaced with 1.09 % of Rh supported on carbon.

As a result, the conversion rate of PGMA was 13.0%, PGME
The selectivity of E was 68.0%.

Example 5 The same operation as in Example 1 was carried out except that the catalyst was replaced with t,oy, which is made by supporting 5% Pt on carbon.

As a result, the conversion rate of PGMA was 24.6%, PGME
The selectivity of E was 71.6%.

Example 6 Example 1 except that the catalyst was replaced with 50% Ni supported on diatomaceous earth 3.09.
The same operation was performed.

As a result, the conversion rate of PGMA was 18.9%, PGME
The selectivity of E was 72.1%.

Example 7 The same operation as in Example 6 was performed except that the reaction temperature was changed to 180°C.

As a result, the conversion rate of PGMA was 45.0%, PGME
The selectivity of E was 70.5%.

Example 8 Into an autoclave having an internal volume of 1'50 cc, 60.0% of 1,4-dioxane was added as a solvent. , 8.09% of the raw material propylene gelicol diacetate (PGDA) is charged. To this, 5% Ru supported on carbon (manufactured by Engelhard Japan) 1.09 was added as a catalyst.
Sealed.

The inside of the autoclave was purged twice with nitrogen gas, and then twice with hydrogen gas. Then, at room temperature, 1 liter of hydrogen gas was added.
It was press-fitted up to 00 kg/cm2G.

Heat the autoclave to 180℃, and at that temperature,
Stirring was continued for 6 hours. Thereafter, the autoclave was cooled to room temperature, and the liquid inside was quantitatively analyzed using a gas chromatograph.

As a result, the conversion rate of PGDA was 38.0%, and the conversion rate of propylene glycol ethyl ether acetate (PGEEA) was 38.0%.
The selectivity of P is 59.7%, the selectivity of propylene glycol diethyl ether (PGDEE) is 23.5%, and the selectivity of PGDEE is 23.5%.
The selectivity of GMEH was 10.2%.

Example 9 The same operation as in Example 8 was carried out, except that the catalyst was replaced with 1.05+ of 5% Pd supported on carbon.

As a result, the conversion rate of PODA was 14.6%, PGEE
The selectivity of A is 61.3%, and the selectivity of PGDEH is 2
The selectivity for PGMEE was 9.8%.

Example 1O In an autoclave with an internal volume of 150 cc, 1 as a solvent was added.
, 4-dioxane so, og, and 5.09 g of ethylene glycol monoacetate (EGMA) as a raw material were charged. To this was added 5% Ru supported on carbon (manufactured by Engelhard Japan) 1.09 as a catalyst, and the container was sealed.

The inside of the autoclave was purged twice with nitrogen gas, and then twice with hydrogen gas. Then, at room temperature, 1 liter of hydrogen gas was added.
It was press-fitted to 00 ky/cm"G.

The autoclave was heated to 150°C and stirring was continued at that temperature for 6 hours. Thereafter, the autoclave was cooled to room temperature, and the liquid inside was quantitatively analyzed using a gas chromatograph.

As a result, the conversion rate of EGMA was 48.9%, and the selectivity of ethylene glycol monoethyl ether was 74.3%.
Met.

[Effects of the Invention] According to the present invention described above, glycol ethers can be produced in high yield and at low cost by hydrogenating glycol esters.

As described above, the present invention has excellent effects and has extremely high industrial value.

Claims (1)

[Claims] 1. A method for producing glycol ethers, which comprises reacting glycol esters with hydrogen in the presence of a catalyst capable of hydrogenating ester bonds to ether bonds.