JPH0222050B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing esters or ethers of glycolic acid.

Glycolic acid esters can be hydrolyzed to yield glycolic acid, hydrogenated to yield ethylene glycol, and ethers of glycolic acid can be hydrogenated to yield cellosolves.
Both are important compounds as industrial intermediates.

A method for producing glycolic acid ester is a method in which paraformaldehyde or trioxane is reacted with formic acid ester in the presence of a strong acid catalyst such as sulfuric acid or an organic sulfonic acid (Japanese Patent Application Laid-open No. 53-98924).
It has been known.

As a result of various studies on the production method of glycolic acid or its derivatives, the present inventors found that by reacting formaldehyde, an alkyl ester of oxybrensted acid other than an organic carboxylic acid, and carbon monoxide in the presence of a strong acid catalyst. , or after carrying out the reaction, an ester or ether of glycolic acid can be obtained by alcoholyzing or hydrolyzing the reaction product, and by appropriately selecting an oxybrensted acid ester. The inventors have now discovered that the production ratio of glycolic acid ester and ether can be controlled, and have arrived at the present invention.

The present invention will be explained in detail below.

The formaldehyde used in the method of the present invention includes, in addition to gaseous formaldehyde, compounds that produce formaldehyde under reaction conditions, such as trioxane, paraformaldehyde, and methylal. Although an aqueous formaldehyde solution can be used if desired, it is not advantageous to carry out the reaction in the presence of water in the method of the present invention, and the amount of water present in the reaction system is 1 mol or less per 1 mol of formaldehyde. , and should preferably be suppressed to 0.5 mol or less.

Examples of alkyl esters of oxybrensted acid include sulfuric acid esters such as dimethyl sulfate, ethyl methanesulfonate, methyl trifluoromethanesulfonate, methyl p-toluenesulfonate, and sulfonic acid esters such as alkylated sulfonic acid cation exchange resins. , sulfinate esters such as methyl benzenesulfinate, carbonate esters such as dimethyl carbonate, phosphate esters such as trimethyl phosphate, phosphite esters such as dimethyl phosphite, and borate esters such as dibutyl borate. Alkyl esters of Brønsted acid are used. In general, the use of highly acidic oxybrensted acid esters increases the selectivity of glycolic acid esters.
When an ester of oxybrensted acid, which has weak acidity, is used, the selectivity for the ether of glycolic acid, that is, alkoxyacetic acid, tends to be high. The amount of these alkyl esters of oxybrensted acid to be used is not particularly limited, but is usually 0.1 mol or more per 1 mol of formaldehyde,
Preferably it is used in an amount of 1.0 mol or more. Further, depending on the case, a large amount of oxybrenstate may be used to serve as a reaction solvent.

The reaction can also be accelerated by adding a small amount of lower alcohol.

Carbon monoxide can be used not only in pure form, but also in one diluted with a gas inert to the reaction, such as nitrogen, helium, argon, hydrogen, or the like. The partial pressure of carbon monoxide in the reaction system is usually 1 to 250 kg/cm ² , preferably 10 to 150 kg/cm ² .

Strong acid catalysts used in the method of the present invention include hydrochloric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, perchloric acid, nitric acid, sulfuric acid, hexafluorophosphoric acid, fluorosulfonic acid, chlorosulfonic acid, etc. Mineral acids, organic acids such as trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, heteropolyacids such as silicotungstic acid, phosphotungstic acid, phosphomolybdic acid, boron trifluoride , Lewis acids such as phosphorus pentafluoride and antimony pentafluoride or strongly acidic cation exchange resins, clay minerals, zeolites, solidified acids,
Examples include so-called solid acids such as inorganic oxides, inorganic salts, and composite oxides. Strongly acidic cation exchange resins whose functional group is sulfonic acid include Diaion PK-228, Diaion HPK25 (above,
products with a styrene-divinylbenzene copolymer skeleton such as Amberlite 200 (manufactured by Rohm and Haas), Nafion
Examples include those having a tetrafluoroethylene polymer skeleton such as 501 (manufactured by DuPont). Examples of clay minerals and zeolites include montmorillonite, kaolinite, bentonite, halloysite, smectite, illite, vermiculite, chlorite, sepiolite, attapulgite, polygorskite, mordenite, and montmorillonite KSF/O (manufactured by Girdler Chemical). ), and those treated with an acid such as hydrogen fluoride, or those in which exchangeable metal ions are exchanged with hydrogen ions, such as H-type zeolite, are preferable. Examples of the solidifying acid include those in which phosphoric acid, boric acid, etc. are supported on a carrier. Examples of inorganic oxides and salts include oxides such as blue tungsten oxide, and salts such as boron phosphate, lanthanum phosphate, aluminum sulfate, and zinc sulfate. Examples of the composite oxide include silica-alumina, silica-zirconia, titania-zirconia, and silica-titania.

Among these, strong acids having an acid strength of 2 or less in pKa value are preferred. The amount of these strong acids used is 0.1 to 1000 meq. per mole of formaldehyde.

Although the use of a solvent is not essential in the method of the present invention, a solvent can also be used in order to carry out the reaction more smoothly. Such solvents include
Ethers such as diethyl ether, diphenyl ether, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, ketones such as acetone, ethyl methyl ketone, dibutyl ketone, acetophenone, nitriles such as acetonitrile, propionitrile, benzonitrile, benzene, toluene , aromatic hydrocarbons such as xylene and ethylbenzene, alkanes such as pentane, hexane, and octane, alkenes such as hexene-1 and octene-2, and N-substituted amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. , sulfoxides such as dimethyl sulfoxide and sulfolane, carbonates such as ethylene carbonate and propylene carbonate, and nitro compounds such as nitromethane and nitrobenzene.

The carbonylation reaction in the method of the present invention can be carried out by either a gas phase method or a liquid phase method, as well as by a homogeneous phase method, a suspended bed method, or a fixed bed method, and the reaction temperature is as follows: Normally 25~250℃,
Preferably, the temperature is appropriately selected within the range of 50 to 200°C.

According to the method of the present invention, alkoxyacetic acid, alkoxyacetic acid ester, and glycolic acid ester are produced as esters and ethers of glycolic acid by reacting formaldehyde, oxybrensted acid ester, and carbon monoxide. A compound containing 1 to 3 glycolic acid components in the molecule, with both ends of the molecule blocked by the acid component and alcohol component of the oxybrensted acid ester is produced. These compounds are readily converted to glycolic acids, alkoxyacetic acids or their esters by alcoholysis or hydrolysis in the presence of acid catalysts, whereas oxybrensted acid esters are converted almost quantitatively. can be recovered.

Alcoholysis or hydrolysis can be carried out by known methods. For example, following the reaction described above, or by removing the catalyst, solvent, part of the reaction products, etc. by distillation, filtration, etc., and using the acid catalyst described above, in the presence of an excess amount of alcohol or water. It is carried out by heating from room temperature to about 200°C.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 In a 300 ml induction stirring autoclave, 15 g of trioxane (500 mmol in terms of formaldehyde), 100 ml of methyl p-toluenesulfonate,
After charging 12.5 mmol of methanol and 10.0 g of strongly acidic cation exchange resin (Diaion PK-228) and pressurizing 60 kg/cm ² of carbon monoxide, the mixture was heated to 110°C.
The reaction was carried out for 3 hours. After cooling the autoclave, the pressure was released, and the resulting solution was analyzed by gas chromatography, which confirmed the production of 3.0 mmol of methyl methoxyacetate and 21.5 mmol of methyl glycolate.

Next, without taking out the product solution from the autoclave, 150 ml of methanol and 10 ml of concentrated hydrochloric acid were added to the autoclave, and methanolysis was performed at 100° C. for 3 hours. When the reaction product solution after methanolysis was similarly analyzed, the amount of methyl glycolate and methyl methoxyacetate produced was 145.6, respectively.
mmol and 5.6 mmol.

Example 2 Example 1 except that 100 ml of dimethyl phosphite was used instead of methyl p-toluenesulfonate.
Carbonylation reaction and methanolysis were carried out in the same manner. As a result, 0.7 mmol of methyl glycolate and 0.7 mmol of methyl methoxyacetate were produced.

Example 3 Example 1 except that 100 ml of trimethyl phosphate was used instead of methyl p-toluenesulfonate.
Carbonylation reaction and methanolysis were carried out in the same manner. As a result, it was confirmed that 1.9 mmol of methyl glycolate and 26.7 mmol of methyl methoxyacetate were produced.

Example 4 Carbonylation reaction and methanolysis were carried out in the same manner as in Example 1 except that 100 ml of dimethyl carbonate was used instead of methyl p-toluenesulfonate. As a result, it was confirmed that 36.9 mmol of methyl glycolate and 4.0 mmol of methyl methoxyacetate were produced.

Claims (1)

[Claims] 1. A method for producing a glycolic acid ester or ether, which comprises reacting formaldehyde, an alkyl ester of oxybrensted acid other than an organic carboxylic acid, and carbon monoxide in the presence of a strong acid catalyst. . 2. Glycolic acid ester or glycolic acid characterized by reacting formaldehyde, an alkyl ester of oxybrensted acid other than organic carboxylic acid, and carbon monoxide in the presence of a strong acid catalyst, followed by alcoholysis or hydrolysis. How to make ether.