JP2003286219A - Method for hydrolyzing ester compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for hydrolyzing an ester compound in high conversion and in high selectivity. <P>SOLUTION: This method for hydrolyzing the ester compound in the presence of a basic compound is characterized by controlling the pH of the reaction solution to less than 7 to hydrolyze the ester compound. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for hydrolyzing an ester compound. In particular, it relates to a method for hydrolyzing an ester compound when the ester compound has a formyl group or when the ester compound and the formyl group-containing compound (aldehyde compound) coexist.

[0002]

It is known that hydrolysis of ester compounds generally proceeds in the presence of an acid catalyst or a base catalyst.

In particular, glyoxylic acid and glyoxylate obtained by hydrolyzing glyoxylic acid ester are industrially useful compounds as intermediate raw materials for various products such as pharmaceutical modifiers, cosmetics, fragrances and agricultural chemicals. Is.

As the method for hydrolyzing the glyoxylic acid ester, a method in which the glyoxylic acid ester hemiacetal is treated with steam in a cascade type reactor countercurrently (JP-A-3-20239), and reactive distillation in the presence of water is carried out. The method (JP-A-11-335320) and the like can be mentioned.

[0005]

However, when the ester compound is hydrolyzed in the presence of an acid catalyst under acidic conditions, the hydrolysis reaction is an equilibrium reaction, and the equilibrium reaction is required to increase the conversion rate of the ester compound. It is necessary to move it to the product side. Specifically, it is possible to use water as a raw material in a large excess with respect to the ester compound, or to remove the carboxylic acid or alcohol that is a product out of the system. However, if a large excess of water is used, it is necessary to remove the water in the subsequent purification step,
Costs increase due to utility fees. When reactive distillation is carried out to remove the carboxylic acid and alcohol, which are products, to the outside of the system, a reactive distillation column is required, resulting in an increase in investment and an increase in utility cost.

On the other hand, such as glyoxylic acid ester,
When an ester compound having a formyl group in the molecule is hydrolyzed under basic conditions in the presence of a base catalyst, the formyl group is unstable under basic conditions and may undergo side reactions such as the Cannizzaro reaction or aldol condensation. , The selectivity decreases. When the ester compound is a glyoxylic acid ester, an oxalic acid ester, an oxalic acid salt, a glycolic acid ester, and a glycolic acid salt are produced by the Cannizzaro reaction.

The present invention has been made in view of the above problems, and an object thereof is to provide a method for hydrolyzing an ester compound having a high conversion rate and a small number of side reactions.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, when the hydrolysis of the ester compound was carried out in the presence of a basic compound, the pH of the reaction solution was It was found that the hydrolysis proceeds at a high conversion rate and a high selectivity by controlling the content of the compound in a specific range, and the present invention has been completed.

That is, the present invention is a method of hydrolyzing an ester compound in the presence of a basic compound, which is characterized in that the reaction solution is controlled to have a pH of less than 7 and then hydrolyzed. The present invention relates to a method for hydrolyzing an ester compound.

The present invention also relates to a method of hydrolyzing an ester compound in the presence of a basic compound, which is obtained by multiplying the value obtained by multiplying the number of moles of the basic compound in the reaction solution by the valence and the hydrolysis. The present invention relates to a method for hydrolyzing an ester compound, characterized in that the hydrolysis is carried out while controlling the molar ratio of the carboxylic acid to be 1 or less.

Further, the present invention is characterized in that the ester compound to be subjected to hydrolysis has a formyl group in the molecule.

Further, the present invention is characterized in that the ester compound is hydrolyzed in the presence of a formyl group-containing compound (aldehyde compound).

The present invention also relates to a method for producing glyoxylic acid and / or glyoxylate, characterized in that the glyoxylic acid ester is hydrolyzed by the above-mentioned hydrolysis method.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The method for hydrolyzing an ester compound according to the present invention will be described in detail below.

The ester compound usable in the present invention is not particularly limited as long as it has an ester group in the molecule.
In particular, it is effective for a compound having an unstable functional group under basic conditions in the ester compound molecule. Examples of functional groups unstable under basic conditions include a formyl group. As the ester compound having a formyl group in the molecule, for example, glyoxylic acid ester, formyl acetic acid ester, formyl propionic acid ester,
Examples thereof include phenylglyoxylic acid ester, formylbenzoic acid ester, formylcinnamic acid ester, acetoxymethylbenzaldehyde and the like. Of these, glyoxylic acid ester is preferable.

When the ester compound having a formyl group is brought into contact with water, water may be added to the formyl group portion to form a hydrate. It may also form an alkyl hemiacetal on contact with alcohol.

In particular, the glyoxylic acid ester easily forms a glyoxylic acid ester hydrate in the presence of water and is stable. Further, in the presence of alcohol, glyoxylic acid ester alkyl hemiacetal is easily formed and stably exists. Further, hydration and hemiacetalization of these are reversible reactions, and can take any form depending on the coexisting substance with glyoxylic acid ester, and may exist as a mixture. However, in the hydrolysis reaction, glyoxylic acid ester, glyoxylic acid ester hydrate, and glyoxylic acid alkyl hemiacetal exhibit similar behavior and can be treated in the same manner.

Hereinafter, glyoxylic acid ester and / or glyoxylic acid ester hydrate and / or glyoxylic acid ester alkyl hemiacetal are referred to as glyoxylic acid esters.

The method for producing the glyoxylic acid ester is not particularly limited, and it can be obtained by a gas phase reaction or a liquid phase reaction. As the gas phase reaction, for example, JP-A-11-2637
It can be preferably obtained by the method disclosed in JP-A-51-51. That is, 1,2-diol ethylene glycol is vapor-phase oxidized in the presence of a molecular oxygen-containing gas to obtain gaseous glyoxal and / or glycol aldehyde (pre-reaction), and subsequently, in a vaporization chamber. By adding gaseous alcohol and / or olefin to a post-reactor connected to the pre-reactor and performing gas-phase oxidation with a molecular oxygen-containing gas in the post-reactor in the presence of a catalyst,
A method for obtaining glyoxylic acid esters may be mentioned.

Specific examples of the alcohol added to the latter-stage reactor are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, iso-butanol, tert-butanol, hexanol, cyclohexanol, octanol. , 2-ethylhexanol, lauryl alcohol, stearyl alcohol, and other commercially available alkyl alcohols having 1 to 18 carbon atoms. Of the above examples, preferably methanol, ethanol, 1-propanol, 2
-Propanol, 1-butanol, 2-butanol, i
carbon number of so-butanol, tert-butanol, etc.
~ 4 alkyl alcohol, more preferably,
They are methanol and ethanol.

Specific examples of the olefin added to the latter-stage reactor include olefins having 2 to 4 carbon atoms such as ethylene, propylene, 1-butene, 2-butene and isobutene.

Also in the liquid phase reaction, glyoxylic acid esters can be obtained by oxidative esterification reaction of glyoxal with alcohol and molecular oxygen in the presence of a catalyst.

Specific examples of the glyoxylic acid ester include:
Glyoxylic acid methyl ester, glyoxylic acid ethyl ester, glyoxylic acid normal propyl ester,
Examples include glyoxylic acid isopropyl ester, glyoxylic acid normal butyl ester, and glyoxylic acid tertiary butyl ester. Of these, glyoxylic acid methyl ester, glyoxylic acid ethyl ester, and glyoxylic acid normal butyl ester are preferable.

As the glyoxylic acid ester hemiacetal, glyoxylic acid ester methyl hemiacetal, ethyl hemiacetal, propyl hemiacetal,
Butyl hemiacetal and the like can be mentioned. This glyoxylate alkyl hemiacetal is conveniently formed by dissolving the glyoxylate in alcohol. This reaction is reversible and there is an equilibrium of glyoxylate hemiacetal with glyoxylate and alcohol. In the present invention, methyl glyoxylate hemiacetal, ethyl glyoxylate ethyl ethyl hemiacetal, and glyoxylate normal butyl normal butyl hemiacetal are preferable.

Specific examples of the glyoxylic acid ester hydrate include glyoxylic acid methyl ester hydrate, glyoxylic acid ethyl ester hydrate, glyoxylic acid normal propyl ester hydrate, glyoxylic acid isopropyl ester hydrate, and glyoxyl. Examples thereof include acid normal butyl ester hydrate and glyoxylic acid tertiary butyl ester hydrate. Of these, glyoxylic acid methyl ester hydrate, glyoxylic acid ethyl ester hydrate, and glyoxylic acid normal butyl ester hydrate are preferable.

The basic compound used in the present invention is not particularly limited as long as it forms a salt with a carboxylic acid produced by hydrolysis. Examples thereof include alkali metal and alkaline earth metal hydroxides, carbonates, hydrogen carbonates, alkoxides, ammonia, amines, and the like, and specifically, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate. , Sodium hydrogen carbonate, potassium hydrogen carbonate, sodium methoxide, potassium methoxide, ammonia, methylamine, ethanolamine,
Examples include aniline, toluidine, pyridine and the like. Among them, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate and sodium methoxide are preferable.

The method for hydrolyzing an ester compound of the present invention is carried out in the presence of a basic compound in the pH of the reaction solution during hydrolysis.
Is controlled to be less than 7, and the hydrolysis is performed. The time of hydrolysis refers to the period from the time when the ester compound and the basic compound are mixed to the time when the conversion rate of the ester compound stops increasing. Since the pH is maintained below 7, the reaction liquid is in acidic condition and the hydrolysis reaction of the ester compound is an equilibrium reaction. Therefore, the conversion rate of the ester compound is governed by the equilibrium and does not exceed the equilibrium conversion rate.

At this time, by adding a basic compound to the reaction solution, the basic compound and the carboxylic acid produced by the hydrolysis of the ester compound form a salt, and the concentration of the carboxylic acid decreases. , The equilibrium of the hydrolysis reaction moves to the product side, and the conversion rate of the ester compound can be improved.

By controlling the pH of the reaction solution to be less than 7, the aldol condensation of the formyl group part and the Cannizzaro reaction can be suppressed and the hydrolysis reaction can proceed at a high selectivity. The pH of the reaction solution is preferably 6 or less, more preferably 5 or less.

The reaction method is not particularly limited, but it is preferable to add a basic compound to the ester compound because the pH can be easily controlled.

The method of adding the basic compound is not particularly limited, and the basic compound may be added all at once or gradually. However, it is better to add them sequentially, the ratio of the pH, the value obtained by multiplying the total number of basic compounds in the reaction solution by the valence of the basic compound, and the total number of moles of the carboxylic acid produced by hydrolysis. Is preferable because it is easy to control.

The amount of the basic compound used is a value obtained by multiplying the total number of moles of the basic compound in the reaction solution at the time of hydrolysis by the valence of the basic compound, and the total number of moles of the carboxylic acid produced by hydrolysis. This is the amount at which the number ratio becomes 1 or less.

The valence of the basic compound means, in this case, how many molecules of the basic compound can form a salt with how many molecules of the carboxylic acid produced by hydrolysis. For example, sodium hydroxide has one molecule and has a valence of 1 because it forms a sodium salt with one molecule of carboxylic acid, and calcium hydroxide has one molecule and has a value of one because it can form a calcium salt with two molecules of carboxylic acid. The number is 2.

The carboxylic acid produced by hydrolysis is
Depending on the concentration and the amount of the basic compound, any form of a free carboxylic acid, a carboxyl ion or a salt with a basic compound can be taken, and it is generally obtained as a mixture thereof. Therefore, the carboxylic acid produced by the hydrolysis in the present invention refers to the sum of free carboxylic acids and carboxylic acids in all forms of salts with carboxyl ions and basic compounds. Hereinafter, free carboxylic acids and carboxylic acids in all forms of salts with carboxyl ions and basic compounds are collectively referred to as carboxylic acids and / or carboxylic acid salts.

The ratio of the value obtained by multiplying the total number of moles of the basic compound in the reaction solution by the valence of the basic compound to the total number of moles of the carboxylic acid produced by hydrolysis is 1 or less means that the basic compound is Is equivalent to or less than the produced carboxylic acid. This is to prevent the carboxylic acid and / or salt obtained by hydrolysis from being lost by a side reaction when the basic compound is more than the equivalent amount.

Time when the ratio of the value obtained by multiplying the total number of moles of the basic compound in the reaction liquid at the time of hydrolysis by the valence of the basic compound to the total number of moles of the carboxylic acid produced by hydrolysis is 1 or less. Is preferably 50% or more of the total reaction time, and 70%
The above is more preferable, and 90% or more is still more preferable. The total reaction time refers to the period from the time when the ester compound and the basic compound are mixed to the time when the conversion rate of the ester compound stops increasing.

Therefore, the ratio of the value obtained by multiplying the total number of moles of the basic compound in the reaction solution by the valence of the basic compound to the total number of moles of the carboxylic acid produced by hydrolysis is 1 or less. It is preferable to add a basic compound depending on the degree of progress of the hydrolysis reaction.

The ratio of the value obtained by multiplying the total number of moles of the basic compound in the reaction solution by the valence of the basic compound to the total number of moles of the produced carboxylic acid is preferably 0.1 or more and less than 1. .
The upper limit of this ratio is preferably 0.95 or less, and more preferably 0.9 or less. The lower limit of this ratio is preferably 0.1 or more, more preferably 0.2 or more, and further preferably 0.3 or more.

The ratio of the value obtained by multiplying the total number of moles of all basic compounds used at the end of the reaction by the valence of the basic compound to the total number of moles of the carboxylic acid formed is preferably 0.1 or more, It is less than 1. The upper limit of this ratio is preferably 0.9
It is 5 or less, and more preferably 0.9 or less. The lower limit of this ratio is preferably 0.1 or more, more preferably 0.2 or more, and further preferably 0.3 or more.

The ratio of water to the ester compound in the hydrolysis method of the present invention varies depending on the kind of the ester compound and the reaction conditions, but is generally equimolar to 100-fold molar, preferably 2-fold molar to 50-fold. It is twice the mole. If it is less than this mole, water may be insufficient, and if it is 100 times or more mole, the concentration of the carboxylic acid and / or the carboxylic acid salt after the reaction may be low, and it may be costly to concentrate.

The reaction temperature is suitably 30 ° C to 300 ° C, preferably 50 ° C to 250 ° C. The reaction pressure can be any of atmospheric pressure, increased pressure, and reduced pressure.

The form of the hydrolysis reaction may be any of continuous type, batch type and semi-batch type, and is not particularly limited.

In the hydrolysis method of the present invention, the time when the pH of the reaction solution is less than 7 is preferably 50% or more, more preferably 70% or more, and further preferably 90% or more of the total reaction time. The total reaction time refers to the period from the time when the ester compound and the basic compound are mixed to the time when the conversion rate of the ester compound stops increasing.

It is preferable that the pH does not exceed 9 even during the time period when the pH of the reaction solution becomes 7 or more.

When the basic compound is added, it is preferable to stir the reaction solution to reduce the bias of pH in the reaction solution. If the stirring is not performed, the pH around the added basic compound is high, and there is a possibility that a side reaction will proceed in that portion. The method of stirring the reaction solution is not particularly limited, and examples thereof include a method using a stirring blade, a method in which the reaction solution is forcedly circulated by a reboiler, a method in which an inert gas is bubbled, and the like.

The hydrolysis method of the present invention can also be carried out in combination with other hydrolysis methods such as reactive distillation. In the reactive distillation, when the boiling point of alcohol by-produced by hydrolysis is lower than that of water, the by-product alcohol can be withdrawn by distillation from the top of the column to move the equilibrium to the product side and improve the conversion rate.

However, in the reactive distillation, it is necessary to separate alcohol and water to some extent, which requires a service charge, and some water is required to raise the conversion rate to 99% or more.

However, the hydrolysis can be carried out more efficiently by adding the basic compound and controlling the pH to be less than 7 while carrying out the reactive distillation.

In the hydrolysis method of the present invention, the ester compound can be hydrolyzed in the presence of the formyl group-containing compound. The formyl group-containing compound is not particularly limited as long as it has a formyl group in the molecule. Examples thereof include formaldehyde, acetaldehyde, propionaldehyde, glyoxal, benzaldehyde, formylbenzoic acid and the like.

The amount of the formyl group-containing compound is not particularly limited, but is preferably 50% by mass or less based on the ester compound.

For example, when an ester compound is synthesized from a formyl group-containing compound, an alcohol and molecular oxygen by an oxidative esterification reaction, and the ester compound is further hydrolyzed, the reaction obtained by the oxidative esterification reaction is carried out. The liquid may contain an unreacted formyl group-containing compound and an ester compound as a product. When the reaction solution is used as it is and subjected to hydrolysis in the presence of a basic catalyst under basic conditions, the residual formyl group-containing compound may undergo a Cannizzaro reaction or an aldol condensation to be changed to another compound. is there. In this case, the formyl group-containing compound which is an unreacted raw material may not be recovered again as a raw material for the oxidative esterification reaction, or purification of the carboxylic acid and / or the carboxylic acid salt obtained by hydrolysis may be difficult. .

However, by using the hydrolysis method of the present invention, the formyl group-containing compound is stably maintained even when the ester compound is hydrolyzed in the presence of the formyl group-containing compound. Then, it can be recovered as a raw material for the oxidative esterification reaction.

In the hydrolysis method of the present invention, either a catalyst or no catalyst may be used. The carboxylic acid produced by hydrolysis of the ester compound is
Since it functions as an acid catalyst, hydrolysis proceeds without adding an additional acid catalyst.

However, an acid catalyst may be added separately in order to accelerate the reaction rate or to relax the reaction conditions. As the acid catalyst, for example, specifically,
Examples thereof include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, heteropolyacid, p-toluenesulfonic acid, acetic acid, glyoxylic acid, acidic ion exchange resin, zeolite, clay and the like. However, when a salt is formed with these acid catalysts when the basic compound is added, the effect of the catalyst may be reduced, and the generated salt needs to be separated in a later step. Therefore, when an acid catalyst is used, it is preferable to add, as a catalyst, a carboxylic acid produced by hydrolysis of a raw material ester compound.

The method for producing glyoxylic acid and / or glyoxylate in the present invention is achieved by using the glyoxylic acid ester as a raw material and carrying out the above-described hydrolysis method.

The produced glyoxylic acid and / or glyoxylate readily becomes a glyoxylic acid hydrate or a glyoxylate hydrate when contacted with water. Also, when it comes into contact with alcohol, it easily becomes an alkyl hemiacetal glyoxylate or an alkyl hemiacetal glyoxylate.

This hydration or alkyl hemiacetalization is an equilibrium reaction, and when water is present in the system after completion of hydrolysis, glyoxylic acid or glyoxylate in the composition is partially or All exist as glyoxylic acid hydrate and glyoxylate hydrate.

If alcohol is present in the system,
The glyoxylic acid or glyoxylate in the composition is present as a part or all of the glyoxylate alkyl hemiacetal or the glyoxylate alkyl hemiacetal according to the equilibrium.

Therefore, glyoxylic acid and / or glyoxylate in the method for producing glyoxylic acid and / or glyoxylate of the present invention may be glyoxylic acid hydrate in addition to free glyoxylic acid depending on the composition and concentration of coexisting substances. In some cases, the glyoxylate salt may take the form of a substance or a glyoxylate alkyl hemiacetal, and the glyoxylate salt may take the form of a glyoxylate hydrate or a glyoxylate alkyl hemiacetal in addition to the free glyoxylate salt.

The glyoxylic acid and / or glyoxylate obtained as described above may be used as a solution or may be concentrated to give a solid. Also, the subsequent storage,
If necessary, it may be purified depending on the transfer method and application. Purification can be carried out by a known method such as extraction or recrystallization.

The glyoxylic acid and / or glyoxylate obtained by the present invention is a pharmaceutical modifier, cosmetic,
It is an industrially useful compound as an intermediate raw material for various products such as fragrances and agricultural chemicals.

[0062]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Reference Example 1 (Production of Glyoxylic Acid Ester) 215 g of glyoxylic acid methyl ester methyl hemiacetal and 73.5 g of phosphoric anhydride were placed in a flask equipped with a V-shaped tube and heated. Of the distilled fractions, the gas phase temperature is 115 to 117
The ° C fraction was obtained as methyl glyoxylate.

When this fraction was analyzed by gas chromatography, no components other than methyl glyoxylate were detected.

Example 1 36.7 g (0.42 g of methyl glyoxylate of Reference Example 1)
mol) and 50.0 g (2.8 mol) of water were placed in a flask equipped with a reflux condenser and a pH meter (D-21 manufactured by Horiba Ltd.), and reacted at 92 ° C. for 1 hour. Then 2
50.2 g of 0 mass% sodium hydroxide aqueous solution (0.25 mol of sodium hydroxide) was added dropwise using a dropping funnel over 3 hours so that the pH of the reaction solution was maintained at 5 or less.

After completion of the reaction, the reaction mixture was analyzed by gas chromatography and liquid chromatography to find that the conversion of methyl glyoxylate was 95.0 mol%.
The yield of glyoxylic acid based on methyl glyoxylate is 9
It was 2.8 mol%.

Comparative Example 1 50.2% aqueous 20% sodium hydroxide solution of Example 1
Example 1 except that 40.1 g of water was used instead of g.
The reaction was performed in the same manner as in.

After completion of the reaction, the reaction solution was analyzed by gas chromatography and liquid chromatography to find that the conversion of methyl glyoxylate was 79.8 mol%.
The yield of glyoxylic acid based on methyl glyoxylate is 7
It was 5.4 mol%.

Comparative Example 2 36.7 g (0.42 g of methyl glyoxylate of Reference Example 1)
mol) and 50.0 g (2.8 mol) of water were placed in a flask equipped with a reflux condenser and a pH meter (D-21 manufactured by Horiba, Ltd.) and the temperature was raised to 92 ° C., and then a 20% by mass aqueous sodium hydroxide solution 140 was added. 0.5 g (sodium hydroxide 0.7
(mol) was added dropwise using a dropping funnel over 1 hour so that the pH of the reaction solution was maintained at 9 or higher. After the reaction,
When the reaction liquid was analyzed by gas chromatography and liquid chromatography, the conversion of methyl glyoxylate was 100 mol%, and the yield of glyoxylic acid based on methyl glyoxylate was 23.5 mol%. A white precipitate was observed in the reaction solution, which was filtered and analyzed to be oxalic acid. When combined with oxalic acid dissolved in the reaction solution, it was 38.2 on the basis of methyl glyoxylate.
Oxalic acid corresponding to mol% was produced. The reaction solution also contained glycolic acid equivalent to 36.5 mol% based on methyl glyoxylate. Since the pH of the reaction solution was 9 or more under the present reaction conditions, it is considered that the Cannizzaro reaction proceeded.

Reference Example 2 (Production of Glyoxylic Acid Esters) First, glyoxylic acid esters used as a raw material were prepared as described in JP-A-11-263.
It was synthesized with reference to Example 1 described in 751 publication. Ie 1,
Glyoxal was synthesized from ethylene glycol as a 2-diol, and methanol was added to the glyoxal to perform gas phase oxidation to synthesize glyoxylic acid methyl esters.

Specifically, first, 6 volume% of ethylene glycol vaporized in advance, air and nitrogen gas were charged into an adiabatic reactor filled with 0.8 g of metallic silver (catalyst) having a particle size of 20 to 30 mesh. A raw material gas obtained by mixing (oxygen concentration 7% by volume) has a reaction temperature of 440 ° C. and a space velocity (SV) of 83.
A reaction gas containing glyoxal was obtained by continuous supply under the condition of 10,000 hr ⁻¹ for gas phase oxidation (oxidative dehydrogenation) (ethylene glycol-based glyoxal yield 81 mol%). Next, the reaction gas (glyoxal concentration 4% by volume), pre-vaporized methanol (20% by volume) and air were mixed in a heat exchange reactor filled with a catalyst composed of ferric phosphate. Mixed gas (oxygen concentration 5% by volume) with a reaction temperature of 250 ° C.
V) A reaction gas containing methyl glyoxylate (yield 61 mol% of methyl glyoxylate based on ethylene glycol) was continuously supplied under the condition of 2,000 hr ⁻¹ for gas phase oxidation (oxidative esterification). Obtained.

Both vapor phase oxidations were carried out continuously. Then, by condensing and collecting the reaction gas, 22% by mass of methyl glyoxylate, 45% by mass of methanol, 27% of water
A reaction condensate containing 3% by weight of methyl glycolate and 3% by weight of glyoxal was obtained.

Example 2 100.5 g of the reaction condensate of Reference Example 2 was placed in a flask,
The temperature was raised to 92 ° C. and kept for 1 hour. Then 10% by mass
80 g of an aqueous sodium hydroxide solution was added dropwise over 3 hours so that the pH of the reaction solution was maintained at 5 or lower.

After completion of the reaction, the reaction solution was analyzed by gas chromatography and liquid chromatography to find that the conversion of methyl glyoxylate was 98.2 mol%.
The yield of glyoxylic acid based on methyl glyoxylate is 9
It was 5.3 mol%. Further, it was found that the reaction liquid contained 1.7% by mass of glyoxal, which was stable even during hydrolysis.

[0075]

The ester compound hydrolysis method of the present invention can improve the conversion rate of an ester compound with the same amount of water, as compared with the case where hydrolysis is carried out under acidic conditions using only an acid catalyst. it can. Further, as compared with the case where hydrolysis is carried out under a basic condition using a base catalyst, the progress of side reactions can be suppressed and the hydrolysis reaction can proceed at a high selectivity.

Claims (5)

[Claims] 1. A method for hydrolyzing an ester compound in the presence of a basic compound, which comprises controlling the pH of the reaction solution to be less than 7 and performing the hydrolysis. Method of hydrolysis. 2. A method of hydrolyzing an ester compound in the presence of a basic compound, which comprises a value obtained by multiplying the number of moles of the basic compound in the reaction solution by a valence and the hydrolysis. A method for hydrolyzing an ester compound, characterized in that the hydrolysis is carried out by controlling the molar ratio of the carboxylic acid to be 1 or less. 3. The method for hydrolyzing an ester compound according to claim 1, wherein the ester compound has a formyl group in the molecule. 4. The method for hydrolyzing an ester compound according to claim 1, wherein the hydrolysis is carried out in the presence of a compound containing a formyl group. 5. A method for producing glyoxylic acid and / or glyoxylate, which comprises hydrolyzing a glyoxylic acid ester by the hydrolysis method according to any one of claims 1 to 4.