JPH07258148A - Production of 3-methylglutaric acid - Google Patents

Abstract

PURPOSE:To enable easy production of 3-methylglutaric acid which is a main starting material for nylon from methyl-pentanediol or the like, a readily available substance, in an industrial scale by oxygen-oxidizing the substance in the presence of an oxidation catalyst and water. CONSTITUTION:A starting compound selected from beta-methyl-delta-valero-lactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol is oxidized with oxygen in the presence of an oxidation catalyst, for example, platinum and bismuth on activated carbon, and water, preferably at 80 to 150 deg.C to obtain the compound. The amount of the water used is preferably 2 to 60 moles per mole of the starting compound. When the reaction is carried out in the presence of an acidic compound in an amount of 0.1 to 5wt.% based on the starting compound, the reaction rate is markedly improved and the acidic compound is preferably a solid acid such as an acidic ion-exchange resin or the like.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 3-methylglutaric acid.

The 3-methylglutaric acid provided by the method of the present invention is useful as a main raw material or additive for polyester polyol, nylon, fiber, lubricating oil, plasticizer, pharmaceutical intermediate, and the like.

[0003]

BACKGROUND OF THE INVENTION α, ω-dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecadioic acid are industrially available. In particular, adipic acid is a polyester polyol, nylon, fiber, lubricating oil, plasticizer. It is used in large quantities as a raw material. All of these α, ω-dicarboxylic acids are linear.

3-Methylglutaric acid is a branched α, ω-
Although it is a dicarboxylic acid and a compound useful as a starting material for polyester, polyurethane, etc., its industrial production method has not been established so far.

For example, conventionally known methods for synthesizing 3-methylglutaric acid include nitric acid oxidation method and malonate ester synthesis method. Khim. Ge
terotsikl. Soedin. , (1), 37
According to -8,1987, a method for synthesizing 3-methylglutaric acid by reacting 4-methyltetrahydropyran with nitric acid at a concentration of 60 to 65% is known. In addition, Reakt.
Osobo Christ. Veshchestv
a, (6), 17-19, 1979 discloses a synthetic method using malonic acid diethyl ester and ethyl crotonic acid as starting materials.

Incidentally, the fact that 3-methylglutaric acid can be obtained from β-methyl-δ-valerolactone or 2-hydroxy-4-methyltetrahydropyran means that
For example, JP-A-60-26018 and JP-A-5-260518
However, the specific manufacturing method is not disclosed at all.

[0007]

If a branched α, ω-dicarboxylic acid can be provided, the properties of conventional polyester polyols, nylons, fibers, lubricating oils, plasticizers, etc. can be improved.

Khim. Geterotsikl.
Soedin. , (1), 37-8, 1987, since nitric acid, which is cheaper than oxygen, is used next as oxygen as an oxidizing agent, it is of great practical value, but corrosion of the reactor, by-product of nitric oxide, There is a risk of rupture or explosion due to the rapid increase in the internal pressure of the container due to the easy reaction of nitric acid with organic substances.

Moreover, 4-methyltetrahydropyran used in this method is not industrially manufactured at low cost, and thus it is difficult to obtain it as a starting material.

Reakt. Osobo Christ.
Veshchestva, (6), 17-19, 19
The malonate ester synthesis method described in 79 is not only unsatisfactory because the reaction step is long and the operation is complicated, and the purity and yield of the target compound are both poor.

[0011]

In view of the above-mentioned conventional techniques, the inventors of the present invention have been keen on an advantageous method for producing 3-methylglutaric acid using as a starting material a raw material that is industrially mass-produced in Japan and easily available. As a result of examination, the present invention has been completed.

That is, according to the present invention, β-methyl-
A compound selected from the group consisting of δ-valerolactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol, which is subjected to oxygen oxidation in the presence of an oxidation catalyst and water. -A method for producing methyl glutaric acid is provided.

Oxygen oxidation of a compound selected from the group consisting of β-methyl-δ-valerolactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol according to the method of the present invention It is carried out by contacting the compound with oxygen gas or an oxygen-containing gas in a water solvent. As the oxygen-containing gas, air, a mixed gas of nitrogen and oxygen at an arbitrary ratio, or a mixed gas of these with helium gas, argon gas, carbon dioxide gas, or the like is used.

The starting materials β-methyl-δ-valerolactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol are used alone or in admixture of two or more. be able to.

These reaction raw materials can be produced by a known method. For example, 2-hydroxy-4-methyltetrahydropyran is an isoprene derivative, 3-
It can be obtained by hydroformylating methyl-3-buten-1-ol with a hydrogen / carbon monoxide mixed gas in the presence of a rhodium complex catalyst. Further, β-methyl-δ-valerolactone is prepared by dehydrogenating 2-hydroxy-4-methyltetrahydropyran in the presence of a catalyst to give 3-methyl-1,5-pentanediol as 2-hydroxy. It can be obtained by hydrogenating -4-methyltetrahydropyran in the presence of a catalyst.

The reaction according to the invention is carried out in the presence of an oxidation catalyst. Examples of the catalyst include a catalyst in which a metal is supported on a carrier. Specifically, examples of the metal include platinum, palladium, and the like, or the one that is supported on the carrier alone, or the one that is supported on the carrier by combining two or more metals. Good. Examples of the carrier include activated carbon, alumina, calcium carbonate, barium carbonate and the like. Further, as the catalyst in which these metals are supported on a carrier, a catalyst partially modified with another metal component selected from tin, lead, bismuth, selenium, tellurium, cerium and the like can be used.

These catalysts are commercially produced and are easily available.

The oxygen oxidation reaction according to the method of the present invention comprises:
Using water as a solvent in the presence of the metal-supported catalyst described above,
Usually, oxygen gas or oxygen-containing gas and a compound selected from the group consisting of β-methyl-δ-valerolactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol are continuously added. Alternatively, it is carried out by supplying intermittently.

The reaction temperature is 50 to 200 ° C., especially 8
Temperatures in the range 0 to 150 ° C. are preferred.

The amount of water used is based on the compound selected from the group consisting of β-methyl-δ-valerolactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol. , Usually 1 to 120
A double molar amount is suitable, and a molar amount of about 2 to 60 times is preferable.

The reaction according to the present invention can be carried out by adding a third component such as an acid or an alkali in addition to the oxidation catalyst and water, and particularly when the reaction is carried out in the presence of an acidic compound, the reaction rate is remarkably high. Is improved. Examples of acidic compounds that can be used for this purpose include mineral acids such as sulfuric acid, organic acids such as p-toluenesulfonic acid, acidic ion exchange resins, and solid acids such as activated clay. Considering the separation between the acidic compound and the produced 3-methylglutaric acid, it is more preferable to use a solid acid such as an acidic ion exchange resin or activated clay.

The amount of the acidic compound used is β-methyl-δ-
Valerolactone, 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanedio-
For compounds selected from the group consisting of
1 to 20% by weight is suitable, and 0.1 to 5% by weight is preferable.

In the method of the present invention, as a reactor, a stirring type reactor, a bubble column type reactor, a perforated plate column type reactor and the like which are commonly used in ordinary gas-liquid contact reactions are used. Although the optimum range of the reaction pressure varies depending on the oxygen concentration in the oxygen-containing gas, the reaction temperature, the catalyst concentration, etc., it cannot be uniquely determined, but it is usually selected from the range of 1 to 30 absolute atmospheric pressure.

The main oxidation reaction can be carried out continuously or batchwise.

Whichever reaction method is adopted, β-methyl-δ-valerolactone,
After driving the reaction until the conversion rate of the compound selected from the group consisting of 2-hydroxy-4-methyltetrahydropyran and 3-methyl-1,5-pentanediol is about 90 to 98%, another reaction is performed. It is good to drive the reaction at a relatively high temperature in a reactor and to decompose a small amount of peroxides mixed in the reaction system.

3-Methylglutaric acid can be separated and obtained by crystallization after removing the catalyst from the reaction mixture after the reaction by filtration and distilling off most of the water.

The crude 3-methylglutaric acid thus obtained has a sufficiently high purity by itself, but can be further purified by recrystallization from its aqueous solvent solution, if necessary.

[0028]

The method of the present invention will be described in detail with reference to the following examples.

Example 1 A pressure resistant reactor having a content of 1 liter equipped with a thermometer, a pressure gauge, an electromagnetic stirrer, an air inlet and an outlet gas line was provided with 4 parts of water.
00 ml (22.2 mol), β-methyl-δ-valerolactone 400 ml (3.7 mol), a catalyst in which activated carbon has 5% platinum and 5% bismuth supported (Degussa Japan KK) (About 50% by weight) was charged and heated while being pressurized to 5 absolute atmospheric pressure with air.
When the temperature inside the reactor became constant at 95 ° C., the contents were stirred at a rotation speed of 700 rpm, and the gas was discharged at a rate of 10 liters / hr to carry out an oxidation reaction for about 120 hours.

The autoclave was allowed to cool, air was released, the reaction mixture was taken out, and the catalyst was filtered off. further,
After 300 ml of water was distilled off from the filtrate using an evaporator and then the mixture was cooled to 10 ° C., white crystals began to precipitate and were separated by filtration. A total of 362 g of white crystals were collected. From various analyses, this white crystal was concluded to be 3-methylglutaric acid. The acquisition rate of 3-methylglutaric acid after recrystallization was 57% based on the mol of added β-methyl-δ-valerolactone.

Example 2 A pressure resistant reactor having a content of 300 ml equipped with a thermometer, a pressure gauge, an electromagnetic stirrer, an air inlet and an outlet gas line was filled with water 1
30 ml (7.2 mol), 2-hydroxy-4-methyltetrahydropyran 70 ml (0.6 mol), a catalyst in which 5% platinum was supported on activated carbon (Degussa Japan Co., Ltd. water content rate about 50 wt. %) 2.8 g was charged and heated while being pressurized to 10 absolute atmospheric pressure with air. When the temperature inside the reactor became constant at 98 ° C, the contents were cooled to 7
The oxidation reaction was carried out for about 110 hours while stirring at a rotation speed of 00 rpm and discharging gas at a speed of 10 l / hr.

The autoclave was left to cool, the air was released, the reaction mixture was taken out, and the catalyst was filtered off. further,
95 mL of water was distilled off from the filtrate using an evaporator, and then the mixture was cooled to 10 ° C. When white crystals began to precipitate, they were separated by filtration. A total of 58 g of white crystals were collected. From various analyses, this white crystal was concluded to be 3-methylglutaric acid. The acquisition rate of 3-methylglutaric acid after recrystallization was 53% based on the mol of added 2-hydroxy-4-methyltetrahydropyran.

Example 3 A pressure resistant reactor having a content of 1 liter equipped with a thermometer, a pressure gauge, an electromagnetic stirrer, an air inlet and an outlet gas line was provided with 4 parts of water.
00 ml (22.2 mol), 3-methyl-1,5-pentanediol 100 g (0.8 mol), a catalyst having 5% platinum and 1% bismuth supported on activated carbon (Degussa Japan Co., Ltd.) 4 g of a water content of about 50% by weight was charged and heated while being pressurized to 5 absolute pressure with air.
When the temperature inside the reactor became constant at 110 ° C,
The contents were stirred at a rotation speed of 1000 rpm, and the oxidative reaction was carried out for about 100 hours while discharging the discharged gas at a speed of 5 liter / hr.

The autoclave was allowed to cool, the air was released, the reaction mixture was taken out, and the catalyst was filtered off. further,
After 300 ml of water was distilled off from the filtrate using an evaporator and then the mixture was cooled to 7 ° C., white crystals began to precipitate, and were separated by filtration. A total of 83 g of white crystals was collected. From various analyses, this white crystal was concluded to be 3-methylglutaric acid. The acquisition rate of 3-methylglutaric acid after recrystallization was 50% based on the mol of added 3-methyl-1,5-pentanediol.

Example 4 A pressure resistant reactor having a content of 1 liter equipped with a thermometer, a pressure gauge, an electromagnetic stirrer, an air inlet and an outlet gas line was charged with 4 parts of water.
00 ml, β-methyl-δ-valerolactone 300 g,
6 g of a catalyst (moisture content of about 50% by weight manufactured by Degussa Japan Co., Ltd.) in which 5% of platinum is supported on activated carbon and 3 g of activated clay (manufactured by Mizusawa Chemical Industry Co., Ltd.) are charged, and the pressure is 5 absolute pressure by air. It heated while pressurizing. When the temperature inside the reactor became constant at 125 ° C, 100 contents were added.
The oxidation reaction was carried out for about 35 hours while stirring at a rotation speed of 0 rpm and discharging gas at a speed of 5 l / hr.

The autoclave was allowed to cool, the air was released, the reaction mixture was taken out, and the catalyst and activated clay were separated by filtration. Furthermore, the filtrate is added to water 300 using an evaporator.
After distilling off ml, the mixture was cooled to 7 ° C., and white crystals began to precipitate. 2 white crystals in total
90g was collected. From various analyses, this white crystal was concluded to be 3-methylglutaric acid. The acquisition rate of 3-methylglutaric acid after recrystallization was 63% based on the mol of added β-methyl-δ-valerolactone.

[0037]

INDUSTRIAL APPLICABILITY According to the present invention, β-methyl-δ-valerolactone, 2-hydroxy-, which is mass-produced and easily available
4-methyltetrahydropyran and 3-methyl-1,
By oxidizing a compound selected from the group consisting of 5-pentadiol with oxygen in the presence of an oxidation catalyst and water, 3
-Methylglutaric acid can be easily produced industrially.

Claims (1)

[Claims] 1. β-Methyl-δ-valerolactone, 2-
Hydroxy-4-methyltetrahydropyran and 3-
A method for producing 3-methylglutaric acid, which comprises oxidizing a compound selected from the group consisting of methyl-1,5-pentanediol with oxygen in the presence of an oxidation catalyst and water.