JPH07133256A - Production of alpha-hydroxyisobutyramide - Google Patents

Abstract

PURPOSE:To provide a process for producing alpha-hydroxyisobutyramide capable of greatly improving the service life of a manganese dioxide catalyst on an industrial scale at a low cost. CONSTITUTION:This alpha-hydroxyisobutyramide is produced by reacting acetone cyanohydrin with water in a liquid phase. A manganese dioxide catalyst having partially fluorinated surfaces is used in this process.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing α-hydroxyisobutyric acid amide. More specifically, by reacting acetone cyanohydrin with water in the liquid phase, α
-A method for producing hydroxyisobutyric acid amide.

[0002]

2. Description of the Related Art It is well known that a corresponding amide compound can be produced by reacting a nitrile compound with water, and .alpha.-hydroxyisobutyric acid amide produced by reacting acetone cyanohydrin with water is used for paints and adhesives. It is useful as a precursor of methyl methacrylate, which is a raw material for molding materials and the like. Various catalysts for reacting this nitrile compound with water are known. The manganese oxide disclosed in US Pat. No. 3,366,639 is one of them. In contrast to the copper-containing catalysts frequently used in the reaction of nitrile compounds with water, which give completely unsatisfactory results in the reaction of α-hydroxynitrile compounds such as acetone cyanohydrin with water, manganese oxides are disclosed in US Pat. As disclosed in No. 3,366,639, it has a characteristic of giving a considerable result even to the reaction of α-hydroxynitrile compound with water.

JP-A-52-222 describes that the yield of α-hydroxyisobutyric acid amide can be increased by adding acetone to a raw material.
As a result of examining an industrial continuous production method of α-hydroxyisobutyric acid amide by reacting acetone cyanohydrin with water using a catalyst suspension bed flow reactor, it was found that the catalytic activity rapidly decreased with time. did. On the other hand, as a method for extending the life of the manganese dioxide catalyst, it is disclosed in JP-A-2-196763 that the hydrogen ion concentration (pH) of the raw material liquid supplied to the reactor is in the range of 4 to 8. An improved preparation method is disclosed in JP-A-3-68447, and a manganese dioxide catalyst added with a second component metal other than manganese is disclosed in US Pat. No. 4,987,256 and European Patent Publication No. 46.
It is described in No. 1,850. However, although the effect is seen in any of these methods, the life of the manganese dioxide catalyst has not reached the stage where it can be industrialized.

[0004]

As described above, as a result of the industrial reaction of acetone cyanohydrin with water in the liquid phase, α-
In order to produce hydroxyisobutyric acid amide, maintaining the activity of the manganese dioxide catalyst for a long time is the most important issue because the catalyst cost increases if the catalyst replacement becomes frequent due to deterioration or deactivation of the manganese dioxide catalyst. .

[0005]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention provides a method for producing α-hydroxyisobutyric acid amide by reacting acetone cyanohydrin and water in a liquid phase, in which the reaction is performed in the presence of partially fluorinated manganese dioxide. A method for producing a characteristic α-hydroxyisobutyric acid amide.

In the present invention, in order to partially fluorinate the surface of manganese dioxide, for example, in a liquid phase method, an aqueous solution of hydrofluoric acid or a soluble salt of fluorine represented by ammonium fluoride or ammonium acid fluoride is used. An aqueous solution and a powder of manganese dioxide or a slurry in which manganese dioxide is dispersed in water is mixed and prepared. The concentration of the hydrofluoric acid aqueous solution or the aqueous solution of fluorine soluble salt is 0.01 to 30 wt%, preferably 0.05 to 15 wt%. The temperature for mixing may be room temperature or heating, but if it is 10 ° to 90 ° C, the operation becomes easy. The mixing time is not particularly limited, but is usually 0.1 to 100 Hr. After completion of the mixing treatment, filtration and drying are performed to prepare the surface-fluorinated manganese dioxide of the present invention. The dried manganese dioxide is sufficiently usable in the present invention, but may be further calcined. The firing temperature is 200 ~ 550 ℃, preferably 300
~ 500 ° C. On the other hand, in the gas phase method, hydrogen fluoride gas or tetrafluoromethane, trichlorofluoromethane,
A gas of fluoromethane represented by dichlorodifluoromethane, chlorotrifluoromethane, hydrochlorodifluoromethane and hydrotrifluoromethane is prepared by contacting with manganese dioxide. The hydrogen fluoride gas or fluoromethane gas can be used as it is without being diluted, but it may be diluted with another gas such as nitrogen or helium before use. The temperature at the time of contact depends on the type and concentration of the gas used, but is 200 to 550 ° C, and preferably 300 to 500.
℃. Further, the contact time depends on the kind and concentration of the gas used, but is usually 0.01 to 5 hours.

In the present invention, the amount of fluorine in manganese dioxide whose surface is partially fluorinated is usually 0.001 to 0.10. Such atomic ratio is
If it is lower than 0.001, the amount on the surface of manganese dioxide is too small to exert a sufficient effect, and if it is higher than 0.10, the amount is too high on the surface of manganese dioxide to prevent the onset of activity. It is preferably 0.005 to 0.07.

The manganese dioxide used in the present invention may be either anhydrous or hydrated. Manganese dioxide is a known method, for example, a method of reacting manganese sulfate with potassium permanganate in the presence of a small excess of caustic soda (US Pat. No. 3,366,639), and a method of reacting manganese sulfate with potassium permanganate in an acidic manner. (Biochem.
J., 50, p. 43 (1951), JP-A-3-68447 and JP-A-3-68447.
4-46145), 20 ° to 100 ° C in the neutral to alkaline range
(7) A method of preparing a 7-valent manganese compound by reduction with
t.Anorg.Allg.Chem. 309 (1961) pages 1-36 and 121.
Pp. 150), a method obtained by reducing a 7-valent manganese salt with hydrohalic acid (JP-A-63-57535), a method of electrolytically oxidizing an aqueous solution of manganese sulfate, and the like are used.

The reactor used in the present invention includes a fixed bed flow type reactor and a suspension bed flow type reactor. When the catalyst of the present invention is packed in a fixed bed reactor, it is usually preferable to mold it into a spherical shape or a columnar shape, and it is preferable to mold it into a representative length of 2 to 10 mm. When used in a suspension bed reactor, powder of 16 to 400 mesh is usually preferable. In the suspension bed reactor, the amount of catalyst used is usually such that the catalyst concentration in the reactor is 0.
It is from 01 to 50% by weight, more preferably from 0.1 to 30% by weight.

The water used for the reaction of acetone cyanohydrin of the present invention with water in the liquid phase to produce α-hydroxyisobutyric acid amide is usually 1 mol or more, preferably 1 mol or more, based on 1 mol of acetone cyanohydrin. Is 5 to 30 mol. Water is usually used as the reaction solvent, but a new solvent inert to the reaction can be used. For example, acetone disclosed in JP-A-52-222 is preferably used. The amount of acetone is preferably in the range of 0.1 to 3.0 mol with respect to 1 mol of acetone cyanohydrin.

The reaction temperature in the present invention is in the range of 0 ° to 200 ° C, preferably 30 ° to 150 ° C. If it is lower than 0 ° C, sufficient activity cannot be obtained, and if it is higher than 200 ° C, a side reaction proceeds, which is not preferable. The reaction pressure may be any of reduced pressure, atmospheric pressure or increased pressure as long as it is a pressure sufficient to maintain the reaction product in the liquid phase at the reaction temperature. When a fixed bed flow type reactor is used, the liquid hourly space velocity is usually 0.01 to 40 Hr ^-1 , preferably 0.1 to 20 Hr ^-1 . When a suspension bed flow type reactor is used, the residence time is usually 0.1 to 50 Hr, preferably 0.5 to 30 Hr.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples. Preparation of Acetone Cyanohydrin A glass round-bottomed flask reactor with an internal volume of 2 liter equipped with a reflux condenser, a stirrer, a thermometer and a liquid inlet was charged with 580 g of acetone and 10 g of a 2% sodium hydroxide aqueous solution and maintained at 20 ° C While injecting 284 g of liquid hydrocyanic acid. After the reaction, sulfuric acid was added to adjust the pH of the solution to 3.5. Next, unreacted hydrocyanic acid and acetone were distilled off under reduced pressure to obtain 840 g of acetone cyanohydrin having a purity of 99.8%. Preparation of manganese dioxide Sulfuric acid was added to 2 liters of a manganese sulfate aqueous solution (concentration: 395 g / l) to prepare a manganese sulfate aqueous solution having pH = 1. After adding 557 g of potassium permanganate to this solution and oxidizing it, 1 liter of water was added to this slurry while maintaining the temperature at around 55 ° C.
Was added and aged for 5 hours. The slurry was suction filtered with an aspirator, washed three times with 1 l of water, and the obtained solid was dispersed in 1 l of water, and aqueous ammonia was added until the pH reached 7. The slurry was suction filtered with an aspirator, washed 5 times with 1 l of water, and then dried with a drier at 110 ° C. for 15 hours to obtain 580 g of manganese dioxide. This manganese dioxide is crushed to 16 ~
It was pulverized to 100 mesh.

Example 1 50 g of manganese dioxide prepared as described above was dispersed in 500 ml of an aqueous 12 wt% ammonium fluoride solution, and the dispersion was allowed to stand at 20 ° C. for 24 hours.
After stirring for an hour, the solution was filtered by a gradient method and dried at 110 ° C. for 15 hours by a drier to prepare a surface-fluorinated manganese dioxide catalyst. The atomic ratio of elemental fluorine to elemental manganese of this catalyst was 0.06. Next, a glass round bottom flask reactor with an internal volume of 500 ml equipped with a glass stirring rod, a thermometer, a raw material supply port and a liquid outlet with a glass ball filter was used to partially fluorinate the surface prepared above. 20 g of the manganese dioxide catalyst and 30
After charging 0 g, the internal temperature was raised to 60 ° C. and kept at this temperature. Next, 36 ml / hr of the raw material solution (acetone cyanohydrin: acetone: water molar ratio 1: 1.5: 18) consisting of acetone cyanohydrin, acetone and water prepared as described above is used.
Was continuously supplied by a metering pump at a flow rate of. While maintaining the temperature in the reactor at 58 ° to 62 ° C, continuous reaction was carried out for 15 days. Table 1 shows changes with time in the yield of α-hydroxyisobutyric acid amide in the resulting α-hydroxyisobutyric acid amide production liquid.
It was shown to.

Example 2 Surface-fluorinated manganese dioxide prepared in the same manner as in Example 1 was further calcined in air at 400 ° C. for 4 hours. Next, using this catalyst, a liquid phase continuous reaction of acetone cyanohydrin and water was performed in the same manner as in Example 1.
Α- in the resulting α-hydroxyisobutyric acid amide product solution
Table 1 shows the daily change of the yield of hydroxyisobutyric acid amide.

Example 3 A catalyst was prepared in the same manner as in Example 1 except that a 2 wt% ammonium fluoride aqueous solution was used, and the atomic ratio of elemental fluorine to elemental manganese was 0.009. Next, using this catalyst, a liquid phase continuous reaction of acetone cyanohydrin and water was performed in the same manner as in Example 1.
Α- in the resulting α-hydroxyisobutyric acid amide product solution
Table 1 shows the daily change of the yield of hydroxyisobutyric acid amide.

Example 4 A catalyst was prepared in the same manner as in Example 1 except that a 1 wt% hydrofluoric acid aqueous solution was used, and the atomic ratio of elemental fluorine to elemental manganese was 0.02. Next, using this catalyst, a liquid phase continuous reaction of acetone cyanohydrin and water was performed in the same manner as in Example 1. Table 1 shows the change with time of the yield of α-hydroxyisobutyric acid amide in the resulting α-hydroxyisobutyric acid amide production liquid.

Comparative Example 1 Using the manganese dioxide catalyst (not fluorinated) prepared as described above, a liquid phase continuous reaction of acetone cyanohydrin and water was performed in the same manner as in Example 1. Table 1 shows the change with time of the yield of α-hydroxyisobutyric acid amide in the resulting α-hydroxyisobutyric acid amide production liquid.

[0018]

[Table 1]

[0019]

INDUSTRIAL APPLICABILITY According to the present invention, the catalyst life of manganese dioxide used in producing α-hydroxyisobutyric acid amide by reacting acetone cyanohydrin with water in a liquid phase is
It is significantly improved by using partially fluorinated manganese dioxide on the surface, and α-hydroxyisobutyric acid amide can be produced industrially advantageously, which is extremely valuable in industry.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Tokuman 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. (72) Sadaaki Yamamoto 1190 Kasama-cho, Sakae-ku, Yokohama, Kanagawa Mitsui Toatsu Chem Within the corporation

Claims (1)

[Claims] 1. A method for producing α-hydroxyisobutyric acid amide by reacting acetone cyanohydrin and water in a liquid phase, wherein the reaction is performed in the presence of manganese dioxide whose surface is partially fluorinated. And a method for producing α-hydroxyisobutyric acid amide.