JPH05255176A - Production of monochloroacetic acid - Google Patents

Abstract

PURPOSE:To increase a reaction rate, to suppress formation of by-products and to effectively obtain the subject compound having a high reaction rate even by dropping reaction temperature and concentration of sulfuric acid in hydrolyzing trichloroethylene, etc., by adding a fluorine-containing cation exchange resin to the reaction system. CONSTITUTION:Trichloroethylene and/or 1,1,1,2-tetrachloroethylene is reacted in the presence of preferably 70-98.5wt.% sulfuric acid preferably at 50-200 deg.C by adding a fluorine-containing cation exchange resin to the reaction system to give the objective monochloroacetic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing monochloroacetic acid by hydrolyzing trichloroethylene or / and 1,1,1,2-tetrachloroethane (hereinafter referred to as tetrachloroethane).

[0002]

BACKGROUND OF THE INVENTION Monochloroacetic acid is a synthetic raw material for carboxymethyl cellulose, medicines such as vitamins B ₁ and B ₆ ,
It is a useful compound having a wide range of uses such as agricultural chemicals such as 2,4-dichlorophenoxyacetic acid, synthetic intermediates such as glycolic acid, thioglycolic acid and malonic acid, chelating agents and surfactants.

Conventionally, as a method for producing monochloroacetic acid, (1) a method of chlorinating acetic acid (2) a method of oxidizing chlorinated organic compounds such as ethylene chlorohydrin and chloroacetaldehyde (3) chlorination of ketene to chloro A method of hydrolyzing as acetyl chloride (4) A method of hydrolyzing trichloroethylene or tetrachloroethane in the presence of sulfuric acid has been reported.

However, (1) has a problem that dichloroacetic acid produced as a by-product is mixed with monochloroacetic acid in the product, and (2) and (3) use expensive raw materials, and the reaction step However, it is not economical because it is long and requires careful handling.

In the case of (4), a dichloro compound is not produced as a by-product, the reaction process is simple, and monochloroacetic acid can be obtained in a high yield. However, in order to increase the reaction rate of hydrolysis, for example, trichloroethylene is used. Taking the case of as an example, 1
It is necessary to use high-concentration sulfuric acid at a high temperature of 30 ° C to 140 ° C (Tokai Electrode Technical Report Vol. 21, No. 1, P. 30).
~ P. 36). When the reaction is carried out using such a high temperature and a high concentration of sulfuric acid, the heating cost increases, and it becomes necessary to carry out the reaction under pressure, and side reactions increase, causing problems such as corrosion of the device. Occurs. The higher the reaction temperature, the greater the problem, and the need to use more expensive and more corrosion resistant equipment materials. Also, lowering the reaction temperature to avoid this problem lowers the reaction rate and increases the yield. There were various industrial problems such as a decrease.

[0006]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In the method for producing monochloroacetic acid by hydrolysis of trichloroethylene or tetrachloroethane, the present inventors have proposed a means for obtaining a large reaction rate even if the reaction temperature or the sulfuric acid concentration is lowered. As a result of earnest research, the present invention has been completed.

[0007]

DISCLOSURE OF THE INVENTION The present invention is characterized by the presence of a fluorinated cation exchange resin in the production of monochloroacetic acid by hydrolyzing trichloroethylene or / and tetrachloroethane. Is the way.

As the trichloroethylene and tetrachloroethane in the present invention, those produced industrially may be used, but the higher the purity, the more preferable. Particularly, perchloroethylene and pentachloroethane which are hydrolyzed to produce dichloroacetic acid as a by-product. It is preferable that there are few impurities such as. Trichloroethylene or tetrachloroethane may be used alone or as a mixture of trichloroethylene and tetrachloroethane, and the composition ratio thereof is not particularly limited.

In the present invention, the hydrolysis reaction is preferably carried out by utilizing the water content in sulfuric acid in the presence of sulfuric acid. Sulfuric acid generally used is sufficient, and the concentration thereof is preferably 50% by weight to 99.5% by weight, more preferably 70% by weight to 98.5% by weight. The concentration of sulfuric acid is 50
If it is less than wt%, the reaction rate becomes very slow and it cannot be said to be practical.

In the reaction, trichloroethylene or / and tetrachloroethane is preferably added in an amount of 0.001 to 50 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the sulfuric acid. 50 trichloroethylene or / and tetrachloroethane
If it is more than the amount by weight, the reaction rate becomes very slow and it becomes impractical. If the amount of trichlorethylene or / and tetrachloroethane is less than 0.001 part by weight, a very large facility is required to obtain a desired amount of monochloroacetic acid, which is not economical.

Examples of the fluorine-containing cation exchange resin used in the present invention include a cation exchange group-containing fluorinated olefin resin, and examples of the cation exchange group include a sulfonic acid group, a carboxylic acid group and a carboxylic acid. Group and a sulfonic acid group, and particularly preferred is a sulfonic acid group. As a preferable specific example of the fluorine-containing cation exchange resin, for example, Nafion-H which is a copolymer of tetrafluoroethylene and perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid.
(Brand name: manufactured by DuPont; Hammett acidity function (H ₀ )-
11--13).

The fluorinated cation exchange resin is not particularly limited in shape, and may be in pellet form or film form.
Further, the method of allowing this to exist in the reaction system is not particularly limited as long as it can be brought into contact with the reaction solution, and even if it is added to the reaction solution, a container filled with pellets becomes the reaction solution. It may be in the form of contact.

The amount of the fluorinated cation exchange resin used is
Although depending on the shape and surface condition of the resin, the total contact surface area of the resin is preferably 30 cm ^{2 to} 100 m ² with respect to 1 kg of trichloroethylene or / and tetrachloroethane,
The amount is more preferably 300 cm ^{2 to} 10 m ² . Three
If it is less than 0 cm ² , the reaction promoting effect cannot be said to be high, and 1
Even if it exceeds 00 m ² , the effect corresponding to the amount of resin used cannot be expected. In addition, a resin having an excessively fine powder or thin film shape to increase the surface area becomes weak in strength and difficult to handle, and thus is not practical.

The reaction temperature in the present invention is preferably 5
The temperature is 0 ° C to 200 ° C, more preferably 70 ° C to 150 ° C in the case of trichlorethylene, and 90 ° C to 180 ° C in the case of tetrachloroethane. If the temperature is lower than 50 ° C., the reaction rate may be slow, and if the temperature is higher than 200 ° C., expensive equipment such as higher pressure resistance equipment and corrosion resistance equipment is required, which is not preferable.

The present invention may be carried out under normal pressure, but may be carried out under pressure if necessary. As the reaction method of the present invention,
Either a batch system or a continuous system is possible. In the case of the batch system, for example, a reactor is charged with a predetermined amount of trichlorethylene or / and tetrachloroethane, and a predetermined concentration and a predetermined amount of sulfuric acid, and the fluorinated cation exchange resin is brought into contact with the reaction solution and heated to a predetermined temperature. And react. In the case of the continuous system, for example, a reactor is charged with a predetermined concentration and a predetermined amount of sulfuric acid and a fluorine-containing cation exchange resin, heated to a predetermined temperature, and a predetermined amount of trichloroethylene or / and tetrachloroethane is continuously added. It may be supplied to carry out the reaction, or vice versa. The product monochloroacetic acid may be accumulated up to about 200 parts by weight with respect to 100 parts by weight of the sulfuric acid. Monochloroacetic acid can be separated and obtained from the product solution by ordinary operations such as distillation and crystallization.

[0016]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. Example 1 Trichloroethylene 28 g, 95 wt% in a glass reactor
Sulfuric acid 71g and Nafion -H resin pellets (trade name, manufactured by DuPont) 1g (total surface area: 540cm ² / trichlorethylene 1Kg) were charged, and the reaction was carried out for 2 hours at 87 ℃. The amount of hydrogen chloride generated was measured every 10 minutes for 1 hour, and the hydrolysis reaction rate was calculated. As a result, as shown in Table 1, it was 0.35 mol / l.hr (based on trichloroethylene).

[0017]

[Table 1]

Examples 2 to 10 Reactions were carried out in the same manner as in Example 1 under the conditions shown in Table 1. The results are shown in Table 1.

Comparative Examples 1 to 5 The reaction was carried out in the same manner as in Example 1 except that Nafion-H resin pellets were not charged and the other conditions were as shown in Table 1.
The results are shown in Table 1.

Of the above examples and comparative examples, the case of using trichloroethylene as a raw material is as follows. For example, comparing the reaction rates in Example 1 and Comparative Example 1, when the reaction temperature was 87 ° C., 95 wt% sulfuric acid was used in substantially the same amount, and the fluorinated cation exchange resin was present (Example 1) Has a reaction rate of 1.8 times that in the case of not allowing it to exist (Comparative Example 1). Also,
The difference is more pronounced when the reaction temperature is lower. Comparing Example 4 with Comparative Example 2, the sulfuric acid concentration was the same as in Example 1 or Comparative Example 1, and the reaction temperature was 7
When the temperature is 5 ° C., the reaction rate in the case where the fluorinated cation exchange resin is present (Example 4) is 2.5 times that in the case where it is not present (Comparative Example 2). Further, even if the sulfuric acid concentration was lowered, the difference in reaction rate was remarkable, and comparing Example 5 and Comparative Example 3, the reaction temperature was 87 ° C.
When approximately the same amount of 0 wt% sulfuric acid was used, and when the fluorine-containing cation exchange resin was present (Example 5), the reaction rate was 3.4 times as high as when it was not present (Comparative Example 3). Is.

As is clear from the comparison between Example 5 and Comparative Example 1, the reaction rate was 0.19 at the reaction temperature of 87 ° C. without the presence of the fluorinated cation exchange resin.
To achieve mol / l · hr, it is necessary to use 95 wt% sulfuric acid (Comparative Example 1), whereas in the case where a fluorinated cation exchange resin is present (Example 5), 90 wt% sulfuric acid is used. By using almost the same amount, the reaction rate (0.17
mol / l · hr) can be achieved.

When tetrachloroethane is used as a raw material,
Comparing Example 8 and Comparative Example 4, when the reaction was carried out at a reaction temperature of 130 ° C. using approximately the same amount of 95 wt% sulfuric acid, and when the fluorine-containing cation exchange resin was present (Example 8), The reaction rate is about twice as high as when not present (Comparative Example 4).

[0023]

The present invention is a process for producing monochloroacetic acid, which comprises hydrolyzing trichloroethylene or / and tetrachloroethane in the presence of a fluorinated cation exchange resin. According to the present invention, Even if the reaction temperature and sulfuric acid concentration are lowered, a large reaction rate can be obtained, the production of by-products is suppressed, and the monochloroacetic acid is produced industrially efficiently and in high yield without corroding the reactor. You can do it.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Teruo Yoshida 1-1 Funami-cho, Minato-ku, Nagoya-shi, Aichi Toagosei Chemical Industry Co., Ltd. Nagoya Research Institute

Claims (1)

[Claims] 1. Trichlorethylene or / and 1,
A method for producing monochloroacetic acid, which comprises presenting a fluorinated cation exchange resin when hydrolyzing 1,1,2-tetrachloroethane to produce monochloroacetic acid.