JP2002363130A - Method for producing carboxylic acid chloride having slight discoloration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily produce a high-purity carboxylic acid chloride in a high yield in a slight discoloration without requiring a distillation process, which was difficult in the past. SOLUTION: A carboxylic acid is reacted with phosgene in the presence of an amide compound catalyst such as an amide compound, etc., to give a reaction mixture containing a carboxylic acid chloride, which is brought into contact with chlorine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for easily producing carboxylic acid chloride having little coloration in high yield.

[0002]

2. Description of the Related Art Carboxylic acid chloride is used as a raw material or intermediate of various compounds and is a useful substance in the chemical industry. Generally, a carboxylic acid chloride can be produced by reacting the corresponding carboxylic acid with a chlorinating agent, in which case the chlorinating agent includes, for example,
Thionyl chloride, phosphorus oxychloride, phosphorus pentachloride, phosgene and the like are used.

[0003] Among such chlorinating agents, thionyl chloride can be easily used in a laboratory, but is industrially expensive in addition to itself. Is necessary, so there is an economic problem.
Further, phosphorus oxychloride and phosphorus pentachloride have a problem that a purification step such as distillation is required in order to separate phosphoric acid by-produced from a desired carboxylic acid chloride.

Further, phosgene can be easily and inexpensively produced from chlorine and carbon monoxide, and the by-products produced by the reaction with carboxylic acid are hydrogen chloride and carbon dioxide. It has the advantage that separation is easy. However, the reaction between carboxylic acid and phosgene is generally slow without a catalyst,
Various catalysts such as dimethylformamide (DMF)
And an amide compound catalyst such as N-methylpyrrolidone (NMP).

[0005] However, when a catalyst such as these amide compounds is used, the mixture after the reaction is colored brown or black, and thus the originally colorless carboxylic acid chloride is also colored. Conventionally, in order to obtain a carboxylic acid chloride with little coloring, a purification step such as distillation was required. However, the distillation step requires not only cost and time, but also, in the case of carboxylic acid chloride having a high boiling point, industrial distillation is practically impossible due to a large distillation loss.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a process for producing a carboxylic acid chloride by reacting a carboxylic acid and phosgene in the presence of an amide compound catalyst, which has been conventionally difficult to produce. It is an object of the present invention to provide a novel method for easily producing a carboxylic acid chloride having a small coloring including an acid chloride in a high yield.

[0007]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems. As a result, the present invention does not require a costly and time-consuming distillation step, and can be easily and in high yield. The present invention has succeeded in developing a method for producing a carboxylic acid chloride with less coloring, and the present invention has the following gist. (1) A method for producing a carboxylic acid chloride having less coloring, wherein chlorine is brought into contact with a carboxylic acid chloride obtained by reacting a carboxylic acid with phosgene in the presence of an amide compound catalyst. (2) For 1 mol of carboxylic acid chloride, 0.0
The method for producing a carboxylic acid chloride having little coloring according to (1), wherein the chlorine is contacted with 01 to 0.5 mol. (3) A method for producing a carboxylic acid chloride having less coloring, which comprises reacting a carboxylic acid with phosgene in the presence of an amide compound catalyst and chlorine. (4) A method for producing a carboxylic acid chloride with less coloring, wherein phosgene and chlorine are supplied to a reaction system having an amide compound catalyst and a carboxylic acid to convert the carboxylic acid to the carboxylic acid chloride. (5) The amount of chlorine is 0.001 to 1 mol of carboxylic acid.
(3) or (4), wherein the carboxylic acid chloride is less colored. (6) The method for producing a less colored carboxylic acid chloride according to any one of (1) to (5), wherein the carboxylic acid chloride has a boiling point of 120 ° C. or higher.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A carboxylic acid as a raw material of a carboxylic acid chloride produced in the present invention is aromatic, aliphatic or alicyclic, as long as it reacts with phosgene to produce a corresponding carboxylic acid chloride. Regardless of tribe,
It can be used irrespective of monocarboxylic acid or polycarboxylic acid, and with or without a substituent. As these carboxylic acids used in the present invention, preferably, acetic acid, propionic acid, butyric acid, isobutyric acid, 2-ethylhexanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, phenylacetic acid Fatty acid carboxylic acids such as 2-phenylpropionic acid, chloroacetic acid and 2-chloropropionic acid; alicyclic groups such as cyclohexanecarboxylic acid, 2-methylcyclohexanecarboxylic acid, 4-methylcyclohexanecarboxylic acid and 4-phenylcyclohexanecarboxylic acid Carboxylic acids, benzoic acid, o
Aromatic carboxylic acids such as -toluic acid, p-chlorobenzoic acid, p-fluorobenzoic acid, p-phenylbenzoic acid, malonic acid, succinic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, And dicarboxylic acids such as diglycolic acid, and the like.

In the present invention, a corresponding carboxylic acid chloride is produced from such a carboxylic acid. Above all,
Conventionally, purification by distillation or the like has been difficult.
The present invention is also advantageously applied to the production of carboxylic acid chloride at a temperature of 20 ° C. or higher, particularly 150 ° C. or higher. Preferred carboxylic acid chlorides produced in the present invention including such a carboxylic acid chloride having a high boiling point include 2-carboxylic acid chlorides.
Aliphatic carboxylic acid chlorides having 8 or more carbon atoms such as ethylhexanoic acid chloride, decanoic acid chloride, dodecanoic acid chloride, tetradecanoic acid chloride, hexadecanoic acid chloride, octadecanoic acid chloride, phenylacetic acid chloride, 2-phenylpropionic acid chloride, cyclohexane Alicyclic carboxylic acid chlorides such as carboxylic acid chloride, 2-methylcyclohexanecarboxylic acid chloride, 4-methylcyclohexanecarboxylic acid chloride, 4-phenylcyclohexanecarboxylic acid chloride, benzoic acid chloride, o-toluic acid chloride, p-chloro Aromatic carboxylic acid chlorides such as benzoic acid chloride, p-fluorobenzoic acid chloride, p-phenylbenzoic acid chloride, malonic acid dichloride, koha Acid dichloride, 1,2-cyclohexanedicarboxylic acid dichloride, 1,4-cyclohexanedicarboxylic acid dichloride, and dicarboxylic acid dichloride such as diglycolic acid dichloride is exemplified.

An amide compound catalyst for producing a carboxylic acid chloride by reacting a carboxylic acid with phosgene is an excellent catalyst capable of obtaining a carboxylic acid chloride in a high yield. The use of an amide compound catalyst has the disadvantage that the produced carboxylic acid chloride is colored, but according to the present invention, such coloring can be reduced. Preferred examples of the amide compound catalyst used in the present invention include:
N, N-dimethylformamide (DMF), N, N-diethylformamide, N, N-dibutylformamide,
N, N-dimethylacetamide, N-methylpyrrolidone (NMP) and the like. The amide compound catalyst is preferably used in an amount of 0.1 to carboxylic acid as a raw material.
001 to 5 mol%, particularly 0.005 to 1 mol% is used.

In the present invention, the reaction conditions for producing carboxylic acid chloride by reacting carboxylic acid and phosgene in the presence of a catalyst are not particularly limited, and known conditions are employed. Among them, in the present invention, the temperature is preferably 20 to 120 ° C., and the pressure is preferably −0.05.
A batch system, a complete mixing continuous system, a piston flow continuous system, and the like are preferably employed. Phosgene is used in an amount of 1 equivalent or more relative to the carboxylic acid, and preferably 1 to 10 equivalents.

As described above, the reaction mixture obtained by reacting the carboxylic acid with phosgene in the presence of an amide compound catalyst varies depending on the type of the amide compound catalyst used. Color brown to black. In the present invention, the amide compound catalyst is removed from the reaction mixture containing the carboxylic acid chloride, and then the colored carboxylic acid chloride is brought into contact with chlorine. Further, chlorine can be brought into contact with the reaction mixture before separation of the amide compound catalyst. However, since the amide compound catalyst is also usually colored, it is preferable to remove the amide compound catalyst and then contact it with chlorine. Various methods are employed for the method of bringing chlorine into contact with such a carboxylic acid chloride. For example, the carboxylic acid chloride obtained after completion of the reaction is brought into contact with chlorine gas by introducing chlorine gas, and during the progress of the reaction, the reaction mixture containing a considerable amount of unreacted carboxylic acid or phosgene is obtained. , May be contacted with chlorine. Further, the reaction can be carried out in the presence of chlorine in the reaction system from the beginning of the reaction.

Further, chlorine may be supplied to the reaction system together with phosgene to be reacted with the carboxylic acid, or phosgene containing chlorine may be supplied to the reaction system. Phosgene containing chlorine can be obtained by adding chlorine to phosgene, or can be obtained by excessively using chlorine when producing phosgene from carbon monoxide and chlorine.

The present invention also provides a reaction system having an amide compound catalyst and a carboxylic acid, wherein chlorine is supplied to the reaction system together with the above-mentioned phosgene, or phosgene containing chlorine is supplied to the reaction system to convert the carboxylic acid. It is a method of converting into carboxylic acid chloride. This method is convenient because it is not necessary to specifically carry out contact with chlorine after the reaction, and the degree of coloring of the carboxylic acid chloride is almost the same as that in the case of contacting with chlorine after the reaction. Or better. In the present invention, the contact with chlorine may be carried out in combination with a means carried out in parallel with the above reaction and a means carried out after the reaction.

If the amount of chlorine used for contact with the reaction mixture is too small, the effect of decolorization is small, and if it is too large, chlorine is wasted, which is not economical and undesired chlorination reaction may proceed. There is. Therefore, the amount of chlorine used is preferably from 0.001 mol to 0.5 mol, particularly preferably from 0.01 mol to 0.3 mol, per 1 mol of the carboxylic acid chloride in the reaction mixture. It is suitable. When chlorine is supplied to the reaction system together with phosgene, the amount of chlorine is preferably 0.001 to 1.5 mol, more preferably 0.1 to 1.5 mol, per mol of carboxylic acid. It is preferable to supply 1.0 mol.

If the temperature at which the reaction mixture comes into contact with chlorine is too low, its effect is small, and if it is too high, undesirable chlorination reactions may become significant. Thus, the temperature is preferably between 30 and 120
C., particularly preferably 50 to 100.degree. This temperature may be the same as the reaction temperature at which carboxylic acid and phosgene react to form carboxylic acid chloride.

The carboxylic acid chloride thus obtained can be obtained with a coloring degree of 6 or less on the Gardner scale without performing a purification operation such as distillation under reduced pressure as in the conventional method.

[0018]

The present invention will be specifically described below with reference to examples. Example 1 A 2-liter flask equipped with a gas blowing tube, a stirrer, a thermometer and a gas outlet was charged with 1000 g (7.81 mol) of cyclohexanecarboxylic acid and 5 g (0.07 mol) of dimethylformamide, and the temperature was lowered. Maintain at 70 ° C., 45 NL / hour of phosgene and 0.45 N of chlorine
The reaction was carried out by blowing at a rate of L / hour for 6 hours.

After the completion of the reaction, nitrogen gas was introduced while leaving to cool to remove unreacted phosgene, chlorine, and by-produced hydrogen chloride. The reaction mixture was a yellow transparent liquid, and a brown liquid derived from dimethylformamide was phase-separated at the bottom of the reactor. The cyclohexanecarboxylic acid chloride in the upper layer was isolated. The yield of cyclohexanecarboxylic acid chloride was 1136 g (7.75 mol), the yield was 99%, and the chromaticity was 5 on the Gardner scale. Further, a part thereof was treated with ethanolic sodium hydroxide to make it acidic with diluted nitric acid, and then titrated with a silver nitrate standard solution to determine the so-called active chlorine content.
% (Theoretical value: 22.8%), indicating that the obtained cyclohexanecarboxylic acid chloride (boiling point: 184 ° C.) was highly pure.

Example 2 Example 1 was completely different from Example 1 except that 1000 g (3.91 mol) of hexadecanoic acid was used instead of cyclohexanecarboxylic acid, and the time for blowing phosgene and chlorine was 3 hours. The reaction was performed in the same manner. After the completion of the reaction, degassing was performed to remove a brown liquid derived from dimethylformamide to obtain 1,040 g (3.79 mol) of hexadecanoic acid chloride. The yield was 97% and the chromaticity was 3 on Gardner scale. Example 1
The active chlorine content determined by the same titration method as in Example 1 was 12.8% (theoretical value: 12.9%), and the obtained hexadecanoic acid chloride (boiling point: 280 ° C.) was found to have high purity.

Example 3 The reaction was carried out in the same manner as in Example 2 except that 1000 g (3.52 mol) of octadecanoic acid was used instead of cyclohexanecarboxylic acid. After completion of the reaction, degassing was performed to remove a brown liquid derived from dimethylformamide to obtain 1,044 g (3.45 mol) of octadecanoic acid chloride. The yield was 98% and the chromaticity was 4 on the Gardner scale. Example 1
The active chlorine content determined by the same titration method as in Example 1 was 11.5% (theoretical value: 11.6%), and the obtained octadecanoic acid chloride (boiling point: 310 ° C.) was found to have high purity.

Example 4 A reaction was carried out in the same manner as in Example 1 except that 1000 g (7.35 mol) of m-toluic acid was used instead of cyclohexanecarboxylic acid. Although m-toluic acid was solid at the beginning of the reaction, it gradually dissolved as the reaction progressed. After the completion of the reaction, degassing was performed to remove a brown liquid derived from dimethylformamide, and
g (7.15 mol) of m-toluic acid chloride were obtained. The yield was 97%, the active chlorine content by the same titration method as in Example 1 was 22.8% (theoretical value: 23.0%), and the obtained m-toluic acid chloride (boiling point: 21%) was obtained.
3 ° C.) was found to be highly pure.

Comparative Example 1 A reaction was carried out in the same manner as in Example 3 except that chlorine was not introduced. After completion of the reaction, degassing was performed to remove a brown liquid derived from dimethylformamide to obtain 1058 g (3.46 mol) of octadecanoic acid chloride. Although the yield was 98%, remarkable black-brown coloring was observed, and the chromaticity was 1 on the Gardner scale.
It was 2. The active chlorine content determined by the same titration method as in Example 1 was 11.5% (theoretical value: 11.6%).

Example 5 12 octadecanoic acid chlorides obtained in Comparative Example 1 on a Gardner scale were charged into the same reactor as in Example 1, and chlorine gas was blown at 40 ° C. for 1 hour at a rate of 1 NL / hour. It is. A decrease in chromaticity was observed as chlorine gas was blown. When the chromaticity was measured after degassing, it was found to be 6 on the Gardner scale, but the active chlorine content was 11.5.
% Did not change.

[0025]

According to the method of the present invention, unlike the conventional distillation method, there is no need for cost and time, and even in the case of carboxylic acid chloride having a high boiling point, high yield and no loss can be obtained. It is possible to easily produce a carboxylic acid chloride with little coloring. Also, the method of the present invention,
By supplying chlorine into the reaction system between the carboxylic acid and phosgene, the reaction can be carried out in parallel with the reaction for producing carboxylic acid chloride, which is simple and efficient.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ryutaro Takei 10 Goi Kaigan, Ichihara City, Chiba Prefecture Asahi Pen Chemical Co., Ltd. F-term (reference) 4H006 AA02 AC47 AD30 BA51 BC10 BC11 BC34 BE52 BE53 BJ20 BJ50 BS10 BS20 BS30 4H039 CA52 CD30

Claims (6)

[Claims] 1. A process for producing a carboxylic acid chloride having less coloring, characterized by contacting chlorine with a carboxylic acid chloride obtained by reacting a carboxylic acid with phosgene in the presence of an amide compound catalyst. 2. A carboxylic acid chloride is added to 1 mole of
The method for producing a carboxylic acid chloride having low coloring according to claim 1, wherein 0.001 to 0.5 mol of chlorine is contacted. 3. A process for producing a carboxylic acid chloride having low coloring, which comprises reacting a carboxylic acid with phosgene in the presence of an amide compound catalyst and chlorine. 4. A method for producing a carboxylic acid chloride having little coloring, wherein phosgene and chlorine are supplied to a reaction system having an amide compound catalyst and a carboxylic acid to convert the carboxylic acid into a carboxylic acid chloride. 5. The amount of chlorine is 0.1 to 1 mol of carboxylic acid.
The method for producing a carboxylic acid chloride having little coloring according to claim 3 or 4, wherein the amount is from 001 to 1.5 mol. 6. The method for producing a carboxylic acid chloride having low coloring according to any one of claims 1 to 5, wherein the carboxylic acid chloride has a boiling point of 120 ° C. or higher.