JPS61251649A - Production of dicarboxylic acid dianilide - Google Patents

Abstract

PURPOSE:To obtain in a high yield a compound useful as a fluidity improver for resins, etc., under a condition of reduced loss of raw material aniline, by condensing a dicarboxylic acid with aniline by the use of a specific solvent under heating. CONSTITUTION:A dicarboxylic acid shown by the formula HOOC-R-COOH (R is 1-10C alkyl, alkenyl or aryl) is condensed with aniline in the presence of a solvent (e.g., ethylbenzene or diethylbenzene) having 80-200 deg.C boiling point to form an azeotropic mixture at atmospheric pressure under heating at 120-200 deg.C to give the aimed substance. The amount of the solvent used is 5-70wt%, preferably 10-40wt% based on the reaction mixture solution, the raw material carboxylic acid and aniline are used in a molar ratio of 1/2-1/10 and the reaction is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing dicarboxylic dianilides.

According to the method of the present invention, the desired dicarboxylic acid dianilide can be produced in good yield under conditions where coloring of the desired product is suppressed and loss of raw material aniline is reduced.

Dicarboxylic acid dianilide is an industrially useful substance that serves as a flow improver for thermoplastic resins such as polyphenylene ether resins (see, for example, Japanese Patent Application Laid-Open No. 60-44547).

Prior art monocarboxylic acid anilides can be produced by, for example, a method (Organic 5y
ntheais, vol. 82 (194
1) ), or a method in which a mixture of formic acid and N-methylaniline is heated in the presence of toluene, and by-produced water is distilled out of the reaction system by azeotropic distillation with toluene (OrganicS
synthesis, vol II, 590 (1955)
), but the disadvantages are that in the former case, aniline is dissolved in the distilled water, resulting in a loss, and in the latter case, formic acid is distilled out together with toluene and water, resulting in a loss of formic acid. Moreover, the above-mentioned literature does not describe any method using dicarboxylic acid as a starting material.

On the other hand, it is already well known that dicarboxylic acid dianilide can be produced from K by reacting the corresponding dicarboxylic acid chloride with aniline. However, in this case, it is considered to be disadvantageous for industrial production because the carboxylic acid chloride is generally expensive and hydrogen chloride is produced as a by-product. Therefore, there is a need for a method for producing dicarboxylic acid dianilides using materials other than dicarboxylic acid chlorides as starting materials, and this has also been studied for some time. For example, a method of mixing and heating dicarboxylic acid and diphenyl urea (Che
M, Ber, Dan, 945 (1953)), a method for reacting dicarboxylic acid and diphenylsulfamide in the presence of pyridine (Chem, Abstr, 899h (
1955)), but in both cases the amidation reagent had to be synthesized from aniline and was not at an industrially satisfactory level.

Problems to be Solved by the Invention The present inventors have investigated a method for producing dicarboxylic acid dianilide by directly reacting -dicarboxylic acid with aniline. However, it has been found that when the reaction is carried out by directly reacting only the dicarboxylic acid and aniline and distilling by-product water out of the system by azeotroping with the aniline, the following drawbacks occur. Firstly, when the by-produced water is efficiently distilled out of the system, the reaction temperature becomes high, which increases side reactions such as thermal deterioration due to aniline, and reduces the dicarboxylic acid dianiline IJ-do product. The hue deteriorates. Furthermore, when unreacted aniline or dicarboxylic acid monoanilide is recycled and reused, the color of the product becomes even worse. Secondly, aniline is dissolved in the water distilled out of the reaction system, resulting in a large amount of loss, which is disadvantageous in industrial implementation.

Summary of the invention The present invention aims to solve the above problems.

That is, the present invention relates to a dicarboxylic acid represented by the general formula HOOC-R-COOH (in the formula, 1R represents an alkyl group, an alkenyl group, or an aryl group of 01 to 10) and an IJ
In the method for producing dicarboxylic acid dianilide by heating and condensing reaction with water in the presence of a solvent, the solvent has a boiling point azeotropically with water in the range of 80 to 200°C under atmospheric pressure, and the amount used is 5 to 70 in weight proportion to the reaction mixture
% range and the heating condensation reaction is carried out in the range of 120 to 200°C.

According to the method of the present invention, side reactions that would deteriorate the hue of the target product can be suppressed, and a dicarboxylic dianilide with a good hue can be obtained, so when it is used as a fluidity improver for resins, etc., it can be colored easily. No such problems arise.

(9) By using a specific solvent, the loss of aniline, which is one of the raw materials, can be reduced, and even if the residual liquid after separating the target product from the reaction mixture is recycled and reused, the problem of deterioration of the color of the target product does not occur. do not have.

DETAILED DESCRIPTION OF THE INVENTION The liquid used in the process of the present invention has a boiling point at atmospheric pressure that is azeotropic with water and has a boiling point in the range of 80 to 200 tl. Specific examples thereof include ethylbenzene, xylene, cumene, diethylbenzene, n-7'' kane, etc., with xylene, ethylbenzene or diethylbenzene being preferred, and ethylbenzene or diethylbenzene being particularly preferred.

The amount of the solvent used is preferably in the range of 5 to 70%, particularly preferably in the range of 10 to 40%, based on the weight ratio of the reaction mixture. If the weight ratio is less than 5%, it is not preferable that side reactions occur due to deterioration of aniline or that the dicarboxylic acid dianilide product is colored. Furthermore, if the weight ratio exceeds 70%, the reaction rate decreases, which is industrially disadvantageous.

The reaction temperature varies depending on the weight ratio of the dicarboxylic acid, aniline, and solvent used, but is generally preferably in the range of 120 to 200°C.

The dicarboxylic acids represented by the general formula HOOC-R-COOH used in the present invention include malonic acid, succinic acid, glutaric acid, adipic acid, pimeline, where R is an alkyl group, alkenyl group, or aryl group of 01 to 1G. Examples include sepacic acid, dodecanoic acid, itaconic acid, fumaric acid, maleic acid, phthalic acid, and the like.

The molar ratio of raw material dicarboxylic acid and aniline used is V2 ~
The range of V1n is preferable, especially "/2, s ~"/s
A range of is preferred. The above molar ratio is 1/! If the amount of dicarboxylic acid increases beyond this value, the amount of unreacted dicarboxylic acid remaining will increase, which is not preferable. Furthermore, if the molar ratio exceeds 1/10 and the amount of aniline is large, the amount of reaction liquid will increase, the pot yield will decrease, and economic efficiency will deteriorate, which is disadvantageous for industrial implementation.

A specific method for implementing the present invention is to heat a reaction mixture consisting of a dicarboxylic acid, aniline, and a solvent, and distill by-produced water out of the reaction system by azeotropy with the solvent, thereby forming a solvent layer and an aqueous layer. A preferred method is to separate the solvent layer and then circulate the solvent layer to the reaction system. Aniline is distilled out together with the azeotrope, but it is particularly preferable to use an aromatic hydrocarbon such as ethylbenzene as the solvent because the loss of aniline to the aqueous layer can be suppressed to a very low level.

After the reaction is completed, the reaction mixture is cooled, dicarboxylic dianilide is crystallized, and the mixture is separated from the furnace to obtain crude dicarboxylic dianilide. By washing this product with lower alcohols such as methanol and ethanol, or aromatic hydrocarbons such as toluene, xylene, and ethylbenzene, white purified dicarboxylic acid dianilide is obtained.

The Pg obtained by filtration K after crystallizing the target product from the reaction mixture contains aniline, dicarboxylic acid, sicarboxylic acid monoanilide, dicarboxylic acid dianilide, and reaction solvent, so it is recycled to the reaction process to obtain dicarboxylic acid. It can be reused as a raw material for acid dianilide.

Experimental Examples Examples 1 to 11 Dicarboxylic acid, aniline, and reaction solvent are shown in Table IK.
Pour into a three-bottle flask with a capacity of 300 m as shown below.
The resulting water was heated and stirred for a predetermined time while being distilled off from the reaction system as an azeotropic mixture with the reaction solvent. After the reaction is completed, the reaction mixture is cooled to below 40C to crystallize crystals.9. The crystals were separated in a furnace, stirred and washed with a solvent, and then dried under reduced pressure. The obtained crystals were confirmed to be dicarboxylic acid dianilide by IR, mass spectra, electrospectroscopy, etc.Aniline in the distilled water was analyzed by gas chromatography.The results of the reaction and analysis were It is shown in Table 1.Here, the reaction temperature is the temperature of the reaction mixture when by-product water starts to distill out of the thread through azeotropy with the reaction solvent, and the temperature of the reaction mixture immediately after stirring for a predetermined period of time. .Also,
The dicarboxylic acid anilide yield is based on the charged dicarboxylic acid 31
(mol) of produced dicarboxylic acid diani! J)
'It is expressed as a ratio of amount (mol). The aniline concentration in distilled water is expressed as the weight percent of aniline based on the sum of the weight of distilled water and the weight of distilled aniline.

(Left below) Comparative Example 1 Adipic acid 43.8 ? (0.3 mol), aniline 1
The reaction was carried out in the same manner as in Examples 1 to 11, except that 76.7 f (1.9 mol) was used and no reaction solvent was added. Reaction temperature: 161-220°C, dianilide yield: 86
．． 5%, and the color of the product remained grayish brown. The amount of distilled water is 9.82, and the aniline concentration in the distilled water is 2.8
It was t%.

Example 12 Adipic acid 43.89 (0.3 mol), aniline 13
9.5F (1.5 mol) and ethylbenzene 26.72
The reaction was carried out in the same manner as in Examples 1 to 11 using . After the reaction is completed, the reaction mixture is cooled to 40° C. or below, and the crystals that have crystallized are separated in a furnace.The F solution obtained is obtained by washing the crystals obtained in the above operation with methanol, and the washing liquid obtained by being separated in a furnace. The residue obtained by concentration was combined as the recovered unreacted material, and adipic acid, aniline, and ethylbenzene were newly added and reacted four times.
I implemented it again. The average yield of adipic dianilide in the five reactions was 95.4% based on adipic acid, and all dicarboxylic dianilide products were white.

Claims (1)

[Claims] (1) General formula, HOOC-R-COOH (wherein R is C
A method for producing a dicarboxylic acid dianilide by subjecting a dicarboxylic acid represented by _1_ to _1_0 (representing an alkyl group, alkenyl group or aryl group) and aniline to a heating condensation reaction in the presence of a solvent, in which the solvent is azeotropic with water. The boiling point under atmospheric pressure is in the range of 80 to 200°C, the amount used is in the range of 5 to 70% by weight of the reaction mixture, and the heating condensation reaction is carried out in the range of 120 to 200°C. A method for producing dicarboxylic acid dianilide, characterized by: