JPH04338370A - Improved method for producing substituted phenoxycarboxylic acid anilide - Google Patents

Abstract

PURPOSE:To increase the isolation yield of the subject compound and simplify production operations in the industrial production of the compound useful as a herbicide. CONSTITUTION:A substituted phenol is reacted with a 2-halocarboxylic acid anilide in the presence of a base in an aromatic hydrocarbon solvent with heating, and the reaction solution is mixed with water to dissolve inorganic contents in the water, and simultaneously cooled to crystallize the objective alpha-(substituted phenoxy)carboxylic acid anilide, which is filtered off. The filtrate is separated, and the oily layer is supplied for the next reaction system as a solvent.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an industrial process for producing compound-substituted phenoxycarboxylic acid anilides useful as useful plant protection agents, particularly herbicides.

0002

[Prior Art] As a method for producing substituted phenoxycarboxylic acid anilides, particularly useful α-(substituted phenoxy)carboxylic acid anilides, substituted phenols and α-
A method is known in which an α-(substituted phenoxy)carboxylic acid derivative is synthesized from a halocarboxylic acid derivative, converted into an α-(substituted phenoxy)carboxylic acid chloride using a reagent such as thionyl chloride, and then reacted with aniline.

Furthermore, JP-A No. 63-170346 discloses that chlorocarboxylic acid anilide is synthesized from chlorocarboxylic acid chloride and aniline, and is reacted with a substituted phenol in an organic solvent in the presence of an inorganic base. An improved method has been proposed.

This method has the advantage that the number of steps is reduced compared to the conventional method and does not require special equipment such as hydrogen chloride waste gas treatment equipment in the acid chloride synthesis process. This is an excellent method that is advantageous in terms of raw material costs, especially when expensive substituted phenols are used, since the phenols are used in the final step. In this case, there are many solvents that can be used in the reaction, but as shown in the examples of the cited patents, alkyl-substituted aromatic hydrocarbons such as toluene or xylene are most suitable. The reason for this is to simplify the practical operation, and the details will be described below.

In other words, it can be used as both a reaction solvent and a crystallization solvent due to its solubility in hot and cold conditions, and since it is virtually immiscible with water, it can be used as it is for removing inorganic components, and filtration The advantage is that both organic and inorganic impurity components can be removed at once by crystallizing in two layers with water without requiring extra operations such as concentration, solvent replacement, extraction washing, etc.

However, a drawback of the purification method by crystallization is that no matter how high the reaction yield is, the amount dissolved by the crystallization solvent is lost, and in order to reduce this loss, cooling must be strengthened, or the crystallization mother liquor must be concentrated and crystallized again. However, this method imposes a heavy burden on equipment and operations.

[0007]

Problem to be Solved by the Invention The present invention provides a method for industrially carrying out the method described in JP-A No. 63-170346, in which the desired substituted phenoxy The purpose is to obtain carboxylic acid anilide.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have studied the details of the synthesis reaction and side reactions of substituted phenoxycarboxylic acid anilides, and have found that even if the reaction solvent is repeatedly used, The present invention was completed based on the discovery that the isolation yield of the product was increased without affecting the quality of the product. That is, the present invention provides the following general formula (1):

0
009]

[C4]

(However, in the formula, X represents a halogen group atom or a lower alkyl group, and n represents 0 or an integer from 1 to 5.)
A substituted phenol represented by and the following general formula (2):

[
0011

[C5]

[0012] A halocarboxylic acid anilide represented by the formula (wherein Y represents a halogen group atom and A represents a linear or branched lower alkylene group) is heated in an aromatic hydrocarbon solvent in the presence of a base. After the reaction, from the reaction mixture,
General formula (3) below:

[0013]

[C6]

Substituted phenoxy represented by (wherein, X represents a halogen group atom or a lower alkyl group, n represents 0 or an integer of 1 to 5, and A represents a straight-chain or branched lower alkylene group) This method for producing a substituted phenoxycarboxylic acid anilide is characterized in that the carboxylic acid anilide is crystallized, filtered and isolated, water is separated and removed from the filtrate, and the organic layer is repeatedly reused as a solvent.

The method of the present invention will be specifically described as follows. A substituted phenol represented by the general formula (1) and a halocarboxylic acid anilide represented by the general formula (2) are mixed in an aromatic hydrocarbon solvent as a reaction and crystallization solvent in the presence of an inorganic base as a deoxidizing agent. Heat and stir to complete the reaction. After the reaction is complete, the desired substituted phenoxycarboxylic acid anilide (general formula (3)) is obtained by adding water to the reaction solution and cooling it while dissolving the inorganic base and its neutralization product remaining in the reaction system. Obtained by filtration as crystals,
Dry to make a product.

On the other hand, the filtrate obtained in the above filtration operation is separated into an organic layer using an aromatic hydrocarbon as a solvent and an inorganic layer using water as a solvent by a liquid separation operation. Using this organic layer as a solvent, substituted phenols of general formula (1), halocarboxylic acid anilide of general formula (2), and an inorganic base were charged in exactly the same manner as at the beginning of the reaction, and the reaction was carried out by heating and stirring. The desired substituted phenoxycarboxylic acid anilide of general formula (3) is obtained by treatment. Furthermore, the filtrate obtained at this time is similarly separated, and the organic layer is repeatedly used as a solvent for the next reaction.

[0017] Since this reaction is a quantitative reaction with almost no side reactions, the loss of raw materials due to the reaction is extremely small, but the greatest loss was in the dissolved matter during crystallization and purification. but,
As mentioned above, by reusing the solvent once used, the dissolved content during crystallization passes through the reaction system together with the solvent and is recovered in the crystallization process again, improving recovery efficiency. I decided to do it. In other words, from the second time onwards, it can be said that the reaction and crystallization are already carried out using a solvent that contains the saturated amount of dissolved target product under the crystallization conditions, and the reaction yield is Almost all of this can be recovered as a product without loss.

The limit on the number of times the solvent can be reused in this way depends on the required purity of the substituted phenoxycarboxylic acid anilide as a product, but also on the purity of the substituted phenol and halocarboxylic acid anilide used as reaction raw materials. That is, if high-purity raw materials are used, almost no impurities will be mixed into the reused solvent, so it can be reused a considerable number of times. However, when using industrially available raw materials, it is possible to carry out the process from 2 to 20 times as an industrially significant number of times, although this cannot be said unconditionally depending on the type and composition of impurities.

Here, general formulas (1), (2) and (3)
Among them, the halogen group atom or the halogen group atom of the lower alkyl group represented by X represents any of the halogen group atoms of fluorine, chlorine, bromine, and iodine, and the lower alkyl group is
A saturated hydrocarbon group having 1 to 4 carbon atoms, such as methyl group, ethyl group, isopropyl group, secondary butyl group,
Examples include tertiary butyl group. Also, as Xn, n
is 2 or more, these halogen group atoms and lower alkyl groups may coexist.

The linear or branched lower alkylene group represented by A is a divalent saturated hydrocarbon group having 1 to 6 carbon atoms, such as methylene group, ethylene group, ethylidene group, 1, Examples include 2-propylene group, 1,1-propylidene group, 2,2-propylidene group, 1,1-n-butylidene group, 1,3-butylene group, and 1,1-n-hexylidene group. Furthermore, the halogen group atoms represented by Y include fluorine, chlorine, bromine, and iodine, and among these, chlorine and bromine are particularly preferred.

The general formula (
Specifically, the substituted phenoxycarboxylic acid anilide of 3) is, for example, phenoxyacetic acid anilide, α-(p
-chlorophenoxy)propionic acid anilide, 2,4-
Dichlorophenoxyacetic acid anilide, α-(2-methyl-
4-chlorophenoxy)propionic acid anilide, α-(
2,4-dichloro-3-methylphenoxy)propionic acid anilide, β-(2,4-dichlorophenoxy)propionic acid anilide, α-(2-methyl-4-chlorophenoxy)valeric acid anilide, α-(2, 4-dichloro-3
Examples include methylphenoxy)heptanoic acid anilide.

The substituted phenols of general formula (1) include phenols containing Xn as a substituent as shown above, such as unsubstituted phenol, o-chlorophenol, p-chlorophenol, etc. -chlorophenol, o-, m-, p-cresol, 2,4-dichlorophenol, 2,4,5-
Trichlorophenol, 2-chloro-4-methylphenol, 2,4-dichloro-3-methylphenol and the like can be mentioned.

The halocarboxylic acid anilide of general formula (2) is a halocarboxylic acid anilide having the above-mentioned A and Y as substituents, such as chloroacetic acid anilide,
Examples include bromoacetic acid anilide, α-chloropropionic acid anilide, α-bromopropionic acid anilide, α-chlorobutyric acid anilide, α-bromovaleric acid anilide, and γ-chlorocaproic acid anilide.

In the reaction, the substituted phenol of the general formula (1) and the halocarboxylic acid anilide of the general formula (2) may be used in equimolar amounts or in excess of either one, but in general, 1 mole of the substituted phenol 0.8 to 1.5 mol, preferably 1 to 1.1 mol, of halocarboxylic acid anilide is used. The base as a deoxidizing agent used in the reaction is preferably one exemplified in the cited patent (JP-A No. 63-170346). Particularly, potassium carbonate is added in an amount of 1 to 1 mol per mole of substituted phenol as a raw material. It is most preferable to use about 2 moles.

Among the reaction solvents listed in the cited patent (Japanese Unexamined Patent Publication No. 63-170346), for the initial purpose, water is added and cooled after the completion of the reaction to precipitate the target product as crystals. Further, as a system that can be reused only by separation after filtration, aromatic hydrocarbons such as toluene and xylene can be mentioned as appropriate and preferable solvents, and the amount used is 2 to 2 to 10% by weight based on the phenol substituted as the raw material. It is appropriate to use 20 times more, preferably about 3 to 10 times more.

The reaction temperature is preferably about 50°C to 150°C, and when toluene or xylene is used, its reflux temperature can be used. The reaction time is not particularly limited, but it can usually be completed in 3 to 48 hours.
Under preferable conditions, the process can be completed in about 6 to 24 hours. Further, when water is added after the reaction is completed and the mixture is cooled for crystallization, the temperature is 40°C or lower, preferably 30°C or lower.

[0027]

[Example] In a glass reactor with an internal volume of 1.5 liters,
Add 54 g of 4-dichloro-3-methylphenol, 58.8 g of α-chloropropionic acid anilide, 63.2 g of finely powdered potassium carbonate, and 354 ml of toluene as a solvent and reflux the toluene solvent in an oil bath while stirring. and reacted for 20 hours. After the reaction is completed, let it cool to 100°C.
When the temperature reached 800 ml of cold water, crystals were precipitated. After cooling for further 6 hours, the crystals were filtered off, washed with water and a small amount of toluene, and dried to obtain 88.2 g of α-(2,4-dichloro-3-methylphenoxy)propionic acid anilide. ...isolated yield 89.2%

0
[028] On the other hand, the filtrate from the filtration operation and the washing liquid were combined and separated, and a small amount of toluene was added to the toluene layer to make 354 ml.
, 54 g of 4-dichloro-3-methylphenol, 58.8 g of α-chloropropionic acid anilide, and 63.2 g of finely powdered potassium carbonate. However, since some water had entered the reaction system, the reaction was carried out by azeotropic distillation using a Dean-Stark water separator to remove water from the reaction system. Similar to the first time, the reaction was completed in 20 hours,
After cooling to 100° C., 800 ml of water was added, and 96.9 g of α-(2,4-dichloro-3-methylphenoxy)propionic acid anilide was obtained by the same operation. This filtrate was also separated in the same way, and the toluene layer was used as a solvent to prepare 354 ml, and the same amount of raw materials as above were charged and reacted in the same manner. When isolated by crystallization, 97.0 g of α-(2,
4-dichloro-3-methylphenoxy)propionic acid anilide was obtained.

Claims (1)

[Claims] Claim 1: A substituted phenol represented by the following general formula (1): [Formula 1] (wherein, X represents a halogen group atom or a lower alkyl group, and n represents 0 or an integer from 1 to 5) and a halocarboxylic acid anilide represented by the following general formula (2): [Chemical formula 2] (wherein, Y represents a halogen group atom and A represents a linear or branched lower alkylene group). After a heating reaction in an aromatic hydrocarbon solvent in the presence of a base, the following general formula (
3): [Formula 3] (However, in the formula, X represents a halogen group atom or a lower alkyl group, n represents 0 or an integer of 1 to 5, and A represents a linear or branched lower alkylene group.) A substituted phenoxycarboxylic acid anilide characterized in that the substituted phenoxycarboxylic acid anilide represented by the formula is crystallized, filtered and isolated, water is separated and removed from the filtrate, and the organic layer is repeatedly reused as a solvent. manufacturing method.