JPS5933573B2 - New manufacturing method for carboxylic acid chloride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing carboxylic acid fluoride using hexafluoro-1,2-epoxypropane (also referred to as hexafluoropropylene oxide, hereinafter abbreviated as HFP0).

Conventionally known methods for synthesizing carboxylic acid fluorides include a method in which the corresponding carboxylic acid chloride is substituted with fluorine (A, G, Pyttman et al., J.

Org, Chem, 1'' 2316) is well known, but it cannot be synthesized in one step from a carboxylic acid. HFPO has recently been used as a monomer for ion exchange resins, and its reactivity has also attracted attention.

The present inventor has discovered that when HFPO is reacted with carboxylic acids in the presence of a tertiary amine, carboxylic acid fluoride can be obtained in high yield under extremely mild conditions, and that a nucleophilic reagent such as an alkinoamine is added to the reaction mixture. They discovered that carboxylic acid derivatives such as esters and amides can be easily produced by adding . The method of the present invention includes:
This is a new method for producing carboxylic acid fluoride, which is characterized by reacting a carboxylic acid with HFPO in the presence of a tertiary amine.

HFPO used in the present invention is produced by oxidizing hexafluoropropylene (HFP, CF3CF=CF2) with hydrogen peroxide or the like in aqueous alcohol-potassium hydroxide. Since HFPO is a gas (boiling point -27.40) at room temperature, the usual method for adding gas or liquid HFPO to the reaction system is adopted as a method for adding it to the reaction system. The addition ratio of HFPO is about 1 equivalent relative to the carboxylic acid as a raw material.

The starting carboxylic acid used in the method of the present invention may be an aliphatic or aromatic carboxylic acid or an alicyclic carboxylic acid.

The aliphatic carboxylic acid may be an unsubstituted or substituted carboxylic acid. Examples include acetic acid propionic acid, butyric acid, and carboxylic acids whose hydrogen groups are substituted with alkyl groups, aryl groups, nitro groups, substituted amino groups, or alkoxyl groups. Divalent or polyvalent carboxylic acids such as adipic acid are also selected. Examples of aromatic carboxylic acids include unsubstituted monocarboxylic acids such as benzoic acid, naphthoic acid, anthracenecarboxylic acid, and substituted monocarboxylic acids having substituents such as alkyl groups, aryl groups, nitro groups, substituted amino groups, and alkoxyl groups. Examples include toluic acid, diphenylcarboxylic acid, nitrobenzoic acid, and methoxybenzoic acid.

In addition, if necessary, polyhydric carboxylic acids such as phthalic acid and trimesic acid are also selected. The tertiary amine used in the process of the invention is usually selected from trialkylamines or mixed tertiary amines of alkyl and aryl groups.

Specifically, the trialkylamines include trimethylamine, triethylamine, tripropylamine,
Mixed alkyl tertiary amine or N・N-N-mer tetramethylethylenediamine [(CH3)2N-CH2-
CH2-N(CH3)2], and hybrid tertiary amines having an alkyl group and an aryl group include, for example, N-N-dimethylaniline, N·N-diethylaniline, and the like. The amount of tertiary amine added is preferably at least the equivalent of HFPO. In the method of the present invention, the solvent is preferably an inert, aprotic polar solvent such as acetonitrile (CH3CN), sulfolane, or dioxane. The reaction temperature is usually selected from room temperature to 80°C, but room temperature is generally sufficient. The reaction pressure may be normal pressure or elevated pressure.

To carry out the method of the present invention, for example, a carboxylic acid and a tertiary amine are dissolved in a solvent, cooled, and then a predetermined amount of H
Add FPO.

After that, the contents are returned to room temperature and kept for about 10 minutes to 90 minutes.
Stir for a minute and allow to react. After the reaction is completed, the carboxylic acid fluoride is separated by a commonly available post-treatment method, such as distillation under reduced pressure. Furthermore, in the case of purification, it is also possible to redistill. Alternatively, it is also advantageous to use the reaction mixture containing the produced carboxylic acid fluoride as it is in the next step, for example, in the step of producing a carboxylic acid derivative by adding a nucleophile such as an alcohol.

For example, in the presence of a tertiary amine, carboxylic acid and HFPO
After reacting with the general formula (in the formula, R represents a residue of an aliphatic compound, alicyclic compound, or an aromatic compound, and X represents a hydroxyl group or a mercapto group) or the general formula (in the formula, R ' represents a hydrogen group or a residue of an aliphatic compound, alicyclic compound, or aromatic compound, and j represents a residue of an aliphatic compound, alicyclic compound, or aromatic compound). carboxylic acid derivatives can be easily produced.

The raw material carboxylic acid, HFPO, tertiary amine, and solvent used in this case are the same as those in the first invention.

Examples of the compound represented by (1) in the above general formula include alcohols, phenols, thiols, and thiophenols.

More specifically, the alcohols include aliphatic alcohols such as methanol, ethanol, propanol, and octanol, alicyclic alcohols such as cyclohexanol, or these alcohols and alkyl groups;
Substituted alcohols substituted with aryl groups, nitro groups, etc.: Phenols include unsubstituted phenols such as phenol and naphthol, and phenols with substituents such as alkyl groups, aryl groups, and nitro groups, such as cresol, xylenol, and nitro groups. Phenols and hydroxybiphenyllithiols include aliphatic thiols such as methylthiol, ethylthiol, and propylthiol (
so-called alkyl mercaptans) or alkyl groups,
Substituted thiols substituted with aryl groups, nitro groups, etc.;
Thiophenols include unsubstituted thiophenols such as thiophenol and thionaphthol, or alkyl groups,
Examples include thiophenols having substituents such as aryl groups and nitro groups, such as thiocresol, mercaptobiphenyl, and nitrothiophenol. The compound represented by (n) in the above general formula specifically represents primary or secondary amines.

For example, aliphatic primary amines such as ethylamine, propylamine, and butylamine; aromatic primary amines such as aniline and naphthylamine; aliphatic secondary amines such as lydiethylamine, dipropylamine, and ethyl-butylamine; methylaniline, Aromatic secondary amines such as ethylnaphthylamine; and other primary or secondary amines listed above, in which the hydrogens of the alkyl and aryl groups are replaced by other substituents, such as alkyl, aryl or nitro groups. Mention may be made of substituted primary or secondary amines. The compound represented by the above general formula (1) or (l) is used in an amount of approximately equivalent to the raw material carboxylic acid.

In this case, the temperature and reaction pressure are the same as those of the present invention described above. To produce this carboxylic acid derivative, first, a carboxylic acid and a tertiary amine are dissolved in a solvent, and after cooling, a predetermined amount of HFPO is added, and then the contents are returned to room temperature to 80°C. Stir and react for 10 to 90 minutes.

Then, the reaction mixture is added with the general formula (1) or (11).
Add the compound represented by and react at room temperature to 80°C for several minutes to several hours. After the reaction is completed, the desired carboxylic acid derivative is separated by a commonly used post-treatment method. Post-treatment methods include, for example, a method in which a reaction mixture containing a carboxylic acid derivative is diluted with water to precipitate a product, followed by filtration and drying to separate the precipitated product; Examples include a method of subsequently extracting with a suitable solvent or a method of distilling the reaction mixture under reduced pressure. Furthermore, if purification is required, recrystallization or redistillation can be performed. In this way, carboxylic acid derivatives such as carboxylic acid esters, carboxylic acid thioesters or carboxylic acid amides can be obtained in high yields. As described above, according to the method of the present invention, carboxylic acid fluoride and carboxylic acid derivatives can be obtained under very mild conditions, that is, at room temperature and around normal pressure, in a high yield.

Furthermore, it is particularly effective when producing carboxylic acid fluorides, esters, thioesters, or amides using thermally unstable carboxylic acids and/or alcohols, thioalcohols, or amines. It is clear that the Hereinafter, the first and second methods of the present invention will be explained in detail using examples.

Example 1 Benzoic acid 2.447 (20mm01), triethyl 5
Amine 2.027 (20mm01), S* as a solvent
Reference Example A mixture of 5 ml of Ruphoran was charged into a pressure-resistant reaction tube, cooled to -75°C in a dry ice-acetone bath, and cooled and liquefied HFPO3.4O7 (20.5 mm01) was added.

After that, the bath was removed and the mixture was left to stand until it reached room temperature (about 15 minutes), and then stirred at room temperature for 30 minutes to react. After the reaction was completed, the contents were taken out and distilled under reduced pressure. Crude benzoyl fluoride (boiling point 75-81°C/46mmHg)2.
33y (yield 94%) was obtained. Further, the crude product was redistilled to obtain pure benzoyl fluoride (boiling point 76°C/50°C).
mmHg) 1.97y (yield 79%). The purified product was confirmed to be benzoyl fluoride by infrared spectroscopy. Example 2 A mixture of 1.487 (20 mm01) of propionic acid, 2.427 (20 mm01) of N-N-dimethylaniline, and 5 ml of sulfolane was charged into a pressure-resistant reaction tube, cooled to -75°C in a dry ice-acetone bath, and cooled. liquefied HFP
3.4 Ot (20.5 mm01) of O was added.

Thereafter, the bath was removed and the mixture was allowed to stand until it reached room temperature, and then stirred at room temperature for 90 minutes to react. After the reaction was completed, the contents were taken out and distilled under reduced pressure. Propionic acid fluoride 1.
31f (yield 86%) was obtained. The infrared spectrum of the product confirmed that it was propionic acid fluoride. Example 3 The procedure was carried out in the same manner as in Example 1, except that isobutyric acid, hydrofuric acid, or P-toluic acid was used as the raw material carboxylic acid, and the tertiary amino acid and reaction time were appropriately selected. Obtained.

A mixture of 3.03y (30mm01) of thylamine and 20ml of acetonitrile as a solvent was charged into a pressure-resistant container.
It was cooled to −75° C. in a dry ice-acetone bath, and 3.057 (18.4 mm 01) of cooled and liquefied HFPO was added.

Thereafter, the bath was removed and the mixture was allowed to stand for about 10 minutes until it reached room temperature, and then stirred at room temperature for 30 minutes to react. Then,
Aniline 1.867 (20 mm01) was added dropwise, and the mixture was stirred again at room temperature for 30 minutes to react. After the reaction is complete, the contents are reduced to 1
The precipitated solid was filtered and dried. Crude propionic acid anilide 1.40f (M.P.lO
57°C) was obtained. On the other hand, the aqueous layer was extracted with ether, washed with water, dried over magnesium sulfate, and the ether was distilled off under reduced pressure.
03°C) 1.217 was obtained. The combined yield of the two products is 95% of crude propionic acid anili*stodo. When the crude propionic acid anilide was recrystallized from carbon tetrachloride, M. P. Pure propionic acid anilide with lO6-7°C was obtained (literature value M.P.lO5-6°C).
The infrared spectrum of the purified product confirmed that it was propionic acid anilide. Reference Example 2 Same as Example 4 except that propionic acid, isobutyric acid, or benzoic acid was used as the raw material carboxylic acid, phenol, aniline, or thiophenol was used as the nucleophile, and the reaction time after addition of the nucleophile was changed. The reaction was carried out using the same procedure.

Claims (1)

[Claims] 1. A novel method for producing carboxylic acid fluoride, which comprises reacting a carboxylic acid with hexafluoro-1,2-epoxypropane in the presence of a tertiary amine.