JPS629584B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a novel compound useful as a precursor of 4-(parahalogenobenzoyl)-2,6-dimethylphenol, which is a monomer for heat-resistant polymers. This invention relates to parahalogenated benzoic acid 2,6-dimethylphenyl ester and a method for producing the same.

(Prior Art) Parahalogenated benzoic acid phenyl esters having no substituent at the 2,6-position are known. For example, phenyl parafluorobenzoate is a crystal with a melting point of 65°C (Pharmaceutical Journal Vol. 78, p. 546,
(1958), phenyl parachlorobenzoate and phenyl parabromobenzoate each have a melting point of 100
℃ and 117℃ (Dictionary of
Organic Compounds Volume 2, Page 602 and Volume 1, Page 421, Oxford University
Press, 1965).

(Means for achieving the object) Parahalogenated benzoic acid 2,6-dimethylphenyl ester having a substituent at the 2,6-position had not been known at all until now, but the present invention The object of the present invention is to provide such a novel compound and a method for producing the same.

That is, the present invention provides the formula () (In the formula, X represents a halogen atom.) This is parahalogenated benzoic acid 2,6-dimethylphenyl ester.

Furthermore, the present invention provides the formula () (In the formula, X and Y represent halogen atoms,
X and Y may be the same or different. ) and parahalogenated benzoic acid halide,
A method for producing parahalogenated benzoic acid 2,6-dimethylphenyl ester, which is characterized by reacting parahalogenated benzoic acid 2,6-dimethylphenyl ester with 2,6-dimethylphenol or an alkali metal salt thereof; and 2,6-dimethylphenol are esterified.

Parahalogenated benzoic acid 2,6-dimethylphenyl ester, which is a novel compound of the present invention, may be produced by any method, but
One of the preferred production methods is to use a parahalogenated benzoic acid halide represented by the formula () and a 2,6-
This is a method of reacting dimethylphenol or an alkali metal salt thereof, and the reaction formula is expressed as follows.

(In the formula, M represents a hydrogen atom or an alkali metal atom, and X and Y are as described above.) This reaction can be carried out without a solvent, but
Of course, it is also a preferable method to use a solvent that does not adversely affect the reaction. Such solvents include halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, and tetrachloroethane; aromatic hydrocarbons such as benzene, toluene, xylene, and tetralin; ethyl acetate, propionic acid, etc. Esters such as ethyl; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, bromobenzene, and chlornaphthalene; nitro compounds such as nitrobenzene, nitrotoluene, and nitromethane; N,N-dimethylformamide, N,
N-dimethylacetamide, tetramethylurea,
Amides such as N-methylpyrrolidone and hexamethylphosphoramide; Sulfur-containing compounds such as dimethylsulfone, dimethylsulfoxide, and sulfolane; diethyl ether, tetrahydrofuran,
Examples include ethers such as dioxane; and 2,6-dimethylphenol itself.

Further, although this reaction proceeds without using a catalyst, it is also possible to use a suitable catalyst. Particularly when 2,6-dimethylphenol is used as a reagent, hydrogen halide is generated, so it is also preferable to coexist with a basic substance in order to neutralize this. Such basic substances include
Tertiary amines such as triethylamine, pyridine, and quinoline; cyclic amidines such as 1,6-diazabicycloundecene-7; N,N-dimethylformamide, N,N-dimethylacetamide, tetramethylurea, N-methyl Examples include aprotic amides such as pyrrolidone; carbonates and hydrogen carbonates of alkali metals or alkaline earth metals such as lithium carbonate, sodium hydrogen carbonate, potassium carbonate, and calcium carbonate.

The temperature and reaction time for this reaction vary depending on other conditions such as the solvent used and the presence or absence and type of catalyst, but are usually in the range of 0 to 350°C and 1 minute to 50 hours, preferably 30 to 250°C. °C for 5 minutes to 20 hours.

The parahalogenated benzoic acid halide used in this reaction may be produced by any method.

Another preferred method for producing the compound of the present invention is a method of dehydrating and esterifying parahalogenated benzoic acid and 2,6-dimethylphenol, the reaction formula of which is expressed as follows.

(In the formula, X is as described above.) In the case of this dehydration esterification reaction, it is preferable to use an acid catalyst. Such acid catalysts include
Mineral acids such as boric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, hydrochloric acid, hydrogen fluoride; dodecamolybdophosphoric acid, dodecamolybdosilicic acid, dodecatungstophosphoric acid,
Heteropolyacids such as dodecatungstosilicic acid;
Halogenated sulfonic acids such as chlorosulfonic acid and bromesulfonic acid; methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid,
Organic sulfonic acids such as toluenesulfonic acid; boron halide, aluminum halide, silicon halide, titanium halide, tin halide, zirconium halide, antimony halide, bismuth halide, iron halide, nickel halide, halogen Lewis acids such as copper chloride and zinc halide; inorganic cation exchangers such as zirconium phosphate and various zeolites; organic cation exchangers having sulfonic acid groups and/or fluoroalkylsulfonic acid groups are used.

Further, this dehydration esterification reaction can be carried out without a solvent, but it is also a preferable method to use a solvent that does not adversely affect the reaction. Such solvents include aliphatic hydrocarbons such as hexane, heptane, and octane; aromatic hydrocarbons such as benzene, toluene, xylene, and tetralin; methylene chloride, chloroform, carbon tetrachloride,
Halogenated hydrocarbons such as dichloroethane, trichloroethane, and tetrachloroethane; Halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, bromobenzene, and chlornaphthalene; Nitro compounds such as nitrobenzene and nitrotoluene; dimethylsulfone, Sulfur-containing compounds such as dimethyl sulfoxide and sulfolane; ethers such as tetrahydrofuran and dioxane are used.

Further, in this dehydration esterification reaction, it is also a preferable method to carry out the reaction while removing generated water from the reaction system. To achieve this, methods are employed in which the reaction is carried out at a temperature higher than the boiling point of water, an inert gas is introduced as an entrainer, or a substance that is azeotropic with water is introduced. Of course, it is also a preferred method when the solvent also serves as an azeotropic agent.

The temperature and reaction time for this dehydration esterification reaction vary depending on the solvent used and the presence or absence and type of catalyst, but are usually in the range of 30 to 350°C and 1 minute to 50 hours, preferably 50 to 300°C. , 5 minutes ~
The range is 20 hours.

(Effects of the Invention) The parahalogenated benzoic acid 2,6-dimethylphenyl ester of the present invention is a monomer for heat-resistant polymers, 4-(parahalogenobenzoyl)-
It is useful as a precursor for 2,6-dimethylphenol. As monomers for such heat-resistant polymers, monomers in which all functional groups are bonded to the para position are particularly important. The compounds of the present invention and parahalogenated benzoic acid phenyls having no substituent at the 2,6-position undergo a Fries rearrangement reaction in the presence of a Lewis acid such as aluminum chloride to easily form parahalogenbenzoylphenols. Can be converted. However, in the case of parahalogenated phenyl benzoate that does not have a substituent at the 2,6-position,
In addition to 4-(parahalogenobenzoyl)phenol in which a parahalogenobenzoyl group and a hydroxyl group are bonded to the para position, 2-(parahalogenobenzoyl)phenol bonded to the ortho position is always produced as a by-product. It is often difficult to separate and purify this orthoform.

On the other hand, in the compound of the present invention, the two ortho positions of the hydroxyl group of the phenol compound to be produced have already been substituted with methyl groups, so even if the Fries rearrangement reaction is performed, no ortho form is produced at all, and the para form is formed. 4
It is very convenient because only -(parahalogenobenzoyl)-2,6-dimethylphenol can be obtained.

(Examples) Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 87.5 g (0.5 mol) of parachlorobenzoic acid chloride, 91.5 g (0.75 mol) of 2,6-dimethylphenol
mol) was placed in a flask equipped with a nitrogen inlet, a stirrer, and a cooling tube, and reacted with stirring at 140 to 150° C. for 9 hours while bubbling dry nitrogen. After the reaction, excess 2,6-dimethylphenol was distilled off under reduced pressure, and the boiling point was 136-138℃/3mmHg.
123 g of a colorless transparent liquid was obtained.

This compound has an infrared absorption spectrum (1735 cm ^-1 : C=O of ester bond) shown in Figure 1,
Proton NMR shown in the figure (δ8.13ppm, 2H,
doublet; δ7.43ppm, 2H, doublet; δ
7.03ppm, 3H, singlet; δ2.13ppm, 6H,
singlet), and mass spectrum (m/e=
260:P) to parachlorobenzoic acid 2,6-
It was identified as dimethyl phenyl ester.
The yield was 94% based on the parachlorobenzoic acid chloride used.

Example 2 15.9 g (0.1 mol) of parafluorobenzoic acid chloride, 14.7 g (0.12 mol) of 2,6-dimethylphenol
The reaction was carried out in the same manner as in Example 1 using mol). After the reaction, excess 2,6-dimethylphenol was distilled off to obtain 23.5 g of a colorless and transparent liquid distilled at 132-134°C/3 mmHg.

This liquid has an infrared absorption spectrum (1735 cm ^-1 : C=O of ester bond) shown in Figure 3 and a proton-NMR (δ8.21 ppm, 2H,
doublet―doublet; δ7.13ppm, 2H, doublet―
doublet; δ7.03ppm, 3H, singlet; δ
It was identified as parafluorobenzoic acid 2,6-dimethylphenyl ester from the 2.13 ppm, 6H, singlet) and mass spectrum (m/e=244:P). The yield was 96% based on the parafluorobenzoic acid chloride used.

Example 3 22 g (0.1 mol) of parabromobenzoic acid chloride,
2,6-dimethylphenol 14.7g (0.12mol)
A reaction was carried out in the same manner as in Example 1. After the reaction, excess 2,6-dimethylphenol was distilled off to obtain 29 g of a colorless and transparent liquid distilled at 135-136°C/2.5 mmHg. This liquid has an infrared absorption spectrum (1735 cm ^-1 : C=O of ester bond) shown in Figure 5 and a proton-NMR spectrum shown in Figure 6.
(δ8.06ppm, 2H, double; δ7.60, 2H,
doblet; δ7.03ppm, 3H, singlet; δ2.13ppm,
6H, singlet), and mass spectrum (m/e=
305:P) to parabromobenzoic acid 2,6-
It was identified as dimethyl phenyl ester.
The yield was 95% based on the parabromobenzoic acid chloride used.

Example 4 Parachlorobenzoic acid 15.7 g (0.1 mol), 2,6
-Dimethylphenol 14.7g (0.12mol), 30g
of polyphosphoric acid in a flask and heated at 100-110℃ for 24 hours.
The reaction was allowed to take place under stirring for an hour. After the reaction, the mixture was cooled to room temperature and water was added. Then, it was extracted with ethyl acetate. The ethyl acetate solution was washed with an aqueous sodium bicarbonate solution to remove unreacted parachlorobenzoic acid. After drying this ethyl acetate solution over anhydrous sodium sulfate, ethyl acetate and excess 2,6-dimethylphenol were distilled off. Next, by distilling under reduced pressure, 21 g of a colorless transparent liquid distilled at 136-138°C/3 mmHg was obtained.

This liquid has exactly the same infrared absorption spectrum and proton NMR as parachlorobenzoic acid 2,6-dimethylphenyl ester obtained in Example 1.
The spectrum was shown. The yield was 91% based on the reacted parachlorobenzoic acid.

Reference Example Parachlorobenzoic acid 2,6-dimethylphenyl ester of the present invention (0.25 mol) and anhydrous aluminum chloride (0.27 mol) are placed in 350 ml of dry orthodichlorobenzene and reacted at 150°C for 4 hours with stirring. The Fries rearrangement reaction was carried out by 4
-(parachlorobenzoyl)-2,6-dimethylphenol was obtained with a yield of 95%.

When a similar reaction was carried out using parachlorobenzoic acid phenyl ester (0.25 mol), 4-
In addition to (parachlorobenzoyl)phenol (80%), 2-(parachlorobenzoyl)phenol (13%) was produced.

[Brief explanation of the drawing]

Figure 1 is the infrared absorption spectrum of the compound obtained in Example 1, Figure 2 is the proton-NMR, Figure 3 is the infrared absorption spectrum of the compound obtained in Example 2, and Figure 4 is the proton-NMR. NMR, FIG. 5 shows the infrared absorption spectrum of the compound obtained in Example 3, and FIG. 6 shows the proton-NMR of the same.

Claims (1)

[Claims] 1 Formula () (In the formula, X represents a halogen atom.) Parahalogenated benzoic acid 2,6-dimethylphenyl ester. 2 formula () (In the formula, X and Y represent halogen atoms,
X and Y may be the same or different. ) and parahalogenated benzoic acid halide,
A method for producing parahalogenated benzoic acid 2,6-dimethylphenyl ester, which comprises reacting 2,6-dimethylphenol or an alkali metal salt thereof. 3. A method for producing parahalogenated benzoic acid 2,6-dimethylphenyl ester, which comprises esterifying parahalogenated benzoic acid and 2,6-dimethylphenol.