JPS6210042A - Production of a,a,a-trifluoro-toluic fluoride - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for agricultural chemicals and pharmaceuticals, etc., economically in high yield, by using a toluic halide as a raw material, and reacting the halide with chlorine and anhydrous hydrogen fluoride in vapor phase in the presence of a specific catalyst and a diluent. CONSTITUTION:The titled compound is produced by using a toluic halide as a raw material, and reacting the halide with chlorine and anhydrous hydrogen fluoride in the presence of a diluent such as carbon tetrachloride, chloroform, etc., using at least one kind of fluoride of a metal selected from Al, Fe and Cr, e.g. hydrated aluminum trifluoride, ferric fluoride, etc., as a catalyst, in vapor phase at 250-600 deg.C, preferably 300-500 deg.C. The amount of the catalyst is 0.01-3mol per 1mol of the toluic halide used as a raw material. The catalyst is mixed with a carrier, formed in granular form having a proper size, and used as a fixed bed, fluodized bed, etc.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides α, a
, a-trifluorotoluic fluoride (hereinafter referred to as T
This invention relates to a new manufacturing method for FTF (abbreviated as FTF).

(Problems with the prior art) Conventionally, as a manufacturing method for TFTP, Japanese Patent Application Laid-Open No. 56-1031
A method described in Japanese Patent No. 38 is known. In this method, O-toluic chloride is chlorinated under ultraviolet irradiation to produce α, α.

a-) Lichlor o-) Luic chloride and 1.1
, 3,3-tetrafluoro-1,3-dihydroisobenzo7ranes, which were then fluorinated in the liquid phase in the presence of a fluorination catalyst to give a,a,α-trifluoro-〇-toluic. This is a method of obtaining fluoride.

However, the first-stage photochlorination reaction generates various by-products and requires a purification process before the second-stage reaction, making continuous production difficult and furthermore requiring a long time for the first-stage photochlorination reaction. There are many problems in implementing this method on an industrial scale, such as the fact that the ultraviolet lamp in the first stage reaction becomes contaminated, forcing the operation to be shut down.

(Backstory for solving the problem) The present inventors focused on performing chlorination and fluorination simultaneously, but according to the experience of the present inventors, phenol derivatives such as p-cresol, anisole, p- - Based on the knowledge that when chlorination and fluorination are performed simultaneously using methylphenylchloroformate etc. as a raw material, decomposition products and tar components are generated and the target product cannot be obtained.
It was expected that applying this method to the production of F would not yield satisfactory results.

However, when toluic halide is used as a raw material and reacted with chlorine and anhydrous hydrogen fluoride in the gas phase in the presence of a specific catalyst and diluent, the desired product can be obtained in surprisingly high yield. The present invention was completed based on the knowledge that the following could be obtained.

(Disclosure of the Invention) - That is, the present invention is characterized in that toluic halide is reacted with chlorine and anhydrous hydrogen fluoride in the gas phase in the presence of a catalyst and a diluent. This is a method for producing Q,Q,(2-)refluoro-toluic fluoride.

Examples of the toluic halide (hereinafter abbreviated as TH) used in the present invention include o-toluic chloride%O-)luic fluoride, p-)luic chloride, p-toluic fluoride, and the like.

Further, as a catalyst, a fluoride of at least one metal element selected from the group consisting of aluminum, iron, and chromium, specifically hydrated aluminum trifluoride (ANF, .3H
20), aluminum trifluoride (AρF, ), hydrated ferrous fluoride (FeF2・8H20), ferrous fluoride (FeF2)
, ferric fluoride (FeF-), hydrated chromium trifluoride (Cr
F3.3H20), chromium trifluoride (CrFz), and the like. The amount of this catalyst to be used cannot be specified depending on the reaction conditions, but it is usually 0 to 1 mole of TH of the raw material.
．． 01 to 3 moles. Usually, this catalyst is mixed with a carrier such as aluminum trifluoride or activated alumina, formed into particles or pellets of appropriate size, and then placed in the form of a fixed bed or a fluidized bed. Alternatively, the catalyst may be present in the form of a fluoride of the metal element directly into the reaction tube;
Industrially, it is advantageous to introduce the metal element in the form of an oxide or chloride into a reaction tube and react with anhydrous hydrogen fluoride to convert it into a fluoride. For example, a molded product in which an oxide or chloride of the metal element such as chromium trioxide or ferric chloride is supported on an alumina carrier is placed in a reaction tube, anhydrous hydrogen fluoride is introduced in advance, and the
The reaction according to the present invention is carried out after the reaction is carried out at 00°C to convert the metal element into a fluoride.

Diluents include carbon tetrachloride, chloroform, methylene chloride, F-112 (CF2ff□・CF ca2), F-
Organic solvents for halogenated hydrocarbons such as 113 (CF2Cff/CFCρ2) and inert gases such as nitrogen, helium, and argon can be used, and these diluents have the function of suppressing combustion, carbonization, and generation of tar-like byproducts. It is something that you have.

In carrying out the present invention, the raw materials and diluent can be supplied to the reactor separately or in a mixed state, and they can be supplied simultaneously or sequentially, all at once or in parts. For example, a mixture of TH and diluent or a mixture of chlorine and hydrogen fluoride is fed separately.

The amount of chlorine and anhydrous hydrogen fluoride to be used cannot be specified depending on the type of TH of the raw material, the reaction equipment, etc., but in general, it is 3 to 10 moles each, preferably 4 to 6 moles, per 781 moles of the raw material. The amount used is normally 7 of the raw materials.
The amount is 3 to 20 moles per 81 moles, preferably 4 to 10 moles.

The reaction temperature is generally 250 to 600°C, preferably 300°C.
~500°C, and the residence time of the reaction mixture in the reaction zone is usually 1 to 50 seconds, preferably 5 to 15 seconds.

Normally, gaseous substances containing fluorinated products mainly composed of TFTP, unreacted hydrogen fluoride and chlorine, intermediate products, by-product hydrogen chloride, and diluent are discharged from the reactor. After passing through appropriate cooling and condensation equipment, these materials are collected as a liquid mixture. By applying ordinary purification processes such as extraction and distillation to this liquid mixture, TFT
F can be obtained with high purity.

If the collected liquid mixture contains intermediate products that have not progressed to the production of TFTF, these intermediate products can be separated and recovered together with unreacted raw materials or diluent, and recycled to the reaction zone. can.

Next, examples of the method of the present invention will be described, but the scope of the method of the present invention is not limited in any way by these descriptions.

Example 1 As a reactor, the reaction part has an inner diameter of 100 mm and a height of 2.30 mm.
0 am, and the height of the catalyst filling part is 800 I from the bottom.
A vertical reactor made of Inconel with a catalyst fluidized bed of 111 was installed, with an inner diameter of 20 mm and a length of 1 mm at the bottom of the reactor.
Two 500III11 Inconel preheating tubes were connected, and the outside of the reaction tube and preheating tube was covered with an electric heater and a heat insulating material so that the temperature of the reaction tube and the preheating tube could be controlled.

3.8 kg of ferric chloride supported on aluminum trifluoride with a particle size of 105 to 255 μ (weight ratio 53:1000)
The reactor was heated to 400°C to activate anhydrous hydrogen fluoride at 3.5 g/min for 1 hour.

Thereafter, it was preheated at 300°C. -) Rubitsuku Kurorai 3
84 g/hour and nitrogen gas at a rate of 700 g/hour through a single heating tube, and 7 g of chlorine gas preheated at 250"C for 7 hours and anhydrous hydrogen fluoride gas at a rate of 300.7 hours through a preheating tube. The residence time of the reaction mixture introduced into the reactor and reacted at a temperature of 400° C. for 110 minutes in the catalyst-packed section was about 7-8 seconds.

The gas discharged from the reactor passes through a cooling/condensing device and a water washing tower, and is collected as a liquid mixture, which is neutralized with sodium bicarbonate water, washed with water, and dried to form an oily substance of 1.03
Got 4 to 8.

When this oily substance was analyzed by gas chromatography, its composition was found to be a, a, a-trifluoro-0-)
Luik fluoride 70.4%, monochloro a, a
, α-trifluoro-0-toluic fluoride 13
．． 4% and others 16.2%.

Examples 2 to 3 3.8 kg of a catalyst, i.e., ferric chloride supported on aluminum trifluoride with a particle size of 105 to 225 μm (weight ratio 53:1000), was transferred to aluminum trifluoride with a particle size of 105 to 225 μm. 8Kg or chromium trifluoride with particle size 105~22
Supported on 5μ aluminum trifluoride (weight ratio 53:100)
Each oily substance was obtained in the same manner as in Example 1 except that 3.8 kg of the 0) sample was used, and the oily substance was analyzed by gas chromatography to obtain the results shown in Table 1 below.

Table 1 (Note) *TFTFI...α, a, α-trifluoroI
:l -0-Toluic fluoride * *CQ-TFTF, ... monochloro α, α, α
-Trifluoro-toluic fluoride Example 4 In Example 1 above, the starting material, i.e. An oily substance was obtained in the same manner as in Example 1, except that p-)luic chloride was used instead of -toluic chloride and the reaction temperature was changed from 400°C to 450°C. This oily substance was analyzed by gas chromatography. The composition was found to be 84% α,a,a trifluoride p-toluic fluoride, monochloro α,α,α-trifluoro-
It was found that p-) Luik fluoride was 6% and others were 10%.6 (Effects of the Invention) According to the method of the present invention, inexpensive raw materials were used, continuous production was carried out in a short period of time, and in high yield. The target product can be obtained with high purity,
Water spraying can be said to be the most suitable method for implementation on an industrial scale.

Claims (1)

[Claims] 1. Toluic halide, chlorine and anhydrous hydrogen fluoride,
A method for producing a,a,a-trifluoro-toluic fluoride, which comprises reacting in a gas phase in the presence of a catalyst and a diluent. 2. The method according to claim 1, wherein the catalyst is a fluoride of at least one metal element selected from the group consisting of aluminum, iron, and chromium. 3. The method according to claim 1, characterized in that the reaction is carried out at a temperature of 250 to 600°C. 4. The method according to claim 1, wherein the diluent is an organic solvent of halogenated hydrocarbon or an inert gas.