JPS58201732A - Post-treatment method of fluorination reaction solution - Google Patents

Abstract

PURPOSE:To obtain the titled substance which is an intermediate for dyes, etc. easily without the fear for corrosion of apparatuses in fluorinating a trichloromethylbenzene derivative in the presence of a catalyst, by bringing a fluorination reaction solution into contact with silica gel, and removing inorganic fluorine compounds. CONSTITUTION:In fluorinating a trichloromethylbenzene derivative in the presence of a Lewis acid catalyst, fluorination reaction solution is brought into contact with silica gel at 0-80 deg.C, preferably 10-30 deg.C, usually for 1-60min to give the aimed compound. The silica gel to be used is powder having >=10mu particle diameter or beadlike silica gel having 30-200 mesh particle size. The fluorination reaction solution is brought into contact with the silica gel by adding the silica gel to the fluorination reaction solution while stirring the fluorination reaction solution or passing the fluorination reaction solution continuously through a column packed with the silica gel. Preferably, the amount of the silica gel to be used is usually 1-20wt% based on the weight of the fluorination reaction solution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly industrially valuable method for treating a fluorinated reaction solution, which removes inorganic fluorine compounds from the reaction solution by bringing the fluorination reaction solution into contact with silica gel. .

Trifluoromethylbenzene derivatives, which are useful in medicine, as agricultural chemicals, and as dye intermediates, are produced industrially by reacting trichloromethylbenzene derivatives with anhydrous hydrogen fluoride FF (hereinafter abbreviated as HF) in the presence of a Lewis acid catalyst. However, at this time, the HP dissolved in the fluorination reaction solution and the fluorine compound of the Lewis acid used as a catalyst not only become a hindrance to the operation of the post-treatment, but also cause corrosion of the equipment material. Therefore, they need to be completely removed. Generally, the following method is used as a post-treatment method for the fluorination reaction solution. 'That is, most of the HF dissolved in the reaction solution is removed by bubbling nitrogen or dry air, and then -
Either add water or an aqueous solution of an inorganic acid and remove by extraction.
Alternatively, a method has been adopted in which the aqueous solution of an inorganic alkali metal salt is added and neutralized to remove it from the fluorination reaction solution.

However, in the extraction removal method, the problem of corrosion of the equipment material is a major obstacle to industrialization because the treatment is performed under strongly acidic conditions or under an aqueous fluorine solution.

In the neutralization method, fine crystals of metal hydroxide are precipitated by the Lewis acid catalyst at the same time as fluorate is produced, and removal by filtration or other means is extremely difficult and the operation is very complicated.
becomes.

In addition, the method using distillation is not preferable because the fluorinated Lewis acid is entrained or the thermal stability of the fluorination reaction solution is affected.゛ ``As a result of intensive studies to solve these various problems, the present inventors and others have found that
The present invention was completed by discovering that inorganic fluorine compounds can be easily and completely removed by bringing the fluorination reaction solution into contact with silica gel.

That is, in the present invention, in the presence of a Lewis acid catalyst, tric...
□ Methylbenzene derivative i In the method of producing trifluoromethylbenzene derivative by fluorination reaction, the inorganic fluorine compound is removed by contacting the ``fluorination reaction liquid'' with the ``gel''. This is a method for post-treatment of a fluorination reaction solution, which is characterized by:

The trichloromethylbenzene derivative as a raw material is obtained by converting a methylbenzene derivative into a lateral element, such as trichloromethylbenzene, 2-chlorotrichloromethylbenzene, 3-chlorotrichloromethylbenzene, 4-10). IJ chloromethylbenzene, 2
．． 4-dichloro) IJ chloromethylbenzene, 2-
Tsuk00 Methyltrichloromethane 4-dichlorotrichloromethylbenzene, bis(4-trichloromethylphenyl)
Carbonate, bis(2-chloro-4-) IJ
Examples include chloromer phenyl) carbonate.

As the fluorination reaction solution that can be used in the present invention, the above-mentioned trichloromethylbenzene derivative can be mixed with known Lewis resins used in the fluorination reaction, such as Atcts, F.
eCLz, WCL@, TiC6l, TiCti8n
CL4, PCl5, TaCt6, Re
A reaction solution used to produce the corresponding trifluoromethylbenzene derivatives by reacting with KHF in the presence of Cts, NdC45, MoC4,,8bF, etc., and if necessary an inert organic compound such as tetrachloroethane. Reaction liquids using a solvent, and liquids in which a Lewis acid catalyst, raw materials, intermediate products, etc. form a complex, etc. can be listed as follows.

Ru.

Other examples that can be treated in the same way as the above reaction solution include repurification treatment when unstable fluorine compounds decompose during storage and are removed from 3-HF, and all other acidic inorganic fluorine compounds. It can be effectively applied to compound removal treatment.

The silica gel used in the invention is for column chromatography,
Various types from fine powder to lumps used in summer for thin layer chromatography, drying, grinding aids and anti-caking agents for pesticides, fertilizers, feed, etc., and matte cutting of paints, etc. Commercially available silica gel can be used.

However, from the viewpoint of cost, processing efficiency, rate, etc., it is preferable to use powder of 10 mesh or more or bead-shaped silica gel of 30 to 200 mesh.

Method 1 of contacting the fluorination reaction solution with silica gel is to add silica gel to the fluorination reaction solution under stirring or to continuously pass the silica gel into a silica gel packed column. This can be done by:

The contact temperature is 0 to 80°C, preferably 10 to 80°C.
The temperature is 30°C. The contact time varies depending on the fluorine removal ability of the silica gel species, but is usually 1 to 6.0 minutes.

The amount of silica gel used varies depending on the content of the inorganic fluorine compound in the fluorination reaction solution, but it is usually 1 to 20% by weight based on the amount of the fluorination reaction solution. The used silica gel can be collected and reused after being recycled.

The fluorination reaction solution treated by the method of the present invention has an inorganic fluorine compound content of S ppm or less, and there is virtually no restriction on the selection of equipment materials in consideration of corrosion caused by inorganic fluorine compounds.

The present invention will now be explained with reference to the following examples.

Example 1 ・250-80
In an 8-part reactor, 195.5 parts of pencitrichloride and 1
Prepared with 98 copies of 5bct.

The temperature was raised to 55°C while stirring. While maintaining this temperature, 66 parts of anhydrous hydrofluoric acid gas was introduced over a period of 5 hours. After the reaction was completed, N gas was aerated at 50 to 55° C. for about 1 hour. At this time, the proportion of inorganic fluorine in the reaction solution was 22 SO
It was ppm. After that, it was cooled to room temperature, and then Jiruton-jin (silica gel manufactured by Mizusawa Chemical) was added, and the inorganic fluorine content in the fluorination reaction solution was determined every time using a fluoride ion meter.The results are shown in Table 1. Showing 0
...Table-1 Example 2 8US reaction of 25C1d 1K27115 parts 〇-)
Re/a C1 methylbenzal chloride and 1.4 parts of 5bct were mixed and heated to 60°C. same temperature 7
- While stirring, 66 parts of anhydrous hydrofluoric acid gas was introduced over a period of 3 hours. After the reaction was completed, aeration with nitrogen was carried out at 50 to 60° C. for 1 hour. The proportion of inorganic fluorine in the reaction solution at this time was 20
'54 ppm. Then, after cooling to 60°C, 6.9 parts of microbead silica gel (manufactured by Fuji Davison) was added.
After stirring for 20 minutes, the proportion of inorganic fluorine in the fluorination reaction solution was quantified using a fluorine ion meter and found to be 29 parts. Table 2 shows the results of the same treatment except for changing the type of silica gel in the reaction solution.

Table-2 Hodogaya Chemical Industry Co., Ltd. 8-

Claims (1)

[Claims] In a method for producing a trifluoromethylbenzene derivative by fluorinating a trichloromethylbenzene derivative in the presence of a Louis x acid catalyst, the fluorination reaction solution is brought into contact with silica gel, and the inorganic fluorine in the nuclear reaction solution is removed. A method for post-treatment of a fluorination reaction solution, characterized by removing compounds.