SU507552A1 - The method of producing benzotrifluoride - Google Patents

Description

one

The invention relates to a method of half a lout and benethrifluoride, which is used to obtain thermal corrosion of youth resistant coatings.

A known method for the preparation of becotrifutus by the interaction of benzotrchloride with hydrogen fluoride at a temperature of 9 ° -130 ° C under pressure of 3CU50 ar, with a direct flow of reagents through the pit zone, with the entire p "8" ionic mass consisting of non-HC1, HPV. and the target npoAjicTa, expelled from the reaction zone, is sent to separate the HC1 into the effluent column, working under pressure from the recovery zone, R, then to the expansion tank to separate the HF.

NsDowns: The cnocoCta imposes the complexity of the technological implementation of the process due to the use of a fairly high 1H, incomplete use of reagents in the HF 11, not the (HF, high output, the total of 17%). addition process

| ycnoK «i .-: - iiLi create a yalki | yarn distillation column for separating the HC 1.

For the improvement of technological process accG, for a more complete use of "similar reagents to increase the yield of 1t of the left product, it is suggested that the flow rates be 1 h 1 h to be supplied countercurrent | zones n to conduct percent ess at a temperature, noc: TeneHiK- {increasing from –c to

, version chastk; rvvk1shootgoyoo ydo to 15O ° C .3 hl. of the honorable zone, under; 13-25 aty, with the result of Kb-: f TJ re; the reaction result is hydrogen chloride output of the short-circuit core of the upper part of the reaction; ecit i, in the last (5 reactions of unresolved reaction of fluorine-hydrogen fluoride of the reaction zone in those The reactor is pushed out and throttled to (atmospheric and leka in a stripper for ioTiOHXH hydrogen fluoride with subsequent) to isolate the target product of rectification ta. Proavss is carried out in a special type reactor consisting of 2 parts of the reaction zone (lower part) and separation column with reverse coldbox by anyone. Part). The conducted reaction of the interaction of benethrichloride with hydrogen fluoride allows us to say that in the absence of a catalyst at elevated temperature (up to) a stepwise replacement of chlorine takes place, as evidenced by the presence of trifluoromethylbenzene monofluorodichloromethylbenzene in the editorial mixture of products. In this case, as shown by experiments, the replacement of the first chlorine atom is easiest. This reaction proceeds with a satisfactory yield even at atmospheric pressure (}), whereas the replacement of the second and, especially, the third chlorine atom requires more severe conditions (increased pressure, a large excess of hydrogen fluoride, the presence of a catalyst). ispol1: the feedstock offers a countercurrent component feed, in which the replacement of the first chlorine atom occurs in the upper part of the reaction zone near the entry point of benzotrichloride, which allows an increase in HF utilization in The deeper substitution of fluorine for chlorine is carried out in the lower part of the reaction zone near the entry point (1 gorium (1% hydrogen), which increases the completeness of rotation of benzotrichloride. The excess HF of the Reaction is from 0 to 1/3 of the theoretical amount. hydrogen chloride and its purification from HF impurities and benzotrifluoride occurs in this apparatus, in its upper part. Selection of hydrogen chloride is carried out on the upper part of the apparatus. It is also possible oi division HC1 in a separate column under the same pressure. The isolated purified hydrogen chloride can be used for various purposes (hydrochlorination, oxychlorination, hydrochloric acid, chlorine, etc.). The mixture of organic products together with unreacted HF at the reaction temperature is continuously withdrawn from the bottom of the reactor and throttled to atmospheric pressure in a stripping apparatus heated to the temperature of USCR equipped with a reflux condenser cooled with water. The hydrogen fluoride distilled at the same time is returned to the process. It is also possible to separate the bulk of the pre-reacted hydrogen fluoride by cooling the reaction mixture to a low heat level (about -25 ° C) followed by delamination. According to the proposed scheme, there can also be other derivatives of benzol with fluorinated alkyl salts. Example 1. In the upper part of the reaction zone, 58.4 kg of benzotrichloride are fed at a rate of kg / h, in the lower part of the reaction zone - 2O kg of hydrogen fluoride at a rate of 3 kg / h, which corresponds to the molar ratio of hydrogen fluoride to benzotrichloride 3, 38: 1. The temperature in the reaction zone is maintained, the pressure is 15 MPa. Hydrogen chloride formed during the reaction, containing 7% HF and 3% benzotrifluoride, is purified from impurities in the upper part of the reaction zone under the same pressure at a temperature of minus 18 ° C. ;. Hydrogen chloride extracted from the top of the reaction zone contains 0.2% hydrogen fluoride and does not contain benzotrifluoride. A liquid mixture of products, almost not containing hydrogen chloride, from the bottom of the reaction zone at the same temperature, is throttled to atmospheric pressure by a stripping apparatus, which is produced from unreacted hydrogen fluoride at a temperature in a cube of 1 ° C and temperature in a reflux condenser, 2 ° C. Hydrogen fluoride recovered in this way is recycled. After separation of the acidic products, 41.1 kg of crude benzotrifluoride containing 95% of the target substance, 2% difluorochloromethylbenzene and 3% of high boiling impurities are obtained. The yield of benzotrifluoride with respect to the external reagents is as follows: for benzotrichloride — 89.7% for hydrogen fluoride — 80.3%; By distillation of the crude obtained, benzotrifluoride is separated with the following characteristics: 20 kip, 1) 1901. Chromatographic analysis: the content of benzotrifluoride is 99.93%, the content of difluorochloromethylbenzene is 0.07%. PRI me R 2, In a reaction zone with a countercurrent at a pressure of 15 atm, 60 kg of Belorotrn Eoril and 25 kg of water fluoride cm — are consumed; speed of 7.5 k1 / hls and - 3.2 kg / h

against The molar ratio of the hydrogen phase to hydrogen benzotrichloride is 4.07: 1. The temperature in the upper part of the reaction zone is maintained at minus 18 ° C and gradually increases from top to bottom, reaching B in its lower part 110 ° C. Hydrogen chloride is removed from the upper point of the reaction zone, and organic reaction products and unreacted hydrogen fluoride remove the lower part of the reaction zone and, after throttling to a level close to atmospheric, are directed to the separation of hydrogen fluoride. The crude benzotrifluoride in the amount of 43 kg, containing 98.33% of the benonefluoride and 1.67 difluorochloromethylbenzene, is purified by rectification under vacuum. The yield of benzotrifluoride is 94.5% for benzotrichloride.

PRI me R 3.

From 50.8 g of benethi-trichloride and 22 g of hydrogen fluoride at a temperature of 60 ° C to 21 atm and in a laboratory autoclave, when hydrogen is fed at a rate of 8.5 g / h, raw benzotrifluoride is obtained, containing 92% of the target substance and 6% of chlorofluoromethylbenzene. The yield of benagrifluoride for a given benzotrahprandu is 83%, and. total yield of fluorinated products - 88.6%.

 Example 4

Into the reactor with a 50 liter of water under reflux and cooled with cooling, 57.3 kg of benzotrichlorium are charged at a time and even at a temperature of -0-0

 growing from 20 to 1O2 C, 23 kg are served

hydrogen fluoride at a rate of 4-5 kg / hour. The pressure is maintained at 15 ati. At the end of the process, as judged by the termination of the pressure growth, the reaction mixture is kept for 1 hour, after which the raw benzotrifluoride is separated from the "impurities" by distillation and subsequently neutralized. Received 42 kg of product containing 96% of besotrnfluoride.

Claims (1)

Invention Formula The method of obtaining benzotriftorvda by the interaction of a ben eotrichlorvd with 5 with hydrogen fluoride at a higher temperature and pressure, distinguishing with the fact that, with the circuit improved in the technological process, more complete use of the initial reagents and increase in the yield of the target product, the initial reagents are fed in countercurrent at different points along the height of the reaction zone and the process leads to 11p, temp & five The temperature was gradually increasing from 5 ° C in the upper part of the reaction zone and 150 ° C in the lower part of the reaction zone, under pressure of 15–25 these, while the resulting hydrochloric acid was –3 ipxneK. .tmsn the reaction zone, and. The reaction to the unreacted fluoroulet hydrogen is taken from the lower hectare of the radioactive zone of the reaction temperature, then throttled to atmospheric pressure into a stripping apparatus for the distillation of fluoride-gas: hydrogen dioxide, followed by discharge, target extraction by rectification.