SU1122643A1 - Process for preparing 1,1,2,3-tetrachoroprene - Google Patents

Abstract

A method for producing 1,1,2,3TETRAHLORPROPEN using 1,2,2,3-tetrachloropropane, a chlorinated chloroM chlorination reaction and dehydrochlorination with an aqueous solution of 1,1,2,2,3-pentachloropropane alkali, characterized in that simplifying the process, 1,2,2,3 tetrachloropropane is dehydrochlorinated with 40–45% NaOH solution at 15–25 ° C in the presence of a 0.51% catalyst of formula (), NClI CgHjl, where R is methyl or ethyl, obtained 1 , 2-3-trichloropropene is chlorinated to 1,1,2,2,3-pentachloropropane, which is dehydrochlorinated at 15-25 ° C in (L in the presence of Alizator using a 20-40% aqueous solution of NaOH.

Description

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The invention relates to an improved process for the preparation of 1,1,2,3-tetrachloropropene is the product of the synthesis of triallate (K, N-diisopropyl-2,3,3-trichloroallyl uJ-H

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NaOH, 95 ° C

thiocarbamate) - a herbicide against varietal herbs in agriculture.

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A known method for producing 1,1, 2,3. Tetrachloropropene according to the scheme

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2. C1

 2: ... Ci hrrV-Cl. t. Г1 ri Г1 Cl

-HCl

NaOH SSC The yield of the desired product in the last two stages is up to 98% in terms of 1,1,2,3-tetrachloropropane. The disadvantage of this method is the need to separate the complex mixture of polychloro-propane compounds formed by reaction (3). Taking into account the high reactivity of chlorine in homolytic chlorination, the possibility of selectively obtaining 1,1,2,2, 3-pentachloropropane in stage (3) under technological conditions is not achieved. The closest to the proposed technical essence and the achieved result is the method of obtaining, 1,1,2,3-tetrachloropropene by dehydrochlorination of 1,2,3-trichloropropane with a 10% NapH aqueous solution at. The yield of 2,3-dichlorprop is 71%. After rectification, 2,3-dichloropropene is chlorinated with molecular chlorine at CZ-AO C. The 1,2,3,3-tetrachloropropane obtained from reactions (2) is subjected to substitution chlorination at 85-90 C in the presence of 0.15% by weight of porophor. The yield of 1,1, 2,2,3-pentachloropropane is not more than 50% and is limited by the conversion of 1,2, 2,3-tetrachloropropane. An attempt to increase the conversion to over 50% results in a significant amount of hexachloropropane, which leads to additional consumption of reagents and degrades the quality of the product. Even with a 50% conversion of the starting 1,2,2,3-tetrachloropropane, up to 3% is formed along with the target product. 1,1j1,2jЗ-pantopropane and up to 8% of deep chlorination products. After rectification, 1,2,2,3,3-pentachloropropane is subjected to dehydrochlorination with 10% aqueous NaOn solution at 20-40 ° С. The yield of 1,1,2,3-tetrachloropropene is 71%, and in the last two stages it does not exceed 35% in terms of 1,2,2, 3-tetrachloropropane 2. The disadvantages of this method are the low yield of the target product , the complexity of the separation of 1,1,2,2, 3-pentachloropropane from the mixture of polychloro derivatives formed in the substitution chlorination stage, and the formation of a large number of by-products, the disposal of which is a complex technological task. The aim of the invention is to simplify the process technology. This goal is achieved in that according to the method for producing 1,1,2,3-tetrachloropropene using 1,2,2,3-tetrachloropropane, chlorination with molecular chlorine and dehydrochlorination with an aqueous solution of alkali 1,1,2,2,3 - fluorochloropropane, 1,2,2,3-tetrachloropropane is dehydrochlorinated with 40-45% NaOH solution at 15-25 C in the presence of a 0.5-1% catalyst of the formula () N CH C IljOROR, where R is methyl or ethylL the resulting 1,2,3-tetrachloropropene is chlorinated to 1,1,2,2,3-pentachloropropane, which is dehydrochlorinated at 15-25 ° C in the presence of this catalyst ra, using 20-40% aqueous NaOH solution. Dehydrochlorination of 2,2,3-tetrachloropropane in the presence of a 0.5-1% catalyst of the formula (C2H5) 3HCl112SbH5 OK is carried out with 40-45% aqueous NaOH at 15-25 ° C for 1-1.5 h The reaction mixture is filtered from the injected NaCl. The organic layer containing 1,2,3-trichloropropene (vkod 95-98%) is dried and sent to a chlorinator. Aqueous layer containing NaOH. return in recycling. A high yield at this stage is provided by using Compound H OlT. Usage) ,, iivjiirtv-t of other quaternary ammonium salts. for example () NCH2C H5 C1-, leads to a reduction in the conversion of 1,2,2,3-tetrachloropropane as well as a decrease in concentration. An increase in the reaction temperature above 25 ° C leads to the appearance of the products of osmol. The dried 1,2,3-trichloropropene is chlorinated at 30-40 ° C and the resulting 1,1,2,2,3-pentachloropropane (yield 98,100%) is sent to the dehydrochlorination reactor. The dehydrochlorination reaction of 1,1,2,2,3-pentachloropropane is carried out with 20-40% aqueous NaOH in the presence of a 0.5-1% catalyst of the formula l () mi {2Cf, where R is methyl, ethyl, at 15-25 ° C. Upon completion of the reaction (1-15 h), the mixture is filtered from precipitated NaCl, the organic layer is dried. The aqueous layer containing NaOH is recycled. The output of 1,1,2,3 tetrachloropropene not less than 98%. The yields of the target products are high, according to the stage, which ultimately allows 434 L to obtain 1,1,2,3-tetrachloropropene with a yield of at least 90% calculated on the initial 1,2,2,3-tetrachloropropane, In addition As can be seen from the diagram, the process is carried out under mild conditions (15-40 C), and the high selectivity in stages precludes the formation of organochlorine wastes and allows the process to be carried out without rectification in stages. Example a) Preparation 1, 2,3trichloropropene. 182 g (1 mol) of 1,2,2,3-tetrachloropropane and 1.82 g (1 wt.%) Of ethoxytriethyl benzyl ammonium are placed in the reactor. With stirring, 80 g (2 mol) of NaOH in the form of a 45% aqueous solution are added with 0.5 h of 0.5 h, after which the reaction mixture is stirred at this temperature for 1 h. At the end of the reaction, the mixture was filtered from the precipitated NaCl. The organic layer was separated and dried. 143 g of 1,2,3, -trichloropropene are obtained, yield 98%. b) Preparation of 1,1,2,2,3-pentachloropropane; 143 g (0.98 mol) of 1,2,3-trichloropropane, obtained in the first stage, are placed in a reactor equipped with a stirrer and hydraulic lock and, with stirring, at 30 -Ze With served at a rate of 1 g / min dry C1l. The reaction is completed in 3-4 hours, the reaction mixture is purged with nitrogen to remove excess chlorine. 209 g of 1,1,2,2,3-pentachloropropane are obtained, yield 99%. c) Preparation of 1,2,2,3-tetrachloropropene. According to the general dehydrochlorination procedure, from 209 g (0.96 mol) of 1,1,2,2,3-pentachloropropane obtained in the second stage, in the presence of 1.67 g (0.8 wt.%) Of ethoxy triethylbenzylammonium, by the action of 60 g (1 , 5 mol) NaOH in the form of a 30% aqueous solution when you get 175 g of 1,1,2,3-tetrachloropropene, yield 99%. The overall yield of 1,1,2,3-tetrachloropropene in the races 1,2,2,3-tetrachloropropane is .96%. Example 2. a). Dehydrochlorination 182 g (1 mol) of 1,2,2,3 tetrachloropropene at 15 ° C using 80 g (2 mol) of NaOH, taken as a 40% aqueous solution, in the presence of 0.75 wt.% (To organochlorine a) methoxy triethyl benzylammonium takes 1.5 hours. 140 g of 1,2,3-trichloropropene 5 are obtained; yield 96%. b) Chlorination of 140 g of 1.2 U3-three chloropropene under the conditions of example IB) results in 15152,2,3-pentachloropropane with a yield of 98%. c) 20 g (0.93 mol) of 1,1,2,2,3,3-pentachloropropane, obtained in the chlorination of 1,2,3-trichloropropene, dehydrochlorinate 56 g (1.5 mol) of NaOH as a 40% aqueous solution at 20 ° C in the presence of 1 wt.% methoxy triethylbenzylammonium. The reaction is completed in 1.5 hours. After the usual treatment, 165 g of 1,1,2,3-tetrachloropropene is obtained. Exit 98%. The total yield of tetrachloropropene per 1,2,2,3-tetrachloropropane is 91%. Example 3. a) At dehydrochlorination, 182 g (1 mol) of 1,2,2,3-tetrachloropropane 80 g (2 mol) of NaOH, taken as a 45% aqueous solution, in the presence of 0.91 g (0 , 5% by weight of ethoxydtriethylbenzylammonium for 2 hours at 25s gives 140 g 1.2,

trichloropropene. Yield 96%.

b) Chlorination of 140 g of 1,2,3-trichloropropene at 35–40 ° C after appropriate treatment gives 1,1,2,2,3 pentachloropropane In an amount of 202 g, 30 Yield 98%.

Dehydration of 202 g of 1,1,2,2,3-pentachloropropane at 15 ° C in the presence of 1 g (0.5 wt.%) Of ethoxyethyl triethylbenzyl-35 ammonium is carried out for 2 hours in an amount of 75 g (2 mol per 1 mol of chloride). 165 g 1,1,2,3-tetrychloropropene are obtained. Yield 98%, 6b1,1,1,2,3-tetrachloropropene 40

osmol products.

Example 6 (comparative), the reaction is carried out according to example 1a, but instead of ztoxide triethylbenzylammonium take triethylbenzylammonium chloride. Obtain 175 g of organic products containing 81% unreacted 1,2,2,3-tetrachloropropane and 19% 1,2 J 3-trichloropropene.

Thus, the proposed method allows to obtain a product with a high yield with a decrease in the number of stages, significantly reduce the consumption of reagents and does not require additional stages by distillation. Per 1, 3-tetrachloropropane 92% ,. Example 4 (comparative). 182 g (1 mol) of 1,2,2,3-tetrachloropropane and 1.8 g (1 wt.%) Ethoxyethyl ethyl benzyl ammonium are placed in the reactor. 80 g (2 mol) of NaOH are added with stirring at 25 ° C over 30 minutes in the form of a 20% aqueous solution. The reaction mixture is then stirred for an additional 1 hour. The precipitated NaCl precipitate is filtered off, the organic layer is separated, cyataT, weighed and analyzed. 177 g of an organic product are obtained, containing 88% unreacted 1,2,2,3-tetrachloropropane and 12% 1,2,3-trichloropropene. Example 5 (comparative). The reaction is carried out according to Example 4, but a 45% aqueous solution of NaOH is used at 40 ° C. The reaction time is 1 hour. The reaction mixture is treated as in Example 1. 13 T g of 1,2,3-trichloropropene (yield 91%) and 12-g pro are obtained.

Claims (1)

METHOD FOR PRODUCING 1,1,2,3 TETRACHLOROPROPENE using 1.2.2.3-tetrachloropropane, the reaction of chlorination with molecular chlorine and dehydrochlorination with an aqueous alkali solution of 1,1,2,2,3-pentachloropropane, characterized in that, in order to simplify the process, 1,2,2,3tetrachloropropane is subjected to dehydrochlorination of 40-45% solution of PaOH at 15-25 ° C in the presence of a 0.51% catalyst of the formula [(c ₂ n ₅ ) ₃ ncii ₂ c ₆ h ₅ P or], where R is methyl or ethyl, obtained 1,2-3-trichloropropene is chlorinated to 1.1.2.2.3 - pentachloropropane, which § is dehydrochlorinated at 15-25 ^ 0 in the presence of the specified catalyst, using a 20-40% aqueous NaOH solution.