JPS5855460A - Manufacture of chlorotrifluoromethylpyridines - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing chlorotrifluoromethylpyridines. ◎ 2,5-dichloro-5-trifluoromethylpyridine compounds are compounds having herbicidal activity, such as those described in European Patent Publication No. 0001473. is an intermediate useful in the preparation of the compounds described in . The 3-chloro-5-trifluoromethylpyridine compound is useful in preparing the intermediate via further ring-chlorination.

It is known that 3-trifluoromethylpyridine can be selectively chlorinated to produce 2-chloro-5-trifluoromethylpyridine (as described in European Patent Publication No. 001!1474). , 3-chloro-5-trifluoromethylpyridine has not been reported in the products of this process.

According to the present inventor's findings, when chlorinating 3-trifluoromethylpyriline and 2-chloro-5-trifluoromethylpyridine in the presence of a copper catalyst,
There is selectivity in that chlorination proceeds at β-positions other than those occupied by trifluoromethyl groups. That is, 3-trifluoromethyl biriline is chlorinated to produce 3-chloro-5-trifluoromethylpyridine and/or 2,3-dichloro-5-
Trifluoromethylpyridine can be produced, and 2-chloro-5-trifluoromethylpyridine can be similarly chlorinated to produce 2.
, 3-dichloro-5-trifluoromethylpyridi/.

According to the invention, therefore, 3-trifluoromethylpyridine or 2-chloro-5-trifluoromethylpyridine is heated at 250°C to 450°C in the presence of a catalyst consisting of a copper oxide, chloride or fluoride. Milk is reacted with chlorine in the gas phase at a temperature in the range of 3-chloro-5
- trifluoromethyl birilin and/or 2 + 3-9 chloro-5-trifluor 1] A method for producing olomethylpyridine is provided, wherein the chlorination reaction is carried out at a temperature in the range of 300°C-380°C. is preferred.

The proportion of chlorine is preferably at least 1 mole (for example 2 to 15 moles) of chlorine per mole of organic feedstock. The catalysts mentioned can be used in the form of a fixed bed or in the form of a fluidized bed.

Copper-gold tin oxide or Halai yiii may not be supported, or may be supported on a supporting material such as aluminum fluoride, alumina, silica or silica-alumina. The chlorination treatment is carried out in the presence of an inert diluent. , conveniently carried out in the presence of nitrogen (e.g. using 2 to 20 liters of nitrogen per mole of organic feedstock), although other inorganic diluents can also be used and the organic diluent Agents such as chlorinated hydrocarbons, especially carbon tetrachloride, may also be used.

The reaction mixture may also contain small amounts of hydrogen fluoride. 7 This hydrogen fluoride can be used, for example, when 2-chloro-5-trifluoromethylbiriline is used as a raw material, and when this is
It can occur when introduced in the form of a gaseous reaction product obtained by the reaction of picoline with chlorine and hydrogen fluoride (as described, for example, in GB 2.045,71 @j2).

The optimum residence time depends on the particular catalyst used, the reaction temperature and the relative proportions of chlorine and organic feed; generally suitable residence times range from 1 to 60 seconds. Chloro-5-trifluoromethylpyridine and/or 2,3-chloro0-5-trifluoromethylpyridine can be separated from other reaction products by e.g. fractional distillation and/or extraction with acids (if desired in conventional manner). can be separated from If desired, the chlorinated by-product can be dechlorinated to produce 3-trifluoromethyl birilin, which is recycled to the chlorination process.

The invention will be illustrated by the following examples. Unless otherwise specified, all divisions and distinctions are based on weight.

Example 1 An aluminum trifluoride support (average particle size 150μ) was impregnated with a water bath solution of a second pot of chloride to form a 7.5-weight iit* Cu
The catalyst is produced by obtaining a catalyst containing the following.

This catalyst (900f) was charged into a vertical Inconel reactor (1150 mm in length, i m in length), and! 100°C
Fluidized with a stream of nitrogen for 1 hour at
5- in 0 nitrogen treated with HP (4 mol/hr) for min.
The trifluoromethyl birilin stream is preheated to 220°C and reacted in a fluidized bed with a chlorine stream also preheated to 220°C. The reaction mixture contains 2.5 moles of chlorine and 6 moles of nitrogen per mole of 3-trifluoromethylpyridine.

The temperature of the fluidized bed was maintained at 320@C; the residence time in the reactor was F117 seconds. Analysis of the reaction products by capillary gas chromatography showed that the major products were the following components: 6-trifluoromethyl birilin 31
5-chloro-5-toIJfluoro)lfruviridine
24-2,3-dichloro-
5-trifluoromethylpyridine 4-trifluoromethylpyridine 2-chloro-5-trifluoromethylpyridine 26-trifluoromethylpyridine Example 2 The catalyst used was the same as described in Example 1. 0,5
mol/hr) 0 stream to 220@C and similarly to 220'
"CK reacted in a fluidized bed with a preheated chlorine stream. Reaction mixture #i contains 9.5 moles of chlorine and 6 moles of nitrogen per mole of 3-trifluoromethylbin.

The temperature of the fluidized bed is maintained at 560@C and the residence time in the fluidized bed is 18 seconds.

Analysis of the reaction product by capillary gas chromatography showed that the major product was the following component: 3-chloro-5-trifluoromethylpyridine 1
6 hours 2.3-! ,? Chloro-5-trifluoromethylpyridine 21.2-Chloro-5-trifluoromethylpyridine 24Is2.5-Dichloro-6-trifluoromethylpyridine 10悌Example 3 2-chloro-5-trifluoromethylpyridine in nitrogen (0.6 mol/h) is preheated to 220'"C and reacted in a fluidized bed with a chlorine stream also preheated to 220'C. The reaction mixture is Contains 7.5 moles of chlorine and 6 moles of nitrogen per mole of piriline.The temperature of the fluidized bed of catalyst (as described in Example 1) was maintained at 360°C and the residence time was 17 seconds. be.

Analysis of the reaction products (by capillary gas chromatography) showed that the main products were: 0 tIJ of unreacted 2-chloro-5-trifluoromethylpyridine.

Claims (1)

[Claims] t3-Trifluoromethylpyriline or #i2-chloro5-trifluoromethylpyridine is prepared from 2506C to 2506C in the presence of a catalyst such as a copper oxide, chloride or fluoride.
Process for the production of 3-chloro-5-trifluoromethylpyridine and/or 2,3-dichloro-5-trifluoromethylpyriline, characterized in that it is reacted with chlorine in the gas phase at a temperature in the range of 450°C. @2. The method according to claim 1, wherein the reaction temperature is in the range of 300"C to 580@C. (5) The proportion of chlorine is at least 1 mole for each mole of organic raw material. Claim 91. 4. The method according to claim 3, wherein the proportion of chlorine is 2 to 15 moles per mole of the organic raw material. 5. The chlorination reaction is carried out in an inert gaseous state. The method according to any one of claims 1 to 4, which is carried out in the presence of a diluent.