CS272883B1 - Method of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine production - Google Patents

Abstract

2-isopropylamino-4-ethylamino-6-chloro-s-triazine is produced by condensation of cyanuric chloride with ethylamine, isopropylamine and sodium hydroxide in an environment of a non-water soluble solvent and aqueous solution of chloride of alkaline metal.2-isopropylamino-4-ethylamino-6-chloro-s-triazine is used as an agricultural herbicide.

Description

The present invention provides a process for preparing 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by reacting cyanuric chloride with ethylamine, isopropylamine and sodium hydroxide in an aqueous solution of sodium chloride from a previous condensation.

Among the best known and most widely produced s-triazine herbicides are 2-isopropylamino-4-ethylamino-6-chloro-s-triazine (atrazine). Herbicidal effects were discovered in Switzerland in 1954 and are described in Swiss Patent 229 227. Preparation of atrazine by reaction of cyanuric chloride, ethylamine, isopropylamine and sodium hydroxide in aqueous chlorobenzene. The environment is described in Czechoslovakian patent 110 352. Preparation of atrazine with cyanuric chloride isopropylamine in an anhydrous organic solvent, wherein anhydrous ammonia is used to bind the resulting hydrogen chloride - described in Swiss patent 508 640. The product obtained contains 92% of atrazine. The effect of pH on atrazine yield is described in the patents NDR and NSR. According to GDR pat. 51,646, the best yield is obtained if, in the first reaction step, i. after addition of the first amine and the alkali metal hydroxide, a pH of 6-8 is maintained in the second reaction stage, i. after addition of the second amine and the alkali metal hydroxide, the pH is maintained at 8.5-9. The atrazine yield is 96%. In the German patent 2,032,861 the pH is given in the first step of 6.5-10. No. 3,328,399 and 3,586,679 disclose a process for preparing atrazine from cyanuric chloride, ethylamine, isopropylamine in an anhydrous environment at a temperature of 120-170 ° C while distilling off the resulting hydrogen chloride. The advantage of the method is that the problem of waste salts containing mineral salts is eliminated. Swiss Patent 564 247 describes an adiabatic process for producing atrazine in a water-insoluble solvent by reacting ethylamine, isopropylamine, alkali hydroxide with cyanuric chloride. In French Pat. No. 2,296,628, Romanian Patent 60,016, Japanese Patent 131,592 (1977), it is recommended that the first isopropylamine be metered into the amines in the atrazine production. Banks C et al. 3, Am. Chem. Soc. 66, 1771 (1944) and Friedheim E., 3rd Am. Chem. Soc. 66 1725 (1944) recommends a temperature of about 0 ° C for the first reaction stage of atrazine production and a second reaction stage for temperatures of 30-50 ° C. In the first reaction step, a mixture of water and ice is used as the reaction medium, optionally water, ice and an organic solvent. In the formation of low temperatures, brine is most often used for cooling, while in the aquatic environment ice often forms on the heat exchange surfaces, which worsens the heat transfer and thus reduces the cooling intensity.

The above drawbacks are alleviated by the preparation of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by reacting cyanuric chloride with aqueous solutions of ethylamine, isopropylamine and sodium hydroxide. The reaction is carried out in an aqueous solution of sodium chloride and a water-insoluble solvent. After completion of the reaction, the water-insoluble solvent was distilled off with steam and the atrazine was filtered from the mother liquor. The sodium chloride-containing mother liquor with the residues of the water-insoluble solvent is used to prepare an aqueous sodium chloride solution in a subsequent reaction of cyanuric chloride with aqueous solutions of ethylamine, isopropylamine and sodium hydroxide.

It is an advantage of the invention that in the preparation of atrazine the advantages of the process for its preparation in the aqueous medium as well as in the water-insoluble solvent environment are exploited. In the production according to the invention, the reaction takes place in an emulsion medium, so that S is more preferred than in the hetprogenic medium of aqueous solutions, where part of the cyanuric chloride can remain unreacted, especially if it is coated with atrazine. There is a portion in the water-insoluble solvent environment. cyanuric chloride dissolved in a water-insoluble solvent and the reaction with an aqueous solution of ethylamine, isopropylamine and sodium hydroxide takes place in an emulsion. In the preparation of atrazine according to the invention, a smaller amount of water-insoluble solvent is used than in the production of atrazine in an environmentally-only water-insoluble solvent, which also consumes less energy to distil. The presence of sodium chloride in aqueous solutions decreases their solids temperature2

CS 272083 B1 forced, which is advantageous in maintaining the reaction temperature at about 0 ° C while cooling! brine does not form on the cooling surfaces that impair the heat transfer. The use of NaCl mother liquor for the preparation of aqueous NaCl solutions for the preparation of atrazine according to the invention will be reduced until the need to add fresh sodium chloride is eliminated, but sodium chloride from previous atrazine preparations is sufficient.

Example 1

180 ml of water were added to the reaction flask in which 20 g of sodium chloride was dissolved, 200 ml of chlorobenzene and 57 g of cyanuric chloride were added. After cooling to 15 ° C, 97 ml of 20.1 wt. aqueous isopropylamine solution for 40 minutes. Then 118 ml of 10.1 wt. aqueous NaOH solution for 15 minutes and the mixture was allowed to stir for 20 minutes. Further, 40.2 ml of 39.8 wt. of an aqueous solution of ethylamine for 10 minutes at 10 ° C. Finally, 115 ml of 10.1 wt. aqueous NaOH solution and the reaction mixture was allowed to react with stirring for 45 minutes. The chlorobenzene was distilled off with steam and the atrazine was filtered from the suspension and washed with 500 ml of water. 62.1 g of technical atrazine were obtained, containing 98.4% of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine, 0.7% by weight. % 2,4-diethylamino-6-chloro-s-triazine and 0.4 wt. 2,4-diisopropylamino-6-chloro-s-triazine. The sodium chloride mother liquor contained 12.8% sodium chloride and 125 mg / l chlorobenzene.

Example 2

The procedure of Example 1 was followed except that 200 ml of the sodium chloride mother liquor of Example 1 was used instead of the prepared aqueous sodium chloride solution and trichlorethylene was used instead of chlorobenzene.

The procedure was repeated 2 times. 63.4 g of technical atrazine were obtained for the first time with a content of 97.8% of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine, the second time 64.2 g of technical atrazine with a content of 98.1% by weight were obtained. 2-isopropylamino-4-ethylamino-6-chloro-s-triazine.

The invention can be used in the production of technical atrazine, which is used as a herbicide in agriculture,

Claims (2)

OBJECT OF THE INVENTION Method of preparation of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by condensation of cyanuric chloride with aqueous solutions of ethylamine, isopropylamine, sodium hydroxide in aqueous sodium chloride solution and water-insoluble solvent which are separated from the reaction mixture by distillation or distillation 2. The method according to claim 1, wherein the aqueous solution of sodium chloride is a mother liquor with the remainder of the water-insoluble solvent from the previous condensation.