CS258211B1 - Method of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine preparation - Google Patents

Abstract

Resolving sá preparation aquatic solutions ethyl- amine, isopropylamine and hydroxide sodium, which sa use it at production atrazine konden # záciou above listed solutions from cyanuric- chloride. After filtered atrazine after reaction sa acquired filtrate used on preparation waters # tions solutions ethylamine, isopropylamine and hydroxide sodium used in following condensation. Atrazine sa using as herbicide in agriculture.

Description

The invention provides a process for the preparation of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by condensation of cyanuric chloride with aqueous solutions of ethylamine, isopropylamine and sodium hydroxide.

Among the best known and most widely produced s-triazine herbicides are 2-12-propylamino-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 is described in Czechoslovak patent 110,352. of an anhydrous organic solvent, wherein anhydrous ammonia is used to bind the resulting hydrogen chloride, as described in Swiss Patent 508,640.

The product obtained contained 92% atrazine. The effect of pH on atrazine yield is described in the patents NDR and NSR. According to the GDR patent 51 646, the best yield is obtained if, in the first reaction step, i.e., the reaction is carried out in a preferred manner. after the addition of the first amine and the alkali metal hydroxide, the pH is maintained at 6-8, in the second reaction stage, i.e. after addition of the heavy amine and the alkali metal hydroxide, the pH is maintained at 8.5 to 9. The atrazine yield is 96%. In the German patent 2,032,861, the pH in the first step is 6.5 to 10.

U.S. Pat. Nos. 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 to 170 ° C by distilling off the resulting hydrogen chloride. The advantage of the method is that the problem of waste waters containing mineral salts is eliminated. Swiss Patent 546 247 describes an adiabatic process for producing atrazine in a water-insoluble solvent by reacting ethylamine, isopropylamine, alkali hydroxide with cyanuric chloride.

Ve čranc. pat. 2,296,628, rum. pat. 60,016, jap. pat. 131 592 (1977), it is recommended that the first isopropylamine be metered in at amine dosing for atrazine production. Banks C et al.

J. Am. Chem. Soc. 66, 1771 (1944) and Friedheim E., J. Am. Chem. Soc. 66, 1725 (1944) recommend at a temperature of about 0 ° C for the first reaction step of atrazine production, and a second reaction step at temperatures of 30 to 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.

Ethylamine, isopropylamine and sodium hydroxide are applied in the form of aqueous solutions prepared from their concentrated solutions by dilution with water to precipitate salts causing water durability in the form of a fine, filterable precipitate. The precipitated salts are most often separated by sedimentation and blowdown of the reservoirs, with the loss of part of the reaction components. After completion of the reaction, atrazdium is filtered from the mother liquor containing sodium chloride. The sodium chloride mother liquor contains calcium and magnesium salts which precipitate upon addition of sodium hydroxide or amines.

The above drawbacks are alleviated by the preparation of amine and sodium hydroxide solutions in the preparation of 2-isopropyl-4-ethylamino-6-chloro-s-triazine by the condensation of cyanuric chloride, isopropylamine, ethylamine, and sodium hydroxide in aqueous Atrazine is added to the medium, which is filtered from the reaction mixture. The sodium chloride mother liquor after filtration contains dissolved sodium chloride and unreacted amines. The sodium chloride mother liquor was used to dilute the amines and sodium hydroxide. In dilute solutions of amines and sodium hydroxide, sodium chloride shall not crystallize and its concentration shall be lower than the concentration of sodium chloride in the saturated solution.

The process according to the invention provides a better utilization of the raw materials ethylamine, isopropylamine, and sodium hydroxide, as it prevents the precipitation of salt during their dilution and thus contamination of the raw materials. At the same time, the amount of waste water is also reduced.

Example 1

To the flask was added 3,500 ml of water cooled to 5 ° C, then 500 g of cyanuric chloride was added and 860 ml of 20.3 wt. aqueous isopropylamine solution and 1800 ml of 10.2 wt. aqueous sodium hydroxide solution. The reaction mixture was allowed to stir for 40 minutes. Then 360 ml of 40.1 wt. aqueous solution of ethylamine and 1800 ml of 10.2 wt. aqueous sodium hydroxide solution. The reaction mixture was allowed to react for 60 minutes. The atrazine obtained was filtered off. The filtrate contained 3.7 wt. sodium chloride, 70 mg / l isopropylamine, 40 mg / l ethylamine.

The filtrate was 7500 ml and discarded. The filter cake was washed with 2500 mL of water. The atrazine was dried at 105 ° C. 560 g of a product containing 94.2 wt. atrazine,

3.1% wt. 2,4-bis-ethylamino-6-chloro-s-triazine (simazine) and 2.4 wt. 2,4-bis-isopropylamino-6-chloro-s-triazine (propazine).

Example 2

The procedure of Example 1 was followed except that the isopropylamine solution was prepared by diluting 200 g of 81.2 wt. isopropylamine with 580 ml of the filtrate of Example 1, a NaOH solution was prepared by diluting 700 ml of 42 wt. aqueous NaOH solution with 2900 ml of the filtrate of Example 1. A monoethylamine solution was prepared by dissolving 125 g of 98.5 wt. of monoethylamine in 175 ml of the filtrate of Example 1. 572 g of a product with a content of 96.1% by weight were obtained. atrazine. The filtrate contained 5.8 wt. sodium chloride.

After the experiment was repeated ten times according to Example 2, the sodium chloride content of the filtrate was stabilized at 7.9 wt%.

The invention is applicable to the production of atrazine, which is used as a herbicide in agriculture.

Claims (1)

OBJECT OF THE INVENTION A process for the preparation of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by reacting cyanuric chloride with aqueous solutions of ethylamine, isopropylamine and sodium hydroxide in an aqueous solution of sodium chloride, wherein 2-isopropylamino-4-ethylamino-6- chloro-s-triazine is filtered from the mother liquor containing sodium chloride, wherein the mother liquor sodium chloride is used to prepare aqueous solutions of ethylamine, isopropylamine and sodium hydroxide for further condensation.