CS229441B1 - Method for the separation 2-isopropylamino-4-ethylamino-6-chlorine-s-triazine - Google Patents

Description

(54) Method for separating 2-isopropylamino-4-ethylamino-6-chloro-s-triazine

The present invention relates to a process for the isolation of 2-isopropylamino-4-ethyl-amino-6-chloro-s-triazine prepared by reaction of cyanurea chloride with aqueous solutions of ethylamine, isopropylamine and sodium hydroxide in a surfactant and defoamer medium.

Among the best known and most sown 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. The preparation of atrazine by reaction of cyanochloride, ethylamine, isopropylamine and sodium hydroxide in aqueous chlorobenzone is described in U.S. Pat. pat. 110 352. The preparation of anthrazine by reaction of cyanochloride with ethylamine, isopropylamine in an anhydrous organic solvent, wherein anhydrous ammonia is described to bind the resulting hydrogen chloride. Swiss patent 508,640 is described. The product obtained contains 92% anthrazine.

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 in the first reaction step, i. after the addition of the first amine and the alkali metal hydroxide, the pH is maintained at 6 to 8, in the second reaction stage, m.p. j. after addition of the second amine and alkali metal hydroxide, the pH is maintained at 8.5-9.

The yield of atrazine is 96%. German Patent 2,032,861 discloses a pH of 6.5-10 in the first stage. U.S. Pat. Nos. 3,328,399 and 3,568,679 disclose a process for preparing atrazine from cyanogen chloride, ethylamine, isopropylamine in an anhydrous environment at a temperature of 120 to 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 546 247 describes an adiabatic process for producing atrazine in a water-insoluble solvent by reacting ethylamine, isopropylamine, an alkali hydroxide with cyanurea chloride. In French. 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. Chani. Soc.

1 725 (1944) recommend! in the first reaction step of the atrazine production, a temperature of about 0 ° C; and the 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, Tad and an organic solvent.

Reference is not made in the literature to disrupt the atrazine foam resulting from the reaction of cyanurea chloride, ethylamine, isopropylamine, alkaline hydroxide in a water-insoluble organic solvent and subsequent distillation with water vapor. Atrazine foam causes problems in the transport of atrazine and its separation from the reaction solution.

The above drawbacks are overcome by the method of separating 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by preparing 2-isopropylamino-4-ethylamino-6-chloro-s-triazine by reaction of aqueous solutions ethylamine, isopropylamine, sodium hydroxide with cyanurea chloride in a water-immiscible organic solvent. The water-immiscible organic solvent is distilled off from the reaction mixture with water vapor after completion of the reaction. Before and / or during and / or after the organic solvent has been distilled off, a surfactant and / or antifoam is added to the reaction mixture.

Of the surfactants, an anionic surfactant is preferably used.

The process according to the invention for the preparation of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine provides a better possibility of distilling off the water-immiscible organic solvent without the risk of foaming the reaction mixture. The invention is of utmost importance in separating 2-isopropylamino-4-ethylamino-6-chloro-s-triazine from its aqueous suspension, since it removes the foam of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine which under normal conditions is strong stable. Since the foam handles a large volume, it also limits the filtration capacity of most filtering devices. During centrifugation, the foam is discarded, and as the suspension flows to the centrifuge, the suspension passes outside the cloth, thereby reducing the yield of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine. The foam is typically composed of the finest particles of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine, which is of the highest quality for herbicide production. The foam causes difficulties in transport in the pipeline, while aerating the pumps. The process according to the invention results in greater suspension homogeneity and the above problems do not occur.

Example 1

500 g of cyanochloride, 3500 ml of chlorobenzene were added to the reaction kettle, and 803 g of 19.9 wt. isopropylamine, 1087 kg of 0.8% aqueous NaOH,

306 g 40.1 wt. % of ethylamine and 1110 g of 10.2 wt. aqueous NaOH solution. After reacting from the cauldron, about 1 L of the reaction mixture was removed and 4 g of a copolymer of ethylene oxide and propylene oxide known under the trade name was added thereto. called Slovanik NT 60 and Slovanik T 610. A 1: 1 volume mixture was used. The chlorobenzene was distilled off from the reaction mixture with steam.

2-Isopropylamino-4-ethylamino-6-chloro-s-triazine was filtered from the resulting suspension.

Example 2

About 1 L of the reaction mixture was removed from the reaction vessel of the experiment described in Example 1, in which chlorobenzene was first distilled off with steam. After distilling off the chlorobenzene, about 1 L of the reaction mixture was removed and allowed to stand in the measuring cylinder for half an hour.

The reaction mixture was stratified to a foam of about 70% v / v, an aqueous solution of about 20% v / v. and to an aqueous suspension of 2-isopropylamino-4-ethylamino-6-chloro-s-triazine of about 10%. After stirring, 3.7 ml of an aqueous methanolic solution of sodium dodecylbenzenesulfonate was added to the reaction mixture while the foam was disrupted.

After 30 min. standing in the cylinder was about 54% vol. of an aqueous solution and about 45 vol. aqueous suspension of technical 2-isopropylamino-4-ethylamino-6-chloro-s-triazine, which was decanted once with 500 ml of water. Then, 2-isopropylamino-4-ethylamino-6-chloro-s-triazine was filtered from the suspension and dried. Technical 2-isopropylamino-4-ethylamino-6-chloro-s-triazine contained 93.1 wt. % 2-isopropylamino-4-ethylamino-6-chloro-s-triazine 3.2 wt. 2,4-diethylamino-6-chloro-triazine and 3.1 wt. 2,4-diisopropylamino-6-chloro-s-triazine.

Example 3

The procedure of Example 2 was followed except that 3.7 ml of 20 wt. aqueous solution of ammonium dodecylbenzenesulfonate and 0.01 g of a silicone oil defoamer. The resulting suspension was filtered.

Example 4

The procedure was as in Example 3, except that 2.5 ml of 32 wt. solution of the triethanolamine salt of dodecylbenzenesulfonic acid known under the trade name Abeson TEA; called Echantillon Nopco NPW. The suspension was then centrifuged and washed with 4 L of water. The filter cake was cut and dried. After drying, the filter cake contained 0.003 wt. Cl?

Example 5

The procedure was as described in Example 1 except that 3.2 ml of sodium alkyl ether sulfate was used as the surfactant, the alkyl being up to C 6, known under the trade name ETOXON EPA; The suspensions were centrifuged, washed with water, dried and cut. The dry matter content was 77.2% by weight. and the Cl 'content was 0.007 wt.

Example 6

The procedure of Example 1 was followed except that an in-service experiment was carried out with a 1,000-tonnage mass of substances. The total amount of the reaction mixture after distilling off the organic solvent with water was about 5.5 m 2. After cooling the reaction mixture to 50 ° C, 6 L of sodium dodecylbenzenesulfonate under the trade name Abeson NAM was added thereto. .

After stirring for 10 min, 10 ml of a polydimethylsiloxane-based defoamer known under the trade name Lukosan S was added. The mixture was centrifuged. During centrifugation, an average centrifuge sample was taken every 5 minutes. Insoluble atrazine was determined in the sample. After centrifugation, the filter cake was washed with water at a flow rate of about 601 / min. After washing, the filter cake was dried on a centrifuge for 30 minutes. Dry matter and chlorides were determined in the filter cake. The operating experiment was compared to that without surfactants and antifoams. The results are shown in Tables no. 1 and 2.

Table 1

Atrazine losses in the filtrate during blasting and washing with water.

Procedure without addition of surfactant and antifoam Surfactant addition procedure and antifoam Time from spinning (min) Concentration atrazine (mg / l) Concentration atrazine (mg / l) 5 370 390 10 210 80 15 460 120 20 320 400 25 180 150 30 1 320 75 35 430 40 1 560 from time to time. washing (min) 5 420 320 10 100 80 15 470 120 20 175 140 25 460 70 Table 2 Concentration of halides in atrazine after drying, depending on time

wash time (min) Procedure without addition of surfactant and defoamer (% by weight) Procedure with addition of surfactant and defoamer (% by weight) 10 1.05 0,012 15 0.73 0,007 20 0.43 0,004 30 0.21 0,003

The invention can be used for the production of technical 2-isopropylamino-4-ethylamino-6-chloro-s-triazine which, after addition of emulsifiers and fillers, finds use as an herbicide in agriculture. Removing the foam reduces the residual water-insoluble solvent from the atrazine, thereby achieving a better wetting of the atrazine with water, thereby improving the washing of the halides from the atrazine. A smaller amount of water can be used in the wash than in the prior art. This will reduce the loss of atrazine in the filtrate.

Claims (2)

OBJECT OF THE INVENTION 1. Method for separating 2-isopropylamino-4-ethylamino-6-chloro-s-triazine prepared by reacting cyanohloride with aqueous solutions of ethylamine, isopropylamine and alkali metal hydroxide in a water-immiscible organic solvent medium, after which the organic solvent is distilled off with water vapor characterized in that, before and / or during and / or after distilling off the organic solvent with water vapor, a tenside and / or antifoam is added to the reaction mixture and 2-isopropylamino-4-ethylamino-6-chloro-s-triazine is distilled off the organic solvent is separated from the suspension. 2. The method of claim 1, wherein the surfactant is an anionic surfactant.