DE1964619C3 - Adiabatic process for the manufacture of N monosubstituted 2,4 dichloro 6 amino s tnazines - Google Patents

Description

N N

Cl

NH-R

in which R is a lower alkyl or alkenyl or a cycloalkyl radical with up to 6 carbon atoms, by reacting cyanuric chloride with an amine of the general formula RNH ₂ , in which R has the meaning given above, in the presence of an acid-binding agent in a two-phase organic aqueous medium, characterized in that the reaction is carried out under adiabatic conditions.

2. The method according to claim 1, characterized in that the amine is first mixed with the acid-binding agent Agent mixes and becomes a solution of cyanuric chloride in an inert organic solvent admits.

The present invention relates to a heretofore uncommon and extremely rapid process for the preparation of N-monosubstituted 2,4-dichloro-6-amino-s-triazines, in which the amino group by a lower alkyl or alkenyl or a cycloalkyl radical with up to 6 carbon atoms is substituted, of very high purity and in very high yields by conversion of cyanuric chloride with an appropriate primary amine in the presence of an acid-binding agent in one two-phase organic-aqueous medium, which is characterized in that one carries out the reaction performs under adiabatic conditions.

Typical examples of alkyl groups are as follows: propyl, isopropyl, butyl, isobutyl, amyl or hexyl; as alkenyl groups it is worth mentioning propenyl or butenyl; Cyclopropyl, cyclobutyl and cyclohexyl may be mentioned as representatives of cycloalkyl groups.

The compounds that can be prepared by the process according to the invention are intermediates which are used for the preparation of di-amino-chloros-triazines, which in turn serve to prevent undesirable vegetation and vegetation and are therefore of extremely great value and of great economic importance as herbicides are. Particularly valuable diamino compounds of the trade that are used as herbicides are, for. B. 2-chloro-4-ethylamino- 6-isopropylamino-s-triazine or 2-chloro-4,6-bis-isopropylamino-s-triazine. These diamino compounds can be used both as selective herbicides for combating link weeds in crop plants and as soil sterilizers for the total suppression of undesirable plants.

The 2,4-dichloramino-s-iriazines which can be prepared according to the invention represent known compounds and are usually made by reaction

'o of cyanuric chloride with primary amines in the lower Temperatures and in the presence of a solvent. When performing this procedure, it is necessary to to neutralize the hydrochloric acid formed during the reaction. The implementation is therefore in The presence of an acid-binding agent. As such, either an excess of to be converted amine or z. B. sodium hydroxide or sodium carbonate.

Although this process yields satisfactory results with regard to the yield and purity of the desired end products, it is nevertheless associated with a number of significant disadvantages. Particular mention should be made here of the long reaction times which are required as a result of carrying out the reaction at low temperature - in practice, temperatures between 0 and f 5 ^C C are used. Another problem is the dissipation of the heat of reaction that occurs. To do this, one proceeds either in such a way that the reaction is carried out in the presence of ice or one uses an apparatus provided with appropriate cooling devices (e.g. cooling jacket and cooling coils). Because of the desired low temperatures, it is necessary to use brine cooling, which further increases the effort involved in carrying out the process.

The inventive method avoids these disadvantages by performing the adiabatic Process. This means that the required reaction

4 = times drastically reduced. The desired end products are obtained after reaction times of 1 to 2 minutes. As a consequence of this, the space-time yield of the process according to the invention increases sharply compared to the known processes, which in turn means that the reactors used can be kept relatively small at the same production level. In addition, the equipment used can be of a very simple design, since there is no need for any cooling devices. Another advantage of the process according to the invention is that it can be carried out continuously, particularly well. In view of the fact that both the starting material and the end products contain hydrolyzable chlorine atoms, it must be regarded as surprising that with the process according to the invention the desired end products with excellent purity of about 99% and with a yield of up to 99.6 ° / q of theory can be obtained, since both starting and end products at temperatures of up to 8O ⁰ C with deir. aqueous alkaline reaction medium come into contact.

To carry out the process according to the invention, the cyanuric chloride is in an inert organic Solvent added. Suitable solvents for this purpose are: toluene, benzene, xylene, acetone or methyl ethyl ketone.

Acid-binding agents that can be used in the present process are to be

imagine: the amine to be converted, alkali metal hydroxides or alkali metal carbonates, for example sodium hydroxide, sodium carbonate, potassium hydroxide or potassium carbonate. As a rule, aqueous solutions of these acid-binding agents are used, usually a 50% sodium hydroxide solution, although of course solutions which are more or less contain less than 50% of the selected acid-binding agent, are usable.

As a rule, stoichiometric amounts of the Reactants used, d. H. about 1 mole of amine, 1 mole of cyanuric chloride and about 1 mole of acid-binding agent Medium. However, if the amine itself is used as an acid binding agent, then of course at least 2 moles of this amine per mole of cyanuric chloride are used.

In one embodiment of the invention, C ^ anurchlor d and isopropylamine are continuously in one working reactor implemented. So z. B. water, a 50% sodium hydroxide solution and Isopropylamine mixed in a mixing tank and the mixture on the continuously working Reactor are fed. Simultaneously with the addition of this mixture to the reactor, a solution of Cyanuric chloride in toluene fed into the reactor and the reaction delivers in a period of 1 to 2 minutes the desired 2,4-dichloro-6-isopropylamino-s-tria-ir ..

Also for the production of 2,4-dichloro-6-isopropylamino-s-triazine, wobu isopropylamine at the same time represents the acid-binding agent, a continuously operating reactor can be used. Water, isopropylamine and toluene, which contains dissolved cyanuric chloride to be reacted, introduced into the reactor, which has a volume of 7.5 liters. The flow rates from the various lines are regulated so that it is practical stoichiometric quantities of the various reaction components are used. the Monitoring the mutual amounts of cyanuric chloride and isopropylamine is particularly important.

The following examples are provided for illustrative purposes of the method according to the invention.

example 1

To a solution of 92.2 g (0.5 mol) of cyanuric chloride in 500 g of toluene at 24 ^C , which is located in a four-necked round bottom flask equipped with a dropping funnel, stirrer, condenser and thermometer, a solution of 29.6 g (0.5 mol) of isopropylamine and 20.0 g (0.5 mol) of sodium hydroxide and 500 g of water at 24 ° C. over a period of 10 seconds with stirring

ίο admitted. The temperature of the reaction mixture increases in less than 30 seconds to 8O ⁰ C. After exactly one minute, the analysis of the final product 99.8% 2,4-dichloro-6 isopropylaminos-triazine, 0.2% of 2,4-bis- isopropylamino-6-chloro-s-triazine and traces of cyanuric chloride.

Example 2

26.8 kg per hour (1 mol) of isopropylamine, 37.2 kg per hour (1.02MoI) 50% sodium hydroxide solution and 163 kg per hour of water were poured into a mixing tank from various lines and the resulting mixture was simultaneously at 558 kg per hour 15 % strength cyanuric chloride solution in toluene in a continuously operating reactor with a volume of 4.15 liters and allowed to flow through. The reaction was started at a temperature of 31 C under adiabatic conditions. The Ausflußtemperatür was 80 C. After ^a festgestillt analysis was that the reaction proceeded to 99.5% and a yield of 98.5% of 99.0% pure 2,4-dichloro-6-isopropylamino-s-triazine was obtained .

Example 3

The reactants were in and out at a rate of 53.6 kg per hour of isopropylamine (2.0 moles), 174 kg per hour of water and 558 kg per hour of 15% strength cyanuric chloride solution in toluene in a continuous reactor of a volume of 7.5 liters let go through. The temperatures at the inlet was 30 ⁰ C and at the outlet 8O ⁰ C. The reaction was 99.5% pure, the yield of 99.0% of 2,4-dichloro-6-isopropylamino-s-triazine was 99.5%.

Claims (1)

ί 964 619 claims: 1. Process for the preparation of N-monosubstituted 2,4-dichloro-6-amino-s-triazines of the general formula Cl