DE1139829B - Process for the preparation of O, O-dimethyl-dithiophosphoryl-acetic acid-N-methylamide - Google Patents

Description

Process for the preparation of O, O-dimethyl-dithiophosphorylacetic acid-N-methylamide The preparation of amides of O, O-dialkyldithiophosphoryl fatty acids can be carried out in a known manner Way by reacting an alkali salt of an O, O-dialkyldithiophosphoric acid with an a> -halogen fatty acid amide.

The disadvantage of this process is that it is difficult to manufacture of the corresponding halogen fatty acid amides, since they are required for their production Halogen fatty acid chlorides are difficult to handle.

It is also known, the O, O-dialkyldithiophosphoryl fatty acid amides mentioned to prepare in such a way that O, O-dialkyl-dithiophosphoryl fatty acid ester with molar amounts of a primary or secondary amine.

This method already means one compared to the former Improvement, but it still has drawbacks. So the required O, O-dialkyl-dithiophosphoryl fatty acid ester are produced and separated in a separate process. In view of the toxicity and offensive odor of such phosphoric acid esters a multi-stage process with separation of the intermediate products on a larger scale difficult to implement in technology.

It has now been found that the O, O-dimethyl-dithiophosphoryl-acetic acid-N-methylamide is obtained without separation of intermediate products if phosphorus pentasulphide is reacted with methanol in a known manner to give O, O-dimethyl-dithiophosphoric acid and this is then removed without separation the reaction mixture at a temperature between 0 and 100 "C, preferably 30 to 70" C, with an equivalent amount of methylamine and a chloroacetic acid ester of the formula Cl CH2COOR in which R is an alkyl or phenyl radical, and where R denotes an alkyl or phenyl radical and A denotes the cation of a strongly alkaline compound. then reacted with one of the O, O-dimethyl-dithiophosphoric acid equivalent amount of a strongly alkaline compound at temperatures from -10 to + 100.degree.

According to the process of the invention, it is first left in a known manner Methanol in an inert diluent, e.g. B. benzene, toluene, methylene chloride or carbon tetrachloride, act on phosphorus pentasulfide. The thus obtained Solution is then with methylamine, with a chloroacetic acid ester and with a strongly alkaline compound implemented. The implementation corresponds to the following Reaction scheme: The first part of the reaction is carried out at one temperature between 0 and 100 "C, preferably wisely at 30 to 70 "C; in the second As part of the implementation, the temperature is lowered to +10 to -10 "C.

The methylamine can either be added dropwise in pure form or as a gas be introduced as well as in a solvent, e.g. B. water, alcohol, ketone, Methylene chloride or toluene, dissolved are added.

Solutions of alkali hydroxides are the most common strongly alkaline compounds in water or an organic solvent, alkali or tertiary alkali alcoholates organic amines into consideration, which liberate the methylamine from its salts be able to set. To achieve a particularly good yield, it is advisable to add a small amount of excess to the reaction mixture before adding the alkali Add methylamine.

One can also use those formed from phosphorus pentasulphide and methanol O, O-dimethyldithiophosphoric acid by treatment with an aqueous methylamine solution transfer from the organic solvent into the aqueous solution, the organic Separate the solvent with any impurities dissolved therein and remove the aqueous Implement solution according to the invention further.

According to the process of the invention, the O, O - dimethyl - dithiophosphoryl - acetic acid methylamide in a surprisingly simple manner with good Yield and in high purity. Above all, without separating intermediate products, z. B. when working in a single conversion vessel, the abovementioned inconveniences when working with phosphoric acid esters, such as odor nuisance and contact with highly toxic intermediates, at a minimum press down if not completely avoid.

It is known that phosphorus pentasulphide is used with alcohols to give the corresponding Implement O, O-dialkyl-dithiophosphoric acids. It is also known to be a salt one O, O-dialkyl-dithiophosphoric acid with a w-halogen fatty acid ester to the corresponding Implement O, O-dialkyl-dithiophosphoryl fatty acid ester and from this with a Amine to produce the corresponding O, O-dialkyl-dithiophosphoryl-fatty acid amide (cf. the German Auslegeschrift 1 076 662 and the published documents of Belgian patent 584 817).

The individual process steps in the process according to the invention are therefore partly known, partly they are similar to known processes. So It is more surprising that the inventive combination of the individual steps leads to a yield which is significantly higher than that from the individual yields the known or similar methods can be calculated.

The process of the invention is further illustrated by the following examples explained. The parts given are parts by weight and the percentages are they are percentages by weight.

Example 1 To 111 parts of phosphorus pentasulfide slurried in 500 Parts of toluene are added at 40 to 50 ° C., 80 parts of methanol. While passing through The mixture is removed from carbon dioxide for 1 hour under gentle boiling and reflux cooling heated. Then 200 parts of toluene are distilled off in vacuo and at 10 to 15 "C parts of a 340 / above aqueous methylamine solution are added, then 108 parts Methyl chloroacetate added. The mixture becomes 2.5 while stirring Heated to 60 "C. for hours, then cooled to 0 ° C. 180 parts are left at 0 to 5" C. run in a 300 ml methanolic sodium methylate solution and stir the mixture then 2 hours at 0 ° C. Thereafter, the aqueous layer is separated and the toluene was distilled off in vacuo from the organic layer. The conversion product remains as a yellowish oil, which largely solidifies when it cools down. the Yield is 212 g (purity 850/0), which corresponds to 790/0 of the theory of purer Compound based on the phosphorus pentasulfide.

The compound has the formula EXAMPLE 2 40 parts of methanol are added at 40 to 500 ° C. to 55.5 parts of phosphorus pentasulfide, slurried in 250 parts of toluene. The mixture is heated under reflux for 1 hour while passing nitrogen through it. Then 100 parts of toluene are distilled off together with dissolved hydrogen sulfide in vacuo. The residue is diluted with 250 parts of toluene and 15.5 parts of gaseous methylamine are passed in at 10 to 20 "C. 54 parts of methyl chloroacetate are then added and the mixture is heated to 60 to 70" C. for 4 hours.

The toluene is then completely distilled off in vacuo. To the arrears 15 parts of 340% aqueous methylamine solution are added dropwise at 0 ° C. in the course of 1.5 hours then in a further 1.5 hours, likewise at 0 ° C., 60 parts of 300 / above sodium hydroxide solution.

After 100 parts of methylene chloride have been added, the organic ones are separated off Layer off, dry it with sodium sulfate and distill the solvent in the Vacuum off. A yellowish oil is obtained.

The yield is 92 g (purity 920 / o). That corresponds to a Yield of 74% of theory, based on phosphorus pentasulfide. The connection has the formula given in example 1.

Claims (1)

PATENT CLAIM: Process for the preparation of O, O-dimethyldithiophosphoryl-acetic acid-N-methylamide of the formula characterized in that phosphorus pentasulphide is reacted with methanol in a known manner to give O, O-dimethyldithiophosphoric acid and this is then without separation from the reaction mixture at a temperature between 0 and 100 "C, preferably 30 to 70" C, with an equivalent amount of methylamine and a chloroacetic acid ester of the formula ClCH2 - COOR in which R is an alkyl or phenyl radical, and then without separating off the ester with an amount of a strongly alkaline compound equivalent to the O, O - dimethyl - dithiophosphoric acid equivalent amount at temperatures of - 10 to + 10 ° C. Documents considered: German Auslegeschrift No. 1,076,662; published documents of Belgian patent No. 584817; G. M. Kosolapoff, "Organophosphorus Compounds" (New York, 1950), p.236; Gazzetta chimica Italiana, Vol. 81 / II, 1951, pp. 601 and 602.