CS215478B1 - Method of preparation of s-chlormethylesters-o,o-dialky - Google Patents

Description

S-chloromethyl esters of dithiophosphoric acids of the formula I are known from the literature

R »0 ^P - ^S ~ CM ₂ - Gl p

wherein R and R 'are C 1 -C 4 alkyl, n is 0, or 1, effective as insecticides. They are prepared by reacting bromochloromethane with potassium dithiophosphoric salt, respectively. of dithiophosphonic acid in methyl ethyl ketone or acetone over a period of 5-7 hours, the bromochloromethane being used in 100% excess, the yield being 60-80% (Austr. pat. 432.101).

Also known are the insecticidally active S-chloromethyl esters of thio- and dithiophosphoric acids of the general formula II in which R and R 'are alkyl of 1 to 4 carbon atoms, X and Y are oxygen or sulfur and m is 0 or 1. These are prepared. from the corresponding organophosphoric acid salts with bromochloromethane in a ketone medium, the bromochloromethane being used in a 100% excess in a yield of 50 to 80% (US Pat. 3,896,219; DOS 1,925,468).

Also known as soil insecticides are S-chloromethyl O, δ-dialkyldithiophosphates, which can be prepared by reacting bromochloromethane with a potassium salt of dithiophosphoric acid in an excess of bromochloromethane at 60 ° C for 24 h to give a yield of 60%, similar to the reaction. in methanol in the presence of sodium iodide as a catalyst in a yield of 71% (NSR Pat. 1.015.794).

A novel process for the preparation of S-chloromethyl esters of Ο, Ο-dialkyldithiophosphoric acid of the general formula III has now been found.

W - CH _Z - Cl wherein R ¹ and R ² the same or different alkyl of 2 to 4 carbon atoms, by reaction with 0,0-bromochloroethane dialkylditiofosforečnou acid, or a sofa, of formula IV

wherein M is hydrogen, ammonium, alkali metal, especially sodium or potassium, R ¹ and R ² are as defined above, preferably extending the use of excess bromochloromethane.

The invention is based on the fact that the reaction is carried out in an aqueous medium in the presence of a catalyst from the group of quaternary ammonium salts of the general formula V

wherein R ³ , R ⁴ and R ⁵ are C 1 -C 4 alkyl, R ⁶ is C 1 -C 4 alkyl, benzyl, R ³ and R ^{4 can form,} together with the nitrogen of the quaternary ammonium salt, a 5 to 6 heterocyclic ring in which the oxygen may be a further heteroatom, Y represents a halogen of the group Cl, Br, I, in an amount of 1 to 10 mol%, the reaction being carried out at a temperature of 20 ° C to the reflux temperature of the reaction mixture.

The preparation of the S-chloromethyl esters-O, O-dialkyldithiophosphoric acid according to the invention has the advantage over the prior art in that substantially higher yields are achieved - approximately 30% - while the reaction time is halved. Both of these factors have a significant impact on the production technologol.

The following examples illustrate the invention in more detail.

Example 1

To 129.4 g of bromochloromethane (1 mol) at reflux temperature (68 ° C) and with vigorous stirring, 79.8 g of an aqueous solution of 0,0-diethyldithiophosphoric acid sodium salt (0.2 mol) and 3 mol. 6 g of a 68% aqueous solution of triethylbenzylammonium chloride. After the addition, the reaction mixture was stirred under the same conditions for 30 minutes, then cooled and the crude product together with bromochloromethane were collected. This was freed of bromochloromethane and volatiles by distillation under reduced pressure. 41 g of product were obtained which contained 94.2% of O, O-diethyl S-chloromethyldithiophosphate. The analysis was determined by gas chromatography in relation to the standards used, given by weight.

The total yield calculated on the starting sodium salt of O, O-diethyldithiophosphoric acid was

82.2%.

Example 2

Of 119.7 g of 97.3% (0.9 mol) of bromochloromethane, 165.3 g of an aqueous solution of sodium 0, 0-diisobutyldithiophosphoric acid (0.3 mol) and 5 g of triethylbenzylammonium chloride of a 68% aqueous solution 81 g of pure O, O-diisobutyl-S-chloromethyldithiophosphate were prepared according to the procedure of Example 1.

The analysis was performed as in Example 1.

The total yield calculated on the starting sodium salt of O, O-diisobutyldithiophosphoric acid was 93.1%.

Example 3

Of 59.9 g of bromochloromethane 97.3% (0.45 mol), 71.8 g of an aqueous solution of sodium O-ethyl O-isobutyldithiophosphoric acid (0.15 mol) and 3 g of triethylbenzylammonium chloride of a 68% aqueous solution according to the procedure of Example 1, 38.5 g of a product containing 95% of O-ethyl-O-isobutyl-S-chloromethyl-dithiophosphate were prepared.

The analysis was performed as in Example 1.

The total yield calculated on the O-ethyl-O-isobutyldithiophosphoric acid starting salt was 90.5%.

Example 4

A mixture of 129.4 g of bromochloromethane (1 mol) and 199.5 g of sodium 0,0-diethyldithiophosphoric acid (0.5 mol) was stirred at 70 ° C for 4 h, the organic layer was separated, bromochloromethane was distilled off under reduced pressure. pressure, the rest

81.3 g contained 88.1% of O, O-diethyl S-chloromethyldithiophosphate, which corresponds to a 53.8% yield.

Claims (1)

Wherein M is hydrogen, ammonium, alkali metal, in particular sodium or potassium, R1 and R2 are as defined above, preferably employing excess bromochloromethane. The invention is based on the fact that the reaction is carried out in an aqueous medium with the presence of a catalyst from the group of the quaternary ammonium salts of the formula V wherein R 3, R 4 and R 5 are alkyl of 1 to 4 carbon atoms, R 6 is alkyl of 1 to 4 carbon atoms, benzyl, R 3 and R 4 may, together with the nitrogen of the quaternary ammonium salt, form a heterocyclic ring 5 to 6 membered in which the oxygen may be further the heteroatom, Y is a halogen of Cl, Br, I, in an amount of 1 to 10 mol%, the reaction being carried out at a temperature of 20 ° C to the reflux temperature of the reaction mixture. The preparation of S-chloromethyl ester-O, O-dialkyldithiophosphoric acid according to the invention has the advantage over the prior art of obtaining substantial higher yields of approximately 30% while reducing the reaction time of half. Both of these factors significantly affect manufacturing technology. The following examples illustrate but do not limit the invention. EXAMPLE 1 Reflux to 129.4 g of bromochloromethane (1 mole) with reflux (68 ° C) and add 79.8 g of aqueous sodium salt of Ο, ety-diethyldithiophosphoric acid (0.2 mol) and 3.6 g with vigorous stirring over 30 minutes. g of a 68% aqueous solution of triethylbenzylammonium chloride. After addition, the reaction mixture was added under the same conditions for a further 30 minutes, then cooled and the crude product was separated with bromochloromethane. This was freed of chloroform and volatile constituents of the distillate under reduced pressure. 41 g of product were obtained, which contained 94.2% of O, O-diethyl-S-chloromethyl-dithiophosphate. The analysis was determined by gas-chromatography relative to the standard used, reported by weight percent. The total yield calculated on the starting sodium β-diethyldithiophosphoric acid was 82.2%. Example 2 From 119.7 g of bromochloromethane 97.3% (0.9 mol), 165.3 g of an aqueous solution of 0.0-diisobutyldithiophosphoric acid sodium salt (0.3 mol) and 5 g of triethylbenzylammonium chloride 68% 81 g of pure O, O-diisobutyl-S-chloromethyldithiophosphate was prepared according to the procedure described in Example 1 above. The analysis was performed as in Example 1. The total yield calculated on the starting sodium salt of Ο, Ο-diisobutyldithiophosphoric acid was 93.1%. Example 3 From 59.9 g of bromochloromethane 97.3% (0.45 mol), 71.8 g of an aqueous solution of 0-ethyl-O-isobutyldithiophosphoric acid sodium salt (0.15 mol) and 3 g of triethylbenzylammonium chloride 68% aqueous solution 38.5 g of a product containing 95% of O-ethyl-O-isobutyl-S-chloromethyldi-thiophosphate were prepared according to the procedure of Example 1 according to the procedure of Example 1. \ t The assay was determined as in Example 1. The total yield calculated on the starting salt of O-ethyl-O-isobutyldithiophosphoric acid was 90.5%. Example 4 A mixture of 129.4 g of bromochloromethane (1 mol) and 199.5 g of 0,0-diethyldithiophosphoric acid sodium salt (0.5 mol) was stirred at 70 ° C for 4 h, the organic layer was separated, bromochloromethane was distilled off under reduced pressure, the 81.3 g residue contained 88.1% of O, O-diethyl-5-chloromethyl-dithiophosphate, corresponding to a yield of 53.8%. SUBJECT sob Method for preparing S-chloromethyl esters of 0,0-dialkyldithiophosphoric acid of the general formula III wherein M is hydrogen, ammonium, alkaline, in particular sodium or potassium, and R 1 and R 2 are as defined above, preferably in excess of bromochloromethane, characterized in that the reaction is carried out in a water medium in the presence of a catalyst of the quaternary salt group generally of formula V 7 P. - S - CH 2 - Cl A / "2 wherein R 1 and R 2 are the same or different alkyl of 2 to 4 carbon atoms, by reaction of bromochloromethane with O, O -dialkyldithiophosphoric acid or its with the salts of formula IV 3 wherein R 3, R 4 and R 5 are alkyl of 1 to 4 carbon atoms, R 6 are alkyl of 1 to 215478 4 carbon atoms, or benzyl, R 3 and R 4 may additionally form a 5-6 membered heterocyclic ring together with the adjacent nitrogen atom, in which the may may be an oxygen further heteroatom and Y are halogen, Cl, Br, J, added in an amount of 1 to 10 mol%, the reaction being effected in the range of 20 ° C to the reflux temperature of the reaction mixture.