CS239373B1 - Process for preparing O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate - Google Patents

Abstract

The invention provides for the preparation of O,O-dimethyl-O-(3-methyl-4-nitrophenyl)thiophosphate by condensation of O,O-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate. O,O-dimethylchlorothiophosphate is prepared by condensation of methanol with PSC13 in a water-insoluble solvent. The obtained solution of O,O-dimethylchlorothiophosphate is condensed with 3-methyl-4-nitrophenylthiophosphate, from which the solvent is distilled off with steam. The water after separation of the solvent is used for condensation of methanol with PSC13 to dissolve the resulting NaCl.

Description

239373

It is an object of the present invention to provide O, O-di-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate from O, O-dimethylchlorothiophosphate and 3-methyl-4-nitro-phenolate. O, O-dimethylchlorothiophosphate is used as an intermediate in the preparation of organophosphorus compounds used as insecticides in agriculture.

It is used, for example, in the preparation of 0,0-dimethyl-O- (3-chloro-4-nitrophenyl) thiophosphate, O, O-dimethyl-O- (4-nitrophenyl) thiophosphate and other insecticides. Ο, Ο-dialkylchlorothiophosphates thereof, in particular, O-dimethylchlorothiophosphate and O, O-diotechlorothiophosphate are prepared therefrom. The various processes of which the most well-known method for the preparation of 0,0-dimethylchlorothiophosphate is based on phosphorous thiochloride, sodium methoxide and methanol according to equation I. 2 CHYONa + P (S) C13 - »- (CH3O) 2P (S) C1 + NaCl (I) Ο, Ο-dialkylchlorothiophosphates can be prepared by chlorination of 0,0-dialkylthiophosphoric acids according to equation II. 2 (RO) 2P (S) SH 4- 3 Cl -> -> 2 (RO) 2P (S) C1 + S2C12 + 2 FEED (II)

According to Czechoslovak AO 166,922 saΟ, Ο-dimethylchlorothiophosphate is prepared from non-isolated O-methylchlorothiophosphate formed by the reaction of phosphorous thiochloride with a 5 to 15 molar excess of methanol in the middle of an inert solvent followed by the addition of 2 to 2.3 molar equivalents of alcalic ice in the form of of a concentrated aqueous solution according to equation III-VI. CH 3 OH + P (S) C 13 -> CH 2 OP (S) C 19 + HCl (III) CH 3 OP (S) Cb + CH 3 OH + NaOH -> (CH 3 O) 3 P (S) Cl + NaCl + N 2 O (IV) (CH. (O) 2 P (S) Cl + CH 3 OH + NaOH -> (OH 3 O) 3 P (S) + Naol + H 2 O (V) HCl 4 NaOH -> NaCl + H 2 O (VI) In CSSR AO 166 992 is used for to improve the divisibility of the toluene layer of the aqueous-methanolic layer by adjusting the pH to 1-3 by adding a mineral acid, preferably hydrochloric acid], to dissolve precipitated impurities Mg (OH) 2 and CaCO 3 to soluble chlorides, thereby substantially "improving the layers. O-dimethyl-O- (3-methyl-4-nitrophenyl) thio-phosphate is used as an effective insecticide, and is less toxic to warm-blooded animals than 0,0-dimethyl-O- (4-nitrophenyl) thio-phosphate Most commonly, O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is prepared by reacting O, O-dimethylchlorophosphate with 3-methyl-4-nitrophenyl. or in the presence of a medium is described, for example, in British Pat U.S. Pat. No. 1,256,417 discloses the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenylthiophosphate) by a mixture of 3-methyl-4-nitrophenol K2CO3 and a powder mixture O, O-dimethylchlorothiophosphate is added in the toluene medium. Franc. pat. 1,272,685 uses chlorobenzene as the reaction medium.

The condensation of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol in anhydrous acetone, methyl ethyl ketone in the presence of Na 2 CO 3 at reflux temperature is described in U.S. Pat. pat. 644 610, franc. The preparation of O, O-dialkyl-O- (4-nitrophenylthiophosphate by reaction of O, O-dialkylchlorothio-phosphate with sodium 4-nitrophenolaxate in chlorobenzene, ethanol or ancillary medium is described by Fletscher J. Am. Chem. Soc. 70 3943 (1948) The preparation of Ο, Ο-dimethyl-O- (3-methyl-4-nitro-phenyl) phosphate by reaction of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol is described in Schultz Berichte deutschen Chem. Gesellschaft, 40 4322. Production of O, O-dimethyl-O - (3-methyl-4-nitrophenyl) thiophosphate by reaction of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitro-phenolate or 3-methyl-4-nitrophenyl No. 4,1124 discloses a polyol in the presence of an acid binding agent.

An insecticidal formulation of O, O-dimethyl-O- (3-methyl-4-nitrophenylthiophosphate and the process thereof by reaction of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenone, or its alkali solda is described in Japanese Patent Nos. 28,075 ( 1959) and 30,541 (1959), in German Pat.1,116,790, U.S. Pat. No. 3,091,565.

Purification of organo-phosphorus pesticides of the general formula

RXO P —X — R'j / 11 r20 x where R i and R 2 is alkyl of 1 to 4 C atoms. X is O or S and R 1 is aryl, optionally aryl substituted with alkyl, halogen and / or carbonitrile, wherein the impurities are distilled off with water vapor; The preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenylthiophosphate according to U.S. Pat. No. 4,1124 and 129,591 is described in U.S. Pat.

The aforementioned drawbacks are avoided by the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenoyl) thiophosphate, the substance of which is that it is prepared by the reaction of thio-phosphorus pentachloride and methanol and aqueous hydroxide solution. sodium in toluene. The sodium chloride formed by the reaction is dissolved in water and the toluene solution of 0, 0-dimethylchlorothiophosphate is condensed with 3-methyl-4-nitrophenolate sodium, and / or 3-methyl-4-nitrophenol in the presence of a chloro-hydrogen binding agent. • p

Claims (3)

239373 5 6 From the toluene solution obtained, 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, toluene is distilled off with water vapor. The water is condensed and separated from toluene. The condensed water is used to dissolve the chloride The reaction of sodium phosphate with methanol and aqueous sodium hydroxide solution in toluene is preferred, and it is advantageous to use substantially distilled water saturated with toluene to dissolve sodium chloride. between a toluene solution of 0,0-dimethylchlorothiophosphate and water precipitated with carbonates, in particular Mg (OH) 2 and CaCO 3, which precipitate by digestion with NaOH and Na 2 CO 3. wherein the separability of the layers is improved by the addition of a small amount of mineral acid, preferably hydrochloric acid, by adjusting the pH to 1-3 to dissolve Mg (OH) 2 and CaCO3. to use practically distilled water saturated with toluene, it is discharged into the effluents, causing pollution. The solubility of toluene is about 0.5 g / L at 20 ° C and toluene is often emulsified. The production of toluene was reduced. Removing the pH adjustment of the mineral acid to a pH of 1 to 3 will reduce the environment and thus make it possible to use more cheap, less refractory materials for the construction of machinery. EXAMPLE 1 72 g of thio-phosphorus pentachloride having a purity of 97.2% by weight and 85 g of toluene were added to a three-necked flask with a stirrer stirrer and a separating funnel. With stirring and cooling at 3 to 7 ° C, 78 g of 99.9% pure methanol was added via a separating funnel. After addition of methanol, 100 g of an aqueous solution of 42% concentration was added at 0 to 7 ° C. wt. After addition of NaOH, the content was stirred without cooling. For better separation of the layers, 15 g of 32% by weight hydrochloric acid were added. 120 ml of water was then added. After stratification, the topsheet contained 197 g of a product with 31.3% by weight. O, O-dimethylchlorothiophosphate. The water-methanolic layer was used to rectify methanol. A toluene solution of 0,0-dimethylchlorothiophosphate was added to 150 ml of toluene and 81 g of sodium 3-methyl-4-nitrophenolate containing 76.4% by weight. and 8 g of technical K 2 CC 3. The mixture was heated under reflux for 5 hours with toluene azeotrope and water. Upon completion of the reaction, 200 ml of water and toluene solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, ZO, O-dimethyl-O- (3-methyl-4-nitrophenyl) thio- phosphate, toluene was separated by water vapor distillation after condensation, toluene was separated from water. 2 The procedure of Example 1 was followed with the difference that the dissolution of the salt (NaCl) by the PSC1; with methanol and sodium hydroxide in toluene, water was used after separation of toluene from Example 1. The intermediate layer formed by Mg (OH) 2 and CaCO 3 was not formed after the addition to separate the layers; O.O-dimethylchlorothiophosphate - 187 g of a toluene solution was obtained, which contained 32.7% by weight, which was treated according to Example 1 with O, O-dimethyl-O- (3-methyl-4-nitro-phenyl) an example of a 3 The procedure of Example 2 was followed. The yield of O, O-dimethylchlorothiophosphate was 193 g of the toluene solution containing 31.2% by weight of O, O-dimethylchlorothiophosphate, which was treated with O, O-dimethyl-O- (3- The invention is applicable to the production of technical O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate which is used as an insecticide. O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, by reacting phosphorous thiochloride with methanol and aqueous sodium hydroxide solution to toluene, with sodium chloride formed by water and a toluene solution of O, O-dimethylchlorothiophosphate is condensed with 3-methyl-4-nitrophenolate sodium in the presence of hydrogen chloride-binding agent, further from the obtained toluene solution of O, O-dimethyl-O-VYNALEZ - (3-methyl-4-nitrophenylthiophosphate) is steam distilled with water vapor and condensation The water is separated from the condensed water characterized in that the condensed water is used to dissolve sodium chloride upon completion of the reaction of phosphorous thiochloride with methanol and aqueous sodium hydroxide solution in toluene. .-3