CS239419B1 - Method of production (I.O-dimethyl-O-ZS-methyl-A-nitrophenyl / thiophosphate - Google Patents

Abstract

The invention solves the production of 0,0-dimethyl-O-p- -methyl-4-nitrophenyl)thiophosphate by condensation of sodium j-methyl-a^nitrophenolate with 0,0-dimethylchlorothiophosphate. 0,0 dimethylchlorothiophosphate reacts with sodium 3- -methyl-4-nitrophenolate in the presence of a hydrogen chloride-binding reagent in an aromatic hydrocarbon environment. After the reaction is complete, the crystalline salts are dissolved in water and the aromatic hydrocarbon is distilled from the aromatic layer with water vapor. After the vapors are condensed, the water is separated from the aromatic hydrocarbon and used for subsequent dissolution of the crystalline salts in the next batch. The invention can be used in the production of 0,0-dimethyl-O-(3-methyl-4-nitrophenyl)thiophosphate, which is used as an insecticide in agriculture.

Description

239419 2

The present invention relates to the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by reacting 0,0-dimethylchlorothiophosphate with 3-methyl-4-nitrophenolate sodium in the presence of hydrogen chloride-binding agent in an aromatic hydrocarbon environment. . O, O-dimethyl-O- (3-methyl-4-nitro-phenyl) thiophosphate is used as an effective insecticide in agriculture. It is much less toxic to humans and to warm-blooded animals such as 0,0-dimethyl-O- (4-nitrophenyl) thiophosphate. Most commonly, O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is prepared by reacting O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol. The preparation in the presence of an acid binding agent or in the presence of a cross-linking medium is described e.g. pat. No. 670,030 and in German Pat. No. 814 297.

French Pat. No. 1,266,417 discloses the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate in the presence of potassium carbonate and a powder medium in a toluene medium of the reaction of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenolate. or potassium; Franc. pat. No. 1,272,689 uses chlorobenzene as the reaction medium. The condensation of 0,0-dimethylhlorothiophosphate with 3-methyl-4-nitrophenol in anhydrous acetone, methyl ketone in the presence of sodium carbonate at reflux temperature is described in U.S. Pat. No. 2 520 393, brit. pat.č. 644 610, franc. pat. No. 957,803. Preparation of O, O-dialkyl O- (4-nitrophenylthiophosphate) by O, O-dialkyl chlorothiophosphate 4-nitrophenol sodium in chlorobenzene, ethanol or aqueous media, is described by Fletcher, J. Am; Soc. 70 3 943 (1948). The preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by the reaction of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol is described by Schultz Berichte der deutschen chem. Qesellschaft, 40, 322. Production of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate with O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenolate or 3-methyl-4-nitrophenol in the presence of reagents for binding acid describes MS. pat. No. 89, 124. An insecticidal preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate and a process for the preparation thereof by reacting O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol or an alkaline salt thereof is described in Japanese Patent No. 28,075 (1959) and No. 30,541 (1959), in U.S. Patent No. 1,116,790, U.S. Pat. 3 091 565. Purification of organophosphorus pestields of general formula ‘P - X - r3

X where

R 1 and R 2 are alkyl of 1 to 4 C atoms, X 2 is O or S a

R 1 is aryl, optionally aryl substituted with alkyl, halogen and / or nitro, wherein the impurities are distilled off with water vapor; pat. No. 129,591. Preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate under Art. pat. No. 89 124 though. 129 591, while water is azeotropically distilled off during the reaction. AD No. 211 804. Preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by reacting 3-methyl-4-nitrophenol with O, O-dimethylchlorothiophosphate in the presence of KgCO3 in methyl ketone, while cooling the reaction mixture. The cured salt is suctioned off, as described by Q. Schrader, Die Entwieklungneuer insektizider Phosphorous Ester, Verlag Chemie GltBH Meinheim p. 293 (1963). 3 239419

The above references do not pay attention to the contamination of 0,0-di-methyl-O- (3-methyl-4-nitrophenyl) thiophosphate by insoluble inorganic compounds, in particular Mg (OH) 2 and CaCO3.

The above drawbacks are eliminated by the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, which consists in reacting O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenolate with sodium in the presence of hydrogen chloride-binding agent, the aromatic hydrocarbon environment to O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate.

Upon completion of the reaction, the inorganic and organic salts, in particular the unreacted 3-methyl-4-nitrophenol sodium, are dissolved by the addition of water by reaction of the formed sodium chloride and hydrogen chloride-binding agent. The aromatic solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is separated from the aqueous solution of dissolved salts. From the aromatic solution of 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, the aromatic hydrocarbon is distilled off with steam. After condensation, the aqueous phase is separated from the aromatic hydrocarbon and used to dissolve the inorganic and organic salts in the following preparation of 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate.

According to the invention, O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate can be obtained which is practically not contaminated with insoluble inorganic salts and need not be subjected to further purification e.g. by sedimentation or filtration and the like.

Distilled water, which is saturated with aromatic hydrocarbon, is used to dissolve the salt. When dissolving salts, in particular hydrogen chloride-binding, e.g., carbonates, hydroxides, alkali metals, CaCO 3 and Mg (OH) 2 do not fall out as when using domestic water. In distillation of the aromatic hydrocarbon with water vapor on the columns, the inorganic insoluble salts settled on the column filler and caused a deterioration of their activity over time.

The water, after separation of the aromatic hydrocarbon, contains about 0.5 g / l of soluble aromatic hydrocarbon and furthermore contains an aromatic hydrocarbon in the form of an emulsion. The water-containing waters must be subjected to purification prior to discharge into the effluent. By using these solutions, the cleaning problem is eliminated, thereby substantially improving the environment.

In addition, a substantial portion of the soluble and emulsified aromatic hydrocarbon is captured. The practice of the invention is simple and simple. Přikladl

To a three-necked flask equipped with a stirrer, a separating funnel and a thermometer, 500 ml of hydrocarbon hydrocarbon, 75 g of 78.2 wt. Sodium 3-methyl-4-nitrophenolate, 10 g KgO 3.

The mixture was heated to 80-85 ° C. 180 ml of 31.2% by weight were metered in at this temperature for 30 minutes. of a toluene solution of 0,0-dimethylchlorothiophosphate. After dosing, the reaction mixture was kept at a moderate boil for 8 hours and the azeotrope was gradually removed by distillation. Upon completion of the reaction, 500 mL of water was added to the reaction mixture to dissolve the crystalline salts. Then, the aqueous layer was separated from toluene. The toluene layer contains a so-called. an intermediate layer which was contaminated with CaCO 3 and Mg (OH) 2. From the toluene layer, toluene and water vapor were distilled off on a column. After condensation, the water was separated from toluene.

Claims (2)

239419 4 ø r 2 The procedure of Example 1 was followed except that the dissolution of the salt was carried out after the toluene was separated in Example 1. The toluene layer obtained was virtually free of insoluble CaCO 3 and MgCl 2. The procedure was repeated threefold to give 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) phosphate concentrate 92.6; 93.8; 91.6 wt%, which could be further processed to a concentration of 96-98 wt%. extracting 3-methyl-4-nitro-phenol by 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) -l-phosphate followed by vacuum drying. The present invention may be used to produce 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) tlophosphate, which is used as the most suitable insecticide. SUMMARY OF THE INVENTION A process for the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) tlophosphate consisting of the reaction of 3-methyl-4-nitrophenolate with Ο, Ο-dimethylchlorothiophosphate in the presence of hydrogen chloride in the presence of an aromatic hydrocarbon, After completion of the reaction, the water-soluble salt was dissolved by the addition of water, the aromatic hydrocarbon was distilled off with steam from the aromatic solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) -l-phosphate, and after condensation the water was separated from the aromatic carbon characterized in that the aqueous phase of the separation of the aromatic hydrocarbon is used to solubilize insoluble salts upon reaction of 3-methyl-4-nitrophenolate sodium with Ο, Ο-dimethylchlorothiophosphate in the presence of hydrogen chloride and an aromatic hydrocarbon. Severografia, n. P., MOST Price 2,40 Kcs