CS232631B1 - A method for producing O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate - Google Patents

Abstract

The invention provides a method for the production of O,O-dimethyl-0-(3-methyl-4-nitrophenol)thiophosphate by condensation of O,O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol and/or its sodium salt in the presence of a hydrogen chloride binding agent. Condensation takes place in the presence of crystalline or a solution of sodium 3-methyl-4-nitrophenolate and mineral salts from the previous condensation. The invention can be used in the production of 0,0-dimethyl-O-(3-methyl-4-nitrophenyl) thiophosphate, which is most often used as an insecticide.

Description

The invention relates to the preparation of O, O-di-ethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by condensation of Ο, Ο-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate in the presence of a hydrogen chloride binding agent.

O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is used as an effective insecticide especially in agriculture and is much less toxic to humans and warm-blooded animals than O, O-dimethyl-O- (4- Most commonly, O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is prepared by reacting O, O-dimethyichiothiophosphate with 3-methyl-4-nitrophenol. The presence of powdered media is described, for example, in British Patent No. 670,030 and in German Patent No. 814,297. French Patent No. 1,266,417 describes the preparation of O, O-dimethyl-O- (3-methyl-4- nitrophenyl) thiophosphate in the presence of potassium carbonate and a powder medium in a thionene medium by reaction of Ο, Ο-dimethylchlorothiophosphate with sodium or potassium 3-methyl-4-nitrophenolate. -dimethyichiorthothiophosphate with 3-methyl-4-nitrophenol in anhydrous acetone, m ethyl ketone in the presence of sodium carbonate at reflux temperature is described in U.S. Pat. No. 2 520 393, brit. pat. no. 644 610, French. pat. no. 957 803; the preparation of O, O-dialkyl-O- (4-nitrophenylene) thiophosate by reaction of O, O-dialkylchlorothiophosphate with sodium 4-nitrophenolate in chlorobenzene, etonolic, or aqueous media, is described by Fletcher in J. Am. Soc., 70, 3943 (1948). O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by reaction of O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol is described in Schultz Berichte der deutschen Chem. Gesellschaft, 40 4322. Production of O, O- dimethyl O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by reacting O, O-dimethylchlorothiophosphate with an alkali metal 3-methyl-4-nitrophenolate, or 3-methyl-4-nitrophenol in the presence of acid binders. No. 89 124. The insecticidal formulation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate and a process for its preparation by reacting Ο, Ο-dimethylchlorothiophosphate with 3-methyl-4-nitrophenol, or its the alkaline salt is described in Japanese Patent Nos. 28,075 (1959) and 30,541 (1959), and in German Patent No. 1,116,790; Purification of organophosphorus pesticides of the general formula

RiO \

P-X-R 3

ZLL

R 2 O X wherein R 1 and R 2 is C 1 -C 4 alkyl, X is O or S, and R 3 is aryl, optionally aryl substituted with alkyl, halogens and / or nitro, the impurities being distilled off with water vapor; pat. no. 129 591.

Preparation of Q, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate according to US Pat. No. 89124 and US Pat.

129 591, wherein water is azeotropically distilled off during the reaction; AO No. 211 804. The preparation of Ο, Ο-dimethyl-O- (3-methyl-4-nitrophenylphthiophosphate) by reacting 3-methyl-4-nitrophenol with O, O-dimethyichiorthothiophosphate in the presence of K21CO3 in methyl ethyl ketone, The reaction mixture is settled and the precipitated salt is filtered off with suction, described by G. Schrader, Die Entwicklung neuer Insectizider Phosphorsaure Ester, Verlag Chemie GMBH Weinheim p.

293 (1963).

In the above references, little attention is paid to separating the prepared solution of O, O-dimethyl O- (3-methyl-4-nitrophenyl) thiophosphate from unreacted or formed salts.

The above drawbacks are overcome by the production of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, which consists in the fact that O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is prepared by condensation of Ο, Ο-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate in the presence of a hydrogen chloride-binding agent in an aromatic hydrocarbon and water environment. The condensation takes place in the presence of crystalline and / or sodium 3-methyl-4-nitrophenolate solution at a concentration of 5 to 95% by weight. and mineral salts from the previous condensation.

The process according to the invention provides a better utilization of sodium 3-methyl-4-nitrophenolate, optionally 3-methyl-4-nitrophenol and a hydrogen chloride binding agent or catalyst.

Due to the sodium 3-methyl-4-nitrophenolate or 3-methyl-4-nitrophenof added to the reaction, a better yield is obtained than in the known processes. Because sodium 3-methyl-4-nitrophenolate or 3-methyl-4-nitrophenolate is used, the amount of wastewater and the content of 3s-methyltenol derivatives in the meh is reduced, thereby improving the environment. it basically does not require new costs and can be converted to a current production facility.

Example 1

A three-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a separatory funnel was charged with 500 ml of toluene, 75 g of technical sodium 3-methyl-4-nitrophenolate containing 77.5 wt. Sodium 3-methyl-4-nitrophenolate and 10 g of industrial K2CO3. The mixture was heated to gentle boiling with stirring. 180 ml of 30.1% by weight was added to the reaction mixture via a separatory funnel. of a toluene solution of Ο, et-dimethylchlorothiophosphate. The reaction mixture was kept under gentle reflux for 1 h. Water was then distilled off azeotropically. After separation of the water, the reaction mixture was reacted at 108 ° C for three hours.

After completion of the reaction, the contents of the flask were cooled and the toluene solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl thiophosphate) was separated from tu232631.

With unreacted sodium 3-methyl-4-nitrophenolate, K2CO3 and NaCl reaction. The yield of O, O-dimethyl-O- (3-methyl-4-nitrophenyl thiophosphate relative to the sodium 3-methyl-4-nitrophenolate reacted was

81.2%.

«Example 1 a d 2

The procedure of Example 1 was followed except that 10 ml of water was added after cooling the reaction mixture. The liquid contents of the flask were separated from the undissolved salts, which were crystallized on the walls of the flask. 673 ml of a toluene solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate was obtained, the yield based on sodium 3-methyl-4-nitrophenolate being 80.4%.

Example 3

The procedure of Example 1 was followed, except that the crystallized salts from the experiment of Example 1 were left in the reaction flask, the sodium 3-methyl-4-nitrophenolate concentration being 87.4% by weight. and to the flask was added 65 g of industrial 3-methyl-4-nitrophenolate with a content of 79.6% by weight. Sodium 3-methyl-4-nitrophenolate and 3 g K2CO3. A 667 toluene solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate was obtained. The yield based on sodium 3-methyl-4-nitrophenolate added to the flask was 92.5%.

Repeating the procedure of Example 3 three times yielded the reaction yields of sodium 3-methyl-4-nitrophenolate 94.2, 88.9, 89.6%.

Example 4

The procedure of Example 2 was followed except that crystallized salts were left in the flask after the experiment described in Example 2, and 65 g of sodium 3-methyl-4-nitrophenolate containing 80.2% by weight was charged to the flask. Sodium 3-methyl-4-nitrophenolate, 5 g K 2 CO 3. The yield based on 3-methyl-4-nitrophenol added to the experiment was 91.2%.

Repeating the procedure of Example 4 three times yielded the reaction yields of sodium 3-methyl-4-nitrophenolate 87.8, 92.6, 92.1%.

B

Example 5

The procedure of Example 1 was followed except that at the beginning, 20 ml of 35 wt. sodium 3-methyl-4-nitrophenolate obtained from the previous condensation. The yield of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate relative to crystalline sodium 3-methyl-4-nitrophenolate was 82.9%.

Example 6

The procedure of Example 5 was followed except that initially 100 ml of an aqueous solution of sodium 3-methyl-4-nitrophenolate (6.2% and 2.1% K 2 CO 3) was added to the reaction mixture. The yield of sodium Ο, Ο-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate relative to crystalline sodium 3-methyl-4-nitrophenolate was 82.4%.

Example 7

The procedure of Example 5 was followed except that 20 ml of a suspension of sodium 3-methyl-4-nitrophenolate containing 9 g of sodium 3-methyl-4-nitrophenolate and 4.1 g of K2CO3 from the previous condensation were initially added to the reaction mixture. The yield of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate relative to crystalline sodium 3-methyl-4-nitrophenolate was 85.7%.

Example 8

The procedure of Example 2 was followed except that the reaction was carried out in a flask in which 34.5 g of unreacted salts remained from the previous condensations. Sodium 3-methyl-4-nitrophenolate was 88.6% by weight. The yield of O, O-dimethyl-O- (3-diethyl-4-nitrophenyl) thiophosphate relative to sodium 3-methyl-4-nitrophenolate added was 91.4 percent.

The invention can be used in the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by condensation of O, O-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate using unreacted 3-methyl-4-nitrophenolate sodium from previous condensation.

Claims (8)

Process for producing O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by condensation of O, O-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate in the presence of a hydrogen chloride binding agent, in an aromatic hydrocarbon or aromatic hydrocarbon environment And water, characterized in that the condensation is carried out in the presence of crystalline and / or sodium 3-methyl-4-nitrophenolate solution at a concentration of 5 to 95% by weight. and mineral salts from previous condensation.