CS239373B1 - Preparation method of %,%-dimethyl-%-/3.methyl-4-nitrophenyl/of thiophosfate - Google Patents

Abstract

The invention provides for the preparation of O, O-dimethyl-O- (3- -methyl-4-nitro-phenyl) thiophosphate by condensation O, O-dimethylchlorothiophosphate with 3-methyl-4-nitrophenolate sulfate. Ο, Ο-dimethylchlorothiophosphate is prepared by condensation methanol with PSC1; in a water-insoluble environment solvent. Solution obtained O, O-dimethylchlorothiophosphate condenses 3-methyl-4-nitro-phenyl / thiophosphate from which the solvent is distilled off with water vapor. Water after separation of the solvent, it is used for condensing methanol with PSC13 to dissolve the resulting NaCl.

Description

The present invention provides the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by condensation of O, O-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate.

Ο, Ο-dimethylchlorothiophosphate was prepared by condensation of methanol with PSClC _; in a water-insoluble solvent environment. The resulting solution of O, O-dimethylchlorothiophosphate is condensed with 3-methyl-4-nitrophenyl / thiophosphate, from which the solvent is distilled off with water vapor. Water after solvent separation is used to condense methanol with PSCl ₃ to dissolve the resulting NaCl.

It is an object of the invention to prepare O, O-diinetyl-O- (3-methyl-4-nitrophenyl) thiophosphate from O, O-dimethylchlorotriophosphate and sodium 3-methyl-4-nitrophenolate.

O, O-dimethylchloro thiophosphate 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 O, O-dimethyl-O- (3-chloro-4-nitrophenyl) thiophosphate, O, O-dimethyl O- (4-nitrophenyl) thiophosphate and other insecticides.

O, O-dialkylchlorothiophosphates thereof, in particular O, O-dimethylchlorothiophosphate and O, O-diotochlorothiophosphate, may be prepared. by various processes, the most well-known process for the preparation of 0,0-dimethylchlorothiophosphate starting from phosphorus thiochloride, sodium methoxide and methanol according to equation I.

CHjONa + P (S) C1 ₃

-> (CH ₃ O) ₂ P (S) Cl + NaCl (I)

The Ο, Ο-dialkylchlorothiophosphates can be prepared by chlorination of O, O-dialkylthiophosphoric acids according to Equation II.

(RO) ₂ P (S) SH 4 - 3 Cl ->

-> 2 (RO) ₂ P (S) C1 + S ₂ C1 ₂ + 2 DRINKING (lij

According to Czechoslovak AO 166 922, Ο, Ο-dimethylchlorothiophosphate is prepared from the un-purified O-methylchlorothiophosphate formed by the reaction of phosphorous thiochloride with a 5 to 15 molar excess of methanol in an inert solvent medium followed by the addition of 2 to 2.3 mol equivalents. alkaline lye in the form of a concentrated aqueous solution according to Equation III-VI.

CH3OH + P (S) C1 ₃ -> CH _H OP (S) Cb + HCl (III)

_CH3 0P {SjClo CHjOH + + NaOH -> (CH ₃ O) ₃ P (S) C 1 + NaCl + N ₂ 0 (IV) (CH.jO) ₂ P (S) C1-CH.jOH + NaOH -> (? H _{3 O):?} P (S) + Naol + H ₂ 0 (E)

HCl 4-NaOH-> NaCl + H ₂ 0 (VI)

In Czechoslovakia AO 166 992, to improve the divisibility of the toluene layer, an aqueous methanolic layer is used to adjust the pH to 1 to 3 by adding a mineral acid, preferably hydrochloric acid], which dissolves the precipitated impurities Mg (OH) ₂ and CaCO ₃ into soluble chlorides. substantially improves the separability of the layers.

O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is used as an effective insecticide. It is much less toxic to warm-blooded animals than O, O-dimethyl-O- (4-nitrophenyl) thiophosphate. Most commonly, O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate is prepared by reacting O, O-dimethyl chlorophosphate with 3-methyl-4-nitrophenol. Preparation in the presence of a binding agent or in the presence of a medium is described e.g. v brit. pat. 670,030 and in German Pat. 814 297. Franc. pat. 1,256,417 describes the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophene triphosphate such that a mixture of 3-methyl-4-nitro-phenol To ₂ CO _3, and the powder mixture in a toluene medium is added H O-dimetylchlórtiofosfát. 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. 2,520,393, brit. pat. 644 610, French. pat. 957 803. The preparation of O, O-dialkyl-O- (4-nitrophenyl) thiophosphate by the reaction of O, O-dialkylchlorothiophosphate with sodium 4-nitroenoxalate in chlorobenzene, ethanol, or aqueous media is described by Fletscher J. Am. Chem. Soc. 70, 3943 (1948).

The preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate by reacting 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 reacting O, O-dimethylchlorothiophosphate with sodium 3-methyl-4-nitrophenolate or 3-methyl-4-nitrophenol in the presence of an acid binding agent is described in U.S. Pat. No. 89,124.

The insecticidal formulation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate and the process for its preparation by reacting O, O-dimethylchlorothiophosphate with 3-methyl-4-iiitrophenone or its alkaline salt is described in Japan. U.S. Patent Nos. 28,075 (1959) and 30,541 (1959); No. 1,116,790, U.S. Pat. 3,091,565.

Purification of organophoeforic pesticides of general formula

RiO \

P - X - RJ / 11 r ₂ ox where R 1 and R ₂ is alkyl of 1 to 4 C atoms, X is O or S and _{R f} is aryl, aryl optionally substituted with alkyl, halogen and / or nitro, wherein the impurities are distilled off with steam, discloses MS. The preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate according to US Pat. Nos. 89124 and 129 591 is described in US AO 211 804.

The above drawbacks are overcome by the preparation of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, which is prepared by the reaction of phosphorous thiochloride and methanol and aqueous sodium hydroxide in toluene. The sodium chloride formed by the reaction is dissolved in water and the toluene solution of Ο, Ο-dimethylchlorothiophosphate is condensed with sodium 3-methyl-4-nitrophenolate, and / or 3-methyl-4-nitrophenol in the presence of a hydrogen chloride binding agent.

• with

From the toluene solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate obtained, toluene is distilled off with water vapor, the water is condensed and separated from toluene, and the condensed water is used to dissolve sodium chloride after phosphorus thiochloride reaction. with methanol and aqueous sodium hydroxide solution in toluene medium.

An advantage of the invention is that practically distilled water saturated with toluene is used to dissolve the sodium chloride. The necessity of breaking the interlayer between the toluene solution of 0,0-dimethylchlorothiophosphate and water-precipitated carbonates, in particular with Mg (OH) ₂ and CaCO2, is eliminated _. that precipitate by deposition of NaOH and Na ₂ CO 3. Podlá čs. AO 166 992, the intermediate layer is removed, thereby improving the divisibility of the layers by the addition of small amounts of a mineral acid, preferably hydrochloric acid) adjusting the pH to 1-3, to Mg (0H) ₂ and _CaCO:> dissolved. Since practically distilled water saturated with toluene is used, it is prevented from being discharged into waste water, where it causes pollution. The solubility of toluene at 20 ° C is about 0.5 g / l and, moreover, toluene is often emulsified. Losses of toluene are reduced during production. By eliminating the need to adjust the pH of the mineral acid to a pH value of 1 to 3, the corrosivity of the environment is reduced, thereby allowing the use of less expensive, less noble materials for the construction of machinery.

Example 1

Into a three-necked flask with a thermometer stirrer and a separatory funnel was added 72 g of phosphorus thiochloride with a purity of 97.2% by weight. and 85 g of toluene. While stirring and cooling in the range of 3 to 7 ° C, 78 g of methanol having a purity of 99.9% by weight were added via a separatory funnel. After the addition of methanol, 100 g of a 42 wt. After addition of NaOH, the contents were stirred without cooling. 15 g of 32 wt. hydrochloric acid]. Then 120 ml of water was added. After stratification, the upper layer contained 197 g of product containing

31.3 wt. O, O-dimetylchlortiofosfátu.

The aqueous methanol layer was used to rectify the methanol. The toluene solution of O, O-dimethylchlorothiophosphate was added to 150 ml of toluene and 81 g of sodium 3-methyl-4-nitrophenolate containing 76.4 wt. and 8 g of technical K ₂ CC>. The mixture was heated for 5 hours. under reflux with azeotropic boiling of toluene and water. After completion of the reaction, 200 ml of water and a toluene solution of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate are added to the mixture.

From O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, toluene was separated by steam distillation. After condensation, toluene was separated from water.

Example 2

The procedure of Example 1 was followed except that the dissolution of the salt (NaCl) after the reaction of PSCl _; with methanol and sodium hydroxide in toluene, water was used after the toluene separation of Example 1. After the addition, there was no intermediate layer formed of Mg (OH) ₂ and CaCl2 ·) to separate the layers, therefore no HCl was added to improve the layer separation. O, O-dimethylchlorothiophosphate - 187 g of toluene solution was obtained, containing

32.7% by weight, which according to Example 1 was converted to O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate.

Example 3

The procedure of Example 2 was followed. The yield of Ο, Ο-dimethylchlorothiophosphate was 193 g of a toluene solution containing 31.2 wt. Ο, Ο-dimethylchlorothiophosphate, which, according to Example 1, was converted to O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate.

The invention is applicable to the production of technical O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, which is used as an insecticide.

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