CS237716B1 - Process for producing 3-methyl-4-nitrophenolate sodium - Google Patents

Abstract

Method for producing sodium 3-methyl-4-nitrophenolate by neutralizing 3-methyl-4-nitrophenol with sodium hydroxide. As a dilute sodium hydroxide solution, an aqueous solution of sodium hydroxide containing as impurities mineral salts, aromatic solvent residues, organic compounds of phosphorus, sulfur or chlorine from the production of 0,0-dimethyl-0-(3-methyl-4-nitrophenyl)thiophosphate is used; sodium 3-methyl-4-nitrophenolate is separated from the mother liquor and impurities by crystallization at a temperature of 0 to 40 °C. Organic impurities are reduced by distillation or adsorption. The process is carried out at an absolute pressure of 1,200 Pa to 101 kPa. The method can be used in the production of sodium 3-methyl-4-nitrophenolate, which is used as an intermediate in the production of insecticides.

Description

(54) Method for producing sodium 3-methyl-4-nitrophenolate

A process for the preparation of sodium 3-methyl-4-nitrophenol by neutralizing 3-methyl-4-nitrophenol with sodium hydroxide. The dilute sodium hydroxide solution used is an aqueous sodium hydroxide solution containing as impurities mineral salts, aromatic solvent residues, organic phosphorus, sulfur or chlorine compounds from the production of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate; Sodium 3-methyl-4-nitrophenolate is separated from the mother liquor and not contaminated by crystallization at 0 to 40 ° C. Organic impurities are reduced by distillation or adsorption. The process is carried out at an absolute pressure of 1200 Pa to 101 kPa.

Spfisob can be used in the preparation of sodium 3-methyl-4-nitrophenolate which is used as an intermediate in the production of insecticides.

The present invention relates to the preparation of sodium 3-methyl-4-nitrophenol by converting 3-methyl-4-nitrophenol to the sodium salt of 3-methyl-4-nitrophenol.

3-Methyl-4-nitrophenol is used to produce plant protection products such as O, O-dimethyl-O- (3-methyl-4-nitrophenol) thiophosphate and 3-methyl-4-dimethylaminophenyl-3-methyl carbonate.

Among the numerous processes for the preparation of 3-methyl-4-nitrophenol, the following are most commonly used: reaction of m-toluidine with sulfuric acid and sodium nitrite; on the

3-methyl-4-nitrophenol with nitric acid, hydrogen peroxide and other oxidizing agents.

The oxidation of 3-methyl-4-nitrosophenol with nitric acid to 3-methyl-4-nitrophenol is described in U.S. Pat. AO 146 179. The preparation of 3-methyl-4-nitrophenol in a medium of a mineral acid solution followed by oxidation of 3-methyl-4-nitrosophenol with nitric acid is described in U.S. Pat. AO 149 726. A similar preparation but in the environment of lower alcohols is in DOS 2,236,571.

The product is obtained in all three cases by crystallization, filtration, washing and drying. Purification of 3-methyl-4-nitrophenol in the presence of aqueous sodium or potassium bisulfite solution is described in Japanese Patent 21,241 (1964).

Purification of 3-methyl-4-nitrophenol and its sodium salt by crystallization in the presence of sodium salts of mineral acids is dealt with in U.S. Pat. AO 147 502 and is described in detail in Macko. J., Vano J., Fulak K., Chem. prflm. 29/54 č. 8, 408 (1979).

The abovementioned references do not address the preparation of sodium 3-methyl-4-nitrophenolate from solutions resulting from the production of organic phosphorus compounds, one of the components of which is 3-methyl-4-nitrophenol and / or its sodium salt.

The above-mentioned drawbacks are eliminated according to the invention by the production process of sodium 3-methyl-4-nitrophenol, which consists in converting 3-methyl-4-nitrophenol into an aqueous solution of sodium salt with dilute sodium hydroxide, which in the presence of mineral salts from The reaction mixture crystallizes and is isolated by crystallization.

For the preparation of dilute sodium hydroxide, an aqueous solution of sodium 3-methyl-4-nitrophenolate, produced from 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate, containing inorganic salts, organic phosphorus compounds, is used, sulfur and / or chlorine, aromatic solvent residues and sodium 3-methyl-4-nitrophenolethe are separated by crystallization from the accompanying impurities at a temperature of 0 to 40 ° C.

Prior to crystallization of sodium 3-methyl-4-nitrophenolate, the concentration of organic phosphorus compounds and organic solvent residues is reduced in solution by distillation or adsorption. Preferably, the process uses a pressure below atmospheric pressure.

According to the process of the invention, it is possible to prepare sodium 3-methyl-4-nitrophenoletate from waste water resulting from the production of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate. The present invention removes waste water and 3-methyl-4-nitrophenol formed therein, which has a positive environmental impact. The waste waters contain mineral salts which are suitable for the salting out of sodium 3-methyl-4-nitrophenolate during crystallization.

Advantageously, a process pressure lower than that of the external atmosphere may be used, thereby avoiding contamination of the working environment with volatile organic compounds, while reducing the need for crystallization. The realization of the invention is simple and unpretentious. It can be implemented on the current alignment, without the need for new investments !.

Example 1 wt. NaOH solution was prepared from 43 wt. % aqueous NaOH by dilution with an aqueous solution of sodium 3-methyl-4-nitrophenolate at a concentration of 1.7 wt. 0.06% wt. toluene and organic phosphorus compounds, expressed as organic phosphorus 0.12 wt.%, organic sulfur 0.10 wt.%, organic chlorine 0.01 wt.%, 17 wt. NaOH was used to neutralize 72 g of industrial 3-methyl-4-nitrophenol at a concentration of 51.8% by weight. at 60-65 ° C.

The resulting pH was 9.2. The mixture was heated to 95 ° C and 25 g of NagCO 3 was added. After stirring for 1 hour, the reaction mixture was heated to boiling point and solvent residues and the organophosphetes were distilled off with steam. The water vapor condensate contained 0.04 wt. % organic phosphorus, 0.04 wt. % of sulfur and 0.03 wt. toluene.

An aqueous solution of sodium 3-methyl-4-nitrophenolate was crystallized by cooling to 15 ° C. The crystals were aspirated. 31 g of industrial 3-methyl-4-nitrophenoleate were obtained, the yield being 97.4% based on the added 3-methyl-4-nitrophenol.

Example 2

The procedure of Example 1 was followed except that 10 g of activated carbon was added to the aqueous solution of sodium 3-methyl-4-nitrophenolate after addition of NagCO 3. After 2 h the activated carbon was separated from the solution and the solution was crystallized by cooling to 15 ° C! and the crystals are filtered off with suction. The yield was 98.4% based on the given 3-methyl-4-nitrophenol.

Example 3

The procedure of Example 1 was followed except that water containing 0.12% by weight was used to prepare the aqueous solution. % 3-methyl-4-nitrophenol, 200 mg / l toluene and 0.01 wt. organic phosphorus. During neutralization, crystallization and filtration, air was sucked off at an absolute pressure of 95 kPa, giving a slight negative pressure over the outside atmosphere. The yield related to the given 3-methyl-4-nitrophenol to the reaction was 93.6%.

Example 4

The procedure of Example 2 was followed except that an aqueous NaOH solution was prepared by diluting 43 wt. NaOH with an aqueous solution of sodium 3-methyl-4-nitrophenolate at a concentration of 1.9% by weight containing 2.1% by weight of NaOH. 1.2 wt. KgCO-1, 0.04 wt. toluene, organic phosphorus compounds expressed as organic phosphorus 0.12 wt.%, organic sulfur 0.08 wt. and did not contain organic chlorine. Crystallization was performed at 40 ° C. The yield was 97.9% except for 3-methyl-4-nitrophenol added.

Example 5

The procedure of Example 1 was followed except that during the cooling the absentee pressure in the bank was gradually reduced from 103 kPa to 1480 Pa. The temperature was 3 ° C. The pressure was reduced so that the mixture did not leak out of the flask. The yield was 98.8% based on 3-methyl-4-nitrophenol added.

Example 6

The procedure of Example 1 was followed. 132 g of industrial 3-methyl-4-nitrophenoleate were obtained. Of all phenol derivatives, the sodium 3-methyl-4-nitrophenolate content was 99.4% by weight. O-Dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate was prepared from the prepared sodium 3-ethyl-4-nitrophenoleate by adding 500 ml of toluene, 75 g of the obtained 3-methyl-4- sodium nitrophenoleate and 10 g potash. The mixture was heated to boiling and 190 ml of 28.2 wt. 0,0-dimetylchlórtiofosfátu;

The reaction mixture was kept under gentle boiling for 2 h. From the obtained toluene solution of O, O-dimethyl-O- (3-methyl-4-nitro-phenyl) -thiophosphate, toluene was distilled off with water vapor and 3-methyl-4-nitrophenol was extracted twice by adding 200 ml of 4 wt. aqueous soda solution. The extraction was carried out with stirring for 2 h. The aqueous layer was separated from the product which dried with Na 2 SO 4. O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate with a purity of 97.4% by weight was obtained.

The invention can be used in the preparation of sodium 3-methyl-4-nitrophenoleate using a solution of sodium 3-methyl-4-nitrophenolate resulting from the production of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate.

Claims (3)

EXAMPLE 6 The procedure of Example 1 was followed. 132 g of technical 3-methyl-4-nitrophenol sodium were obtained. Of all phenol derivatives, the sodium content of 3-methyl-4-nitrophenolate was 99.4% by weight. From the prepared 3-ethyl-4-nitro-phenolate sodium, 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate was prepared by adding to the flask 500 ml of toluene, 75 g of the obtained 3-methyl- Sodium 4-nitrophenol and 10 g potash. The mixture was heated to boiling, and 190 mL of 28.2 wt% was added to the top for 1 h. O, O-diaethylchlorothiophosphate The reaction mixture was kept under gentle boiling for 2 h. From the toluene solution of O, O-dimethyl-O- (3-ethyl-4-nitro-phenyl) thiophosphate, toluene was distilled off with 3-methyl-4 water vapor. -nitrophen01 was extracted by adding 200 ml of 4% w / w twice. aqueous soda. The extraction was continued with stirring for 2 h. The aqueous layer was separated from the product which was dried with Na 2 SO 4. There was obtained 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thio-phosphate with a purity of 97.4% by weight. The invention can be used to produce sodium 3-methyl-4-nitrophenolate, utilizing a solution of sodium 3-methyl-4-nitrophenolate in the absence of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate. OBJECT OF THE INVENTION A process for the preparation of 3-methyl-4-nitrophenolate sodium consisting of converting 3-methyl-4-nitrophenol into an aqueous sodium hydroxide solution with sodium hydroxide which crystallizes out of the reaction mixture in the presence of mineral salts and is isolated by filtration, using sodium hydroxide containing 3-methyl-4-nitrophenolate sodium from the production of 0,0-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate with impurities such as inorganic salts, organic phosphorus compounds and / or chlorine, residues and the 3-ethyl-4-nitrophenolate sodium is separated from the accompanying impurities by crystallization at 0 to 40 ° C. 2. A method according to claim 1, wherein, prior to crystallization of the 3-methyl-4-nitro-phenolate, the aqueous solution is subjected to distillation before the concentration of the phosphorus, sulfur and / or chlorine organic compounds is reduced. or adsorption i. 3. A method according to claim 1 or 2, wherein an absold pressure of 1200 to 101 kPa is used. Severografia, n. P., MOST Price?., 40 Kcs