CS240380B1 - Process for producing 3-methyl-4-nitrophenol - Google Patents

Abstract

The invention relates to chemistry. The invention solves the production of 3-methyl-4-nitrophenol by nitration of 3-methylphenol and subsequent oxidation of the resulting 3-methyl-4-nitrosophenol with nitric acid in an excess of mineral acid. Part of the excess mineral acid is used to precipitate 3-methyl-4-nitrophenol from a solution of sodium 3-methyl-4-nitrophenolate containing organic compounds of phosphorus, sulfur and/or chlorine as impurities. Nitric acid partially deodorizes organic compounds of phosphorus, sulfur and/or chlorine. The procedure is preferably carried out in the presence of a defoamer.·

Description

240380

The present invention relates to the preparation of 3-methyl-4-nitrophenol used as an intermediate for the preparation of organophosphate insecticides of Q, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate.

Most often, 3-methyl-4-nitrophenol is prepared by two-stage nitration of 3-methylphenol and oxidation of 3-methyl-4-nitosophenol with nitric acid. In nitration with HNO 3, other yield-reducing isomers are formed in addition to the desired 3-methyl-4-nitrophenolea. It is known to prepare 3-methyl-4-nitrophenol by reacting methyl toluidine with sodium nitrite in the presence of sulfuric acid. Furthermore, 3-methyl-4-nitrophenol is prepared by nitrosation of 3-methylphenolp with nitrous acid and subsequent oxidation of 3-methyl-4-nitrosophenol to 3-methyl-4-nitrophenol in sulfuric acid [Bridge Morgan, J. Am. Chem. Soc. 20,766 (1898)], in concentrated sulfuric acid (US Pat. No. 1502,849). The oxidation of 3-methyl-4-nitrosophenol is accomplished by nitric acid [Koelsch, J. Am. Chem.Soc. 06, 2,019 (1944), Cs. pat. 146 179 and ČSSRAO 149 726). Oxidation of 3-methyl-4-nitrosophenol with hydrogen peroxide in an alkaline medium is described in Travagli, Chem. Abstr.45, 7594 e (1951). The above reference references do not mention the production of 3-methyl-4-nitrophenol from the effluent produced in the production of O, O-dimethyl-O - (3-methyl-4-nitrophenyl) thiophosphate.

The above-mentioned references do not disclose the recovery of 3-methyl-4-nitrophenol from the waters resulting from the treatment of 3-methyl-4-nitrophenolate sodium to 0.0% of 3-methyl-4-nitrophenolate sodium to 0 , O-dimethyl-4- (3-methyl-nitrophenyl) thiophosphate.

The above drawbacks are overcome by the production of 3-methyl-4-nitrophenolunitrification of 3-methylphenol by an alkaline nitrate in excess mineral acid and by oxidation of the resulting 3-methyl-4-nitrosophenol with nitric acid to 3-methyl-4-nitrophenol. . SUMMARY OF THE INVENTION The invention is based on the fact that some of the excess mineral acids are reacted with an aqueous solution of 3-methyl-4-nitrophenolate sodium from the production of O, O-dimethyl-O- (3-methyl-4-nitrophenyl) thiophosphate which is an impurity such as organic compounds of phosphorus, sulfur, and / or chlorine, residues of aromatic solvent, mineral salts, especially NaCl and alkali carbonates, potassium carbonate, 3-methyl-4-nitrophenol sodium reacts with mineral acid to methyl 4-nitrophenol and potassium carbonate react to the mineral potassium salt. After reaction, 3-methyl-4-nitrophenol is separated from the fatty acids with impurities.

Organic phosphorus, sulfur and / or chlorine compounds have a typical odor that is unpleasant. Excess nitric acid, which is not used in the oxidation of 3-methyl-4-nitro-phenol, deodorizes the unpleasant odor of the phosphorus, sulfur and / or chlorine compounds.

Mineral acid has a pKa of less than the pKa of 3-methyl-4-nitrophenol and carbonic acid. It is advantageous to use a defoamer to remove the foam resulting from the decomposition of the alkali carbonates with a mineral acid.

The aqueous sodium 3-methyl-4-nitrophenolate solution may contain 0.2 to 40 wt. Sodium 3-methyl-4-nitrophenolate. The mother acid, after filtration of sodium 3-methyl-4-nitrophenolate, contains 0.1 to 40% by weight of mineral acids.

According to the invention, 3-methyl-4-nitrophenol is recovered from the waste water which is discharged into the sewage system.

Since the water contains K 2 CO 5, sodium 3-methyl-4-nitrophenolate cannot be obtained from it, since it may contain potassium 3-methyl-4-nitrophenolate, which is less stable, to increase the explosiveness of sodium 3-methyl-4-nitrophenolate. With mineral acid, potassium carbonate reacts with the mineral which is filtered off in the parent acid from 3-methyl-4-nitrophenol. The nitric acid partially reacts with the phosphorus, sulfur and / or chlorine organic compounds to deodorize the 3-methyl-4-nitrophenolate sodium obtained. Organic phosphorus, sulfur, and / or chlorine compounds remain virtually absorbent mineral acids. According to the invention, 3-methyl-4-nitrophenol from waste water is utilized to eliminate clogging, thereby improving the environment. Example 1

The flask was charged with 485 g of 60.1% by weight of H 2 SO 4 and 490 g of 99.1% by weight. The 3-methylphenol. The mixture was cooled to 0 ° C. Then, 102 g of 36.1 wt. the aqueous solution of sodium nitrite, while the temperature does not exceed 5 ° C. After half an hour, 325 g of 9.0% by weight was added to the reaction mixture. nitric acid and maintained at 35-45 ° C. The addition time was 105 µm. To the reaction mixture was added 20 ml of an aqueous solution of 3-methyl-4-nitrophenolate sodium, followed by a 37.2% by weight mass. Sodium 3-methyl-4-nitrophenolate, 0.03%. organic phosphorus, 0.02% organic sulfur, 0.02% organic chlorine, 3.5% K 2 CO 3, 4.1% NaCl. The temperature of the sodium 3-methyl-4-nitrophenolate solution was 98 ° C. The mixture was stirred for 1 hour while cooling to 17 ° C. 3-Methyl-4-nitrophenol was filtered off from unreacted acids. 126.4 g of 3-methyl-4-nitrosophenol were obtained at a concentration of 52.4% by weight. Example 2

The procedure of Example 1 was followed with the difference that 20 ml of an aqueous solution of 3-methyl-4-nitrophenoic acid was added to the reaction mixture.

Claims (4)

Sodium Compound 240380 5% by weight. Sodium 3-methyl-4-nitrophenolate, 0.03%. organic phosphorus and 0.01% organic sulfur and 5.1% K 2 CO 5. 127.1 g of 3-methyl-4-nitrophenolconcentration of 51.8% by weight were obtained. EXAMPLE 3 The procedure of Example 1 was followed by adding 50 ml of 0.8% by weight to the reaction mixture. an aqueous solution of 3-methyl-4-nitrophenol containing 0.06% by weight of organic phosphorus, 0.02% by weight; % organic sulfur, 0.03 wt. of organic sulfur, 9.2%. wt. K 2 CO 3, 4.2 wt. NaCl, 2.4 ° / wt. NasSO-i. During the addition of 550 ml 0.8%. wt. 0.1 g of polydimethylsiloxane (Lu-kosan S], which was added as defoamer) to the reaction mixture was added to the reaction mixture. 186 g of 51.9% by weight of 3-methyl-4-nitro-phenol were obtained. of Example 1, with the proviso that 3-methyl-4-nitrophenol was prepared by precipitating 600 ml of 7.2% by weight sodium 3-methyl-4-nitrophenolate with a content of 8.2% NaCl, 4.6% by weight. % K 2 CO 3, 0.05 for organic phosphorus, 0.03% for organic chlorine, 0.02% for organic sulfur, 400 mL of sulfuric acid, 40.3% by weight of H 2 SO 4 and no HNO 3 for precipitation. The resulting 3-methyl-4-nitrocresol was smelled of organophosphorus compounds EXAMPLE 5 Example 1 was followed with the difference that 450 ml of 24.2 wt% HCl was used in place of H2SO4. 128.4 g of 3-methyl-4-nitrophenol with a concentration of 52.7% by weight were obtained. 1. Process for the production of 3-methyl-4-nitrophenol by the destruction of 3-methylphenol by alkaline nitrite in an environment of excess mineral acid and subsequent oxidation of the resulting 3-methyl-4-nitrosophenol, dilute acid-free to 3-methyl-4- nitrophenol, characterized in that a portion of the excess mineral acids are reacted with an aqueous solution of 3-methyl-4-nitrophenolate sodium from the O, O-dimethyl-O- (3-methyl-4- nitrophenyl) thiophosphate concentrations of 0.2 to 40% by weight, containing as impurities organic compounds of phosphorus, sulfur and / or chlorine, residual aromatic solvent, mineral salts, in particular NaCl and alkali carbonates, in particular potassium carbonate, resulting in a concentration of mineral acids % is 0.1 to 40 wt. and 3-methyl-4-nitrophenol is separated from the mineral acids and impurities. THE INVENTION 2. A process according to claim 1, wherein the partial deodorization of the organic compounds of phosphorus, sulfur and / or chlorine is agitated with excess nitric acid after oxidation of 3-methyl-4-nitrosophenol. 3. The process of clauses 1 and 2, wherein the alkali carbonate is converted with a mineral acid having a pKa of the carbonic acid and pKa. Of 3-methyl-4-nitro-phenol to an alkali metal salt of a mineral acid which is separated from the 3-methyl-4-nitrophenol. 4. Process according to claim 1, characterized in that the precipitation of 3-methyl-4-nitrophenol is an aqueous salt and the reaction of inorganic salts with mineral acids is carried out in the presence of an antifoam.