SU857121A1 - Method of preparing sodium salt of m-nitrobenzensulfoacid - Google Patents

Description

(54) METHOD FOR GETTING SODIUM SALT OF M-NITROBENEULSULFHOKIS LOT S

one

This invention relates to an improved process for the preparation of the sodium salt of m-nitrobenzo-sulphonic acid (ludigol), which finds use as an intermediate in the synthesis of dyes.

Known methods for producing sodium salt of m-nitrobenzenesulfonic acid by oxidizing aminobenzenesulfonic acid with hydrogen peroxide in acetic acid followed by treatment with sodium bicarbonate with a yield of 42% or sulfonating nitrobenzene with sulfur trioxide in two stages with separation of the desired product by treating sodium sulfate with mate.

The disadvantages of these methods are low output of the target and the use of sulfuric anhydride as a sulphating agent, the work with which encounters certain difficulties.

The closest to the proposed route | g 4 is the method of assaying

that is, nitrobenzene is subjected to sulfonation with 2O-65% oleum at a temperature of 10 ° -115 ° C, followed by separation of the desired product from the sulphmass and washing with sodium chloride. The filtrate and washings are directed to the treatment plant. The yield of the target product 7O% 13.

The disadvantages of this method include the relatively low yield of the target product, as well as the formation of a large amount (14.5 m per ton of finished product) polluted with sulfuric acid (15.5%), sodium chloride (14%) and ludigol (2-6 %) Wastewater.

The purpose of the invention is to increase the yield of the target product and utilize the wastewater.

Claims (3)

This goal is achieved by combining the process of producing ludigop, which implies that nitrobenzene is subjected to sulfonation by 2O-H-oleum at a temperature of 110-115 ° C, followed by separation of the target product from the sulfomass and washing it with a solution of sodium mineralic acid, separation. and washing the target product is carried out with a filtrate and washing waters after they are neutralized with caustic soda or soda ash and the excess sodium sulfate is formed. Example 1, 13.95 g are sequentially charged to the 4OO ml flask under reflux while the mixer is running. 2O% and 13.95 g of 65% oleum. The contents of the flask are heated to 4 ° C. While stirring, 15 g of nitrobenzene are evenly introduced into the flask for 15 minutes. At the end of the nitrobot loading, the ash is heated to a temperature of 110-115 ° C and Sch) H is heated to this temperature for 1 hour. The resulting sulfonase is cooled to 4 ° C and fed to the distribution of ludigol. To do this, 348 g of filtrate with wash water is loaded into a 0.5 liter glass before performing the operation obtained in the amount of 42 O g at the stage of separating and washing the excess sodium sulfate and 2% of sulphate and sodium chloride and dissolved in sulphate and 4% Ludigo. Then sulfomass is introduced into the beaker, during its reception the temperature rises from to and the mass at this temperature is charged for 30 min. After this, the contents of the glass are cooled slowly with vigorous stirring until the resulting ludigol suspension is transferred from the glass to a vacuum powder and filtered. Paste Ludi Goia is washed with the remaining 72 g of filtrate with wash water remaining after separation. 49.5 g of paste are obtained. The composition is ludigol 55.4, sulphate and chloride of early 7.4, sulfuric acid 0, 2 and water 3 Dry at 90 ° C to constant weight. In a tank with a filter and wash water in the amount of 293.6 g (39.2 g of sulfate and sodium chloride, 14.6 g of sodium bisulfate, 18.5 g of sulfuric acid and 12 g of ludigol), 47.5 g of 42% are added with stirring 8th caustic soda. Neutralization of hydrophobic acid to pH 7fr8, followed by a temperature which should not exceed 6 ° C. The reaction mass, having 12 g of ludigol, 83.2 g of sulfate and sodium chloride and 4. 4 45.9 g of water, is cooled to 18C and transfer to a vacuum funnel to expel excess sodium sulfate into crystalline hydrate. Filtration is carried out at a temperature of 2 ° C, crystalline powder from a vacuum funnel is transferred to a glass with 23.6 g of water for washing from impurities of ludngol and partial dissolution for a subsequent operation, for which the mixture in the glass is stirred for 1 O-15 missions. The contents of the glass are again transferred to a vacuum funnel and filtered, taking the WATER washes with dissolved sodium sulfate in the same container as the filtrate of the filtration stage of the unwashed crystalline hydrate. After dissolution and 1FOMY with fresh water, sodium sulfate crystalline hydrate in the amount of 52.6 g remains. The filtrate and wash water in the amount of 42Og, containing in dissolved form 2O% sulfate and sodium chloride and 4% ludigol, is returned to the staging and washing steps of the next operation to obtain ludigol. Ludigol paste is dried at a temperature of 9 ° C to a constant weight. A dry product is obtained in an amount of 30.6 g of a ludigol content of 87%. The yield of the target product is 98%. Example 2. 26.3 g of ZO% oleum are loaded into the reactor. Next, the experiment was carried out analogously to example 1. A product was obtained in the amount of an RO, 9 g with a ludigol content of 86%. The yield of the desired product is 98%. Example 3. In a four-ml flask with a capacity of 2OO ml, equipped with a blender, reflux condenser and oil bath, technical nitrobenzene and 65% oleum are continuously fed at rates of 1OO, 6 and 12O g / h. Sulfonation lead gfy temperature 115 C for 1 h. The sulfomass from the sulfoator enters the reaction flask with a capacity of 1OO ml, equipped with a blender and water bath, where it is mixed with the filter in the washwater waters of the sodium sulfate recovery stage of the given production, PS at a rate of 10OO g / h at a temperature of 30 min. The ludigol precipitates were filtered off and washed from sulfuric acid at a temperature of 1820 ° C with the same filtrate and wash water that was applied to the precipitate at a rate of 10Og / h. Get ludigol paste containing O; 5O% target 5. shchzpuktu-, 4O, 6% water, 9% sulfate and sodium,. O, 3% sulfuric acid in O, T% u ymesei | in the amount of 365, Зг / Фщпьрар and washings from the stage of excretion and strikes of the target solvent are neutralized with 42% caustic soda supplied to a neutralizer with a capacity of 1OO ml with a pH meter electrodes with a stirrer R with a density of 197.8 g / h at a temperature. The precipitate of sodium sulfate crystalline hydrate is filtered off and washed with water at a rate of 69.9 g / h. Get I2g / h of sodium sulfate ;; The filtrate and Sch) omnye water containing 2O% sulfate and sodium chloride and 4% ludigol are returned to the stages of isolation and washing of the ludigol at rates of 1OO and 200 g / h. The ludigol paste is dried and analyzed: The yield of ludigol was in-98%. The invention of the method of obtaining the sodium salt of m-nitrobenzenesulfonic acid sulfonium21 "by nitrobenzene 2O-5% oleum at a temperature of IIO-IIS C followed by isolating the desired product with a sulfo-mass. Washing it with a solution of a sodium salt of mineral acid, in order to increase the yield of the target arducts in wastewater disposal, the isolation and {washing of the target product s | x water with filtrate and washing water production after their neutralization with caustic soda or calcined and separating state with excess of sodium sulfate. Information sources, . arch examinations taken into account. 1.RJHim, 24F 181, 1977. 2.US Patent NJ 3.492.342 Cl. 26O-5O5, published. 197О 3. Technological regulations for the production of sodium salt of m.trobenzene sulfonic acid (ludkgola), Kemerovo, 1977, No. 16-3 (prototype).