SU1081161A1 - Process for recovering sodium salt of m-nitrobenzosulfonic acid - Google Patents

Abstract

METHOD FOR THE INTRODUCTION OF SODIUM SALT M-NITROBENZEN SULPHATE FROM THE REACTION BACKGROUND During its preparation by sulfonation of nitrobeisol and neutralization of the sulfo mass using separation of byproducts, which are characterized by the fact that, in order to simplify the process, the latter is carried out when the content of the desired product in the reaction mixture is 56% and a temperature of 80-105 C.

Description

X

Mia

C: The invention relates to methods for isolating the sodium salt of m-nitro-benzenesulfonic acid (a ludigala which finds use as an intermediate in the synthesis of dyes. A method is known for producing and isolating ludigol, which nitrobenzene sulfates 20-65% oleum G at 110- 115 p. After that, the sulfomass is treated with a portion of the filtrate with industrial waters from the previous operation of obtaining a ludigol is kept at 50 ° C, cooled to 18 ° C, filtered and washed with the rest of the filtrate with direct water, then the filter The acid from Ludigol is neutralized to neutral with caustic soda or soda ash, stirred at 60 ° C, cooled until the precipitated sodium sulfate is filtered off and rinsed with water. The resulting filtrate and the washing water are returned to the extraction and washing stages of the ludigol. 98% 1. The disadvantage of this method is the low quality of the target product, since the content of the target product is 87%, mineral salts 13%, sulfons 1.5%, sulfuric acid 0.5%. The closest to the present invention is a method of obtaining and isolating ludigol, the conclusion being that nitrobenzene is subjected to sequential sulfonation in the usual way — by treating with 20-651-oleum wise at 60-110 ° C, neutralizing sulfomass with a solution of soda ash B of the filtrate with wash water production and an oxidizing agent at 70-100 ° C, the excess sodium sulfate precipitated in the precipitate is separated from the sulfone with a subsequent precipitate from the filter of the target product by cooling to 30-50 ° C, while the ludigol precipitates washed, filtered and dried, and sodium sulfate remains in solution. The content of the target product is 95-96%. The duration of the process without taking into account the drying stage is 118 h 23. The disadvantage of the known method is the COMPLEXITY of isolating the target product, since the method involves filtering sodium sulfate with sulfons, isolating and filtering the suspension of the target product and drying the resulting paste, which takes a very long time. The aim of the invention is to simplify the process of isolation of the target product. This goal is achieved by the method of separating ludigol from the reaction mixture by sulphurization with oleum and neutralizing the sulphmass, treating the reaction mass with production wash waters and an oxidizing agent so as to contain 35-56%. ludigola and kept at 80-105 ° C. At the same time, the target product goes completely into the solution, which can be immediately applied for drying or without drying and used in the synthesis of 1-aminoanthraquinone, and sodium sulfate, sulfones or gypsum are precipitated as crystals, which are washed and the washings are returned to the neutralization stage. The processing time (without taking into account the drying stage) is 15 hours. The yield of the target product is 98%, the product is white in color, with a ludigol content of at least 95%. Carrying out the process by the proposed method allows it to be mined to the stage of isolation and filtration of the target product, since the desired product obtained by this method is already a marketable product. A decrease in temperature at the stages of neutralization and separation of a precipitate of 80 ° C and a ludigol content in the solution of 35% leads to a deterioration in the quality of the ludigol, at a temperature of: 105 ° C the solution boils and does not dissolve in water at a concentration of 56%. The process technology is as follows. Nitrobenzene sulphate oleukumy sequentially at 60 and, in an aqueous solution of the calcined salt is poured sulfomass or sulfomassu and suspension of chalk. The total amount of water (taking into account the reaction water and the wash water from the precipitate from the previous operation of producing ludigol) is taken or left after evaporation in accordance with the calculation to obtain a 35-56% solution of ludigol. The neutralization temperature support 80-105 ° C. The resulting neutral solution is treated with an oxidizing agent (for example, perhydrol, hypochlorite) and maintained at 80-105 s. The ludigol then completely goes into solution, and the sodium sulfate or gypsum is released in the form of crystals. Next, the ludigol solution is separated from the precipitate (sodium sulfate or gypsum) and sent for drying or used as a marketable product immediately, and the water lines from sodium sulfate or gypsum are returned to the neutralization step. Ludigol obtained by the proposed method, the quality is not inferior to the product obtained by a known method. Example 1. A four-necked flask with a capacity of 150 ml under reflux was charged with 60 g of nitrobenzene and 71.47 g was charged with a stirrer running for 30 min.

b5% oleum. Mass temperature When entering oleum support no more. Next, the sulpholumbus is kept for one hour successively at 60 and fed to the flask (neutralizer) with a pre-heated slurry for 2 hours. To prepare the sodine suspension, 62.3 g of soda ash, 40 ml of sodium sulfate wash water from the previous operation for obtaining ludigol and 150 ml of aqueous solution are charged into the neutralizer. Next, neutralized mass at the same temperature is treated with 5.29 g of perhydrol. By distilling off the water from the reaction mass, the content of ludigol in the solution was adjusted to 56% and at 105 ° C the solution of the ludigol was separated from sodium sulfate and sulfone. The precipitate is washed with 40 ml of 9598 ° C water. The washings are returned to the neutralizer for the next step of producing ludigol. The ludigol solution is fed for drying. The content of the target product in dry ludigol is 97%. The product yield is 98%.

Example 2. The experiment was carried out similarly to Example 1, with the difference that sodium hypochlorite and mass exposure and sodium sulfate separation were used for oxidation with a ludigol content of 48% and a temperature of 93 ° C. The content of the target product in dry ludigol is 95%. The product yield is 98.2%.

Example 3. Nitrobenzene is sulfonated in the same manner as in Example 1. The neutralizer is loaded with sediment wash waters from the previous operation for producing ludigol and 25.5 g of soda ash. The pH of the neutralizer is adjusted to a weakly acidic reaction by supplying sulfomass. Then in the neutralizer simultaneously load the sulphmass and chalk suspension in such a way. zom to r reaction mass. & weakly acid reaction (according to Congo /. Neutralization is carried out at 80 ° C and at the same temperature, the reaction mass is treated with 3 g of perhydrol. The content of ludigol in solution is 40%. Ludigsl solution

5 is separated from gypsum and sulfone at 80 ° C. The precipitate is washed (200 ml, with water. The washings are returned to the neutralizer for the next step of preparing the ludigol. The udigol solution is fed for drying. The content of the desired product in the dry ludigol is 98.5%. The yield is 98, one%.

Example 4. The experiment was carried out analogously to example 3 with the difference

5 that the release of luligol from the reaction mass is carried out with a ludigol content of 35% and a ludigol solution obtained after bluntlining from gypsum is used to synthesize 1-amino antraquinone. Content target

0 product in dry ludigol 98.3%, in a solution of 40%, product yield 98.1%,

The proposed method in comparison with the known technology simplifies, reduces the duration of the process of obtaining

5 ludigol from 118 to 15 h (without taking into account the stage of the substance and increases the capacity of the plant by 4 times.

Claims (1)

METHOD FOR ISOLATING SODIUM SALT OF M-NITROBENZENESULPHANIC ACID from the reaction mixture during its preparation by sulfonation of nitrobenzene and neutralization of sulfomass using separation of precipitate by-products, characterized in that, in order to simplify the process, the latter is carried out when the target product is contained in the reaction mixture 35-56 % and a temperature of 80-105 ° C.