Production method for preparing sodium m-aminobenzene sulfonate by means of continuous hydrogenation reduction

Abstract

The invention belongs to the field of fine chemical engineering, and in particular relates to a production method for preparing sodium m-aminobenzene sulfonate by means of continuous hydrogenation reduction. The method is characterized in that a sodium m-nitrobenzene sulfonate solution is pumped into multiple stages of hydrogenation reaction kettles which are in series connection, and a multi-element catalyst is added into all the reaction kettles; overflow pipes used for conveying a reaction solution are arranged among all the hydrogenation reaction kettles, and a microporus filter used for filtering the catalyst is installed at the front end of each overflow pipe; the reaction solution enters the next kettle by means of liquid level difference after being filtered by the microporus filter; furthermore, balance pipes used for transmitting hydrogen are arranged among all the hydrogenation reaction kettles so as to maintain all the hydrogenation reaction kettles to be communicated with one another in a pressure balance way; therefore, the sodium m-aminobenzene sulfonate can be prepared by means of continuous hydrogenation reduction. After the catalyst provided by the invention is adopted, a condensation side reaction producing azo compounds and oxidized azo compounds is effectively avoided in a high concentration hydrogenation process, dimer and polymer side reactions caused by a deamination reaction can be avoided, and the problem that tarry matters, formed in the side reactions, cover the surface of the catalyst and become catalyst poisons can be solved.

Description

technical field [0001] The invention belongs to the field of fine chemical industry, and specifically relates to a production method for preparing sodium m-aminobenzenesulfonate through continuous hydrogenation reduction. Background technique [0002] Sodium m-aminobenzenesulfonate, English name: metanilic acid; is an important chemical intermediate, mainly used in the following aspects: 1) Preparation of azo, reactive, sulfur and vat dyes, etc.; 2) Preparation of m-hydroxy Benzenesulfonic acid, p-aminosalicylic acid, m-aminophenol, vanillin and sulfonamide agents, etc.; 3) Because it can increase the water solubility of other insoluble substances, it is widely used in detergents and oil additives to protect engines ; 4) Sulfonated polyaniline prepared by doping m-aminobenzenesulfonic acid and aniline compounds has great advantages in device manufacturing, such as chemical sensors, biosensors, light-emitting diodes, optical switches, optical resistors and molecular devices ...

AI Technical Summary

Problems solved by technology

The continuous hydrogenation production and preparation of sodium aminoaryl sulfonate must solve two scientific problems. The first is that the cost of the catalytic hydrogenation catalyst is too high due to the poisoning and loss of activity of the hydrogenation noble metal catalyst in the raw material, which makes the hydrogenation continuous Second, when the concentration is high in the hydrogenation reduction process, the condensation side reactions of azo compounds and azo oxide compounds are prone to occur, and the dimer and polymer side reactions caused by the deamination reaction are also prone to occur. Reaction, the formation of tar-like substances covering the surface of the catalyst becomes a catalyst poison, making the continuous hydrogenation process unstable, and the hydrogenation of low-concentration substrates tends to have low production efficiency and high energy consumption

[0004] German Bayer Company has improved its technology by adopting series reflux reactors (US5144056), studied a series of continuous hydrogenation processes of nitroarylsulfonic acid intermediates, and the production efficiency has been mentioned, but the reaction substrate concentration is very low, M-nitrobenzenesulfonic acid can only reach 9%, the efficiency is still not enough, and a large amount of waste water is produced

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