Method for recovering, treating and recycling quaternary ammonium base

Abstract

The invention discloses a method for recovering, treating and recycling quaternary ammonium base. According to the invention, the method overcomes disadvantages in conventional recovery and treatmentof quaternary ammonium base produced in preparation of p-aminodiphenylamine by using a nitrobenzene process; the method of the invention has an extra procedure of solvent extraction and recovery of p-aminodiphenylamine and macromolecular viscous organic substances in the quaternary ammonium base, thereby lowering the content of p-aminodiphenylamine and macromolecular viscous organic matters in theammonium base, reducing the viscosity of the recovered quaternary ammonium base, decreasing difficulties in desalting filtering of the recovered quaternary ammonium base, improving desalting effect on the recovered quaternary ammonium base and promoting normal implementation of subsequent condensation reactions and reduction reactions.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and more specifically relates to a method for reducing the content of organic substances and carbonates in quaternary ammonium bases and improving the quality of the quaternary ammonium bases. Background technique [0002] In the process of preparing p-aminodiphenylamine by nitrobenzene method, nitrobenzene and aniline undergo condensation reaction under the catalysis of quaternary ammonium base to generate p-(sub)nitrodiphenylamine, and the condensation liquid containing quaternary ammonium base is hydrogenated and reduced to generate p-aminodiphenylamine. Aminodiphenylamine, the reducing solution is filtered through the hydrogenation catalyst and extracted with water, the quaternary ammonium base is extracted into the water phase, the water phase is treated to recover the quaternary ammonium base, and the recovered quaternary ammonium base is used for condensation reaction, the quaternary...

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Problems solved by technology

[0003] At present, there is no information about the application of quaternary ammonium alkali treatment in the process of preparing p-aminodiphenylamine by nitrobenzene method. Related data CN101531600A mentions quaternary ammonium alkali and its preparation method and application. CN102372640A mentions that the condensation catalyst used is a phase transfer catalyst and an inorganic The alkali is added in the reaction system in the form of solid to catalyze the condensation of nitrobenzene and aniline. CN101735074A is a method for preparing 4-nitrodiphenylamine and 4-nitrosodiphenylamine from carboxanilide. The condensation catalyst is potassium hydroxide and four Butyl ammonium bromide is difficult to recover, Zhou Zhiguo et al. have carried out the research on the synthesis of 4-aminodiphenylamine with quaternary ammonium salt composite catalyst

[0004] In the existing nitrobenzene method for preparing p-aminodiphenylamine, the treatment method for recovering quaternary ammonium base is to add the carbonate radical in the recovery quaternary ammonium base to the corresponding inorganic base to form carbonate, filter and discharge the carbonate salt slag, and reduce the recovery rate. Carbonate content in the quaternary ammonium base, however, the existence of organic impurities in the recovery of the quaternary ammonium base, especially the existence of p-aminodiphenylamine and macromolecular viscous organic substances, makes the recovery of the quaternary ammonium base thicker, and the recovery of the quaternary ammonium base cannot Normal dehydration and desalination lead to the quality of the recovered quaternary ammonium base not meeting the requirements of production and operation, thus affecting the normal progress of the subsequent condensation reaction and reduction reaction