Preparation method of N-alkyl m-aminophenol

Abstract

The invention relates to a preparation method of N-alkyl m-aminophenol, which comprises the following steps: placing m-aminophenol and halogenated hydrocarbon in a reaction vessel containing a solvent, adding stannic chloride as a selective catalyst, then stirring while heating, starting reflux when the temperature reaches 30-90 DEG C, then adding an alkaliferous aqueous solution step by step, continuing to react for 1-10 hours to obtain a reaction liquid after the alkaliferous aqueous solution is added, then adding toluene into the reaction liquid, carrying out still standing, sedimentation and then extraction delamination to separate out an upper organic substance and a lower organic substance, filtering or rectifying the upper organic substance separated out through extraction delamination to obtain the high purity N-alkyl m-aminophenol. The reaction using water or corresponding alcohol as the solvent and stannic chloride as the catalyst has high selectivity, the product purity canreach more than 98 percent without refined purification, and the yield is high, the purification process in a traditional production method is saved, and the production cost is lowered.

Description

technical field [0001] The invention relates to a preparation method of materials used for producing heat-sensitive dyes and heat-sensitive paper additives, in particular to a preparation method of N-alkyl m-aminophenol, which belongs to the technical field of fine chemicals. Background technique [0002] N-Alkyl m-aminophenol is an important intermediate for the manufacture of fluoran dyes and heat-sensitive paper additives, and is widely used in chemical production, especially in the production of asymmetric fluoran series heat-sensitive dyes. Thermal recording paper is currently being used more and more widely, such as invoices, schedules, recording materials for ticket roll machines used in banks, taxation, post and telecommunications, hotels, etc., and recording paper for fax machines, computers, and instruments. [0003] Introducing different substituents into the structure of fluoran dyes and heat-sensitive paper additives can not only obtain monochromatic blacks of v...

AI Technical Summary

Problems solved by technology

The process route of this method is long, and it must go through the steps of reduction, alkylation, alkali fusion, acidification, etc., and the process is complex; and the reduction with iron powder will produce a large amount of waste residue, and the steps of alkali fusion and acidification will produce a large amount of waste water, causing environmental pollution. The cost is also high, not suitable for mass production

[0005] Japanese Patent JP55-105648 and U.S. Patent US5113018 disclose a method of N-alkyl m-aminophenol, firstly use resorcinol to react with organic amine under the action of catalyst and solvent at 120-210°C, and then undergo rectification , solvent recrystallization or extraction to obtain N-alkyl m-aminophenol, but using this method to produce N-alkyl m-aminophenol, the primary conversion rate of the raw material resorcinol is not high, usually 50.4% to 56.5%, The product contains about 40% unreacted resorcinol and 1-5% N, N-disubstituted alkyl meta-aminophenol impurities. The process of purifying N-alkyl meta-aminophenol from the product is very complicated. As a result, the yield of N-alkyl m-aminophenol is very low, and the purity is only about 90%, and the production cost is relatively high

Images