Preparation method of tetraacetylethylenediamine

Abstract

A preparation method of tetraacetylethylenediamine is provided. The method includes (1) adding ethylenediamine and a catalyst into a kettle, raising the temperature in a gradient manner, adding aceticacid dropwise into the kettle, and performing staged temperature maintaining and synthesis of N,N'-diacetylethylenediamine; (2) subjecting the reaction product of the step (1) to gradient temperatureraising, adding acetic anhydride in batches into the kettle, performing reaction at maintained temperature in different temperature gradients, subjecting the filtrate to vacuum external evaporation,and then performing cooling and crystallization, filtration, washing and drying to obtain tetraacetylethylenediamine crystals. According to the method, under a constant pressure, acylation reagents are added in batches at different reaction temperatures and staged temperature maintaining is performed, and vacuum external evaporation is performed after the reaction is finished to remove byproduct water and acetic acid. The method avoids a high amount of solvent and energy consumption for external evaporation at the same time of reaction in traditional methods, ensures concentrations of materials before a system reaches an equilibrium state, effectively increases the reaction yield, shortens the reaction times, reduces energy consumption and reduces the product production cost.

Description

technical field [0001] The invention belongs to the technical field of organic compound synthesis, and in particular relates to a preparation method of tetraacetylethylenediamine. Background technique [0002] Bleaching agent is an important auxiliary agent in detergent and papermaking industry. At present, there are mainly two categories of chlorine-containing and oxygen-containing bleaching agents. Oxygen-containing bleaches have the advantage of not damaging fibers, so they have better development prospects than chlorine-containing bleaches. However, due to the high oxygen release temperature of oxygen-containing bleaching agents, in order to reduce energy consumption and meet the requirements of chemical fiber fabrics that are not easy to be washed at high temperatures, adding bleach activators can reduce the washing temperature by 20~40°C, thus providing a wide range of applications for the development of bleach activators market. [0003] Tetraacetylethylenediamine (...

AI Technical Summary

Problems solved by technology

However, increasing the reaction temperature will increase the side reactions, and the color of the obtained product will deepen, which will affect the appearance quality of TAED products.

Chinese patent CN1332153A discloses a catalyst using concentrated sulfuric acid, concentrated phosphoric acid or concentrated hydrochloric acid as a catalyst, under the action of a dehydrating agent such as butyl acetate, and synthesizes tetraacetylethylenediamine in the same kettle in two steps; patent CN1255376C introduces a During the synthesis process, add diisobutyl ether, toluene, ethylbenzene, xylene, chlorobenzene, 1,3-dimethylcycloethane or octane which azeotropes with acetic acid and does not react with acetic acid and acetic anhydride. Any one or their mixed system is used as water-carrying agent to catalyze the synthesis of diacetylethylenediamine and tetraacetylethylenediamine. This method adopts water-carrying agent or reacts while reducing pressure distillation method in the whole reaction backflow state The reaction mode that produces by-product water or HAc moves out of the system, while transferring by-products, causes the concentration of reactants and products in the system to change at the same time, thereby reducing product yield, increasing production energy consumption and product cost, and high production cost is also an influence The main factor that the product market price has been high

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