Method for preparing 1,4-dihydroxy anthraquinone

Abstract

The invention discloses a method for preparing 1,4-dihydroxy anthraquinone by taking a boric acid dehydration compound as a catalyst. The method comprises the following steps: (1) heating boric acid at 100-250 DEG C to prepare the boric acid dehydration compound; (2) adding fuming sulphuric acid, phthalic anhydride, the boric acid dehydration compound and parachlorophenol into a condensation kettle in sequence, and carrying out condensation reaction at 100-250 DEG C; (3) adding a proper amount of water and the materials in the condensation kettle into a hydrolysis kettle, carrying out hydrolysis reaction at 50-115 DEG C, discharging a reactant, filtering the reactant by pressing, washing and drying the reactant to prepare 1,4-dihydroxy anthraquinone. According to the method, the boric acid dehydration compound is used as the catalyst, so that the addition amount of the raw materials including fuming sulphuric acid and phthalic anhydride is reduced; the resource consumption can be reduced; the cost is reduced; the waste emission is reduced; the method is relatively environmentally-friendly and economical.

Description

technical field [0001] The invention relates to the technical field of 1,4-dihydroxyanthraquinone synthesis, in particular to a method for preparing 1,4-dihydroxyanthraquinone by using a boric acid dehydration compound as a catalyst. Background technique [0002] 1,4-Dihydroxyanthraquinone, commonly known as quinazine, is an important dye intermediate, which can be used in the production of disperse dyes, solvent dyes, acid dyes and vat dyes, etc. important raw material. [0003] The traditional production process of 1,4-dihydroxyanthraquinone mainly includes hydroquinone method and p-chlorophenol method: the hydroquinone method uses boric acid as a catalyst, and uses hydroquinone and phthalic anhydride to carry out ring closure reaction in sulfuric acid Generate 1,4-dihydroxyanthraquinone. The disadvantages of this process are the shortage of domestic hydroquinone, high price, severe carbonization of hydroquinone in the reaction process, low yield, high production cost, et...

AI Technical Summary

Problems solved by technology

[0006] The traditional process uses boric acid as a catalyst. When the concentration of oleum is lower than a certain value, the reaction will be affected. In order to ensure the effective progress of the reaction, more sulfuric acid or oleum is often added, which not only increases the production cost, but also Excess raw materials are often discharged in the form of wastewater, which not only wastes resources, but also seriously pollutes the environment

[0007] The Chinese patent with publication number CN103664567A discloses a 1,4-dihydroxyanthraquinone production process using oleum as a solvent and a dehydrating agent and boric acid as a catalyst, which achieves a good yield, but the hair The mass ratio of nicotinic acid to p-chlorophenol is as high as 5.28, a large amount of raw materials are wasted, and the cost of post-treatment is also too high

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