Preparation method of p-hydroxyanisole

Abstract

The invention discloses a preparation method of p-hydroxyanisole. The preparation method includes: mixing and stirring benzenediol, methanol, solid catalysts and benzoquinone, increasing the temperature, performing constant-temperature backflow reaction for 8 hours, performing midpoint control reaction by the aid of GC (gas chromatography), filtering the catalysts (indiscriminately used for methanol washing) after reaction, recovering the methanol and performing reduced pressure distillation so that the p-hydroxyanisole is obtained. The mass ratio of the benzenediol to the methanol is 1:5, the mass ratio of the benzenediol to the solid catalysts is 2:1, the mass ratio of the benzenediol to the benzoquinone is 2.5:1, and the solid catalysts can be indiscriminately used for methanol washing. The preparation method of the p-hydroxyanisole has the advantages that in the whole process, no wastewater but only a small quantity of distillation residues are produced, environmental damage is avoided, and the catalysts can be indiscriminately reused. Besides, the p-hydroxyanisole is high in quality and yield, the content and the yield of the p-hydroxyanisole are higher than 99.7% and 95% respectively, and the p-hydroxyanisole is extremely high in market competitiveness.

Description

technical field [0001] The invention relates to a preparation method of p-hydroxyanisole. Background technique [0002] As a fine chemical intermediate, p-hydroxyanisole has many domestic and foreign reports on its synthetic route, from p-methoxybenzaldehyde to hydrogen peroxidation acid catalytic oxidation method, anisole hydroxylation method, hydroquinone and dimethyl sulfate Esters, hydroquinone and dimethyl carbonate, hydroquinone and methyl chloride, hydroquinone and methanol to diazotization hydrolysis of p-aminoanisole, etc., and are in the process of continuous optimization. At present, p-hydroxyanisole is mainly synthesized from quinone as raw material at home and abroad by dimethyl sulfate method or methanol catalytic method. The shortcoming of dimethyl sulfate method is that dimethyl sulfate is highly poisonous, stench, and the easily polluting environment product yield is low, only has 47.18%. And methanol catalytic method such as Huang Kuisheng etc. report ad...

AI Technical Summary

Problems solved by technology

The shortcoming of dimethyl sulfate method is that dimethyl sulfate is highly toxic, stench, and the product yield that easily pollutes environment is low, only has 47.18%

And methanol catalytic method such as Huang Kuisheng etc. report in patent CN201010287410.0 adopts sulfuric acid to produce p-hydroxyanisole as catalyst, and the total yield reaches about 93%, although yield improves greatly, three wastes pollution and equipment corrosion are serious in the production process