Method for preparing p-hydroxyacetophenone by catalytically oxidizing paraethyl phenol with metalloporphyrin-metal salt composite catalyst

Abstract

The invention relates to a method for preparing p-hydroxyacetophenone by catalytically and selectively oxidizing paraethyl phenol with a metalloporphyrin-metal salt composite catalyst. The method is characterized in that paraethyl phenol is taken as a raw material, methanol is taken as a solvent, metalloporphyrin expressed by a formula (I) or a formula (II) and a metal salt is taken as a composite catalyst or metalloporphyrin expressed by a formula (I), a formula (II) or a formula (III) is taken as the catalyst, the concentration of metalloporphyrin is 5-100ppm, the concentration of the metal salt is 500-2000ppm, the molar ratio of sodiumhydroxide to ethyl phenol is (1-2.5): 1, the oxygen pressure is 0.2-0.5MPa, the reaction temperature ranges from 60 to 90 DEG C, the reaction time is 3-7h, and p-hydroxyacetophenone is obtained under all the conditions. According to the invention, the dosage of the catalyst is extremely low and the reaction time is short; after reaction, the catalyst does not need to be separated and recovered; the consumption of resources and the operating cost are reduced in the reaction process, and the purposes of saving energy and reducing emission are achieved while the environmental pollution is reduced.

Description

technical field [0001] The invention relates to a method for preparing aromatic ketones, in particular to a method for preparing p-hydroxyacetophenone by catalyzing and selectively oxidizing p-ethylphenol with a metalloporphyrin-metal salt composite catalyst. Background technique [0002] p-Hydroxyacetophenone (its structural formula is as follows) is an important fine organic chemical, which is widely used in various fields such as medicine, pesticides, dyes, liquid crystal materials, etc., and it is also a synthetic choleretic, antipyretic and analgesic, and anti-premature drug , raw materials and important intermediates of asthma inhibitors, with important application value. [0003] [0004] At present, the preparation methods of p-hydroxyacetophenone mainly include the Fries rearrangement method using phenol and acetic anhydride as raw materials, the Friedel-Crafts acylation method using anisole and acetyl chloride as raw materials, and the direct method using p-ethy...

AI Technical Summary

Problems solved by technology

[0007] (1) The amount of catalyst used is very large (up to 5000ppm), and it needs to be separated and recovered after the reaction, and the separation and recovery of the catalyst will cause high cost, high energy consumption, and a lot of three wastes, and serious environmental pollution;

[0008] (2) The reaction time is long (more than 10h), and the reaction efficiency is low, the energy consumption is large and the operating cost is high;

[0009] (3) the method must use N-hydroxyphthalimide as a free radical initiator, and the consumption is relatively large (consumption is 10000ppm), and the separation of catalyst and initiator after the reaction is difficult, which increases the product preparation cost, At the same time, there are still problems such as serious environmental pollution and high energy consumption.

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