Methods for the synthesis of salicylic acid. A review

Abstract

The review considers and analyzes methods for the synthesis of salicylic acid based on phenol, ortho-cresol, and benzoic acid reported in scientific and technical literature. The current trends in the progress of the “Kolbe–Schmitt process”-oriented technology (obtaining aromatic and heteroaromatic hydroxy acids by the action of CO2 on alkali metal phenolates) are shown. Data are presented on the effect of catalytic system composition and conditions of benzoic acid hydroxylation on the achieved values of conversion, selectivity, and purity of the product. The review can be useful in choosing a suitable source of raw materials and a method of precursor transformation for creating domestic production of salicylic acid, an important compound used in various industries.