O - The Synthesis Of Methyl Salicylate

2,3-Cresotic acid is an important kind of dye and medical intermediate, which is mainly made from o-cresol by carboxylation. The phenol's carboxylation is a typical organic chemical reaction, which was discovered years ago. The equation is the reaction named Kolbe-Schmitt.This paper mainly aims to investigate the 2,3-cresotic acid's composion by carboxylation and its pilot-plant test.In early times, the method of direct carboxylation on solid phase was often adopted in the phenol's carboxylation. In 1970's, solvent suspensic carboxylation was used step by step overseas. The suspensic carboxylation in this paper was carried out to compose 2,3-cresotic acid with the additive, using o-cresol as feedstock and kerosene made at home as solvent.The investigation obtained good results. The investigation tried to find out the affective elements of Kolbe-Schmitt's carboxylation. Then the appropriate process conditions were acquired: the ratio of plenol and sodium in feedstock was 1.0-1.1:1, the stir speed > 400rpm, reaction temperature 140~220C, reaction pressure 4~8kg/cm2, reaction time 20~60mins. The reaction was carried out 2~3times. On the above process conditions, the single pass yield was >35% based on NaOH, the total yield >60% based on o-cresol.The pilot-plant test achieved good results based on the investigation above.