General procedure for the synthesis of 2-chloroisophthalic acid and 2-chloro-3-methylbenzoic acid from 2,6-dimethylchlorobenzene: In a reaction system, 140 g of 2,6-dimethylchlorobenzene, 0.14 g of Co(OAc)2, 0.14 g of NaBr, and 14 g of acetic acid were added, and the system was heated to 95 °C with stirring until the catalyst was completely dissolved. 64 g of atmospheric pressure was introduced into the system and maintained for 6.7 hours. Sample tests were performed during the reaction and showed that 20% of the feedstock 2,6-dimethylchlorobenzene remained, 40% of the product 2-chloro-3-methylbenzoic acid, 30% of 2,6-dicarboxychloride, 5% of 2-chloro-3-carboxybenzaldehyde, and 5% of 2-chloro-3-methylbenzaldehyde. After completion of the reaction, the reaction solution was cooled to room temperature. After post-treatment, the solid product 2-chloro-3-methylbenzoic acid was obtained in 30% yield.
