Highly Selective Oxidative Monochlorination To Synthesize Organic Intermediates: 2-Chlorotoluene, 2-Chloroaniline, 2-Chlorophenol, and 2-Chloro-4-methylphenol

An alternative manufacturing process scheme was developed to synthesize monochloro-substituted aromatic compounds in high selectivity, involving oxidative chlorination by using HCl−H2O2. Thus, 2-chlorotoluene, 2-chloroaniline, and 2-chlorophenol were synthesized by oxidative chlorination followed by desulphonation or decarboxylation. Oxidative chlorination of 4-methylbenzenesulphonic acid, 4-methylbenzoic acid, 4-aminobenzoic acid, and 4-hydroxybenzoic acid by using a suitable ratio of reactant:HCl:H2O2, and their subsequent desulphonation or decarboxylation, gave 60−85% yield of the desired products. Oxidative chlorination of 4-methylphenol by using HCl−H2O2 gave as high as 98% selectivity to the desired 2-chloro-4-methylphenol.