A new process for the direct chlorination of 3-methyl-pyridine with special catalyst to yield 2-chloro-5-methyl-pyridine in the airlift loop reactor has been considered. The effects of reaction temperature, the molar ratio of palladium chloride to 3-methyl-pyridine, concentration of 3-methyl-pyridine, chlorine gas flowrate and the ratio of the inside diameter of the draft tube to that of the reactor on the molar yield of 2-chloro-5-methyl-pyridine were investigated and discussed, and an optimum operation condition was found. The average molar yield of 2-chloro-5-methyl-pyridine comes up to 60% under the optimum operation condition. (C) 2003 Elsevier Science B.V. All rights reserved.