Macroscopic reaction kinetics of the chlorination reaction of isophthalonitrile(IPN) to produce tetrachloroisophthalonitrile(TPN) was studied and the optimal design and operating conditions of a fluidized bed reactor for the chlorination of IPN were investigated experimentally. Comparing the experimental data obtained from a fixed bed reactor with the theoretical ones, the IPN→X→TPN type consecutive reaction mechanisms and pseudo-first order reaction rate for each step were found satisfactory and the kinetic rate constants for each step at 300℃ were obtained. Experiments were conducted in a lab-scale fluidized bed column in order to obtain the information on the minimum fluidizing velocity of catalyst which in turn served as the basis for the design and operation of a bench-scale fluidized bed reactor. The chlorination reactions were undertaken in this reactor using the 30wt% FeCl₃/activated carbon particles of -70+100 mesh sizes as the catalyst to determine the optimal operating conditions for the production of TPN of purity greater than 95%, which include temperature, molar ratio of Cl₂/IPN in the feed and mean residence time. Optimal H/D ratio was proposed also for the design.