Experiments were carried out in a vibrated fluidized bed to investigate the dynamic process of UV-enhanced synthesis of chlorinated polyvinyl chloride (PVC) using a gas-solid method, where a UV-Vis online analysis system was used to record the kinetics of chlorination. Meanwhile, a comprehensive mathematical model incorporating the distributed activation energy model was established to describe the hindrance effect of Cl atoms already inserted on the PVC polymer chain on the later insertion during the chlorination process. Each of the hypotheses in the model was validated by the well-designed experiments, and the model predictions matched well with the experimental data under various operating conditions. Sensitivity analyses of three primary operating parameters, that is, temperature, chlorine concentration, and UV intensity, were made for better understanding of the mechanism of PVC chlorination. It is anticipated that the modeling methodology in this work would be also suitable for similar gas-solid reaction systems. (c) 2014 American Institute of Chemical Engineers AIChE J, 60: 2235-2243, 2014