Kinetics of iodine poisoning of hydrophobic Pt/SDBC catalyst for hydrogen isotopic exchange reaction

Changes with time in the isotopic exchange reaction rate between H 2 and HDO ( v ) over a hydrophobic Pt/SDBC (styrene‐divinylbenzene copolymer) catalyst induced by iodine have been studied experimentally. The addition of a trace amount of I 2 to the reactor caused a remarkable decrease in the activity of the catalyst. The measurement results by means of the gas chromatographic pulse technique show that the H 2 adsorption onto the catalyst surface was strongly inhibited by iodine. A kinetic model for the poisoning was developed in terms of the competitive adsorption of I 2 with H 2 onto the catalytic active site. The experimental results were explained reasonably by the proposed kinetic model based on the site balance by assuming that I 2 adsorbs non‐dissociatively on the active site. The poisoning could be prevented by the conversion of I 2 to I − or IO 3 − through redox reactions.