Catalytic activity of organic semiconductors. Hydrogen conversion on triphenylene-alkali metal ion radical salts

Abstract

An extensive study was made of the kinetics and the mechanism of the orthoparahydrogen conversion, the deuterium exchange reaction, and the hydrogen-deuterium equilibration over solid triphenylene-alkali metal ion radical salts (K-, Rb-, and Cs- salts). Two species, mono- and dinegative anion salts, were stoichiometrically prepared. Two different reaction paths, one through the chemisorption process and the other via the exchange process, were observed. With simultaneous measurements of the rate of hydrogen adsorption and also of the time course of ortho-parahydrogen conversion on the salt catalysts, a novel kinetic analysis, based on the two processes, was presented. In comparing these processes, the chemisorption process was found to be predominant in every reaction over the complexes in question. Further, it was observed that the catalytic activity depends strongly on the valency of anions and on the sort of alkali metal; the rate constant of the dianion salt was much larger than that of the monoanion salt, and the activity increased in the order of K, Rb, and Cs.