The Efficiency of Argon as a Radiochemical Catalyst.

Abstract

When the catalytic or sensitizing effect of inert gases on gaseous reactions produced by alpha particles from radon was first disco,vered by Lind and Bardwe-11 (6), they pointed out certain puzzling facts. It appeared strange that a radiochemically inert gas such as carbon dioxide should apparently not catalyze reactions in which it is formed. Furthermore, a peculiar "depletion" effect was observed; quite generally, after the partial pressure of reactants decreased beyond the point at which half of the total ionization fell upon the catalyst, the accelerating influence of the latter diminished rapidly.It is now known that carbon dioxide actually does speed up the carbon monoxide oxidation (8), its effect being small compared to that of krypton, helium, and nitrogen. In the original study of radiochemical sensitiza-

Benzene Formation in the Radiochemical Polymerization of Acetylene

“…In view of the above considerations, it appears safe to assume that the benzene is formed simultaneously with the high-polymeric product and is not an intermediate product. that the benzene was missed by earlier workers (4,12) because of the fifty-to hundred-fold higher radiation intensity employed, which accelerated the secondary polymerization of benzene. A report (10) that the weight in air of the cuprene-like solid produced was equal to the weight of reacted acetylene is vitiated by the known capacity of the polymer to absorb large quantities of oxygen (6).…”

“…The velocity of this -eaction (13, 14) is insufficient in itself to account completely for the small benzene deficiency. It is necessary to assume a "'catalytic effect" of the large excess of acetylene similar to that of inert gases (5,12). In column 8 are listed the benzene pressures to be expected if the fraction of acetylene reacting to form benzene remains constant at 20 per cent and the secondary benzene reaction proceeds at an enhanced rate.…”