Kinetics of ice particle conversion to the hydrates of HCl

Reaction rates for the conversion of ice nanocrystals within 3-D arrays to mono-, tetra- and hexahydrates of HCl have been determined for different HC l(g) exposure levels and reaction temperatures. The extent of reaction was monitored and the hydrate product identified, using transmission FT-IR spec troscopy. The direct method of observation provides evidence that HCl diffu sion through the hydrate encrusting the ice particles is often the rate-lim iting factor in the conversion of ice to a hydrate phase. Values for the HC l diffusion coefficient for the mono- and tetrahydrate are reported. By com parison, diffusion of HCl in ice is considered to be a nonfactor in most ic e-HCl interactions.