Reactions of Hydrogen Atoms with Solid, Thin Films of Acetone and 2‐Propanol at 13 K

Open Access
Publisher Website
Google Scholar
Abstract
In the interstellar clouds, a number of oxygen-containing organic compounds such as alcohols and carbonium compounds have been observed. In order to investigate the role of grain processes for the formation and destruction of these compounds, thin films of acetone and 2-propanol deposited on the copper metal surface at 13 K were reacted with cold gas-phase H atoms (~27 K). The major products from acetone were found to be methane and alcohols (smaller than propanol). 2-propanol was not detected as a reaction product. This indicates that the disproportionation reaction is the major process, but that the recombination one is minor in the reaction of H with the intermediate (CH3)2COH radical. The reaction of H with 2-propanol led to the formation of methane, alcohols, and acetone as major products. The dependences of the film thickness, reaction time, and reaction temperature on the product yields were measured. It is suggested that the diffusion length of the H atoms in the 2-propanol film is longer than that in the acetone film, and consequently greater product yields were obtained for 2-propanol than for acetone with thicker sample films. The temperature-independent product yields in the range of 13-80 K invoke the tunneling processes in the reactions.