Evidence for production of the hydroxycarbonyl radical in the decomposition of formic acid on platinum

Abstract

Formic acid molecules highly diluted in argon were passed through a clean platinum screen at 420–730 K and condensed onto an 8‐K CsI window. The well‐known decomposition products, CO₂, CO, and H₂O, were observed in the infrared spectra of the resulting matrices. In addition, new absorptions which are attributed to the OCOH free radical were also observed. Experiments with partially deuterated formic acids confirmed that the carbon‐hydrogen bond of the formic acid was lost in the formation of the new intermediate species. The activation energy for CO₂ production, E_a = 3.5 ± 0.2 kcal/mol, was determined by monitoring its appearance rate at several different catalyst temperatures.