Chemiluminescent Glow Research Articles

Carbon monoxide oxidation: Chemiluminescence and ignition

The present work is a study in carbon monoxide oxidation of the instabilities ignition, glow, oscillation and of slow reaction. It pertains to the region of the upper limit in an acid-washed quartz vessel. The key range of conditions is that achieved by varying proportions of H 2 in CO+O 2 from 1% to 200 ppm, and isolated experiments have been performed in extremely “dry” compositions of CO+O 2 . Experimentally, stress is laid on quantitative measurements not only of pressure change but also of light intensities, extents of reaction and, in some experiments, temperature change. Ignition is identified by its intensity, completeness and brevity. Chemiluminescent glow is distinguished from ignition by its duration and its incompleteness of reaction: light intensity-time records show a peak (smaller than that of ignition) followed by a protracted tail. Oscillatory chemiluminescence can occur wherever glow is seen. It is dependent for its occurrence on the previous history of the vessel surface. The modes of behavior that can be detected and distinguished from one another depend crucially on the amount of hydrogenous material: when more than 0.2% H 2 is present, only slow reaction and ignition are observed. In mixtures containing between 0.2% (2000 ppm) and 0.02% (200 ppm), chemiluminescent glow and oscillations occur as well, and they are quite distinct from slow reaction and ignition. The boundary between slow reaction and chemiluminescence (glow and oscillation) is sharp. In very dry mixtures, which contain about 10 ppm of hydrogenous material, only chemiluminescence and dark, slow reaction can be observed. Previous locations of ignition limits in very “dry” CO+O 2 mixtures are those for chemiluminescent glow.