The slow oxidation of methane

Abstract

Mixtures of methane and oxygen behave in a reproducible manner at temperatures of 440 to 520°C and initial pressures of 100 to 350 mm when reacting in Pyrex vessels freshly cleaned with hydrofluoric acid. The apparent order of the reaction ranged from 2∙3 to 2∙6 and the overall activation energy from 29 to 41 kcal/mole. Analyses of the products formed have been made, together with measurements of pressure change. Formaldehyde is formed from the commencement of the reaction including the induction period, but its concentra­tion reaches a maximum near the stage where the pressure rise is a maximum, and then falls off. Hydrogen peroxide is also formed, less rapidly in the earliest stage, but its rate of formation overtakes that of formaldehyde and it reaches an even higher concentration. No other peroxides were detected, nor was methanol found. Hydrogen was present in the gaseous products. These observations are not in full accord with some of the conclusions derived from earlier investigations.