Free-radical reactions involved in C1-C3 hydrocarbons interaction with oxide catalysts

Experimental proofs of a free radical mechanism in methane oxidative coupling, with homolytic rupture of the C---H bond are given. High concentrations of free radical sites are produced by mechanical milling of SiO₂. A study of C₁---C₃alkanes interaction with these sites allows to simulate the, processes of alkanes oxidation and oxidative dehydrogenation. The reactivity of ethane and propane is higher than that of methane in accordance with the Polanyi-Semenov rule. Oxidative dehydrogenation of ethane is studied on Cd-containing zeolites. CH₄, C₂H₆ and C₃H₈ oxidative dehydrogenation by O₂ or CO₂ is studied on a MNO/SiO₂ catalyst. The initiation of radical reactions of hydrocarbons on Cl-containing catalysts proceeds via chlorine atoms generation.