γ-radiolysis of methane adsorbed on γ-alumina. Part 3.1, 2—Influence of additives on product desorption

Abstract

Previous studies showed that methane adsorbed on γ-alumina undergoes radiolysis to form chemisorbed precursor species. These decompose when heated to give C₁–C₃ alkane and alkene products together with hydrogen. The present study uses nitric oxide, nitrous oxide, sulphur hexafluoride, oxygen and carbon dioxide as additives to interfere with product formation, and so allows probable structures to be deduced for each precursor. Both alkane and alkene precursors involve alkylaluminium groups which decompose by homolytic fission of the Al—C bond. The alkane precursor has an accessible hydroxide ion from which a hydrogen atom can be extracted during desorption, whereas the alkene precursor does not.