Formation of Nitrogen-Containing Compounds in the Photochemical Reaction of Methane—Ammonia—Water Mixture

Abstract

Methane is a major component of natural gas and obtainable all over the world. Methane is utilized as an energy source, but the chemical usefulness is not extensive due to its low reactivity. In the present study, the conversion of methane to a more valuable substance has been tried by the photochemical reaction. The photolysis of the gas mixture of CH4, NH3, and H2O.with a low-pressure mercury lamp (185nm light) gave methylamine, ethylenediamine, methanol, ethane, and hydrogen gas as the major products. In the first step of the reaction, methane is activated by hydrogen abstraction by the hydroxyl radicals which are formed by the photolysis of water vapor. Ammonia also splits into. NH2 and. H by the absorption of the light of 185 nm. The formation of CH3NH2, CH3OH, and C2H6 is ascribed to the mutual couplings of. CH3,. NH2, and. OH. The activation energy for the formation of methylamine was estimated to be 4. 4±0. 4 kcal.mol-1. The study by spin-trap-ESR method revealed that. CH2NH2 was formed as a reaction intermediate in the photolysis of CH4—NH3—H2O mixtures. It was therefore concluded that NH2C2H4NH2 is formed by the coupling reaction of. CH2NH2. © 1989, The Chemical Society of Japan. All rights reserved.