PRODUCTION OF LARGE O-CONTAINING NEUTRAL HYDROCARBON SPECIES BY A CH4-O-2 MICROWAVE-DISCHARGE

The product of O-containing species in CH4-O-2, plasmas has been studied as a function of the oxygen partial pressure in a microwave flow tube with 2.465 GHz, 6 W, and 2.2 torr total pressure. Mass spectrometry, coupled with Li+-ion attachment techniques, was used for the identification of the products. Studies have clearly shown the presence of various O-containing stable polymer molecules, CnH2n+2O, C-n H2nO, and C-n H-2n O-2 (n goes up to 9). The relative concentration profiles of these products have been determined as a function of O-2 composition in the feed gas. An assumption was presented that alcohols, aldehydes, and possibly O-containing radical species form in the CH4-O-2 plasma. A reaction scheme is speculated which may account for these observed profiles.