Oxygenates from light alkanes catalyzed by NOx in the gas phase

The partial oxidations of light alkanes (methane, ethane, propane, and iso- butane) catalyzed by NOx in the gas phase have been studied at a pressure o f less than 1 bar. For all the alkanes tested, the addition of NO to the mi xture of alkanes and O-2 enhanced the selectivities and the yields of oxyge nates remarkably. It was suggested that NO2 generated from NO and O-2 initi ated the oxidation of alkanes and would specifically accelerate the C-C bon d fission, enhancing the formation of C-1-oxygenates from ethane, propane, and iso-butane. NO2 and NO could be used as a homogeneous catalyst at >600 degrees C because nitroalkanes formed were decomposed completely, releasing the NOx. The comparison of the product distributions for the decomposition and oxidation of nitroalkanes and alkylnitrites strongly suggested that th e oxygenates (HCHO, CH3CHO, and CH3COCH3) were formed from the correspondin g alkylnitrites which must be the reaction intermediates during the oxidati on of alkanes with an O-2 and NO mixture. (C) 1999 Academic Press.