Factors and intermediates governing byproduct distribution for decomposition of butane in nonthermal plasma

Abstract

Plasma chemical decomposition of butane was investigated with a ferroelectric parked-bed plasma reactor to obtain the information on the fundamental chemical processes occurring in nonthermal plasma. It has been shown that butane decomposition efficiencies are higher in nitrogen rather than in air. This fact suggests that energy transfer from hot electrons to butane is mainly responsible for the initial decomposition of butane. Nitrogen incorporation was observed for acetonitrile only in dry nitrogen and for nitromethane in air. Barium titanate and water have been shown to act as monooxygen transfer agents in nitrogen. Lattice oxygen atoms in barium titanate can be consumed in the formation of N 2O and CO, depending on reaction conditions. Water is much more reactive than barium titanate as an oxidant in nonthermal plasma, and it can oxygenate butane to butanols, epoxidize 1- and 2-butenes, and oxidize CO to CO2. Water, which has a dichotomic nature regarding oxygenation/hydrogenation in plasma, can act as a hydrogen source toward alkyl radicals formed in the initial decomposition of butane. In air, triplet oxygen molecules are the most reactive oxygen source in the presence or absence of water and carbon balance can be improved with suppression of byproducts due to promoted autoxidation processes.