Synthesis of higher order hydrocarbons on hot tungsten filaments

Abstract

Using a quadrupole mass spectrometer whose sensitivity is 10 −15 torr (N 2 equivalent), this study shows the synthesis of acetylene, ethane, propylene and propane from methane on a hot tungsten filament. This study follows the partial pressures of these hydrocarbons with variation of filament temperature. Demonstrated also, is the constancy of the product composition for a given temperature at two partial pressures of methane. Acetylene, the most abundant of the hydrocarbons synthesized, is found to have a partial pressure only about one decade less than the parent methane. The measurement of total pressure in the ultra high vacuum regions by hot filament gauges may be erroneous due to this kind of synthesis.