EXPERIMENTS ON THE PYROLYSIS OF GASEOUS PARAFFINS, WITH SPECIAL REFERENCE TO THE PRODUCTION OF ETHYLENE

On passing natural gas, containing 4.8% ethane, through an electrically heated tungsten spiral, the formation of liquid products was observed at 1050 °C.On passing the same gas over an electrically heated 4-mm. carbon rod enclosed in an uninsulated silica tube 2.0 cm. wide, 7.7% of the gas was converted to liquid and solid hydrocarbons at a rod temperature of 1050–1100 °C. No liquids or solids except carbon were formed when the silica tube was insulated.By replacing the 2.0-cm. silica tube by a water-cooled Pyrex tube, 3.2 cm. wide, no liquid or solid hydrocarbons were obtained, but 17% of the gas was converted to gaseous unsaturated hydrocarbons at 993 °C. On passing ethane through the 3.2-cm. water-cooled reaction tube at rod temperature of 989 °C., 50.5% of the entering gas was converted to ethylene, and 90.0% of the ethane decomposed did so according to the equation C2H6 → C2H4 + H2.The dehydrogenation of ethane was found to be greatly accelerated by the presence of reduced copper in the tube, the metal being used in the form of a cylindrical wire gauze and placed around the carbon rod. Copper bronze coated with molybdic oxide was also found to be active under the same conditions.