Aromatization of Ethylene and C4Hydrocarbons Using a Thermal Diffusion Column

Thermal diffusion columns, consisting of water-cooled glass tubes and a coaxial red-hot metal wire, were applied as the reactor to dehydrogenative coupling of ethylene or C4 hydrocarbons. This application was intended to separate hydrogen spontaneously from other products, especially from aromatics, leading to enhanced yields. Hydrogen gas would ascend the red-hot wire, while the aromatics would descend the cold glass walls. When the metal wire was actually red-hot in the reactant hydrocarbon flow, oily products were really formed, most of which were mono- and bicyclic aromatic compounds such as benzene, styrene, and naphthalene. Product distributions were measured for different reactant species, wire metals, wire temperatures, and a few additional variables. Especially notable was the selective formation of 4-vinyl-1-cyclohexene from 1,3-butadiene at relatively low temperatures near 600 °C.