On the catalytic cyclization of aliphatic hydrocarbons. II

Abstract The products formed by the passage of a number of pure hydrocarbons over an aromatizing catalyst have been analysed by a spectroscopic technique. The occurrence of two different types of isomerization has been demonstrated. One may be exemplified by the formation of p- and m-xylenes from n-octane. This isomerization accompanies ring closure and proceeds smoothly at 475° C; it entails the formation and rupture of a subsidiary ring. The apparent discrepancy between the observations of Hoog, Verheus & Zuiderweg (1939), who report that 2 . 2 . 4-trimethyl pentane does not aromatize, and the observations of Green & Nash (1941), who report that a considerable quantity of aromatics is formed, has been shown to arise from the different temperatures employed. The formation of aromatics from substituted pentanes is a general phenomenon; the products from all the isomeric octanes in question have been analysed. The isomerization proceeds through a five-six carbon atom ring mechanism.