MEASUREMENT AND PREDICTION OF METHYL-SUBSTITUTED NAPHTHALENE ISOMER-RATIOS IN LIQUID-HYDROCARBON FUELS

Results for the relative isomer abundance of di- and trimethylnaphthalenes in crude and processed products from petroleum, shale oil, and coal tar are reported, together with several procedures for the calculation of the isomer distribution at equilibrium. The data suggest that the isomer distributions can approach the equilibrium values in certain circumstances. The mechanisms by which such equilibria are achieved may equally explain the distribution of the lower alkylbenzenes, with respect to both isomer distribution and equilibria involving trans-alkylation reactions. This is at variance with the mechanism postulated for the acid-catalyzed isomerization of alkylnaphthalenes in which only intramolecular methyl migrations are thought to occur. The thermodynamic calculations employed here are easily extended to other polycyclic systems.