The dealkylation of alkyl aromatic hydrocarbons. III. The dealkylation of polynuclear aromatics

The studies of thermal dealkylation1, 2 have been extended to the polycyclic hydrocarbons. In the temperature interval of 560 to 660°, at a pressure of 100 atm. and with a large excess of hydrogen, α- and β-methylnaphthalene, a methylnaphthalene oil and a number of coal-tar fractions were studied. On the assumption of the same mechanism as for toluene dealkylation1 the results were fitted to a 1.5-order reaction mechanism. The energies of activation for α- and β-methylnaphthalenes agree well with the proposed mechanism. Naphthalene oils of coke-oven origin should be capable of giving quantitative yields of naphthalene. Oils of vertical-retort origin are too rich in paraffin content. Little dealkylation was obtained with a coke-oven anthracene oil.