Cracking of dinaphthylethane in 9,10-dihydrophenanthrene and diphenylethane in tetralin in the absence or in the presence of dispersed catalysts such as Mo-S and Ru was studied under hydrogen atmosphere. The amounts of hydrogen transferred from a gas phase and a donor solvent were determined and the amounts of hydrogen required to stabilize free radicals derived from the model compound were estimated from the products distributions. Most of the hydrogen required to stabilize free radicals seemed to come from the hydrogen donor solvent, even in the presence of an active catalyst.
