“…While the latter group of bicyclic aromatic compounds was found to be intermediates of iPB dehydrogenation, a side reaction of the iPB disproportionation, both groups of them are hardly observed over medium-pore zeolites, regardless of their structure type. However, we were not able to detect any di-iso-propylated 2,2-diphenylpropane (dipDP) species in this study, unlike the disproportionation of other aromatic hydrocarbons, including m-xylene, ethylbenzene, and n-propylbenzene, 12,17,18 in which formation of dialkylated diphenylalkane species as reaction intermediates has been clearly confirmed. To better understand the results described above, we have calculated the strain energies of three mipDP, three mip = DP, or six dipDP isomers embedded within the structures of zeolites studied, together with the relative energies of all species (i.e., reactant, reaction intermediates, transition states, and products) in the 84T H-Y model, using the mixed quantum-mechanical and semi-empirical ONIOM method.…”