Alkylbenzenes. XIV. Diphenylalkanes as Intermediates in Fragmentation, Rearrangement, and Disproportionation Reactions of Alkylbenzenes

n-Propylbenzene Disproportionation: An Efficient Tool for Assessing the Framework Topology of Large-Pore Zeolites

“…This possibility is reasonable if the energy difference between these two types of carbenium ions is not very large. In fact, the variation of deprotonated positions in the propyl groups of both n PB and D n PBs has long been recognized. , Then, the initial intensity increase of peaks 12a,b can also be understood in a similar manner: a transformation of more stable CH 3 –CH 2 –CH 2 PhCH + –CH 2 –CH 3 ions to less stable CH 3 –CH 2 –CH 2 PhCH 2 –CH + –CH 3 ions. The resulting PhCH 2 –CH + –CH 3 and CH 3 –CH 2 –CH 2 PhCH 2 –CH + –CH 3 ions can, in turn, be converted into 1p2pP and 1pp2P species by reaction with n PB and benzene, respectively.…”

“…In fact, the variation of deprotonated positions in the propyl groups of both nPB and DnPBs has long been recognized. 25,26 Then, the initial intensity increase of peaks 12a,b can also be understood in a similar manner: a transformation of more stable CH We next examined the evolutions of mpDP, 1p2pP, and 1pp2P species as a function of TOS within LaNa-Y during nPB disproportionation. As shown in Figure 4, the mpDP signals were found to increase continuously with increasing TOS and then to become almost constant after about 1200 min on stream.…”

“…Of course, these four decomposition products can react with one another or with n PB, yielding other different types of bicyclic aromatic compounds that might be related to peaks 9a–c, 10a,b, and 14a–c in Figure . Therefore, n PB disproportionation produces not only benzene and D n PBs but also toluene, EB, and various C 10–11 aromatics even at temperatures below 473 K, conditions under which it is difficult for the monomolecular propyl-transfer reaction mechanism to effectively operate. , …”

“…Therefore, nPB disproportionation produces not only benzene and DnPBs but also toluene, EB, and various C 10−11 aromatics even at temperatures below 473 K, conditions under which it is difficult for the monomolecular propyltransfer reaction mechanism to effectively operate. 25,26 Figure 5 shows the GC−MS total ion chromatograms of the CH 2 Cl 2 extracts from the proton forms of six zeolites with different framework structures after nPB disproportionation at 443 K for 10 h on stream. Whereas the chromatogram from LaNa-Y with a considerably higher Al content (Si/Al = 2.6) is also included for comparison, the segments covering the dpDP and 1pp2pP signals are not shown because of their weak intensities.…”

Acid-catalyzed rearrangements of polymethylnaphthalenes

“…was heated for 72 hr, a Meg-naphthalene (20, 20%) and a Mev-naphthalene (19, 2%), whose precursory role to the formation of 20 was confirmed independently, were obtained besides unreacted 18 (38%) and polymeric materials (40%). Both 19 and 20 were isolated and their structures determined as 1,2,3,4,5,6,7-ß7-and 1,2,3,5,6,7-Meg-naphthalene for 19 and 20, respectively, by spectroscopy joined with a rational mechanistic account. 10 Analogously, the main reaction of the following naphthalenes, none of which has any methyl substituents in peri positions, was the dealkylation.…”