Tracerkinetische Untersuchungen zur Isomerisierung und Synthese von C₈-Aromaten I. Die heterogenkatalytische Isomerisierung von Xylolen in der Gasphase

Isotopic Labeling and Kinetic Isotope Effects

“…Thus, p-xylene can be directly formed from o-xylene via 1,2,4-trimethylbenzene (proven by labeled methyl groups) [20,52,53]. A monomolecular mechanism occurs via a 1,2-methyl shift along the benzene ring, excluding a direct conversion of o-xylene into p-xylene.…”

“…6). Using similar 14 C-labeled xylene mixtures, Dermietzel et al [52,58] observed a higher extent of the bimolecular isomerization route on Pt/Al 2 O 3 /SiO 2 under nitrogen instead of hydrogen. Evidently, the bimolecular mechanism -the so-called ''triangular'' reaction scheme -yielded better data fitting of both concentration and radioactivity curves.…”