C-13 Mas Nmr and Related Studies of Coke Formation on H-Zsm-5

C-13 MAS NMR measurements of coke deposits formed from C-13-enriched CH3OH or C2H4 in contact with H-ZSM-5 were carried out after reaction at increasing temperatures. Depending on the reaction conditions and properties of the catalysts, alkyl chains, alkyl groups attached to aromatics, alkoxy groups, enylic and aromatic cations, aromatics and alkyl carbocations were identified. These investigations confirmed the earlier discrimination between low- and high-temperature coke and were supported by complementary UV-Visible studies on the same systems