Formation of Coke in the Disproportionation of n-Propylbenzene on Zeolites

• Published in: Journal of catalysis Vol. 142; no. 2; pp. 664 - 671
• Main Authors: Liu, S.B., Prasad, S., Wu, J.F., Ma, L.J., Yang, T.C., Chiou, J.T., Chang, J.Y., Tsai, T.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.08.1993; Elsevier
• Subjects: 02 PETROLEUM; 020400 - Petroleum- Processing; 400201 - Chemical & Physicochemical Properties; ADSORPTION ISOTHERMS; ALKYLATED AROMATICS; ALUMINIUM 27; ALUMINIUM ISOTOPES; AROMATICS; CARBON 13; CARBON ISOTOPES; CATALYSIS; CATALYSTS; CATALYTIC EFFECTS; Catalytic reactions; CHEMICAL REACTION KINETICS; CHEMICAL REACTIONS; Chemistry; COKE; DAYS LIVING RADIOISOTOPES; DEACTIVATION; EVEN-ODD NUCLEI; Exact sciences and technology; General and physical chemistry; HETEROGENEOUS CATALYSIS; INORGANIC ION EXCHANGERS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; INTERMEDIATE MASS NUCLEI; INTERNAL CONVERSION RADIOISOTOPES; ION EXCHANGE MATERIALS; ISOMERIC TRANSITION ISOTOPES; ISOTHERMS; ISOTOPES; KINETICS; LIGHT NUCLEI; MAGNETIC RESONANCE; MATERIALS; MINERALS; NUCLEAR MAGNETIC RESONANCE; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; OXIDATION; RADIOISOTOPES; REACTION KINETICS; REDUCTION; RESONANCE; SILICATE MINERALS; STABLE ISOTOPES; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; XENON 129; XENON ISOTOPES; ZEOLITES; Catalytic reaction; Disproportionation; Deactivation; Hydrocarbon; Coke; Adsorption isotherm; Xenon; NMR spectrometry; Zeolite; Experimental study; Molecular sieve; Gas solid adsorption; Heterogeneous catalysis; Benzenic compound; Catalyst
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1006/jcat.1993.1239

We investigated the formation of coke on zeolitic catalysts in the disproportionation of n-propylbenzene by means of 129Xe, 27Al, and 13C NMR spectroscopy. According to 13C CP-MAS (proton cross polarization with magic angle spinning) spectra, the coke formed in USY and ZSM-5 zeolites was classified into aliphatics and aromatics. It was found that aliphatic coke could be removed by a simple evacuation procedure. The location of the coke determined from 129Xe NMR spectra and xenon adsorption isotherms varied with the zeolite catalysts. For zeolite USY, the coke was formed inside the supercages and is mainly polyaromatic. For zeolite ZSM-5. the coke is alkykaromatic and tended to deposit at the openings of the channels rather than at their intersections. In regard to the mechanism, the reaction on USY followed bimolecular kinetics, whereas on ZSM-5 the reaction was monomolecular.