ANALYTICAL CHEMISTS APPROACH TO HETEROGENEOUS CATALYSIS - GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC CHARACTERIZATION OF POLYCYCLIC AROMATIC HYDROCARBONS AS A FINGERPRINT OF ACTIVE SITES IN HYDROCARBON-REFORMING CATALYSTS

摘要

The analytical CC-MS characterization of polycyclic aromatic hydrocarbons (PAHs), formed as by-products in the model reaction of methylcyclopentane reforming, is proposed as a convenient tool for fingerprinting the nature of active sites in heterogeneous catalysts. The by-products obtained with non-acidic Pt/KL and Pt/NaY catalysts (platinum particles inside zeolite cages) were characterized as 2-4 condensed-ring PAHs. The distribution and the structure of such by-products were demonstrated to be related to the geometry of the zeolite framework. With acid catalysts, families of isomers of all the polymethyl-derivatives of three- and four-ring aromatics were obtained. Careful analyses of total-ion GC profiles via single-ion monitoring allowed the identification of each family of isomers. [References: 13]