fig9
Figure 9. (A) Dependence of ethylene selectivity and E/P ratio on the proportion of (T2 + T4) sites; and (B) relationship between the olefin selectivity or O/P ratio and the acid amount. The (T2 + T4) site proportion was obtained from the 27Al MAS NMR spectra. The acid amount was measured by Py-IR and NH3-TPD techniques. E/P: Ethylene to propylene; O/P: olefin to paraffin; MAS NMR: magic angle spinning nuclear magnetic resonance; Py-IR: pyridine-adsorption infrared spectroscopy; TPD: temperature-programmed desorption.
