Simultaneous quantification of Bronsted- and Lewis-acid sites in a USY zeolite

In this report, experimental methods and calculation procedures are describ ed for direct and simultaneous quantification of the Bronsted- and Lewis-ac id site concentrations in a sample of USY zeolite. The concentrations of bo th types of acid sites are characterized by solid-state P-31 MAS NMR spectr oscopy of trimethylphosphine oxide probe molecules. The errors associated w ith the area measurements in the NMR spectrum, and hence the errors in the concentration measurements reported, are estimated with Monte Carlo simulat ions applied with spectral line-fitting and deconvolution procedures. (C) 1 999 Academic Press.