MCM-22 (IZA code MWW) zeolite with Si/Al of 15 and 34 was characterized by N2 adsorption isotherm, 27Al and 29Si MAS RMN spectroscopy, infrared spectroscopy (FTIR), X - ray photoelectron spectroscopy (XPS) and microcalorimetry. The as-synthesized samples gives a signal from four-coordinated framework Al, and the calcined samples gives two signals, from four-coordinated framework Al and from six-coordinated extra-framework Al (EFAl). In the 29Si NMR spectra showed five at seven different signals. XPS spectra of N1s binding energies showed two types of sites: Brönsted and Lewis. Pyridine adsorbed on Brönsted and Lewis sites appeared at 1545 cm-1 and 1455 cm-1, respectively (FTIR). Both samples of MCM-22, show a relatively high proportion of strong Brönsted sites. The observed Lewis acidity can be related with extraframework Al species, indicating that some dealumination took place during the calcination step. Microcalorimetry experiments indicate the presence of three type of acid sites.
