The acid–base properties of modified aluminas (SO2–4, PO3–4, Cl–, F–, Mg2+ and Na+, 0.2– 2.0 wt.%) have been investigated by FTIR spectroscopy of probe molecules (pyridine and CDCl3), CO2 TPD and the dehydration of 4-methyl-pentan-2-ol. The results of these methods and those of previous NH3 TPD studies were compared in order to establish a classification of our aluminas. There is very good agreement between the results of the ...