DOES THE CAL-AD METHOD DISTINGUISH DIFFERENCES IN THE ACID SITES OF H-MFI

Recent claims that calorimetric measurements of solid acidity can be p erformed more effectively in the presence of a solvent, the ''cal-ad'' method, were examined using vapor-phase measurements for the coadsorp tion of pyridine and n-hexane in H-MFI. The results indicate that equi librium is not achieved for pyridine titration measurements in a solve nt at room temperature. Therefore, the ability of the cal-ad method to distinguish Bronsted-acid sites of widely different strengths in H-MF I is unproven.