A microcalorimetric estimation of the surface acidity of NiSO4·xH2O and catalytically active Al2O3

Abstract

The relative surface acidity of several alumina powders with a variety of specific surface areas has been measured by a microcalorimetric technique. The alumina surfaces studied here are those for which the catalytic activity for alcohol dehydration has been measured. The technique used was to measure the heats of immersion (ΔH_i) in pyridine and 2,6-dimethyl pyridine. A maximum in ΔH_i for both liquids was observed as a function of a particle size corresponding to a maximum in the catalytic activity. The technique was also applied to NiSO₄·xH₂O samples, and the results were compared to other surface acidity measurements for these samples.