Abstract
BPO4 catalysts which were prepared under different conditions from a mixture of boric acid and phosphoric acid were characterized in terms of specific surface area, amounts of the residual reactants unreacted, and acidic properties. Then the correlation between those physicochemical properties and those catalytic activity. It was revealed that the most important factor was to dissolve boric acid in phosphoric acid as completely as possible, avoiding the condensation of boric acid and/or that of phosphoric acid, because those condensates are catalytically inactive and in addition they block the active sites of BPO4 catalysts. The active sites were also revealed to be Bronsted acid sites by their measurement of pyridine adsorbed on BPO4 catalysts.
