HEATS OF IMMERSION OF BORON PHOSPHATES IN PYRIDINE AND MAGNESIA IN BENZOIC-ACID SOLUTION

The heats of immersion of the systems B2O3-P 2O5 and Na2O-B2O3-P 2O5 in pyridine have been measured by the use of a solution microcalorimeter. In the composition range R ≤ 1 (R = atomic ratio, B/P) the heat of immersion was relatively small and was almost independent of R. The heat increased markedly with boron content in R > 1. The increase of heat qualitatively parallels that of surface acidity. Introduction of the Na2O component reduced both heat of immersion and acidity. MgO was immersed in a benzene solution of benzoic acid. The heat of immersion increased with an increase of surface basicity.