Niobic acid - a new heterogeneous catalyst for processes in petrochemical and organic syntheses

Questions associated with the application of niobium compounds in catalysis are considered. Niobic acid Nb₂O₅^.nH₂O contains an appreciable amount of water, but its surface exhibits a high acidity – equivalent to the acidity of 70% sulfuric acid. This unusual solid acid manifests not only a high activity and sensitivity but also an appreciable stability as a catalyst in reactions in which water is present or is evolved (condensation, hydration, dehydration, and esterification). It may be used also as a catalyst in other reactions. The structure and properties of the surface of niobic acid are examined. The bibliography includes 54 references.