Crystallization of Metastable Aluminas in the Presence of V2O5

In investigating possible effects of high temperatures on a V2O5/γ-Al2O3 catalyst, it was found that metastable aluminas with unusually well-developed crystallinity can be prepared in the presence of V2O5. With control of firing temperature, time, and atmosphere, δ-, θ-, and k-Al2O3 could be obtained in this state. X-ray powder diffraction patterns containing many more lines than usually observed were indexed, unit-cell dimensions calculated, and values compared with previous data. All preparations contained small amounts of V which could not be removed by H2O2; ESR revealed V4+ ions in them.