Crystallization of Metastable Aluminas in the Presence of V ₂ O ₅

Abstract

In investigating possible effects of high temperatures on a V 2 O 5 /γ‐Al 2 O 3 catalyst, it was found that metastable aluminas with unusually well‐developed crystallinity can be prepared in the presence of V 2 O 5 . With control of firing temperature, time, and atmosphere, δ‐, θ‐, and k ‐Al 2 O 3 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 H 2 O 2 ; ESR revealed V 4+ ions in them.