The chem. of the prepn. of VOHPO4.0.5H2O, precursor in the formation of (VO)2P2O7 (the active phase in butane selective oxidn.) was studied. VOHPO4.0.5H2O was prepd. from an acid aq. soln. of VO2+ and H3PO4 or H4P2O7. The pptn. of the insol. VOHPO4.0.5H2O occurs only in highly concd. solns., where a sol of VOHPO4 or (VO)2P2O7 forms which constitutes the precursor phase of the cryst. VOHPO4.0.5H2O. The necessity of the formation of this precursor phase is related to the difficulty of the pptn./crystn. process, as compared with other metal(IV) hydrogen phosphate prepns. Different methods of prepn., which do not give this intermediate, did not lead to the formation of VOHPO4.0.5H2O. The role of the method of prepn. in obtaining pure VOHPO4.0.5H2O is also discussed. [on SciFinder(R)]
On the chemistry of vanadium-phosphorus oxides. Note V. Crystallogenesis of vanadyl hydrogen phosphate
CENTI, Gabriele;
1985-01-01
Abstract
The chem. of the prepn. of VOHPO4.0.5H2O, precursor in the formation of (VO)2P2O7 (the active phase in butane selective oxidn.) was studied. VOHPO4.0.5H2O was prepd. from an acid aq. soln. of VO2+ and H3PO4 or H4P2O7. The pptn. of the insol. VOHPO4.0.5H2O occurs only in highly concd. solns., where a sol of VOHPO4 or (VO)2P2O7 forms which constitutes the precursor phase of the cryst. VOHPO4.0.5H2O. The necessity of the formation of this precursor phase is related to the difficulty of the pptn./crystn. process, as compared with other metal(IV) hydrogen phosphate prepns. Different methods of prepn., which do not give this intermediate, did not lead to the formation of VOHPO4.0.5H2O. The role of the method of prepn. in obtaining pure VOHPO4.0.5H2O is also discussed. [on SciFinder(R)]Pubblicazioni consigliate
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