Catalytic activity of zirconium phosphate and some derived phases in the dehydration of alcohols and isomerization of butenes

• Published in: Journal of catalysis 1987-02, Vol.103 (2), p.346-356
• Main Authors: La Ginestra, A., Patrono, P., Berardelli, M.L., Galli, P., Ferragina, C., Massucci, M.A.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts: preparations and properties; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; General. Nomenclature, chemical documentation, computer chemistry; Theory of reactions, general kinetics; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/0021-9517(87)90126-6

The catalytic activity of α-Zr(HPO 4) 2 · H 2O prepared by different methods and of phases derived from it by heating between 200 and 1100 °C or by ion exchange with Na +, Cs +, or Ag +, has been investigated by means of different acid-catalyzed test reactions, namely, isopropanol, 1- or 2-butanol dehydration, and 1-butene isomerization. The active centers of both Zr(HPO 4) 2 and ZrP 2O 7 phases are mainly the surface Brønsted sites, as indicated by the strong decrease or annihilation of their catalytic activity after surface Cs + poisoning. An explanation of the low residual activity detected for some samples is given. As deduced from the products of 1-butene isomerization, the acidic sites are generally of medium strength. However, on heating between 350 and 700 °C, when partial or total condensation of hydrogen phosphate to P-O-P groups occurs (with progressive formation of the layered pyrophosphate phase) they transform into sites of medium-high Strength.