ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Selective methane oxidation to formaldehyde using polymorphic T-, M-, and H-forms of niobium(V) oxide as catalysts
Beata Michalkiewicz, Joanna Sreńscek-Nazzal, Piotr Tabero, Barbara Grzmil, and Urszula Narkiewicz
Institute of Chemical and Environment Engineering, Szczecin University of Technology, PL 70-322 Szczecin, Poland
Received: 24 March 2007 Revised: 13 July 2007 Accepted: 17 July 2007
Abstract: The investigations of selective methane oxidation to formaldehyde over T-Nb2O5, the mixture of M-Nb2O5 and H-Nb2O5 as well as H-Nb2O5 were carried out. The tests were conducted under atmospheric pressure, in the temperature range 420–750°C, using oxygen as
the oxidizing agent. T-Nb2O5 samples were examined at the contact time 0.7–1.8 s (GHSV 2000–5143 h−1). Other polymorphic forms of niobium(V) oxide were examined at the contact time 0.9 s. Various polymorphic forms of Nb2O5 displayed various formaldehyde and carbon dioxide yield. Using H-Nb2O5 and M-Nb2O5 phases with a block type structure, made it possible to obtain higher formaldehyde selectivity (78 % at 0.9 s) as compared
to T-Nb2O5 (47 % at 0.9 s), a polymorphic form which does not have a block type structure. However, the highest space time yield of
formaldehyde (46 g per kg of catalyst per h) was obtained over T-Nb2O5 supported on SiO2.
Keywords: methane - formaldehyde - niobium(V) oxide - selective methane oxidation
Full paper is available at www.springerlink.com.
Chemical Papers 62 (1) 106–113 (2008)