Open AccessA Spectroscopic Paradox: The Interaction of Methanol with ZSM-5 at Room Temperature
Author(s) -
Andrea Zachariou,
Alexander P. Hawkins,
Russell F. Howe,
Nathan S. Barrow,
Jonathan P. Bradley,
Paul Collier,
David Len,
Stewart F. Parker
Publication year - 2021
Publication title -
topics in catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.732
H-Index - 111
eISSN - 1572-9028
pISSN - 1022-5528
DOI - 10.1007/s11244-021-01462-9
Subject(s) - methanol , dissociation (chemistry) , chemistry , zeolite , infrared spectroscopy , adsorption , spectroscopy , photochemistry , catalysis , hydrogen bond , inelastic neutron scattering , inorganic chemistry , neutron scattering , molecule , organic chemistry , neutron , physics , quantum mechanics
The adsorption of methanol in HZSM-5 at low temperatures has long been regarded as an associative process involving hydrogen bonding to the acidic zeolite hydroxyl groups. Recent studies employing inelastic neutron scattering spectroscopy (INS) have reported that complete dissociation to methoxylate the zeolite occurs at 298 K, and infrared evidence for a partial dissociation at 298 K has also been described. Here we investigate the apparent contradictions between different techniques, using a combination of INS, infrared spectroscopy and solid-state NMR spectroscopy, including isotopic substitution experiments. Different possible explanations are proposed and considered; we conclude that at room temperature methanol is very largely associatively adsorbed, although the presence of some small extent (>1%) of methoxylation cannot be ruled out.