Water-Saturated Mesoporous MCM-41 Systems Characterized by 1H NMR Spin-Lattice Relaxation Times

Autor:	Eddy W. Hansen, Duncan Akporiaye, Ralf Schmidt, Michael Stoecker
Rok vydání:	1995
Předmět:	Silanol chemistry.chemical_compound Chemistry Relaxation (NMR) Enthalpy General Engineering Spin–lattice relaxation Proton NMR Analytical chemistry Bound water Physical and Theoretical Chemistry Mesoporous material Molecular sieve
Zdroj:	The Journal of Physical Chemistry. 99:4148-4154
ISSN:	1541-5740 0022-3654
DOI:	10.1021/j100012a040
Popis:	Combining spin-lattice relaxation time measurements and signal intensity measurements vs temperature of water confined in mesoporous molecular sieves (MCM-4 1 materials) gives information regarding the activation enthalpy of bound water and the width of the log-normal distribution of correlation times of the water molecules. Three different water “phases” are observed which have significantly different relaxation strength. The overall spin-lattice relaxation rate is shown to be strongly dependent on the number of silanol protons. “Analytical” formulas for the average spin-lattice relaxation rates are derived.
Databáze:	OpenAIRE
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