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Hydrogen Bonding of Ethanol in Supercritical Mixtures with CO 2 by 1 H NMR Spectroscopy and Molecular Simulation
Author(s) -
Reiser S.,
McCann N.,
Horsch M.,
Hasse H.
Publication year - 2013
Publication title -
chemie ingenieur technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 36
eISSN - 1522-2640
pISSN - 0009-286X
DOI - 10.1002/cite.201250747
Subject(s) - thermodynamics , science and engineering , chemistry , physics , computer science , engineering , engineering ethics
High pressure 1 H NMR spectroscopic studies of mixtures of CO2 and ethanol (EtOH) were conducted at a wide range of temperatures (293.15, 308.15, 323.15, and 338.15 K), pressures (5 25.5 MPa) and concentrations (xEtOH = 0.0017 – 1.0 mol/mol). The relative chemical shift of the protons in the hydroxyl group was used to describe the degree of hydrogen bonding in ethanol. The dependence of the results on pressure is only weak. The quantification of hydrogen bonding was based on the assumption that the observed shift results from a superposition of the shifts of ethanol molecules differing in the way they are hydrogen bonded. Three different types were distinguished: monomer, donor and acceptor. The monomer shift was found from an extrapolation of the NMR data. Molecular dynamics simulations based on force fields from the literature were carried out for the same mixtures at *Manuscript