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High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems
Published on: January 24, 2014
High-pressure and -temperature viscosity measurements of methanol and 4:1 methanol:ethanol solution
Brent Grocholski1, Raymond Jeanloz
1Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA. brent@eps.berkeley.edu
Abstract:
Viscosity (eta) measurements using rolling sphere viscometry in a resistance-heated diamond-anvil pressure cell yield activation energies of 18-98 kJmol over a pressure range of 1.1-6.1 GPa for methanol and 26-78 kJmol over a pressure range of 2.9-5.4 GPa for a 4:1 methanol:ethanol solution. Nonlinear models of log eta (free-volume and power-law models) yield statistically better fits than the Arrhenius model at room temperature and extrapolate to lower glass-transition (10(12) Pa s) pressures. Glass-transition pressures for the free-volume model change little over the temperature range studied (298-338 K), whereas the power-law values converge to those of the Arrhenius model at temperatures above 320 K.
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