Ssn. Murthy, Detailed study of ice clathrate relaxation: Evidence for the existence of clathrate structures in some water-alcohol mixtures, J PHYS CH A, 103(40), 1999, pp. 7927-7937
Dielectric relaxation technique (10(+6)-10(-3) Hz) and differential scannin
g calorimetry are used to study the existence of clathrate hydrates in aque
ous solutions Of a number of alcohols and nonhydrogen-bonded liquids. The a
queous solutions studied are those of methanol, ethanol, 2-propanol, tert-b
utyl alcohol, acetone, and p-dioxane. The corresponding solid-liquid phase
diagrams are also determined to support the dielectric results. Evidence fo
r the existence of clathrate hydrates in 2-propanol and tert-butyl alcohol
is provided. The clathrate hydrate of 2-propanol is metastable. No clathrat
e structure is found in methanol mixtures. The composition of the new clath
rate found in 2-propanol and tert-butyl alcohol is suggested to be around A
. 5H(2)O-A. 6H(2)O. The clathrate hydrate relaxation (including that: of th
e, two hydrates of ethanol) has been studied down to its kinetic freezing t
emperature T-g and is analyzed in terms of the Arrhenius equation. Also stu
died are the relaxation rates of the clathrate hydrates of acetone, tetrahy
drofuran, and p-dioxane down to their respective T(g)s. The nature of the d
ielectric relaxation is discussed.