A study has been made of the infrared 0-H bands for CH30H, DOH, and H z O in solution and of their correlation with hydrogen bonding and solvent basicity. Infrared bands for the three fundamentals and the first bending overtone of HzO and for the 0-H stretching fundamentals of DOH and C H 3 0 H have been measured between 30 and -40°C in a solvent range extending from weakly interacting fluorocarbons to strongly hydrogen-bonding organic amines. The 0-H stretching bands for the weakly acidic solutes CH30H, DOH, and H z O are mostly Lorentzian in shape and move to lower frequencies with higher extinctions in the more basic solvents. Many correlations are found between the stretching frequencies and band areas, and between the frequencies and solvent basicity. Monofunctional C H 3 0 H is found to be a stronger acid and forms stronger hydrogen-bonds with a given base than do the doubly bonded DOH and HOH which show equal dibasic acid strengths.The wide, overlapped, fundamental stretching bands for H 2 0 strongly hydrogen-bonded to the tertiary amines and for ice have been partially resolved and unequivocally assigned, showing that there is no cross-over of the v3 and v, bands despite the strong hydrogen-bonding.At higher temperatures in solvents containing both hydrophobic and strongly basic groups water was found with the lower C, type symmetry, in which unbonded 0-H groups gave sharp bands in the 3680-3650 cnl-' region in addition to the wide hydrogen-bonded bands at lower frequencies. Aux temperatures superieures dans les solvants contenant des groupes hydrophobes et fortement basiques I'eau possede la symetrie inferieure de type C, suivant laquelle des groupes 0-H non-lies procurent des bandes fines dans la region 3680-3650 cm-' en plus des bandes larges causees par les liaisons hydrogenes aux frkquences inferieures.

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Computer simulation studies of the structure I clathrate hydrates of methane, tetrafluoromethane, cyclopropane, and ethylene oxide

Densities at 10 °C and proton magnetic resonance (p.m.r.) chemical shifts at 0 °C have been measured for aqueous ethylene oxide over the whole solution composition range. Ice freezing points have been determined for solutions containing up to 2 mole % ethylene oxide in water and in deuterium oxide. The deuterium oxide freezing point is 3.809 ± 0.003 °C and its freezing enthalpy is −1510 ± 8 cal. The freezing point measurements show water and deuterium oxide having unexpected negative deviations from Raoult's law. A maximum thermodynamic stabilization of water is found for solutions containing 4 mole % ethylene oxide. Partial molar volume evaluation shows a water volume maximum at 3.2 mole % ethylene oxide and a minimum at about 89%. Proton magnetic resonance measurements indicate weak H-bonding of water to ethylene oxide involving only one lone pair per ethylene oxide molecule. An abnormal shoulder in the direction of lower magnetic field for the water chemical shift is found, with the anomaly maximum at 4 to 6 mole % ethylene oxide.Correlating with the 20 and 24 water molecules encaging ethylene oxide in its clathrate hydrate, these new solution measurements show that when 20 to 30 water molecules are associated with each ethylene oxide at lower temperature, the water solvent exhibits a free energy minimum, a volume maximum, and an anomalous increase of water H-bond strength. At these compositions each ethylene oxide molecule is apparently surrounded by its own H-bonded water coordination shell to which it is weakly H bonded.

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