We have observed suppression in the specific rate of hydrolysis of five organic halides in three water-based liquid mixtures near their respective equilibrium consolute points. The systems examined were tert-amyl chloride in isobutyric acid + water, tert-butyl chloride in isobutyric acid + water, tert-butyl bromide in triethylamine + water, 3-chloro-3-methylpentane in 2-butoxyethanol + water, and 4-methylbenzylbromide in 2-butoxyethanol + water. The first two have upper consolute temperatures, while the second three have lower consolute temperatures. The slowing down effect occurred within a few tenths °C on either side of the consolute temperature. In the case of tert-amyl chloride in isobutyric acid + water, the effect followed a shift in consolute temperature produced by a change in the initial concentration of tert-amyl chloride. This indicates that all points along the critical line are equivalent. These observations demonstrate the existence of critical slowing down of chemical reaction rates in liquid mixtures.

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Equilibrium isotherms for water have been measured on three samples of Saran charcoal between 10" C and 60" C. The heats of adsorption at very low surface coverage are as high as 15,000 callmole, but for most of the water adsorbed are only slightly greater than the heat of liquefaction. On desorption, there is no hysteresis loop.Water adsorbs more slowly than a hydrocarbon of comparable size. At low relative