Assays for water content can be readily and simply carried out using the technique of thermal titrations. The method is based on measuring the endothermic heat of reaction exhibited when 2,2-dimethoxypropane is brought into contact with water in the presence of an acid catalyst. The apparatus is simple, requiring a constant delivery rate buret, a recording thermistor thermometer, and a stirred, thermally insulated reaction container. The 2,2-dimethoxypropane reagent used for the water assays is environmentally friendly ("green"). It is stable, pleasant smelling and economical. Working curves in three solvents, acetonitrile, tetrahydrofuran and 1,4-dioxane, show excellent precision and linearity with increasing water concentrations to at least 0.07 M. Four different kinds of samples were subjected to this method of water assay to demonstrate its versatility: ethanol, nickel (II) nitrate hexahydrate, concentrated sulfuric acid, and two kinds of fuels. In each case, the method worked accurately and reproducibly with a minimum of time required.
Wilson, Edmond W. Jr. and Reagan, Reagan
"Moisture Determination by Thermal Titrimetry Using the Enthalpy of Reaction of 2,2-Dimethoxypropane with Water,"
Journal of the Arkansas Academy of Science: Vol. 55
, Article 21.
Available at: http://scholarworks.uark.edu/jaas/vol55/iss1/21