The melting points of mixtures were measured with a differential scanning calorimeter (DSC) (Instrument Specialists Incorporated DSC 550). Samples were prepared by adding 3-10 mg of the mixture to an aluminum pan and lid. The DSC was operated with a heating rate of 2 °C/min. under a constant flow of nitrogen gas. The water content of the larger mass samples was measured immediately before measuring the density, or viscosity.