Determining hildebrand solubility parameter by ultraviolet spectroscopy and microcalorimetry

Abstract

The solubility parameter (δ) of a molecule is extremely important, since that new molecules are frequently developed to be applied in liquid systems. In this work, we looked for simple and reliable alternative techniques to determine δ of low and high molecular weight molecules. Pyrene, phenanthrene and naphthalene had their δ determined by microcalorimetry (μDSC), ultraviolet (UV) and calorimetry (DSC). UV results were similar to those obtained by DSC and to those cited in the literature. Polystyrene and sulfonated polystyrene samples had their δ determined by UV, μDSC and intrinsic viscosity ([η]). The [η] results were similar to those obtained by UV. UV procedure was relatively simple, easy operation and reliable for determining d of molecules in a wide range of molar mass, can be used when developing new molecules. The μDSC procedure still requires some adjustments to become more accurate than [η] procedure. © 2013 Sociedade Brasileira de Química.