The specific heat capacities of aqueous solutions of 2-(hexyloxytetraethoxy)ethanol (C6E5) have been measured from 283 to 338 K within the whole composition range by DSC. Changes of specific, partial and apparent molar heat capacities of investigated system were analysed and considered as a effect of structural transformations. For each solution, the temperature dependences of the differential heat flow were also analysed in order to find the curve of phase coexistence, i.e. the boundary between one- and two-phase area for the examined system. (c) 2004 Elsevier B.V. All rights reserved.