Apparent molal volumes of HMT and TATD in aqueous solutions around the temperature of maximum density of water

Apparent molal volumes VϕVϕ have been determined from density measurements for several aqueous solutions of 1,3,5,7-tetraazatricyclo[3.3.1.1(3,7)]decane (HMT) and 1,3,6,8-tetraazatricyclo[4.4.1.1(3,8)]dodecane (TATD) at T = (275.15, 275.65, 276.15, 276.65, 277.15, 277.65 and 278.15) K as function of composition. The infinite dilution partial molar volumes of solutes in aqueous solution are evaluated through extrapolation. Interactions of the solutes with water are discussed in terms of the effect of the temperature on the volumetric properties and the structure of the solutes. The results are interpreted in terms of water structure-breaking or structure forming character of the solutes.

►  VϕVϕ for HMT and TATD in aqueous solutions around the temperature of maximum density of water are reported.
► VϕVϕ is linear in m form m = 0.025 for all the aqueous solutions investigated.
► Variation of V¯2∞ with T obeys a second grade polynomial trend.
► The solutes are classified as structure breakers according to Hepler’s criterion.