title: Energetic, entropic, and volumetric effects in nonaqueous associated solutions.
abstract: On the basis of a simple two-state association model (TSAM), a comprehensive study of thermodynamic response functions for nonaqueous associated solutions is presented. The excess isobaric heat capacities C(p)(E)(T) and excess thermal expansivities V(p)(E) ≡ (∂V(E)/∂T)(p) for a number of alcohol-alkane, amine-alkane, alcohol-ether, and alcohol-alcohol mixtures have been experimentally determined at atmospheric pressure within 278.15-338.15 K for C(p)(E) and 283.15-333.15 K for V(p)(E)(T). A rich variety (in some cases unreported) of temperature dependences for C(p)(E)(T) but also for V(p)(E)(T) curves has been observed. This thermodynamic information has been rationalized with the TSAM, which is found to qualitatively account for all observations. Specifically, the model provides a detailed dissection of the energetic and entropic effects of association that are reflected on C(p)(E)(T), and of the volumetric effects that are echoed on V(p)(E)(T). The latter, almost unexplored to date, are found to be opposite to what is currently being conjectured for "low-temperature water", and they stimulate further experimental studies on aqueous solutions of nonelectrolytes.
authors.affiliation: Departamento de Física Aplicada, Universidad de Vigo, Campus del Mar, As Lagoas s/n, Ourense 32004, Spain.
authors.forename: Concepción
authors.initials: C
authors.lastname: Paz-Ramos
authors.forename: Claudio A
authors.initials: CA
authors.lastname: Cerdeiriña
authors.forename: Miguel
authors.initials: M
authors.lastname: Costas
mesh_terms: D000438:Alcohols / Q000737:chemistry; D000473:Alkanes / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D001274:Atmospheric Pressure; D004573:Electrolytes / Q000737:chemistry; D019277:Entropy; D004987:Ethers / Q000737:chemistry; D008958:Models, Molecular; D012996:Solutions / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000438:Alcohols; D000473:Alkanes; D000588:Amines; D004573:Electrolytes; D004987:Ethers; D012996:Solutions; D014867:Water