The density, viscosity and ultrasonic velocity (2 MHz) of pure solvents: ethanol, MEK and DMF, and BCFA solutions (0.5-4 wt%) were investigated at three different temperatures: 30, 35 and 40 degrees C. Various acoustical parameters such as isentropic compressibility (K,), internal pressure (pi), free volume (V-f), free path length (L-f) and solvation number (S-n) were determined and correlated with concentration (C). Fairly good to excellent linear relationships are observed at three temperatures. The linear decrease of K-s, pi and L-f with C and linear increase with temperature; and linear increase of Vf with C and Tin DMF system, nonlinear increase with C and Tin EtOH system and nonlinear decrease with C and increase with Tin MEK system indicated strong molecular interactions in the solutions and solvophilic nature of BCFA, which is further supported by positive values of solvation number. The observed solvation trend is EtOH > MEK > DMF. (c) 2007 Elsevier B.V. All rights reserved.