The density and sound velocity of the solutions of room temperature ionic liquid 1-butyl-3-methyl-imidazolium bromide, BMIMBr, in water, methanol, and ethanol have been measured at T = (298.15 to 318.15) K at atmospheric pressure. Apparent molar volume and the apparent molar isentropic compressibility values have been evaluated from the experimental density and sound velocity data and fitted to a Redlich + Mayer type equation from which the apparent molar volume and apparent molar isentropic compressibility of the solutions at the infinite dilution have also been calculated at working temperatures. The obtained limiting apparent molar volume values and the limiting slope of the apparent molar volume versus molality(1/2) indicate that ionic liquid + solvent interactions in water are stronger than the alcoholic solutions. An intersection point in isotherms of isentropic compressibility was observed for aqueous solutions may be an indication of the structural interactions and clathrate formation. (c) 2005 Elsevier Ltd. All rights reserved.