The density, rho, and speed of sound, u, of methyl acetoacetate, ethyl acetoacetate in aqueous 1-butyl-3-methylimidazolium bromide solutions have been measured in the temperature interval T = (288.15, 293.15, 298.15, 303.15, and 308.15) K and atmospheric pressure. These data have been used to calculate apparent molar volumes (V-phi), and apparent molar adiabatic compressibility (K-phi,K-s) of these mixtures. The standard partial molar volumes (V-phi(0)), standard partial molar volumes of transfer (Delta V-phi(0)), standard partial molar adiabatic compressibility (K-phi,s(0)), and standard partial molar adiabatic compressibility (Delta K-phi,s(0)) of transfer have been determined from these density and speed of sound data. The results have been interpreted in terms of solute-solvent interactions. Later, the temperature dependence of the apparent molar volume was used to calculate apparent molar expansivity phi(0)(E) and the Hepler's constant values, (partial derivative V-2(phi)0/partial derivative T-2) to confirm the conclusions obtained from volumetric and speed of sound properties. (C) 2013 Elsevier B.V. All rights reserved.