A novel high-pressure, ultrasonic cell of extremely reduced internal dimensions (similar to0.8 (.) 10(-6) m(3)) and good precision for the determination of the speed of propagation of sound in liquids was conceived and built. It makes use of a non-intrusive methodology where the ultrasonic transducers are not in direct contact with the liquid sample under investigation. The new cell was used to carry out speed of sound measurements in 2-propanone (acetone) in broad ranges of temperature (265 < T/K < 340) and pressure (0.1 < p/MPa < 160). (p,p, T) data for acetone were also determined but in a narrower T,p range (298 to 333 K; 0.1 to 60 MPa). In this interval, several thermodynamic properties were thus calculated, such as: isentropic (kappa(s)) and isothermal (kappa(T)) compressibility, isobaric thermal expansivity (alpha(p)), isobaric (c(p)) and isochoric (c(v)) specific heat capacity, and the thermal pressure coefficient (gamma(v)). Comparisons with values found in the literature generally show good agreement. (C) 2004 Elsevier Ltd. All rights reserved.