Excess enthalpies, excess isobaric heat capacities, densities and speeds of sound of the mixtures ethyl formate + benzene, + ethanol, and + 2,2,2-trifluoroethan-1-ol, were measured at 298.15 K; the densities were also measured at 303.15 K. The excess volumes were estimated from the density, and the isentropic and isothermal compressibilities and isochoric heat capacities were estimated from the density, speed of sound and isobaric heat capacity. The H m E of the HCOOC 2H 5 + CF 3CH 2OH system changes anomalously from negative (minimum value −140 J mol −1) to positive (maximum 200 J mol −1) with the concentration of HCOOC 2H 5. The C P,m E is large and negative (the minimum value is −6.3 J K −1 mol −1). However, V m E, κ S E and κ T E for the mixture are very large but positive, and these maxima are 0.8 cm 3 mol −1, 52 TPa −1, and 98 TPa −1 respectively. All of these can be attributed to the formation of unlike association and the destruction of cluster structure in pure CF 3CH 2OH by mixing, and the breakage of intermolecular association of HCOOC 2H 5. The H m E and C P,m E of HCOOC 2H 5 + C 2H 5OH are large and positive, and their maximum values are about 1380 J mol −1 and 9.2 J K −1 mol −1. However, the V m E, κ S E and κ T E are very small. Comparing with the mixture of CH 3COOC 2H 5 + C 6H 6 reported before, the H m E (maximum 350 J mol −1) and V m E (maximum 0.29 cm 3 mol −1) of the HCOOC 2H 5 + C 6H 6 system are apparently larger, although the C P,m E, κ S E and κ T E are also very small.