Abstract: Densities of ternary mixture (1-butanol+N,N-dimethylformamide+water) at 298.15 Khave been measured. The apparent molar volumes of 1-butanol in DMF+water mixed solvents have been evaluated from density data. Asimilar feature between Φ₂^0,E～f_m and V_DMF^E～f_mcurves, and opposite feature between B 1 ～f_mand Φ₂^0,E～f_mcurves have been observed, where Φ₂^0,Eis the excess apparent molar volume of 1-butanol at infinite dilution, V_{DMF^{E is the excess partial molar volume of DMFin DMF+water binary mixture, B 1 is the second volumetric virial coefficients and fmis the mole fraction of DMFin DMF+water mixed solvents. These relationships reflec the interplay between solute solvation and solutesolute interactions. For hydrophobic solutes such as 1butanol, the stronger the solute was hydrated, the weaker the solutesolute interactions become. By using the special particle theory, the effect of cavity volume and interaction volume on the features of B1～fmand Φ20～fmcurves have been discussed.}}

Key words: 1-Butanol, DMF, Water, Apparent molar volume, Solute solvation, Special particle theory