Liquid-liquid equilibrium data of the solubility curves and tie-line end compositions are presented for mixtures of [water (1) + formic acid, or acetic acid, or propanoic acid (2) + 1-heptanol (3)] at T = 293.15 K and P = (1101.3 +/- 0.7) kPa. The properties and liquid-liquid equilibria (LLE) of associated ternary systems have been correlated using a solvatochromic approach SERLAS. The tie-lines were also predicted using the UNIFAC-original model. The proposed model appears to be an improvement in data fit for the ternary systems yielding a mean error of 3.8% for all the systems considered.