Measurement and correlation of solid–liquid equilibrium for abietic acid + alcohol systems at atmospheric pressure

Using a laser monitoring observation technique, the solubility of abietic acid in alcohols (isopropanol, isobutanol, 1-pentanol, isopentanol) has been measured by a dynamic method at atmospheric pressure. The melting point and enthalpy of fusion of abietic acid were determined by differential scanning calorimetry (DSC). The solubility of abietic acid in four solvents increased with an increase of temperature and the number of carbon atoms of alcohol chain, respectively. Experimental solubility data were correlated by means of the Wilson, NRTL and λh equations utilizing parameters derived from the related solid–liquid equilibrium (SLE) data. The results indicated that the above three equations are suitable for the description of the solubility data of abietic acid in the alcohols investigated.