Enthalpies of phase change for para substituted benzonitriles applied solution calorimetry-additive scheme approach

Benzonitriles are basic compounds in manufacturing LED lamps. To get high quality and stability of the lamps it is crucial to know phase transition thermodynamics. Therefore, studying on solvation and evaporation enthalpies of the substituted benzonitriles have been crucial working. The solvation and evaporation enthalpies are determined the additive scheme approach and solution calorimetry method. In addition, evaporation enthalpy measured at 298.15 K solution calorimetry method from solvation enthalpy and solution enthalpy of the compounds. Enthalpy of solution values of the compounds into benzonitrile solvent are measure in high accuracy which their standard deviation are less than 1 kJ mole-1. Accordingly, the values obtained in this work were compared to those literature data, there is got them with higher accuracy as well as the para position affect on phase transition enthalpies.