【Abstract】 The heat capacities C_p and excess heat capaciries C_p~E of four binarysystems cyclohexanone-benzene, cyclohexanone-toluene, cyclohexanone-elhylbenzene,cyclohexanone-isopropylbenzene are measured at 298.15K and under latm by the Calvet microcalorimeter.The error of mole fraction is ±0.0002, of C_p±0.0085, of C_p~E±0.055,arld of temperature ±0.01K. The C_p~E values of the four systems are always positive forwhole ranges of mole fractions. The excess heat capacities decrease with the increase ofnumber of carbon atoms of aromatic hydrocarbon. The experimental results are at variance with the Prigogine-Flory corresponding state theory. The effect of changes of solutionorientational order on C_p~E is also investigated. The intermolecular orientational order entropy parameter θ2S12 is introduced to the Flory model. The Flory model including θ2S12is improved for the estimation of _p~E values.更多还原