Molar Heat Capacity of 1,2-Cyclohexanediol Isomers From (173 to 428) K

Abstract

Heat capacities of cis-1,2-cyclohexanediol and trans-1,2-cyclohexanediol enantiomers have been determined in the solid state in the temperature range T = (173 to 368) K for the cis-isomer and T = (173 to 373) K in the case of the trans-isomer and in the liquid state at temperatures up to 428 K. Measurements were carried out by differential scanning calorimetry using the enthalpic method. For the cis-isomer, the results show that, before the liquid state is reached, a highly disordered phase is formed. The trans-enantiomers show only a one-step fusion process. The values obtained for the solids are quite well predicted by Goodman’s power law group contribution method, except for the lower temperatures. The Rika method was tested for the prediction of liquid state heat capacity values giving results (15 to 20) % lower than the experimental values.