The Enthalpies of Combustion and Formation of Cholesterol [cholest-5-en-3-ol (3 β )].

The enthalpy of combustion of cholesterol was measured in an adiabatic, rotating-bomb calorimeter capable of high precision with relatively small samples. The random error for the experimental measurements was 0.006 percent which may be compared with approximately 0.3 percent for prior investigations on this substance. The results obtained for the enthalpy of combustion and the derived enthalpy of formation together with the estimated overall uncertainties are: $\Delta H{c}^{°}\left({25}^{°}\text{C}\right)=-16524.0\pm 3.9\text{kJ/mol}$ $\Delta H{f}^{°}\left({25}^{°}\text{C}\right)=-674.8\pm 4.1\text{kJ/mol}$ The results of prior investigations are discussed briefly.