About the possibility of applying empirical methods of estimation of standard enthalpies of formation of organic compound for fullerenes

Due to the high practical significance and, as a consequence, active study of carbon nanomaterials, the question of methods for investigating their physicochemical, in particular, thermodynamic properties is relevant. In the present work, several approaches are considered to estimate the standard enthalpy of formation of fullerenes in the gas phase. The standard enthalpies of formation of C-60 and C-70 fullerenes in the gas phase have been calculated using the Laidler, Franklin, Souders-Matthews-Hurd and Joback-Reid methods. A number of analytical dependences of the standard enthalpy of formation in the gas phase on the number of carbon atoms in fullerenes molecules were obtained. The obtained values were compared with experimental data and the relative error of calculation was determined. It is concluded that the proposed methods are limitedly applicable for determination of standard enthalpy of formation of fullerenes in the gas phase. The obtained values of the standard enthalpy of formation by the most satisfactory method from the considered ones for fullerenes C-60 and C-70 are 2448,90 and 2857,05 kJ/mol, and the relative errors are 4,44% and 5,95%, respectively. This is the Souders-Matthews-Hurd method. The presented analytical dependences allow for an express estimation of the standard enthalpy of formation of fullerenes in the gas phase with a small amount of input data.