Fitting the heat capacity of liquid n-alkanes: new measurements of n-heptadecane and n-octadecane

Literature data for the molar heat capacities of liquid n-alkanes from pentane to hexacosane were fitted to a function of temperature and number of carbon atoms in the chain. The part of the heat capacity curves directly after the melting point was not taken into consideration. The function Cp = {43.9 + 13.990 (n − 1) + 0.05430·(n − 1)T} J K−1 mol−1 describes the experimental data to within the experimental error. The average percentage deviation is 0.18%. New measurements for the liquid heat capacity of heptadecane and octadecane are reported.