Estimation of melting point of flexible molecules: Aliphatic hydrocarbons

Molecular flexibility and rotational symmetry were used to develop an empirical equation for predicting the entropy of fusion for non‐rigid organic molecules. The equation was applied to a series of alkanes of varying degrees of flexibility. The heats of fusion for these compounds were estimated from additive constitutive properties. The melting point, TM, is equal to ΔH/ΔS, the ratio of heat of fusion to entropy of fusion. The equations developed for ΔH and ΔS were successfully used to estimate the melting points of these compounds.