where 𝑁 𝑘 is the number of 𝑘 groups in the molecule, 𝑀 is the component molar mass, 𝑁 𝑐𝑠 is the number of carbons in the alcoholic part of the ester and 𝑁 𝑐 is the total number of carbon atoms in the molecule. The remaining parameters are obtained by regression.