A reliable model for assessment of melting points of cyclic hydrocarbons containing complex molecular structures, isomers and stereoisomers

Abstract

Cyclic hydrocarbons with desirable melting points are attractive candidates as liquid fuels such as jet fuels due to the presence of high strain energy in some derivatives but available predictive methods may give large deviations for their melting points. A simple model is introduced for reliable prediction of melting points of cyclic hydrocarbons with complex molecular structures, isomers and stereoisomers that include cyclic alkane, alkene and/or alkyne, cage molecules, bridged cyclic and multicyclic hydrocarbon structures. It is based on the number of carbon atoms and two correction terms that correspond to increasing and decreasing values of the melting point resulting from specific structural parameters. Experimental data of melting points for 297 cyclic hydrocarbons were collected from different sources where data of 136 and 161 molecules are used as training and test sets, respectively. The calculated outputs of both training and test sets for the new model are compared with one of the best predictive methods. The values of average absolute deviation (AAD) of the training set for the new and comparative models are 21.0 and 52.1 K, respectively. Meanwhile, the values of AAD of the test set for these models are also 23.8 and 40.6 K, respectively. Further statistical parameters also confirm the higher reliability of the new model.