Estimating the melting point, entropy of fusion, and enthalpy of fusion of organic compounds via SPARC

The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency’s administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Abstract

The entropy of fusion, enthalpy of fusion, and melting point of organic compounds can be estimated through three models developed using the SPARC (SPARC Performs Automated Reasoning in Chemistry) platform. The entropy of fusion is modelled through a combination of interaction terms and physical descriptors. The enthalpy of fusion is modelled as a function of the entropy of fusion, boiling point, and flexibility of the molecule. The melting point model is the enthalpy of fusion divided by the entropy of fusion. These models were developed in part to improve SPARC’s vapour pressure and solubility models. These models have been tested on 904 unique compounds. The entropy model has a RMS of 12.5 J mol⁻¹ K⁻¹. The enthalpy model has a RMS of 4.87 kJ mol⁻¹. The melting point model has a RMS of 54.4°C.

Keywords:

• Entropy of fusion
• enthalpy of fusion
• melting point
• organic compounds
• SPARC

Acknowledgements

The authors would like to thank the University of Georgia for their support of this project.

Notes

The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency’s administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.