Forecasting the smallest super molecular formations for alkanes of normal and isomeric structure

DmytroTregubov

National University of Civil Defence of Ukraine

http://orcid.org/0000-0003-1821-822X

Andrei Sharshanov

National University of Civil Defence of Ukraine

http://orcid.org/0000-0002-9115-3453

Dmitry Sokolov

National University of Civil Defence of Ukraine

https://orcid.org/0000-0002-7772-6577

Flora Tregubova

National University of Civil Defence of Ukraine

https://orcid.org/0000-0003-2497-7396

DOI: https://doi.org/10.52363/2524-0226-2022-35-5

Keywords: cluster, substance, melting point, "even-odd" molecules, alkanes, normal and isomeric structure, calculation

Аnnotation

The problem of melting points adequate prediction (t_mp) hydrocarbons as a base temperature for many practical calculations, based on modeling their supramolecular structure, is considered. Oscillatory dependences of t_mp(n_С) in homologous series of normal and isomeric structure alkanes are analyzed. A review of methods for taking into account in the parameters calculation of substance properties of the "evenness-oddness" effect of molecules by carbon atoms number for alkanes is performed. The substance smallest structural unit in the form of a cluster with a certain coordination number is considered. It is shown that dependences of t_mp on the molecular weight of the cluster for hydrocarbons and metals differ significantly. A conclusion is made about the determining influence of the cluster structure on t_mp (linear structure for hydrocarbons and in the form of a crystal lattice for metals). 3 calculation methods of the cluster length on the values basis of the molecule l_av and coordination number are considered. It is found that calculations based on one molecule parameters give insufficient correlation for t_mp alkanes – 0,92, after adapting the method to determine the cluster length reached R²=0,984, the calculation of the equivalent cluster length increases R² to 0,993. It is shown that calculation of t_mp should take into account the equivalent length n_Сeq and the molecular weight M of the cluster. The complex parameter "melting ease" as n_СeqM^0,2 and the corresponding analytical dependence for tmp with R²=0,99 for 90 compounds of series of hydrocarbons with the normal and isomeric structure were developed. The presence and determining influence of the substance cluster structure on t_mp is proved indirectly. The predicting possibility for t_mp(n_С) of hydrocarbons with the oscillation adequate reflection for the t_mp(n_С) dependence is achieved.

References

1. Tregubov, D., Tarakhno, О., Sokolov, D., Trehubova, F. (2021). The identification of hydrocarbons cluster structure by melting point. Problems of Emergency Situations, 34, 94–109. doi:10.52363/2524-0226-2021-34-7
2. Boese, R., Weiss, H.-Ch, Bläser, D. (1999). The Melting Point Alternation in the Short-Chain n-Alkanes: Single-Crystal X-Ray Analyses of Propane at 30 K and of n-Butane to n-Nonane at 90 K. Angewandte сhemie, 38(7), 988– doi:10.1002/(SICI)1521-3773(19990401)38:7<988::AID-ANIE988>3.0.CO;2-0
3. Atume, E. T. (2020). Absolute Prediction of the Melting and Freezing Points of Saturated Hydrocarbons Using Their Molar Masses and Atume’s Series. Advanced Journal of Chemistry, 3(2), 122– doi:10.33945/SAMI/AJCA.2020.2.2
4. Li, H., Higashi, H., Tamura, K. (2006). Estimation of boiling and melting points of light, heavy and complex hydrocarbons by means of a modified group vector space method. Fluid Phase Equilibria, 239(2), 213–222. doi:10.1016/j.fluid.2005.11.004
5. Črepnjak, М., Tratnik, N., Pleteršek, Р. (2018). Predicting melting points of hydrocarbons by the Graovac-Pisanski index. Fullerenes, Nanotubes and Carbon Nanostructures, 26 (5), 239– doi:10.1080/1536383X.2017.1386657
6. Thalladi, V. and Boese, R. (2000). Why is the melting point of propane the lowest among n-alkanes? New J. Chem., 24, 579– doi:10.1039/B004283H
7. Doroshenko, I. Yu. (2017). Spectroscopic study of cluster structure of n-hexanol trapped in an argon matrix. Low Temperature Physics, 3(6), 919–926. doi:1063/1.4985983
8. Gun’ko, V., Nasiri, R., Sazhin, S. (2014). A study of the evaporation and condensation of n-alkane clusters and nanodroplets using quantum chemical methods. Scientific Reports. Fluid Phase Equilibria, 366, 99–107. doi:10.1016/j.fluid.2014.01.010
9. Yang, K., Cai, Zh., Jaiswal, A., Tyagi, M., Moore, J.S., Zhang, Y. (2016). Dynamic Odd–Even Effect in Liquid n-Alkanes near Their Melting Points. Angewandte Chemie, 55(45), 14090–14095. doi:10.1002/anie.201607316
10. Tarakhno, О. V., Tregubov, D. G. et al. (2020). Osnovni polozhennya protsesu horinnya. Vynyknennya protsesu horinnya. Kharkiv, NUTSZU, 408. Retrieved from: http://repositsc.nuczu.edu.ua/handle/123456789/11382
11. Litinskii, G. B. (2008). Statistical thermodynamics of mixtures of polar liquids in the model of hindered rotation of molecules. J.Ph.Ch, 82(9), 1475–1479. doi:10.1134/S0036024408090124
12. Tregubov, D. G., Tarakhno, О. V., Kyreev, O. O. (2018). Influence of cluster structure of liquids technical mixtures on the value of characteristic temperatures. Problems of Emergency Situations, 28, 99–110. doi:10.5281/zenodo.2598054
13. Laguna, A. (2008). Modern Supramolecular Gold Chemistry: Gold Metal Interactions and Applications. Weinheim, WileyVCH, 505. doi:10.1002/9783527623778
14. Tregubov, D., Gonar, S. (2015). Sproshchennya ta pidvyshchennya tochnosti rozrakhunku temperatury samospalakhuvuannya spyrtiv. Naukovyy visnyk budivnytstva, 80, 278–281. Retrieved from: http://repositsc.nuczu.edu.ua/handle/123456789/3229
15. Hydrocarbons – Physical Data. Engineering ToolBox. (2022, 24.04). Retrieved from: https://www.engineeringtoolbox.com/hydrocarbon-boiling-melting-flash-autoignition-point-density-gravity-molweight-d_1966.html
16. Novikov, O. I., Petrukhin, S. Yu. (2017). Orhanichna khimiya. Kharkiv, FVP NTU KhPI, URL: https://core.ac.uk/download/pdf/196573292.pdf