Optimized intermolecular potential for nitriles based on Anisotropic United Atoms model

Mohamed Hadj-Kali (1) , Vincent Gerbaud (1) , Xavier Joulia (1) , Corinne Lacaze-Dufaure (2) , Claude Mijoule (2) , Philippe Ungerer (3)

1 LGC - Laboratoire de Génie Chimique
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 Institut Français du Pétrole

An extension of the Anisotropic United Atoms intermolecular potential model is proposed for nitriles. The electrostatic part of the intermolecular potential is calculated using atomic charges obtained by a simple Mulliken population analysis. The repulsion-dispersion interaction parameters for methyl and methylene groups are taken from transferable AUA4 literature parameters [Ungerer et al., J. Chem. Phys., 2000, 112, 5499]. Non-bonding Lennard-Jones intermolecular potential parameters are regressed for the carbon and nitrogen atoms of the nitrile group (–CN) from experimental vapor-liquid equilibrium data of acetonitrile. Gibbs Ensemble Monte Carlo simulations and experimental data agreement is very good for acetonitrile, and better than previous molecular potential proposed by Hloucha et al. [J. Chem. Phys., 2000, 113, 5401]. The transferability of the resulting potential is then successfully tested, without any further readjustment, to predict vapor-liquid phase equilibrium of propionitrile and n-butyronitrile.

Mots clés: Nitriles; Vapor-Liquid Equilibrium; Molecular Simulation; Gibbs Ensemble Monte Carlo Method; Anisotropic United Atoms model

Domaines: Génie chimique

Mohamed Hadj-Kali, Vincent Gerbaud, Xavier Joulia, Corinne Lacaze-Dufaure, Claude Mijoule, et al.. Optimized intermolecular potential for nitriles based on Anisotropic United Atoms model. Journal of Molecular Modeling, 2008, vol. 14 n° 7., 571-580 available on : http://oatao.univ-toulouse.fr/928/1/gerbaud_928.pdf. ⟨10.1007/s00894-008-0301-4⟩. ⟨hal-00475978⟩