Physical properties of liquid hexane and derived polar by-products of hexane autoxidation: molecular dynamics calculations using the TraPPE-UA force field

Abstract

Densities, viscosities, thermal conductivities and dielectric constants were calculated at ambient conditions for liquid n-hexane and the aldehyde, ketone, alcohol and carboxylic acid obtained by artificially modifying the tail group of alkane. All calculations were carried out using non-equilibrium molecular dynamics simulations relying on available TraPPE-UA parameterisations. Comparison with experimental data allowed us to evaluate the suitability of such TraPPE-UA models in the estimation of the aforementioned properties. In general, the calculated viscosities and dielectric constants were in good agreement with the experimental observations. Conversely, the simulated thermal conductivities underestimated the empirical data by almost the same amount . In addition, we used our results to judge the influence of the terminal chemical group in determining the physical characteristics of potential by-products generated during hydrocarbon autoxidation. The viscosity of the alkane was found to be affected most by the presence of linear acids. Conversely, its dielectric response was influenced most by linear alcohol traces.