The application of the perrin–agishev model for calculation of the translational diffusion coefficients of liquid dichloroalkanes

Abstract

The article presents the translational diffusion coefficients calculated for dichloroalkanes series C _n H_{2 n} Cl₂ (where n = 6, 8, 10, 12) in the liquid state, with the use of the Perrin and Agishev model. It has been shown that the molecules of dichloroalkanes assume a mutually parallel arrangement in three possible coordinations. The model of arrangement, orientations and packing of the molecules has been presented. The activation parameters of the compounds studied have been discussed. The physical and structural properties of the liquids studied (macroscopic density, electron density and molecular weight) are correctly described within the van der Waals model predicting their orientations and packing. The formulae linking the diffusion, viscosity and temperature for the liquids have been presented. The assumption that each molecule can be approximated by an ellipsoid of the semiaxes lengths a, b and c has been justified. The translations become slower with increasing volume and weight of the molecule. The diffusion coefficients decrease with increasing molecular weight.

Keywords:

• Diffusion
• X-ray analysis
• Model of Perrin and Agishev
• Viscosity
• Dichloroalkanes

Acknowledgement

The work was performed within the research project No. 201319101 KBN financially supported by the State Committee for Scientific Research (Republic of Poland).