Fickian and thermal diffusion coefficients of binary mixtures of isobutylbenzene and n-alkanes at different concentrations from the optical beam deflection technique

Filipe Arantes Furtado; Abbas Firoozabadi

doi:10.1063/1.5082963

Fickian and thermal diffusion coefficients of binary mixtures of isobutylbenzene and n-alkanes at different concentrations from the optical beam deflection technique

J Chem Phys. 2019 Jul 14;151(2):024202. doi: 10.1063/1.5082963.

Authors

Filipe Arantes Furtado¹, Abbas Firoozabadi¹

Affiliation

¹ Chemical Engineering Department, Yale University, 9 Hillhouse Avenue, New Haven, CT, 06511, United States.

PMID: 31301727
DOI: 10.1063/1.5082963

Abstract

We report the Fickian diffusion (D₁₂), thermal diffusion (D_T), and Soret (S_T) coefficients of 4 binary mixtures of isobutylbenzene (IBB) and n-alkanes (n-hexane, n-octane, n-decane, and n-dodecane) at 298.15 K and atmospheric pressure. The concentration is varied in the whole range. The Optical Beam Deflection technique is used in the measurements. We first verify our measurements with published data. The concepts of molecular similarity and mobility are invoked to investigate D₁₂ and D_T dependency on molecular weight and concentration. Our analysis reveals a combined effect of molecular mobility and similarity dependency of D_T on concentration and molecular weight of the n-alkanes. The mobility of individual molecules describes the D₁₂ dependency on concentration and molecular weight of alkanes. The dependency of D₁₂ on concentration weakens as the n-alkane molecular weight increases. D_T increases with IBB concentration for nC₆ and nC₈ and decreases with IBB concentration for nC₁₀ and nC₁₂. In this work, we demonstrate that the temperature contrast factors can be accurately estimated without the use of an interferometer.