Thermodiffusion, molecular diffusion and Soret coefficients of aromatic+n-alkane binary mixtures

Area of Science:

• Physical Chemistry
• Thermodynamics
• Transport Phenomena

Background:

• Understanding thermodiffusion is crucial for predicting mixture behavior under thermal gradients.
• Aromatic-alkane mixtures are common in industrial processes, necessitating detailed property analysis.

Purpose of the Study:

• To measure the thermodiffusion coefficient for 51 binary liquid mixtures.
• To investigate the relationship between thermodiffusion, mass fraction, and molecular weight.
• To determine molecular diffusion and Soret coefficients for these mixtures.

Main Methods:

• Thermogravitational technique for thermodiffusion coefficient measurement.
• Sliding symmetric tubes technique for molecular diffusion coefficient measurement.
• Analysis of data at 25°C across the entire mass fraction range.

Main Results:

• Thermodiffusion coefficient exhibits a linear dependence on mass fraction for all mixtures.
• Limiting thermodiffusion values in dilute solutions show linear correlation with the inverse of molecular weight product.
• The product of molecular diffusion coefficient and viscosity remains constant for each mixture series.

Conclusions:

• Established linear relationships provide predictive models for thermodiffusion in these systems.
• Findings contribute to the fundamental understanding of transport phenomena in liquid mixtures.
• The constant product of diffusion and viscosity suggests specific interaction dynamics within the studied series.