Determination of molecular diffusion coefficient in n-alkane binary mixtures: empirical correlations

Area of Science:

• Physical Chemistry
• Thermodynamics
• Transport Phenomena

Background:

• Understanding molecular diffusion is crucial for chemical engineering processes.
• N-alkanes are fundamental components in many industrial applications.

Purpose of the Study:

• To measure molecular diffusion coefficients in n-alkane binary mixtures.
• To investigate the relationship between diffusion coefficient, viscosity, and concentration.
• To develop a predictive model for diffusion coefficients.

Main Methods:

• Sliding symmetric tubes technique used for diffusion measurements.
• Experiments conducted at 298 K and 1 atm.
• Systematic variation of n-alkane chain lengths and concentrations.

Main Results:

• Diffusion coefficient is inversely proportional to mixture viscosity at 0.5 mass fraction.
• Diffusion coefficients were measured for nC(i)-nC(6), nC(i)-nC(10), and nC(i)-nC(12) series.
• A method to calculate diffusion coefficients from molecular weight and viscosity was established.

Conclusions:

• Molecular diffusion in n-alkane binary mixtures is strongly influenced by viscosity.
• The developed calculation method provides a reliable way to predict diffusion coefficients.
• Findings contribute to the understanding and modeling of transport phenomena in liquid mixtures.