Binary Diffusion Coefficients for Short Chain Alcohols in Supercritical Carbon Dioxide-Experimental and Predictive...

Area of Science:

• Thermodynamics
• Chemical Engineering
• Physical Chemistry

Background:

• Supercritical fluids, particularly carbon dioxide, are crucial in various industrial processes.
• Understanding diffusion in these systems is vital for process optimization.
• Short-chain alcohols are common components in chemical reactions and separations.

Purpose of the Study:

• To experimentally determine binary diffusion coefficients.
• To investigate the impact of temperature, density, and molecular size on diffusion.
• To evaluate the accuracy of existing correlation models.

Main Methods:

• Taylor dispersion technique was employed for measurements.
• Experiments were conducted at temperatures from 306.15 K to 331.15 K.
• Measurements were performed along the 10.5 MPa isobar of supercritical carbon dioxide.

Main Results:

• Binary diffusion coefficients were found to be in the order of 10^-8 m² s^-1.
• Diffusion coefficients showed clear dependence on temperature, solvent density, and solute molecular size.
• Classic correlation models generally overestimated experimental values.

Conclusions:

• Existing models are limited in accurately predicting diffusion coefficients in supercritical carbon dioxide.
• Model accuracy is restricted, particularly in lower-density regions.
• Further refinement of models is needed for reliable predictions in supercritical systems.