Solubility Parameter of Carbon Dioxide-An Enigma

Area of Science:

• Physical Chemistry
• Thermodynamics
• Solvent Science

Background:

• Carbon dioxide solubility is vital for chemical processes.
• Hildebrand solubility parameter (δH) predicts dissolution via dispersion forces.
• Standard δH calculation is unsuitable for gaseous CO2.

Purpose of the Study:

• To analyze and discuss discrepancies in reported δH values for carbon dioxide.
• To address the challenge of determining δH for a gas at relevant temperatures.
• To explore Hansen solubility parameters for CO2 due to its polarizability and hydrogen bonding.

Main Methods:

• Review and analysis of indirect methods for determining δH(CO2,T).
• Consideration of Hansen solubility parameters for CO2.
• Examination of δH for supercritical CO2 (δH(scCO2,T,P)).

Main Results:

• Significant discrepancies exist in reported δH(CO2,T) values.
• Indirect methods are necessary for gaseous CO2 solubility parameter determination.
• Hansen parameters offer additional insights into CO2-solvent interactions.

Conclusions:

• Accurate δH determination for CO2 is complex but essential.
• Understanding CO2 solubility parameters is key for its use as a solvent, especially in supercritical form.
• Further research is needed to reconcile conflicting δH data.