High volatility of superbase-derived eutectic solvents used for CO₂ capture

Area of Science:

• Chemistry
• Materials Science
• Environmental Science

Background:

• Eutectic solvents (ESs) are commonly assumed to be nonvolatile.
• High volatility in solvents can lead to flammability hazards, explosion risks, reduced regeneration efficiency, and air pollution.

Purpose of the Study:

• To investigate the volatility of superbase-derived ESs.
• To understand the implications of ES volatility for CO2 capture and solvent design.

Main Methods:

• Experimental analysis of mass loss in ESs at room temperature and atmospheric pressure.
• Characterization of the volatilization mechanism of a specific ES (ethylene glycol: 1,8-diazabicyclo[5.4.0]undec-7-ene).

Main Results:

• Superbase-derived ESs exhibit significant volatility, with mass loss up to 43.5% after 20 hours at 25 °C.
• The ES ethylene glycol: 1,8-diazabicyclo[5.4.0]undec-7-ene (EG:DBU) demonstrates a three-stage volatilization process.
• ESs remain volatile even after CO2 capture.

Conclusions:

• The assumption of nonvolatility for ESs is incorrect, particularly for superbase-derived systems.
• The high volatility of these ESs necessitates safety considerations for applications like CO2 capture.
• Findings provide insights for designing novel ESs with reduced volatility.