Biofuel Extraction Techniques

14Role of CO₂ Triggered Switchable Polarity Solvents and Supercritical Solvents During Biofuel Extraction

Anupama Sharma¹, Pinki Chakraborty^1*, Karthikay Sankhyadhar¹, Sandeep Kumar² and Monisha Singh¹

¹ School of Basic and Applied Sciences, Galgotias University, Greater Noida, India

² School of Pharmacy, Sharda University, Greater Noida, India

Abstract

Switchable-polarity solvents (SPS) or “reversible ionic liquids” usually change their polarity from lower to higher when applied with a trigger such as acids, oxidants, CO₂, etc. Among all, CO₂ is a non-toxic and eco-friendly trigger to synthesize the switchable materials. These CO₂ triggered SPS also find application in the extraction of bio-oils from the organic bio-masses. Due to their non-toxicity, low volatility, and reversible polarity, these are viable solvents for bio-fuel extraction. SPS like N-ethylbutylamine (EBA) and dipropyl amine are used for extraction of bio-oil from microalgae. SPS also acts as recyclable capture-electrolyte media for CO₂ capture to produce syngas. 1, 8-Diazabicyclo [5.4.0] undec-7-ene (DBU), another switchable solvent undergoes transesterification directly to produce biodiesel.

On the other hand, supercritical fluids are also reported as an excellent media to extract bio-fuels from biomasses that are potential and renewable feedstock for production of bio-fuels. In fact, super-critical carbon dioxide (SC-CO₂) with an azeotropic mixture of co-solvents (Hexane + Ethanol) is utilized for the ...