Insight into the glycerol extraction from biodiesel using deep eutectic solvents

Area of Science:

• Green Chemistry
• Computational Chemistry
• Chemical Engineering

Background:

• Large-scale biofuel production faces challenges with impurity removal, including glycerol.
• Deep eutectic solvents (DESs) offer a promising alternative for extracting glycerol from biodiesel.
• Choline chloride (ChCl)/urea and methyltriphenylphosphonium chloride (MTPPCl)/ethylene glycol (EGL) are effective DESs for glycerol extraction.

Purpose of the Study:

• To investigate the formation mechanism of ChCl/urea and MTPPCl/EGL based DESs.
• To explore the application of these DESs in glycerol extraction from biofuel.
• To elucidate the molecular interactions governing the glycerol extraction process.

Main Methods:

• Density Functional Theory (DFT) calculations using Gaussian09 (B3LYP basis set).
• Classical all-atom molecular dynamics (MD) simulations using Gromacs (GROMOS force field).
• Analysis of intermolecular interactions and hydrogen bond formation.

Main Results:

• Chloride ions play a crucial role in DES-biofuel complex formation.
• High HOMO-LUMO gaps indicate the stability of ChCl/urea and MTPPCl/EGL based DESs.
• DESs exhibit stronger interactions with glycerol than with biofuel, facilitating glycerol extraction.

Conclusions:

• Choline chloride and methyl triphenyl phosphonium-based DESs are effective for glycerol extraction from biofuel.
• DFT and MD simulations provide detailed insights into the molecular mechanisms of DES-mediated glycerol removal.
• The study summarizes the molecular formation and application of these DESs in biofuel purification.