Microwave-assisted extraction of lignin from coconut coir using deep eutectic solvents and its valorization to aromatics

High-purity lignin from selective biomass fractionation with ternary deep eutectic solvents

“…31 Other authors screened several combinations of choline chloride-carboxylic acid DES and reported that the weaker lactic acid provided friendlier separation of lignin without damaging the other valuable fibres. [32][33][34] Furthermore, Mankar et al (2022) were able to achieve an extremely high lignin yield of 82% if the coconut coir was pretreated with choline chloride/lactic acid (ChCl/LA in a 1 : 4 molar ratio) in combination with microwave heating. Although choline chloride is a ubiquitous chemical, there is little literature examining delignification using DES based on other hydrogen bond acceptors.…”

Economical production, optimization, and characterization of bio-vanillin (4-hydroxy-3- methoxybenzaldehyde) using lignocellulosic waste

“…There is a vast scope for using coconut coir as they are rich in lignocellulosic biomass (Lebedeva et al, 2022). Previous reports describe the different approaches to converting coconut coir waste's lignocellulosic biomass to valorize into value-added aromatics (Mankar et al, 2022;Rejani and Radhakrishnan, 2022). Lignocellulosic biomass is an inexpensive, zero-waste raw material (Harshvardhan et al, 2017).…”

New Parameters to Model Microwave-Assisted Deep Eutectic Solvent Extraction of Lignin Using Analytical Pyrolysis–GC/MS

“…In most of the available literature, optimal extraction conditions are established by determining the mass yield of lignin as a function of experimental parameters. Structural features of the lignins obtained under optimal conditions are evaluated with infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies, ,, thermogravimetric (TG) analysis, size-exclusion or gel permeation chromatography, and analytical pyrolysis–gas chromatography–mass spectrometry (Py–GC/MS). ,, However, very limited information is available on how these features are affected by the experimental parameters . A more detailed knowledge of the structure and composition of DES lignin as a function of the process parameters could disclose new strategies to obtain lignin with desirable properties that could prove more suitable for specific upgrading or valorization strategies.…”

“…26,27 In most of the available literature, optimal extraction conditions are established by determining the mass yield of lignin as a function of experimental parameters. Structural features of the lignins obtained under optimal conditions are evaluated with infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies, 12,28,29 thermogravimetric (TG) analysis, 19 size-exclusion or gel permeation chromatography, 26 and analytical pyrolysis−gas chromatography−mass spectrometry (Py−GC/MS). 15,20,30 However, very limited information is available on how these features are affected by the experimental parameters.…”

“…Numerous papers are currently available describing the extraction of lignin with DESs. − DESs obtained with choline chloride and carboxylic acids are particularly promising for lignin extraction and solubilization. , Microwave-assisted heating has also shown promising results, significantly reducing the time and temperature required to perform the extraction. − The use of microwave-assisted heating for large-scale lignin processing is still an unexplored field, but applications for the extraction of other materials have been discussed in recent publications. − Once isolated from the carbohydrate fraction of lignocellulose, lignin is usually retrieved by precipitation with an antisolvent, the most common being water. The performances of water as antisolvent generally depend on the presence of pH modifiers, the structural features of lignin, and its molecular weight distribution .…”