Understanding interactions between lignin and ionic liquids with experimental and theoretical studies during catalytic depolymerisation

Effect of Acidity of Ionic Liquids on Hydrogen Bonding Interaction between Ionic Liquids and Lignin Monomers

“…This study also affirmed that no π‐π or p‐Π interactions (e. g. –NH/π, ‐OH/π, ‐CH/π etc.) between neither imidazolium (cation) ([BMIM][Cl] IL) nor Chloride (anion) and benzene (cumene) rings were detected, due to non‐alteration in the chemical shift value, which was also proven in the previous reports . Eventually, the ionic charge on ILs is considered as neutral.…”

“…Moreover, by varying the cation and anion of imidazolium based ILs, catalytic and interaction results have been varied and shown in previous reports . In view of this observation, the experimental {NMR (1D: 1 H/ 13 / 15 N and 2D: HSQC/HMBC/NOESY) and RAMAN) and theoretical (DFT) studies were carried out to show the actual mode of interaction via altering the combination of cations and anions within lignin derived aromatic monomers, dimers and actual substrate lignin with ILs . These findings have pointed out that cations have more specific interaction compare to anion which is confirmed from literature as well ,.…”

“…However, it is a combination of cation and anion ions and by altering the ions, they can gain acidic or basic properties. Moreover, by varying the cation and anion of imidazolium based ILs, catalytic and interaction results have been varied and shown in previous reports . In view of this observation, the experimental {NMR (1D: 1 H/ 13 / 15 N and 2D: HSQC/HMBC/NOESY) and RAMAN) and theoretical (DFT) studies were carried out to show the actual mode of interaction via altering the combination of cations and anions within lignin derived aromatic monomers, dimers and actual substrate lignin with ILs .…”

“…In contrast, the interaction of cellulose in ionic liquids is well documented in literature . Few reports are based on the lignin or natural bioactive homologues molecules and ionic liquids interaction,, the interactions were confirmed by experimental and computational mechanistic studies . The interaction between a protonated histidine and a Π system plays an important role for the stabilising protein structure and ligands in the cells and known as a cation/Π interaction, donor‐acceptor/charge‐transfer/Π/Π or CH/Π interaction .…”

Oxidative depolymerization of lignins for producing aromatics: variation of botanical origin and extraction methods

“…Several approaches, using or not catalysts, were reported in order to convert lignins into valuable chemicals and were partly reviewed 6,[8][9][10][11][12][13] : they include, hydrolysis [14][15][16][17][18][19][20] , solvolysis 2,[21][22][23][24][25][26][27][28][29] , thermal liquefaction [30][31][32][33][34][35][36] , pyrolysis [37][38][39][40][41] , hydrogenolysis [42][43][44][45][46][47][48][49][50][51][52][53][54][55] , hydrogenation 43,…”