Understanding pretreatment efficacy of four cholinium and imidazolium ionic liquids by chemistry and computation

Abstract

Understanding specific combinations of cations and anions of ionic liquids for biomass pretreatment.

Efficient biomass pretreatment using ionic liquids derived from lignin and hemicellulose

“…Taken together, compositional analysis and molecular modeling data suggest that lignin removal efficiency is a better indicator of switchgrass pretreatment performance compared with β and net basicity values when comparing benzylammonium and furfurylammonium ILs to those of imidazolium. These results are in agreement with previous findings in our group whereby cholinederived ILs with high lignin removal efficiency and high experimentally obtained β values resulted in high sugar yields across a broad range of pretreatment temperatures (42). It is thought that the mechanism of action of the lignin-and hemicellulose-derived ILs is therefore more akin to other biologically derived ILs, such as ILs prepared from choline.…”

“…A slight shielding of the methylene carbons in the α position were also observed when converting the amine δ = 45.9 ppm (2C) and δ = 54.8 ppm (1C) to the IL δ = 45.3 ppm (2C) and δ = 54.6 ppm (1C PO 4 ] were also selected based on their subtle differences in polarity and substituent effects. The polarity of an IL has been correlated with its ability to solubilize both lignin (42,43) and cellulose (44)(45)(46) PO 4 ] were used to dissect the role of these substituents on the relative acidity of the cation and relate these effects to biomass pretreatment.…”

“…Quantum chemical reactivity descriptors predicted acidity, basicity, and net basicity, and showed good correlation with experimentally observed values for [C 2 mim][OAc] (4). These results provide a basis to describe the observed experimental delignification trend for a set of ILs (42). These descriptors were used to derive the molecular basicity, acidity, and net basicity values for the [C 2 where E is the total energy of the system, N is the number of electrons in the system, and vðrÞ is the external potential.…”

Life-Cycle Greenhouse Gas and Water Intensity of Cellulosic Biofuel Production Using Cholinium Lysinate Ionic Liquid Pretreatment

“…Hou et al (2012) 18 found choline-based ILs to be effective pretreatment solvents with high polysaccharide digestibility and sugar yields. Sun et al 19 reported that [Lys] anions provided greater delignification (70-80% vs. 16-50%) and higher glucose yields (78-96% vs. 56-90%) compared to [OAc] anions. ILs containing the lysinate anion afforded greater delignification and higher glucose yields than other anions such as carboxyl, hydroxyl, and aromatic groups 26 .…”

“…A variety of ILs, including 1-ethyl 1-methylimidazolium acetate ([C 2 MIM][OAc]) [14][15][16] , 1-ethyl 1-methylimidazolium chloride ([C 2 MIM][Cl]) 17 , and cholinium lysinate ([Ch][Lys]) [18][19][20] , have been explored for the pretreatment of various lignocellulosic biomass feedstocks including corn stover 14,[21][22] , switchgrass 9,12 , pine 23 , miscanthus 15,24 and mixed feedstock 25 . Choline-based ILs, sometimes referred to as "bionic liquids" because they are bio-derived, are particularly attractive because they can be produced using cheaper raw materials and simpler synthesis methods than [C 2 MIM]-based ILs 20 .…”