title: Theoretical Insights into the Role of Water in the Dissolution of Cellulose Using IL/Water Mixed Solvent Systems.
abstract: The use of certain ionic liquids (ILs) as pretreatment solvents for lignocellulosic biomass has gained great interest in recent years due to the IL's capacity for efficient cellulose dissolution in aqueous solution as compared to other common pretreatment techniques. A fundamental understanding on how these ILs in aqueous environments act on cellulose, particularly at lower IL concentrations with water as a cosolvent, is essential for optimizing pretreatment efficiency, lowering pretreatment cost, and improving IL recyclability. The IL 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) is one of the most efficient cellulose solvents known, greatly altering cellulose structure for improved enzymatic saccharification. To understand the role of water as a cosolvent with [C2C1Im][OAc], we investigated the dissolution mechanism of microcrystalline cellulose, type Iβ, in different [C2C1Im][OAc]:water ratios at room (300 K) and pretreatment (433 K) temperatures using all atom molecular dynamics (MD) simulations. These simulations show that 80:20 ratios of [C2C1Im][OAc]:water should be considered as "the tipping point" above which [C2C1Im][OAc]:water mixtures are equally effective on decrystallization of cellulose by disrupting the interchain hydrogen bonding interactions. Simulations also reveal that the resulting decrystallized cellulose from 100% [C2C1Im][OAc] begins to repack in the presence of water but into a less crystalline, or more amorphous, form.
authors.affiliation: Deconstruction Division, Joint BioEnergy Institute , Emeryville, California 94608, United States.|Biological and Engineering Sciences Center, Sandia National Laboratories , Livermore, California 94550, United States.
authors.forename: Ramakrishnan
authors.initials: R
authors.lastname: Parthasarathi
authors.affiliation: Chemical Laboratory, CSIR-Central Leather Research Institute , Adyar, Chennai 600 020, India.
authors.forename: Kanagasabai
authors.initials: K
authors.lastname: Balamurugan
authors.affiliation: Deconstruction Division, Joint BioEnergy Institute , Emeryville, California 94608, United States.|Biological and Engineering Sciences Center, Sandia National Laboratories , Livermore, California 94550, United States.|Current with Department of Biosystems & Agricultural Engineering, University of Kentucky , Lexington, Kentucky 40546, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.affiliation: Chemical Laboratory, CSIR-Central Leather Research Institute , Adyar, Chennai 600 020, India.
authors.forename: Venkatesan
authors.initials: V
authors.lastname: Subramanian
authors.affiliation: Deconstruction Division, Joint BioEnergy Institute , Emeryville, California 94608, United States.|Biological and Engineering Sciences Center, Sandia National Laboratories , Livermore, California 94550, United States.
authors.forename: Blake A
authors.initials: BA
authors.lastname: Simmons
authors.affiliation: Deconstruction Division, Joint BioEnergy Institute , Emeryville, California 94608, United States.|Biological and Engineering Sciences Center, Sandia National Laboratories , Livermore, California 94550, United States.
authors.forename: Seema
authors.initials: S
authors.lastname: Singh
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D008962:Models, Theoretical; D056004:Molecular Dynamics Simulation; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D012997:Solvents; D014867:Water; D002482:Cellulose