Cellobiose as a model system to reveal cellulose dissolution mechanism in acetate-based ionic liquids: Density functional theory study substantiated by NMR spectra. (20th September 2016)

• Record Type: Journal Article
• Authors: Cao, Bobo; Du, Jiuyao; Du, Dongmei; Sun, Haitao; Zhu, Xiao; Fu, Hui
• Is Part Of: Carbohydrate polymers. Volume 149(2016)
• Page Start: 348
• Page End: 356
• Publication Date: 2016-09-20
• Subjects: Cellulose -- Ionic liquid -- Hydrogen bond -- Dissolution mechanism -- DFT -- NMR spectra; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2016.04.128
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: NMR spectra suggested hydrogen bonds are the driving force of cellulose dissolution in acetated-based ionic liquids, which was further studied and characterized by DFT modeling. Highlights: Cellulose dissolution mechanism in ILs was studied in experiment and DFT modeling. NMR spectra indicated hydrogen bonds were the driving force of dissolution. Hydrogen bonds were studied and characterized in AIM, RDG and NBO method. Abstract: Cellulose dissolution mechanism in acetate-based ionic liquids was systematically studied in Nuclear Magnetic Resonance (NMR) spectra and Density Functional Theory (DFT) methods by using cellobiose and 1-butyl-3-methylimidazolium acetate (BmimAc) as a model system. The solubility of cellulose in ionic liquid increased with temperature increase in the range of 90–140 °C. NMR spectra suggested OAc − preferred to form stronger hydrogen bonds with hydrogen of hydroxyl in cellulose. Electrostatic potential method was employed to predict the most possible reaction sites and locate the most stable configuration. Atoms in molecules (AIM) theory was used to study the features of bonds at bond critical points and the variations of bond types. Simultaneously, noncovalent interactions were characterized and visualized by employing reduced density gradient analysis combined with Visual Molecular Dynamics (VMD) program. Natural bond orbital (NBO) theory was applied to study the noncovalent nature and characterize the orbital interactions between cellobiose and Bmim[OAc].