title: Free energy landscape for glucose condensation and dehydration reactions in dimethyl sulfoxide and the effects of solvent.
abstract: The mechanisms and free energy surfaces (FES) for the initial critical steps during proton-catalyzed glucose condensation and dehydration reactions were elucidated in dimethyl sulfoxide (DMSO) using Car-Parrinello molecular dynamics (CPMD) coupled with metadynamics (MTD) simulations. Glucose condensation reaction is initiated by protonation of C1--OH whereas dehydration reaction is initiated by protonation of C2--OH. The mechanisms in DMSO are similar to those in aqueous solution. The DMSO molecules closest to the C1--OH or C2--OH on glucose are directly involved in the reactions and act as proton acceptors during the process. However, the energy barriers are strongly solvent dependent. Moreover, polarization from the long-range electrostatic interaction affects the mechanisms and energetics of glucose reactions. Experimental measurements conducted in various DMSO/Water mixtures also show that energy barriers are solvent dependent in agreement with our theoretical results.
authors.affiliation: Department of Chemical Engineering, University of Arkansas, Fayetteville, AR 72701, United States. Electronic address: xqian@uark.edu.
authors.forename: Xianghong
authors.initials: X
authors.lastname: Qian
authors.affiliation: Department of Mechanical Engineering, Colorado State University, Ft Collins, CO 80521, United States.
authors.forename: Dajiang
authors.initials: D
authors.lastname: Liu
mesh_terms: D003681:Dehydration; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011522:Protons; D012997:Solvents; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D011522:Protons; D012997:Solvents; D014867:Water; D005947:Glucose; D004121:Dimethyl Sulfoxide
keywords: Condensation; DMSO; Dehydration; Free energy surface; Glucose