title: Free energy landscape for glucose condensation reactions.
abstract: Ab initio molecular dynamics and metadynamics simulations were used to determine the free energy surfaces (FES) for the acid catalyzed β-D-glucose condensation reaction. Protonation of C1-OH on the β-D-glucose, breakage of the C1-O1 bond, and the formation of C1 carbocation is the rate-limiting step. The effects of solvent on the reaction were investigated by determining the FES both in the absence and presence of solvent water. It was found that water played a critical role in these reactions. The reaction barrier for the proton-catalyzed glucose condensation reaction is solvent induced because of proton's high affinity for water. During these simulations, β-D-glucose conversion to α-d-glucose process via the C1 carbocation was also observed. The associated free energy change and activation barrier for this reaction were determined.
authors.affiliation: Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Dajiang
authors.initials: D
authors.lastname: Liu
authors.forename: Mark R
authors.initials: MR
authors.lastname: Nimlos
authors.forename: David K
authors.initials: DK
authors.lastname: Johnson
authors.forename: Michael E
authors.initials: ME
authors.lastname: Himmel
authors.forename: Xianghong
authors.initials: X
authors.lastname: Qian
mesh_terms: D002236:Carbohydrate Conformation; D005947:Glucose / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D013816:Thermodynamics
chemical_list: D005947:Glucose