Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, United States.
J Phys Chem B. 2012 Sep 6;116(35):10898-904. doi: 10.1021/jp303842g. Epub 2012 Aug 27.
Car-Parrinello molecular dynamics simulations (CPMD) coupled with metadynamics (MTD) simulations were conducted to investigate glucose isomerization to fructose in acidic aqueous solution. Glucose to fructose isomerization is initiated by protonation of the C2-OH and the formation of a furanose aldehyde intermediate. Fructose is produced via a hydride transfer from C2 to C1 on the furanose aldehyde followed by the rehydration of the C2 carbocation. Hydride 1,2 shift to form a C2 carbocation is an energetically favorable process but the barrier is relatively high at around 35 kcal/mol. The final step during glucose to fructose isomerization involves the rehydration of the C2 carbocation with an estimated barrier of 25 kcal/mol from our CPMD-MTD simulations.
采用 Car-Parrinello 分子动力学模拟（CPMD）与元动力学（MTD）模拟相结合的方法，研究了酸性水溶液中葡萄糖异构化为果糖的过程。葡萄糖异构化为果糖是由 C2-OH 的质子化和呋喃醛中间物的形成引发的。果糖是通过呋喃醛上的 C2 到 C1 的氢化物转移生成的，然后再对 C2 碳正离子进行水合。形成 C2 碳正离子的氢化物 1,2 迁移是一个能量有利的过程，但能垒相对较高，约为 35 kcal/mol。在葡萄糖异构化为果糖的最后一步中，涉及到 C2 碳正离子的水合，我们的 CPMD-MTD 模拟估计其能垒约为 25 kcal/mol。
