异构化
化学
催化作用
动力学同位素效应
分子内力
果糖
氢化物
光化学
反应机理
氘
酮糖
药物化学
醛糖
立体化学
有机化学
氢
糖苷
物理
量子力学
作者
Jinqiang Tang,Xiawei Guo,Liangfang Zhu,Changwei Hu
标识
DOI:10.1021/acscatal.5b01237
摘要
The nature of the active aluminum species and their interaction with glucose in water are studied to establish a detailed mechanism for understanding AlCl3-catalyzed glucose-to-fructose isomerization. The combination of activity results with electrospray ionization tandem mass spectrometry (ESI-MS/MS) reveal that [Al(OH)2(aq)]+ species contribute a lot to the isomerization. Attenuated total reflection infrared spectroscopy (ATR-IR) results show that glucose undergoes a ring-opening process which is accelerated by the [Al(OH)2(aq)]+ species. The binding of acyclic glucose with [Al(OH)2(aq)]+ species occurs at the C1–O and C2–O positions of glucose, which initiates the hydride shift of the aldose-to-ketose isomerization. The in situ 27Al NMR data elucidate the maintenance of the hexa-coordinated form of Al species throughout the reaction. An obvious kinetic isotope effect occurs with the C2 deuterium-labeled glucose, confirming that the intramolecular hydride shift from the C2 to C1 positions of glucose is the rate-limiting step for the isomerization. The apparent activation energy (Ea) of the AlCl3-catalyzed glucose-to-fructose isomerization reaction is estimated to be 110 ± 2 kJ·mol–1.
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