Document type
ArticleVersion
Accepted versionPublication date
All rights reserved
Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/154538
Understanding competition of polyalcohol dehydration reactions in hot water
Journal Title
Director/Tutor
Journal ISSN
Volume Title
Related resource
Abstract
Dehydration of biomass-derived polyalcohols has recently drawn attention in green chemistry as a prototype of selective reactions controllable in hot water or hot carbon- ated water, without any use of organic solvents or metal catalysts. Here we report a free energy analysis based on first-principles metadynamics and blue-moon ensemble simulations to understand the mechanism of competing intramolecular dehydration re- actions of 1,2,5-pentanetriol (PTO) in hot acidic water. The simulations consistently predict that the most dominant mechanism is the proton-assisted SN2 process where the protonation of the hydroxyl group by water and the C-O bond breaking and formation occurs in a single step. However the free energy barriers are different between the reac- tion paths: those leading to five membered ether products, tetrahydrofurfuryl alcohol (THFA), are few kcal/mol lower than those leading to six membered ether products, 3-hydroxytetrahydropyran (3-HTHP). A slight difference is seen in the timing of the protonation of the hydroxyl group of THFA and 3-HTHP on their reaction pathways. The detailed mechanism found from the simulations shows how the reaction paths are selective in hot water and why the reaction rates are accelerated in acidic environments, thus giving a clear explanation of experimental findings for a broad class of competing dehydration processes of polyalcohols.
Citation
Citation
CHANG, Yong Lik, et al. Understanding competition of polyalcohol dehydration reactions in hot water. Journal of Physical Chemistry B. 2019. Vol. 123, num. 7, pags. 1662-1671. ISSN 1520-6106. [consulted: 14 of June of 2026]. Available at: https://hdl.handle.net/2445/154538