27826-73-9Relevant articles and documents
Selective Dehydration of Mannitol to Isomannide over Hβ Zeolite
Yokoyama, Haruka,Kobayashi, Hirokazu,Hasegawa, Jun-Ya,Fukuoka, Atsushi
, p. 4828 - 4834 (2017)
Isomannide is a potential feedstock for the production of super engineering plastics. A prospective route to obtain isomannide is dehydration of mannitol derived from lignocellulosic biomass, but homogeneous acid catalysts reported in the literature produce a large amount of 2,5-sorbitan as a byproduct in the dehydration reaction. In this work, we initially studied the mechanism of proton-induced dehydration of mannitol by density functional theory calculations, which suggested that local steric hindrance around acid sites designed at the angstrom level can tune the selectivity toward isomannide formation. Based on this prediction, we found that the precisely defined microporous confinement offered by Hβ provides improved selectivity and high catalytic activity for the production of isomannide, where 1,4-dehydration is favored by 20 kJ mol-1 of activation energy. The optimization of the Si/Al ratio of Hβ to balance the acid amount and hydrophobicity improved the catalytic activity and achieved 63% yield of isomannide, far exceeding the best result reported previously (35% yield).
Selective C?O Bond Cleavage of Sugars with Hydrosilanes Catalyzed by Piers’ Borane Generated In Situ
Zhang, Jianbo,Park, Sehoon,Chang, Sukbok
supporting information, p. 13757 - 13761 (2017/10/09)
Described herein is the selective reduction of sugars with hydrosilanes catalyzed by using Piers’ borane [(C6F5)2BH] generated in situ. The hydrosilylative C?O bond cleavage of silyl-protected mono- and disaccharides in the presence of a (C6F5)2BH catalyst, generated in situ from (C6F5)2BOH, takes place with excellent chemo- and regioselectivities to provide a range of polyols. A study of the substituent effects of sugars on the catalytic activity and selectivity revealed that the steric environment around the anomeric carbon (C1) is crucial.
Intramolecular dehydration of mannitol in high-temperature liquid water without acid catalysts
Yamaguchi, Aritomo,Sato, Osamu,Mimura, Naoki,Shirai, Masayuki
, p. 45575 - 45578 (2014/12/12)
Intramolecular dehydration of mannitol in high-temperature liquid water without adding any hazardous acid catalysts and its kinetic analyses were carried out. The dehydration behavior of mannitol was compared with that of sorbitol. 2,5-Anhydromannitol and 1,4-anhydromannitol were major products from the mannitol monomolecular dehydration in contrast with the only major product, 1,4-anhydrosorbitol, from the sorbitol monomolecular dehydration.