- Importance of the synergistic effects between cobalt sulfate and tetrahydrofuran for selective production of 5-hydroxymethylfurfural from carbohydrates
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In this study, an effective catalytic system (CoSO4·7H2O/THF) for selective conversion of fructose to 5-hydroxymethylfurfural (HMF; yield: 88%) was developed. The synergistic effects among Co2+, SO42-, crystal water and tetrahydrofuran (THF) were crucial for achieving selective dehydration of fructose to HMF. Co2+ worked as a Lewis acid for catalyzing mainly dehydration of fructose to HMF but not the further decomposition of HMF to levulinic acid. THF could help to retain HMF while CoSO4 could coordinate with HMF, enhancing the thermal stability of HMF in THF. The crystal water in cobalt sulfate could help to coordinate with fructose, which facilitated the conversion of fructose via dehydration reactions. The CoSO4·7H2O/THF catalytic system could also catalyze the conversion of inulin and cellulose into HMF. The main advantages of the CoSO4·7H2O/THF catalytic system are the low cost, the easy recycling of the CoSO4·7H2O catalyst and the easy separation of HMF from volatile THF.
- Dong, Dehua,Hu, Xun,Li, Qingyin,Li, Xueli,Shao, Yuewen,Sun, Kai,Wang, Yi,Ye, Zhengmao,Zhang, Lijun,Zhang, Shu
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p. 2293 - 2302
(2020/04/20)
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- Towards Improved Biorefinery Technologies: 5-Methylfurfural as a Versatile C6 Platform for Biofuels Development
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Low chemical stability and high oxygen content limit utilization of the bio-based platform chemical 5-(hydroxymethyl)furfural (HMF) in biofuels development. In this work, Lewis-acid-catalyzed conversion of renewable 6-deoxy sugars leading to formation of more stable 5-methylfurfural (MF) is carried out with high selectivity. Besides its higher stability, MF is a deoxygenated analogue of HMF with increased C/O ratio. A highly selective synthesis of the innovative liquid biofuel 2,5-dimethylfuran starting from MF under mild conditions is described. The superior synthetic utility of MF against HMF in benzoin and aldol condensation reactions leading to long-chain alkane precursors is demonstrated.
- Galkin, Konstantin I.,Ananikov, Valentine P.
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p. 185 - 189
(2018/12/05)
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- Study of the diels-alder and retro-diels-alder reaction between furan derivatives and maleimide for the creation of new materials
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The Diels-Alder reaction leads to a mixture of two diastereomers, one called endo and the other one exo. The cyclo-reversion temperature of the first one is lower than the exo adduct and the ratio between endo and exo adducts varies according to the substituents of the Diels-Alder partners and experimental parameters. Therefore, the influence of some reaction parameters such as the substituents of furan and maleimide derivatives, the reaction temperature and the presence of a nucleophile on the endo/exo Diels-Alder ratio and/or the retro-Diels-Alder reaction have been studied. For instance, furan and maleimide derivatives with electron withdrawing substituents induced the creation of the endo adduct preferentially. Also the presence of a far electron withdrawing substituent on furan and/or an electron attracting mesomeric substituent on maleimide resulted in a faster reversibility of the endo adduct. Finally, a high temperature and the presence of a nucleophile (thiol) also induced faster retro-Diels-Alder kinetics. Moreover, it was proved that isomerization from the endo to the exo diastereomer is preceded by a retro-Diels-Alder reaction of the endo adduct. The presence of a nucleophile in the mixture confirmed this result. This study allowed the highlighting of different parameters of the Diels-Alder reaction to obtain as much endo adduct as possible, and a fast and/or full retro-Diels-Alder reaction of this adduct.
- Froidevaux,Borne,Laborbe,Auvergne,Gandini,Boutevin
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p. 37742 - 37754
(2015/05/13)
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