Journal ArticleDOI
Insights into the Interplay of Lewis and Brønsted Acid Catalysts in Glucose and Fructose Conversion to 5‑(Hydroxymethyl)furfural and Levulinic Acid in Aqueous Media
Vinit Choudhary,Samir H. Mushrif,Christopher R. Ho,Andrzej Anderko,Vladimiros Nikolakis,Nebojsa Marinkovic,Anatoly I. Frenkel,Stanley I. Sandler,Dionisios G. Vlachos +8 more
TLDR
Extended X-ray absorption fine structure spectroscopy and Car-Parrinello molecular dynamics simulations indicate a strong interaction between the Cr cation and the glucose molecule whereby some water molecules are displaced from the first coordination sphere of Cr by the glucose to enable ring-opening and isomerization of glucoseAbstract:
5-(Hydroxymethyl)furfural (HMF) and levulinic acid production from glucose in a cascade of reactions using a Lewis acid (CrCl3) catalyst together with a Bronsted acid (HCl) catalyst in aqueous media is investigated. It is shown that CrCl3 is an active Lewis acid catalyst in glucose isomerization to fructose, and the combined Lewis and Bronsted acid catalysts perform the isomerization and dehydration/rehydration reactions. A CrCl3 speciation model in conjunction with kinetics results indicates that the hydrolyzed Cr(III) complex [Cr(H2O)5OH](2+) is the most active Cr species in glucose isomerization and probably acts as a Lewis acid-Bronsted base bifunctional site. Extended X-ray absorption fine structure spectroscopy and Car-Parrinello molecular dynamics simulations indicate a strong interaction between the Cr cation and the glucose molecule whereby some water molecules are displaced from the first coordination sphere of Cr by the glucose to enable ring-opening and isomerization of glucose. Additionally, complex interactions between the two catalysts are revealed: Bronsted acidity retards aldose-to-ketose isomerization by decreasing the equilibrium concentration of [Cr(H2O)5OH](2+). In contrast, Lewis acidity increases the overall rate of consumption of fructose and HMF compared to Bronsted acid catalysis by promoting side reactions. Even in the absence of HCl, hydrolysis of Cr(III) decreases the solution pH, and this intrinsic Bronsted acidity drives the dehydration and rehydration reactions. Yields of 46% levulinic acid in a single phase and 59% HMF in a biphasic system have been achieved at moderate temperatures by combining CrCl3 and HCl.read more
Citations
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Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability
TL;DR: Recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass to IPCs (i.e., ethanol, 3-hydroxypropionic acid, isoprene, succinic and levulinic acids, furfural, and 5-hydroxymethylfurfural) are overviewed.
Journal ArticleDOI
Advanced glycoxidation and lipoxidation end products (AGEs and ALEs): An overview of their mechanisms of formation
TL;DR: The aim of the present review is to group the main AGEs and ALEs and to describe, for each of them, the precursors and mechanisms of formation.
Journal ArticleDOI
Catalytic dehydration of C6 carbohydrates for the production of hydroxymethylfurfural (HMF) as a versatile platform chemical
TL;DR: In this paper, a review summarizes recent progress with bi-functional catalyst systems for tandem glucose/fructose isomerization and subsequent fructose dehydration, thereby realizing highly selective HMF production directly from the more abundant and cheaper C6 sugar feedstock, glucose.
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Fluid phase equilibria
TL;DR: In this article, the authors propose a method for measuring the performance of a single node in a set of images.ING and INDEXING, e.g., this article.
Journal ArticleDOI
Review: Sustainable production of hydroxymethylfurfural and levulinic acid: Challenges and opportunities
TL;DR: A review of the various reaction systems that have been developed to produce HMF and LA from various substrates has been looked at and their merits, demerits and requirements for commercialisation outlined in this article.
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