Production of Hydroxyl-rich Acids from Xylose and Glucose Using Sn-BEA Zeolite

Abstract

Sn‐BEA zeolite is known to catalyze the aldose‐to‐ketose isomerization of xylose and glucose; however, the selectivity to pentose and hexose isomers is not stoichiometric, suggesting the formation of other products. In the present study, we have observed near‐complete conversion of all pentose and hexose isomers when xylose and glucose were reacted in the presence of Sn‐BEA at 140 °C and 200 °C, respectively. The previously unidentified products were identified by nuclear magnetic resonance and mass spectrometry to be hydroxyalkanoic acids and their derivatives. The hydroxyl‐rich acids comprise a significant fraction of the converted sugars and are potential monomers for the synthesis of hyper‐crosslinked, biodegradable polymers.

NMR Spectroscopic Isotope Tracking Reveals Cascade Steps in Carbohydrate Conversion by Tin‐Beta

“…[9] Subsequentr esearch has illuminateds ome mechanistic details of the reactions that form ML from triosesa nd hexoses in methanol solvent. [14][15][16][17][18][19][20] Most of these new products are a-hydroxy acids such as lactatea nd some show potentiala sp olymer buildingb locks. [14][15][16][17][18][19][20] Most of these new products are a-hydroxy acids such as lactatea nd some show potentiala sp olymer buildingb locks.…”

Quantitative NMR Approach to Optimize the Formation of Chemical Building Blocks from Abundant Carbohydrates

“…Biomass can be utilized to provide access to both existing and new types of buildingb locks, and research into this area has steeply increasedd uring the last decade. [12][13][14] Conversions of C5 and C6 carbohydratesi nto the acyclic unsaturated a-hydroxyc ompounds 1 and 12 have been achieved using Sn-Beta in methanol [13,14] or in water [12] at temperatures The future role of biomass-derivedc hemicals relies on the formation of diversefunctional monomers in high yields from carbohydrates. Directc onversion of sugars to at arget chemical by heterogeneous catalysis offers the best chance of lowering the process costs.…”

“…[12][13][14] C5 and C6 carbohydrates yield around3 0% for C5-carbohydrate substrate Me-1 and around1 5% for C6-carbohydrate substrate Me-12,r espectively. AS n-Betazeolite synthesized under hydrothermal conditions using hydrofluoric acid as the mineralizing agent was the most efficient catalystf or this reaction.…”

“…a) Structureoft he C6 analogueofc ompound 1, trans-2,5,6-trihydroxy-3-hexenoic acid methylester(12). b) Spectral comparison of the areas of the olefinic carbon shifts of compound 12 in ethanol(top) and methanol (bottom) reaction solvents.…”

Dehydration of xylose to furfural in butanone catalyzed by Brønsted‐Lewis acidic ionic liquids

“…The soluble products from xylose conversion were divided into three main categories, namely oxygenated aliphatics, furans, and cyclohexenones. 43 Oxygenated aliphatics mainly consisted of acetic acid (5), 2-ethyl-hexenal (6), 5-methyl-4-hepten-3-one (7), 3,4-dimethyl-3-hexen-2-one (8), and 4-hydroxy-4-methyl-2-pentanone (9), and they comprised 2%-14% of the soluble products. Other furan products from xylose conversion mainly included 3-(2-furanyl)-3-penten-2one (2), 5-hydroxy-4,5-dimethyl-2,5-dihydrofuran-2-one (3), and 5-methyl-2(5h)-furanone (4), and all the furans account for over 73% of the soluble products (2) could come from the aldol condensation reaction between (1) and pentanone intermediates from retroaldolization of xylose.…”