Microwave-induced controlled-isomerization during glucose conversion into lactic acid over a Sn-beta catalyst

Abstract

Microwave was introduced for the controlled-isomerization of glucose, facilitating its efficient conversion into lactic acid with a very high yield of 68.3 wt% at 180 °C for 30 min over...

Sn-Beta Catalyzed Transformations of Sugars—Advances in Catalyst and Applications

“…Hence, hierarchical Sn-Beta zeolite synthesized with polydiallyldimethylammonium chloride as SDA gave a higher catalytic activity than that of microporous Sn-Beta and post-synthesized meso-Sn-Beta zeolites for glucose conversion, due to a combined promotional effect of mesoporosity, hydrophobicity and Lewis acidity on the retro-aldol condensation of fructose [86]. In addition, to enhance the efficiency of the catalytic transformation of glucose into lactic acid microwave irradiation was introduced for the controlled-isomerization of glucose, facilitating a very high lactic acid yield of 68.3 wt.% at 180 • C in 30 min over a "monolithic" Sn-Beta catalyst in water [87]. The consecutive reactions involved in the conversion of sugars to lactic acid can also be promoted by acid or base co-catalysts.…”

Insight into the dehydration of high-concentration fructose to 5-hydroxymethylfurfural in oxygen-containing polar aprotic solvents

“…Correspondingly, the fructopyranose tautomers (a-pyranose and b-pyranose) are the major precursors for the unwanted formation of humins. 27,28 Glucose contains only 1% furanose isomer in aqueous solution, 42 whereas fructose contains 27% furanose isomer, 43 which is why fructose is more efficient at converting into 5-HMF. The tautomer distributions in various oxygen-containing polar solvents and their 5-HMF yield are presented in Fig.…”

Promoted Production of Lactic Acid from Glucose by Calcium Hydroxide in the Presence of Hydrogen

“…β zeolite modulated by Y or Yb was found to exhibit a good yield of lactic acid with the value of above 45 %. Fewer byproducts were formed in the presence of more Brønsted acids contained in the catalyst, facilitating glucose transformed to lactic acid [30] . Although the catalytic activity of barium hydroxide for the reaction was high, but the reaction time is too long and the separation process is difficult, meanwhile, the catalytic performances of the heterogeneous catalysts still need to be improved.…”

“…Insoluble or slightly soluble metal hydroxide such as Ca(OH) 2 was also adopted for glucose conversion, and showed a promising approach for the production of lactic acid [25] . In addition, some heterogeneous catalysts including copper oxide, zinc oxide and modified beta catalysts were applied for glucose conversion to lactic acid [26–31] . β zeolite modulated by Y or Yb was found to exhibit a good yield of lactic acid with the value of above 45 %.…”

“…[25] In addition, some heterogeneous catalysts including copper oxide, zinc oxide and modified beta catalysts were applied for glucose conversion to lactic acid. [26][27][28][29][30][31] β zeolite modulated by Y or Yb was found to exhibit a good yield of lactic acid with the value of above 45 %. Fewer byproducts were formed in the presence of more Brønsted acids contained in the catalyst, facilitating glucose transformed to lactic acid.…”