An eco-benign catalytic system in which Mn-doped bismuth oxyiodide (BiOI) was combined with H-ZSM-5 as a catalyst for direct hydrolysis and oxidation of cellulose into glycolic acid at 180 °C in an O 2 atmosphere achieved excellent catalytic performance with a yield of 82.6%. The prominent catalytic performance was largely attributed to the synergistic effect between Mn species with BiOI and the stronger Brønsted acid sites over H-ZSM-5. Furthermore, the as-synthesized catalyst displayed extraordinary catalytic performance after five successive reaction runs. Most importantly, this study provides an eco-friendly strategy to design efficient heterogeneous catalysts for converting biomass resources into biofuels and high-value-added chemicals.
Lactic acid is a versatile and potential building block for generating biodegradable plastics and polylactic acid, as well as in chemical and pharmaceuticals industry. Nevertheless, the achievement of lactic acid production in large quantities remains an enormous challenge. Herein, a series of yttriummodified composite metal oxide catalysts were synthesized for production of lactic acid starting from renewable biomass cellulose. Interestingly, Y 2 O 3 /Al 2 O 3 showed outstanding chemoselectivity towards lactic acid due to its predominant Lewis acid sites (Y 3 + ) and weak Brønsted acid sites (hydroxyl group) together with appropriate total surface acidity. The structure-activity relationship was systematically investigated by a combination of XRD, BET, NH 3 -TPD, PyIR, SEM, FTIR, and XPS characterization techniques. A nearly complete conversion of cellulose and as high as 72.8 % yield of lactic acid could be achieved under the optimum conditions. Importantly, the resultant catalysts were reusable without appreciable loss in catalytic activity after five consecutive cycles. This study provides an efficient, cost-efficient and facile strategy for fabricating promising heterogeneous catalysts for conversion of biomass resources to highly valuable chemicals.
Catalytic conversion of cellulose to liquid fuel and highly valuable platform chemicals remains a critical and challenging process. Here, bismuth-decorated β zeolite catalysts (Bi/β) were exploited for highly efficient hydrolysis and selective oxidation of cellulose to biomass-derived glycolic acid in an O2 atmosphere, which exhibited an exceptionally catalytic activity and high selectivity as well as excellent reusability. It was interestingly found that as high as 75.6% yield of glycolic acid over 2.3 wt% Bi/β was achieved from cellulose at 180 °C for 16 h, which was superior to previously reported catalysts. Experimental results combined with characterization revealed that the synergetic effect between oxidation active sites from Bi species and surface acidity on H-β together with appropriate total surface acidity significantly facilitated the chemoselectivity towards the production of glycolic acid in the direct, one-pot conversion of cellulose. This study will shed light on rationally designing Bi-based heterogeneous catalysts for sustainably generating glycolic acid from renewable biomass resources in the future.
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