Synergetic combination of H₂Zr₁PW₁₂O₄₀ and Sn‐Beta as potential solid acid catalyst for direct one‐step transformation of glucose to ethyl levulinate, a biofuel additive

Abstract

Ethyl levulinate (EL) has found wide applications as chemicals and biofuel additives. Efficient catalytic conversion of abundantly available glucose to ELs over solid acid catalyst having optimum Brønsted (B) and Lewis (L) acidity is highly appreciated. Present work demonstrated, direct one‐step synthesis of EL from glucose over synergized Brønsted (H2Zr1PW12O40) and Lewis (Sn‐Beta) acid catalyst. H2Zr1PW12O40 is prepared by exchanging H+ of tungstophosphoric acid (H3PW12O40‐heteropolyacid) with Zr, improves the heterogeneity in polar medium by 50%. The combination of a physical mixture of H2Zr1PW12O40 + Sn‐Beta with 80:20 weight ratio was found to be optimum for the maximum EL yield formation of 54% from glucose at 180°C for 3 h, which is probably the highest than reported over the heterogeneous catalyst in ethanol medium. An optimal combination of B and L catalyst and its ratio is found to be crucial for the direct transformation of glucose to EL in one step. The present study also explored that this combined physical mixture of H2Zr1PW12O40 + Sn‐Beta can tolerate glucose concentration up to 30 g/L, which is probably the higher than reported. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

An alumina‐coated UiO‐66 nanocrystalline solid superacid with high acid density as a catalyst for ethyl levulinate synthesis

“…This indicated that a synergistic effect between ZrO 2 and Al 2 O 3 produced obvious B acid sites. Studies have shown that B acid and L acid co‐catalysts significantly increase the yield of EL 70 . Dai et al .…”

Synthesis of ethyl levulinate from cellulose over a double acid site catalyst

“…This effect occurred because the alcoholysis of the cellulose generated a large amount of humus that was deposited on the surface of the catalyst, so that the catalytic activity decreased. 54 At 180 °C, the yield of EL continued to increase along with the reaction time, although the yield after 6 h was only increased by 0.1 to 42.6 mol% compared with that after 5 h. These results are attributed to the need for high temperatures to induce complete depolymerization of the cellulose. However, with the rapid depolymerization of the cellulose, a large amount of humus would be formed, resulting in decreased activity.…”

“…This occurred because, with the increased number of active sites, the amount of reactant species and the quantity of active sites reached an optimal level, beyond which the addition of more active groups hindered contact between the reactants and the substrate, thus reducing the yield. 54 Nandiwale et al 56 used the solid acid HPW/MESO-HZ-5 to catalyze the transformation of furfuryl alcohol to EL. When the HPW loading was increased from 5 to 15 wt%, the EL yield increased from 14.0 to 24.0 mol%, while a further loading increase to 20 wt% actually resulted in a slight decrease in yield.…”

Directional Catalytic Conversion of Biomass Carbohydrates into High Added‐value Levulinates with Bifunctionalized Metal‐supported Carbon‐based Catalyst

“…The catalyst also demonstrated better catalytic activity compared to other carbon-based solid acids (HTC-400-S and AC-Fe-SO 3 H), possibly due to superior structural properties and B-and L-acid synergies.Therefore, catalyst 300-AC-Cr-SO 3 H is an efficient catalyst for the alcoholysis of glucose. Glucose ZrY6(0.5) 180 °C, 3 h 35 [12] Glucose Sn-SBA-15 160 °C, 20 h 34.9 [25] Glucose Amberlyst-15 160 °C, 5 h 24 [26] Glucose H-USY(6) 160 °C, 20 h 49 [27] Glucose* 4-HPWFe-MMTSi 180 °C, 1 h 22.5 [28] Glucose* HTC-400-S 200 °C, 2 h 37 [13] Glucose AC-Fe-SO…”