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Various iridium supported carbon catalysts were prepared and screened for the direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF). Amongst these, 5% Ir/C showed excellent results with complete FFR conversion and highest selectivity of 95% to 2-MF at a very low H2 pressure of 100 psig. Metallic (Ir°) and oxide (IrO2) phases of Ir catalyzed the first step hydrogenation involving FFR to FAL and subsequent hydrogenation to 2-MF, respectively. This was confirmed by XPS analysis and some control experiments. At a low temperature of 140 °C, almost equal selectivities of FAL (42%) and 2-MF (43%) were observed, while the higher temperature (220 °C) favored selective hydrodeoxygenation. At optimized temperature, 2-MF was formed selectively while higher pressure and higher catalyst loading favored ring hydrogenation of furfural rather than side chain hydrogenation. With the combination of several control experimental results and detailed catalyst characterization, a plausible reaction pathway has been proposed for the selective formation of 2-MF. The selectivity to various other products in FFR hydrogenation can be manipulated by tailoring the reaction conditions over the same catalyst. [ABSTRACT FROM AUTHOR]

A new and effective unique two-phase reaction system is investigated for the high yield production of tri(furyl)methane from furfural and furan. This strategy includes the use of an acidic aqueous phase (water + –SO3H functionalized IL) and furan phase, which significantly suppresses polymer formation, thereby increasing the yield of tri(furyl)methane. Furan serves as a reactant as well as an extraction solvent for the recovery of the condensation products. For comparison, different –SO3H functionalized ionic liquids are prepared and their performances evaluated for the condensation of furan and furfural. The ionic liquids with alkyl chain linkers are found to be more effective and acidic than those with imidazolium linked N-sulfonic acids. In addition, an increase in carbon chain length between imidazole/tri-ethylamine/pyridine and –SO3H, increases the catalytic activity of the respective ionic liquids. Among the several prepared ionic liquids, the strongly acidic imidazolium based butylsulfonic acid 6 shows the best activity with a maximum condensation product yield of 84%. This strategy offers a significantly high yield of the condensation products of furan and furfural compared to the traditional mineral acid route. The activity and stability of the –SO3H functionalized 6 is confirmed from seven successful recycles, in which there is no reduction in its activity. Finally, this new strategy is successfully extended for the condensation of furan derivatives (e.g. furan and 2-methylfuran) with several different aldehydes, ketones and alcohols. [ABSTRACT FROM AUTHOR]

Several copper based catalysts were prepared, characterized and evaluated for the hydrogenation of levulinic acid and its methyl ester. Among these, nanocomposites of Cu–ZrO2 and Cu–Al2O3 quantitatively catalyzed the hydrogenation of levulinic acid and its methyl ester to give 90–100% selectivity to γ-valerolactone in methanol and water respectively. Both the Cu–ZrO2 and Cu–Al2O3 nanocomposites were prepared by the co-precipitation method using mixed precursors under controlled conditions. XRD results showed that the main active phase of the reduced Cu–ZrO2 catalyst was metallic copper and particle size was found to be of 10–14 nm by HRTEM. The active metal leaching was at a maximum for the Cu–Al2O3 catalyst in a water medium due to the formation of a copper–carboxylate complex that was blue in colour. Surprisingly, copper leaching was completely suppressed in the case of the Cu–ZrO2 catalyst in methanol in spite of the substrate loading was increased from 5 to 20% w/w. The excellent recyclability of the Cu–ZrO2 catalyst with complete LA conversion and ＞90% GVL selectivity makes it a sustainable process having a commercial potential. [ABSTRACT FROM AUTHOR]