Study of the oxidative esterification of furfural catalyzed by Au25(glutathione)18 nanocluster deposited on zirconia

Abstract

Au/ZrO 2 catalyst prepared from Au 25 (SG) 18 nanoclusters (SG stands for glutathione) deposited on ZrO 2 has shown to be an efficient system for the oxidative esterification of furfural with methanol. The influence of the supported nanoclusters was studied and showed that partial calcination of the supported nanoclusters at 300 °C was sufficient for a quantitative formation of methyl-2-furoate even in the absence of a base. In the presence of 0.27 mol% of Au, initial activities up to 250 h -1 were obtained at 100 °C under 6 bar of O 2 .The reactivity was extended to the oxidative esterification of furfuryl alcohol and the formation of various products and intermediates was discussed.

Base‐free Oxidative Esterification of HMF over AuPd/nNiO‐TiO2. When Alloying Effects and Metal‐support Interactions Converge in Producing Effective and Stable Catalysts

“…For all these reasons, the oxidative esterification to FDMC has recently moved into the limelight of research on chemo‐catalytic processes for HMF upgrading to value‐added chemicals. Although non‐precious metal based catalysts, in particular Co‐based and Mn‐based systems, have been successfully proposed in the literature, [15,18,37–44] noble‐metal based catalysts, specifically supported Au NPs, still remain the most studied catalysts for the oxidative esterification of HMF to FDMC [10,26,45–55] …”

“…Although non-precious metal based catalysts, in particular Co-based and Mn-based systems, have been successfully proposed in the literature, [15,18,[37][38][39][40][41][42][43][44] noble-metal based catalysts, specifically supported Au NPs, still remain the most studied catalysts for the oxidative esterification of HMF to FDMC. [10,26,[45][46][47][48][49][50][51][52][53][54][55] According to the literature, the reaction would proceed through an acetalization-oxidation-esterification mechanism (Scheme 1), although an alternative pathway involving alcohol oxidation to 2,5-diformylfuran (DFF) has been rarely reported. [18,37] The acetalization-oxidation-esterification mechanism implies the initial formation of a hemiacetal intermediate (A), which is unstable and cannot be detected by a gas chromatographic analysis.…”

Zn Promoted Mg-Al Mixed Oxides-Supported Gold Nanoclusters for Direct Oxidative Esterification of Aldehyde to Ester

“…Supported gold catalysts are a great promising candidate for this kind of reaction due to their unique selectivity under mild conditions [13][14][15][16][17][18]. Various transition-metaloxides and mixed oxides were explored as supports for synthesis of the supported gold catalysts [15][16][17][18].…”

“…Supported gold catalysts are a great promising candidate for this kind of reaction due to their unique selectivity under mild conditions [13][14][15][16][17][18]. Various transition-metaloxides and mixed oxides were explored as supports for synthesis of the supported gold catalysts [15][16][17][18]. Nevertheless, their catalytic performances were largely dependent on the particle size of gold [15], the interaction between gold and the carrier [16], as well as the acidic-basic properties of the supports [15,17].…”

Chemoenzymatic conversion of furfural to methyl‐2‐furotate

“…In most of these studies, metal catalysts containing elements such as Au, Pd, and Co have been used widely. For instance, in the presence of oxygen, Au/ZrO 2 , [13][14][15][16] Au/CeO 2 , 17,18 Au/ TiO 2 , 13,15,19,20 Au-MgO, 21 Au-K 2 CO 3 , 22 Au/CMK-3, 23 AuPd/ HAP-T, 24 Co x O y -N@C, 25 and Co-N-C/MgO 11 can obtain high yields of MF. The process involved in the conversion of FF to MF is an oxidative esterification reaction that, at present, relies completely on expensive chemical catalysts (precious metals) and high temperatures (100-120 °C) to be completed in a single step.…”