Selective aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over nanojunctions of cobalt–ceria binary oxide in water

Abstract

Non-precious cobalt–ceria binary oxide was synthesized by a facile citric acid sol-gel method, which can effectively introduce the interfaces into the as-prepared cobalt-ceria binary oxide among CeO2 and Co3O4 and...

Cobalt-Ceria Binary Oxide Nanojunctions for Aqueous-Phase Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid: The Role of Interfaces

“…Assuming first-order reaction for each step during the HMF oxidation to FDCA, 54 the kinetic rate constants of k 1 (8.8 × 10 −4 s −1 ), k 2 (5.9 × 10 −5 s −1 ), and k 3 (3.2 × 10 −3 s −1 ) were estimated from the result in Figure S1, which respectively corresponded to the reactions of HMF to HFCA, HFCA to FFCA, and FFCA to FDCA. Therein, the HFCA oxidation to FFCA with the smallest rate constant was the rate-controlling step in the HMF oxidation to FDCA, which has been proposed in our previous work 33 and also could be speculated from the reaction results in Figures 7, 8, and S1. In detail, HMF with an α-aldehyde group can quickly convert to an intermediate of geminal-diol 1 with the presence of OH − 51 in step 1 in Figure 9b.…”

“…CoCe binary oxide nanojunctions were synthesized using different organic acids by the sol–gel method. The preparation procedures were described in our previous study . In brief, 46.80 mmol of Co­(NO 3 ) 2 ·6H 2 O, 3.12 mmol of Ce­(NO 3 ) 4 , and 59.90 mmol of organic acid were dissolved in 12.0 mL of water to form a solution after treating with ultrasound for 20 min.…”

“…18 So, to efficiently transform FDCA from HMF, many studies have been reported in HMF oxidations using multicomponent catalysts, such as Au−Ce, 10 Au−Cu, 19 Au−Pd, 20,21 Pt−Bi, 22 Pt−Pb, 23 Pt−Sn, 24 Pt−Ni, 25 Zn−Fe−Ru, 26 Sr−Mn, 27 Mn− Ce, 28,29 Mn−Co, 30 Mn−Fe, 2831 Cu−Mn−Ce, 32 and so on. Recently, the nonprecious CoCe binary oxide also have been designed for HMF oxidation 33,34 because Co 3 O 4 and CeO 2 are functional candidates in the oxidation of organic compounds. 35 Given our previous study, 33 the exposed interfaces among Co 3 O 4 and CeO 2 in the CoCe binary oxide might play a crucial role during HMF oxidations, but it does not still uncover the intrinsic effects of interfaces on HMF oxidations.…”

“…Recently, the nonprecious CoCe binary oxide also have been designed for HMF oxidation 33,34 because Co 3 O 4 and CeO 2 are functional candidates in the oxidation of organic compounds. 35 Given our previous study, 33 the exposed interfaces among Co 3 O 4 and CeO 2 in the CoCe binary oxide might play a crucial role during HMF oxidations, but it does not still uncover the intrinsic effects of interfaces on HMF oxidations.…”

Progress in the biosynthesis of bio-based PET and PEF polyester monomers

“…The conversion of CoCe-15 HMF was achieved close to 100% under molecular oxygen and alkaline conditions. 47 To improve FDCA yields, researchers based their work on a novel ionic liquid (IL)-promoted non-precious metal catalytic reaction system. With strong hydrogen bond formation, good thermal stability, and free formation of defined structures, 1-butyl-3-methylimidazolium chloride (BmimCl) was the best IL without the addition of a base.…”