Hu W, She J, Fu Z, Yang B, Zhang H, Jiang D. Highly efficient and tunable visible-light-catalytic synthesis of 2,5-diformylfuran using HBr and molecular oxygen.
RSC Adv 2021;
11:23365-23373. [PMID:
35479798 PMCID:
PMC9036589 DOI:
10.1039/d1ra00865j]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/12/2021] [Indexed: 01/11/2023] Open
Abstract
This paper discloses that inexpensive hydrobromic acid (HBr) is active and highly selective to the photo-oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) with dioxygen (O2) or even with water under visible light illumination, which can achieve the highest 89.1% DFF yield in DMSO at 80 °C under pure O2 atmosphere. More importantly, under bifunctional acid-photooxidation catalysis of HBr, fructose can be directly converted to DFF and its two-step cascade conversion in DMSO provides a far higher DFF yield (80.2%) than the one-step cascade conversion in MeCN (42.1%). The results of HMF photooxidation catalyzed by hydrohalic acids, free radical quenching tests and EPR spectrum support that the Br atom and superoxide (O2−˙) anion radicals generated by HBr photolysis in O2 are active species for the oxidation of HMF to DFF and their activities are adjusted by the reaction medium. This photo-synthetic protocol is very simple and practical, especially with low operating costs, showing a good industrial application prospect.
HBr is a very cheap and efficient bifunctional catalyst for the synthesis of DFF from the photooxidation of HMF by O2 and from the cascade conversion of fructose via a one-step or especially the two-step protocol.![]()
Collapse