Base-free oxidation of 5-hydroxymethyl-2-furfural to 2,5-furan dicarboxylic acid over basic metal oxide-supported ruthenium catalysts under aqueous conditions

Abstract

Polyethylene terephthalate (PET) is the third-largest globally produced polymer, and many efforts have been made to replace PET with a renewable polymer. One renewable alternative to PET is polyethylene furanoate (PEF), which is prepared using 2,5-furan dicarboxylic acid (FDCA) as a precursor instead of terephthalic acid (TPA). Biomass-derived hydroxymethyl-2-furfural (HMF) can be converted to 2,5-furan dicarboxylic acid (FDCA) through multiple oxidation reactions. Metal oxide-supported Ru catalyst prepared by simple methods for the oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furan dicarboxylic acid (FDCA) in the absence of a base under aqueous conditions is reported. This study clearly explains that the nature of basicity of the support has an important role on the selective oxidation of HMF to FDCA. Among the various materials studied magnesium oxide (MgO)-supported Ru catalyst afforded a 100% HMF conversion and more than 90% FDCA yield with 90 psi of O 2 at 160 • C in 4 h and it could be used 5 times without a significant drop of FDCA yields.

Clean Catalytic Oxidation for Derivatization of Key Biobased Platform Chemicals: Ethanol, Glycerol, and Hydroxymethyl Furfural

“…For similar metal loadings, lower times were required when basic supports were used instead of carbon supports (entries 17–18). MgAlO led to a quantitative yield, but the catalyst was not stable . The support partly dissolved in the strong acid media resulting from the oxidation.…”

“…Supports with basic sites, hydroxyapatite (HAP), MgAlO, and MgO allowed 100% conversion and good yields. Gao et al attributed the almost stoichiometric yield to the availability of both acidic and basic sites around the highly dispersed RuNP on the surface of HAP support.…”

“…MgAlO led to a quantitative yield, but the catalyst was not stable. 150 The support partly dissolved in the strong acid media resulting from the oxidation. Ru/MgO with the same metal loading led to a slightly lower yield, and it was stable for six cycles.…”

2,5-Furandicarboxylic acid production via catalytic oxidation of 5-hydroxymethylfurfural: Catalysts, processes and reaction mechanism

“…In addition to HT and LDH, some novel basic supports have been reported recently. Cho et al [101] investigated a series of basic metal oxide supported Ru catalysts and found the catalytic activity for HMF oxidation was related primarily to the basicity of support in the order of MgAlO > MgO > ZrO 2 > CeO 2 ) La 2 O 3 . Unexpectedly, the most active MgAlO support was not stable under the catalytic condition and seriously dissolved due to the poor resistance to the acidic nature of the produced FDCA.…”

Reactivity of Aliphatic Dicarboxylic Acids in Wet Air Oxidation Conditions

“…However, the stability of individual intermediates formed during the oxidation has received relatively little attention, and this limits the use of partial WAO in order to obtain fine chemicals. There is considerable data concerning acetic and formic acid, which are frequently formed in the process and have high resistance to oxidation; they are classified as major byproducts. − Previous investigations have shown that DCAs can be attainable via different types of oxidative conversion of organic wastes and biomass. − Moreover, there are reports on WAO processes where DCAs were obtained, but these were primarily focused only on short-chain DCA. − Some researchers have demonstrated the complete removal of these short-chain DCAs under specific conditions, − although the wider spectrum of their reactivity has not been studied. Accordingly, there is still a deficiency of information on how environmentally friendly routes such as WAO can be used for the production of DCAs, especially for DCAs with longer aliphatic chains ( n > 4).…”