FDCA Yield Research Articles

Efficient Aerobic Oxidation of 5‐Hydroxymethylfurfural in Aqueous Media with Au–Pd Supported on Zinc Hydroxycarbonate

AbstractBimetallic catalysts with Au–Pd supported on zinc hydroxycarbonate (ZOC) were synthesized by a simple deposition–precipitation method and analyzed by transmission electron microscopy to have a narrow‐size distribution of predominantly 1–2 nm. The prepared Au–Pd/ZOC catalysts exhibited excellent activity towards 5‐hydoxymethylfurfural (HMF) oxidation in water in the presence of the base NaHCO3 at benign conditions of 80 °C and 3 bar O2, resulting in quantitative yield of 2,5‐furandicarboxylic acid (FDCA). The addition of base not only enhanced the yield of FDCA but also stabilized the support ZOC by preventing ZOC from the reaction with formed carboxylic acid intermediates/products, thus allowing Au–Pd/ZOC to be recycled for at least six times without significant loss of activity. The basicity of ZOC could play an important role in obtaining the improved yield of FDCA as compared to other supports.

Integrating Electrocatalytic 5-Hydroxymethylfurfural Oxidation and Hydrogen Production via Co–P-Derived Electrocatalysts

Electrocatalytic biomass valorization with renewable energy input represents a promising way to produce sustainable and nonfossil-based carbon products. Even more desirable is that the oxidative biomass upgrading can be integrated with H2 production in a single electrolyzer. Herein, we report that electrodeposited Co–P can act as competent electrocatalysts for 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA) at the anode and H2 production at the cathode simultaneously in alkaline media. When serving as a catalyst precursor on the anode, Co–P was able to achieve a current density of 20 mA/cm2 for HMF oxidation in 1.0 M KOH with 50 mM HMF at 1.38 V vs RHE, prior to the takeoff of the competing reaction, O2 evolution. Long-term chronoamperometry demonstrated a nearly 100% conversation of HMF and a ∼90% yield of FDCA. When HMF oxidation and H2 evolution were integrated in one electrolyzer with a Co–P/Co–P catalyst couple, the potential required to achieve a current density of 20 mA...

Optimization of Co/Mn/Br-Catalyzed Oxidation of 5-Hydroxymethylfurfural to Enhance 2,5-Furandicarboxylic Acid Yield and Minimize Substrate Burning

2,5-Furandicarboxylic acid (FDCA) is a valuable nonphthalate biomass-based plastic precursor with the potential to replace terephthalic acid (TPA) in a variety of polymer applications. In this work, the Co/Mn/Br-catalyzed semicontinuous oxidation of 5-hydroxymethylfurfural (HMF) to FDCA has been demonstrated at temperatures lower than those employed in the traditional Mid-Century (MC) process. As HMF is more susceptible to side reactions (e.g., the overoxidation to CO and CO2), lower temperatures compared to the MC process are typically used to prevent substrate burning. However, lower temperatures afford a much reduced FDCA yield compared to that of TPA in p-xylene oxidation. Therefore, optimization of other operating variables such as catalyst composition, water concentration in the acetic acid solvent, and pressure is essential to maximize FDCA yield. Using such optimization, we show that the FDCA yield can be enhanced to 90% at a 1/0.015/0.5 molar ratio of Co, Mn, and Br, 7% (v/v) water, 30 bar (CO2/O...

Controlled deposition of Pt nanoparticles on Fe3O4@carbon microspheres for efficient oxidation of 5-hydroxymethylfurfural

We report core/shell structured magnetically recyclable catalysts with a well-defined spherical morphology. Using these as catalysts for the oxidation of HMF, a 100% yield of FDCA could be achieved in just 4 h at 90 °C in water .

Efficient oxidation of biomass derived 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid catalyzed by Merrifield resin supported cobalt porphyrin

In this study, a new method was developed for the oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) over Merrifield resin supported Co(II)–meso-tetra(4-pyridyl)-porphyrin (abbreviated as Merrifield resin-Co-Py). Diffuse reflectance spectra showed that Co(II)–meso-tetra(4-pyridyl)-porphyrin was successfully bonded on the Merrifield resin. The Merrifield resin-Co-Py catalyst was used for the oxidation of HMF into FDCA, and several parameters were studied. Tert-butyl hydroperoxide was the best oxidant among other common oxidants. The reaction solvent greatly affected both HMF conversion and product selectivity. High HMF conversion of 95.6% and FDCA yield of 90.4% were obtained at 100°C after 24h. Time course of HMF conversion over Merrifield resin-Co-Py showed that 2,5-diformylfuran was the intermediate for the conversion of HMF into FDCA. The catalyst could be reused without the significant loss of its catalytic activity.

Catalytic Conversion of Fructose and 5-Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid over a Recyclable Fe3O4–CoOx Magnetite Nanocatalyst

A nano-Fe3O4–CoOx catalyst was prepared via a simple wet impregnation method. The nano-Fe3O4–CoOx catalyst showed good catalytic performance for the conversion of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid (FDCA) with t-BuOOH as the oxidant. Several important reaction parameters were explored, with the highest FDCA yield of 68.6% obtained from HMF after 15 h at a reaction temperature of 80 °C. One-pot conversion of fructose into FDCA was also successful via two steps. Catalytic conversion of fructose over Fe3O4@SiO2–SO3H yielded 93.1% HMF, which was oxidized in situ into FDCA with a yield of 59.8%. Furthermore, recycling of nano-Fe3O4–CoOx was accomplished with the help of a magnetic field. Nano-Fe3O4–CoOx showed high stability in the reaction process. The use of nonprecious metals and no requirement of a base additive made this method much more economical and environmentally friendly.

Aerobic oxidation of 5-hydroxymethylfurfural (HMF) effectively catalyzed by a Ce0.8Bi0.2O2−δ supported Pt catalyst at room temperature

98% yield of FDCA was obtained within 30 min at room temperature when HMF oxidation was catalyzed by Pt/Ce0.8Bi0.2O2−δ.

Purification of biomass-derived 5-hydroxymethylfurfural and its catalytic conversion to 2,5-furandicarboxylic Acid.

A simple and effective water extraction method is presented for the purification 5-hydroxylmethylfurfural (HMF) obtained from a biomass dehydration system. Up to 99% of the HMF can be recovered and the HMF in aqueous solution is directly converted to 2,5-furandicarboxylic acid (FDCA) as the sole product. This purification technique allows an integrated process to produce FDCA from fructose via HMF prepared in an isopropanol monophasic system, with an overall FDCA yield of 83% obtained. From Jerusalem raw artichoke biomass to FDCA via HMF prepared in a water/MIBK (methyl isobutyl ketone) biphasic system, an overall FDCA yield of 55% is obtained.

Influence of support on the aerobic oxidation of HMF into FDCA over preformed Pd nanoparticle based materials

Here, the preparation and evaluation of supported nanoparticle based catalytic material is reported. Polyvinylpyrrolidone (PVP) stabilized palladium nanoparticles with a mean particle size of 1.8nm were synthesized in ethylene glycol and subsequently deposited onto different metal oxide supports (TiO2, γ-Al2O3, KF/Al2O3, and ZrO2/La2O3). The prepared catalysts were applied to the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) in aqueous solution at atmospheric pressure (T=90°C, pO2=1bar) and compared regarding their catalytic performance and stability. The highest FDCA yield (>90%) was obtained for the Pd/ZrO2/La2O3 catalysts which additionally showed a relatively stable catalytic performance when the material was reused. Various characterization methods including XRD, TEM, XPS, and AAS were applied to obtain information about the Pd NP before and after utilization in HMF oxidation. For the Pd/TiO2 the least changes in Pd NP structure were observed after using the material in HMF oxidation. This was attributed to a stronger interaction between the Pd NP and the TiO2 support compared to other supports used in the studies.

Synthesis of 2,5-furandicarboxylic acid by the aerobic oxidation of 5-hydroxymethyl furfural over supported metal catalysts

Supported Pt catalysts are synthesized, characterized and are used in the liquid phase air oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Under the optimum reaction conditions of a stepwise increase in the reaction temperature (75 and 140 °C for 12 h each), we achieved as high as 96 % FDCA yield in presence of 1 bar oxygen pressure over Pt/γ-Al2O3. It is shown that as the oxygen pressure increases (1–10 bar), the FDCA yields decrease, since at higher partial pressure of oxygen, overoxidation reactions of substrate and product(s) are possible. It is interesting to note that even with air as an oxidant, we obtained similar yields of FDCA as that with oxygen. Moreover, the effects of base (weak or strong), its concentration (equimolar or excess) were studied in detail. It is important to increase the reaction temperature in a stepwise manner to achieve higher yields of FDCA since at higher temperatures HMF undergoes self-degradation and thus the yields of FDCA decrease. The self-degradation of HMF is also proved by undertaking the reaction under nitrogen environment. The study on the effect of substrate-to-catalyst ratio is done to improve up on the economics of overall process. The effect of supports (reducible and non-reducible) and their oxygen storage capacity is discussed and is proposed to be one of the factors to change the course of reaction. Furthermore, we have shown that FDCA formed in the reaction can be successfully isolated (91 %, isolated yield) in the pure form and its purity is confirmed by NMR, melting point, and elemental analysis. The catalysts were characterized with X-ray powder diffraction, transmission electron microscopy and inductively coupled plasma-optical emission spectroscopy techniques.

Synthesis, Characterization, and Application of PVP-Pd NP in the Aerobic Oxidation of 5-Hydroxymethylfurfural (HMF)

PVP stabilized Pd nanoparticles (Pd NP) were prepared in ethylene glycol at three different NaOH/Pd ratios and characterized by XRD, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The Pd NP were applied in the aerobic oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) in an alkaline aqueous solution (T = 90 °C, pO2 = 1 bar). The highest yield of FDCA (90 %) was obtained in the presence of Pd NP with a mean diameter of 1.8 nm, prepared with a 4:1 molar ratio of NaOH:Pd. Thus prepared Pd NP could be stored in their alkaline synthesis solution under ambient conditions and showed consistently good catalytic performances after up to one month storage time, in contrast to Pd NP prepared with 2:1 and 1:1 ratio and stored in neutral or acidic environment.

Selective aqueous phase oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over Pt/C catalysts: influence of the base and effect of bismuth promotion

5-Hydroxymethylfurfural (HMF) was quantitatively oxidized to 2,5-furandicarboxylic acid (FDCA) at 100 °C under 40 bar air in moderately basic aqueous solution in the presence of active carbon supported platinum and bismuth–platinum catalysts. The transformation of HMF into FDCA proceeded via the 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) and 2,5-diformylfuran (DFF) intermediates; both of these were very reactive and rapidly oxidized to 5-formylfurancarboxylic acid (FFCA), the subsequent oxidation of which was found to be the rate-limiting step. The preparation method of the platinum catalysts influenced the particle size of metallic platinum and modified the surface of the support, therefore determining the activity. The addition of a carbonate base (Na2CO3/HMF molar ratio = 2) led to faster overall conversion than bicarbonate (NaHCO3/HMF = 4) by maintaining an appropriate pH for the oxidation reaction. The ex situ or in situ addition of a bismuth promoter still accelerated the reaction; the highest activity was observed for a Bi/Pt molar ratio of ca. 0.2. Furthermore, the promoter helped to prevent some deactivation of the Pt catalyst upon recycling experiments. Quantitative conversion of HMF (0.1 M) and >99% yield of FDCA were achieved using a molar ratio of HMF to Pt of 100 and Na2CO3 as the homogeneous base in less than 2 h.