Oxidation Of Furfural Research Articles

Capability of single and double elements doped perovskite oxide catalysts in 5-hydroxymethyl furfural oxidation

Capability of single and double elements doped perovskite oxide catalysts in 5-hydroxymethyl furfural oxidation

Anodic Cross-Coupling of Biomass Platform Chemicals to Sustainable Biojet Fuel Precursors

Electrocatalytic conversion of biomass platform chemicals to jet fuel precursors is a promising approach to alleviate the energy crisis caused by the excessive exploitation and consumption of non-renewable fossil fuels. However, an aqueous electrolyte has been rarely studied. In this study, we demonstrate an anodic electrocatalysis route for producing jet fuel precursors from biomass platform chemicals on Ni-based electrocatalysts in an aqueous electrolyte at room temperature and atmosphere pressure. The desired product exhibited high selectivity for the jet fuel precursor (95.4%) and an excellent coulombic efficiency of 210%. A series of in situ characterizations demonstrated that Ni2+ species were the active sites for the coupling process. In addition, the coupling reaction could be achieved by generating radical cations and inhibiting the side reaction. First, the electrochemical process could activate the furfural (FF) molecule and generate radical cations, resulting in an average of 2.0 times chain propagation. The levulinic acid (LA) molecules played a vital role in the coupling reaction. The adsorption strength of LA on Ni3N was higher than that of FF, which could inhibit the side reaction (the oxidation of FF) and achieve high selectivity. Meanwhile, the LA molecules were adsorbed on the Ni3N surface and then disrupted the formation of Ni3+ species, thus favoring the coupling reaction. This work demonstrates an efficient route to produce jet fuel precursors directly from biomass platform chemicals and provides a comprehensive understanding of the anodic coupling process.

Insight into the α-MnO2 boosts concentrated furfural or xylose conversion to furoic acid over 1,4-dioxane-H2O mixed solvent

Conversion of furfural or carbohydrates at concentrated feeds is highly desirable on an industrial scale of biobased fuels and chemicals but challenging. In this contribution, α-MnO2 was presented as an effective catalyst for the oxidation of concentrated furfural (10 wt%) to FA in 1,4-dioxane-H2O cosolvent media, offering satisfactory FA yields of 90%. Especially, an outstanding space-time yield (STY) of 23.2 kg m−3·h was achieved, which is the highest value achieved so far among the reported catalytic system. Importantly, 1,4-dioxane served not only functioned to improve the dispersity of furfural to strengthen the interaction of furfural with α-MnO2 but also contributed to lessening their tendency to polymerize via the solvation effect and significantly cuts down the solubility of base additive, improving the stability of furfural in 1,4-dioxane-H2O cosolvent media. Additionally, α-MnO2 with superior characteristics, including high lattice oxygen ratio as well as oxygen coordination capacity, boosting the excellent activity for furfural oxidation via the redox of Mn4+-Mn3+. Eventually, efficient synthesis of FA from concentrated xylose (20 wt%) by a two-step process without furfural separation was realized with an overall yield of 58%.

Promoting and controlling electron transfer of furfural oxidation efficiently harvest electricity, furoic acid, hydrogen gas and hydrogen peroxide

Conventional chemical oxidation of aldehydes such as furfural to corresponding acids by molecular oxygen usually needs high pressure to increase the solubility of oxygen in aqueous phase, while electrochemical oxidation needs input of external electric energy. Herein, we developed a liquid flow fuel cell (LFFC) system to achieve oxidation of furfural in anode for furoic acid production with co-production of hydrogen gas. By controlling the electron transfer in cathode for reduction of oxygen, efficient generation of electricity or production of H2O2 were achieved. Metal oxides especially Ag2O have been screened as the efficient catalyst to promote the oxidation of aldehydes, while liquid redox couples were used for promoting the kinetics of oxygen reduction. A novel alkaline-acidic asymmetric design was also used for anolyte and catholyte, respectively, to promote the efficiency of electron transfer. Such an LFFC system achieves efficient conversion of chemical energy of aldehyde oxidation to electric energy and makes full use the transferred electrons for high-value added products without input of external energy. With (VO2)2SO4 as the electron carrier in catholyte for four-electron reduction of oxygen, the peak output power density (Pmax) at room temperature reached 261 mW/cm2 with furoic acid and H2 yields of 90% and 0.10 mol/mol furfural, respectively. With anthraquinone-2-sulfonate (AQS) as the cathodic electron carrier, Pmax of 60 mW/cm2 and furoic acid, H2 and H2O2 yields of 0.88, 0.15 and 0.41 mol/mol furfural were achieved, respectively. A new reaction mechanism on furfural oxidation on Ag2O anode was proposed, referring to one-electron and two-electron reaction pathways depending on the fate of adsorbed hydrogen atom transferred from furfural aldehyde group.

Selective Oxidation of Furfural at Room Temperature on a TiO2-Supported Ag Catalyst

The catalytic performance of the Ag/TiO2 catalyst was evaluated in the oxidation of furfural (FF) to furoic acid (FA) in an alkaline aqueous solution under 15 bar of air in a batch reactor. The catalytic activity, yield, and stability of the catalyst were compared as a function of different reaction parameters including temperature (25–110 °C), nature of the atmosphere, base equivalent (nbase/nFF = 0.25–3), and nature of the inorganic bases used (NaOH, NaHCO3, and Na2CO3). Under optimum conditions, the yield of FA (96%) was achieved at room temperature, with an excellent carbon balance (>98%). The recyclability of the catalyst was also studied and the catalytic activity of the Ag/TiO2 catalyst slightly declined due to an increase in particle size as confirmed by TEM studies.

Selective Aerobic Oxidation of Furfural into Furoic Acid over a Highly Recyclable MnO2@CeO2 Core–Shell Oxide: The Role of the Morphology of the Catalyst

Selective Aerobic Oxidation of Furfural into Furoic Acid over a Highly Recyclable MnO₂@CeO₂ Core–Shell Oxide: The Role of the Morphology of the Catalyst

Integrated Environmental and Exergoeconomic Analysis of Biomass‐Derived Maleic Anhydride

AbstractLife cycle analysis and exergy analysis are applied to compare the production of maleic anhydride from different feedstock, both biomass‐ and petrochemical‐derived raw materials, in order to evaluate the sustainability of alternative biorefinery processes to conventional routes. The considered processes involve two options: gas and aqueous phase furfural oxidation with oxygen (air) and hydrogen peroxide as oxidants, respectively, considered as sustainable technologies because of the use of renewable feedstock. Conventional routes, used as benchmarks, include the current production processes using benzene or butane as raw materials. The results show that the aqueous phase process is far from being viable from an energy and environmental point of view due to the high exergy destruction and the use of H2O2 as oxidant (whose production entails important environmental drawbacks). On the contrary, the gas phase oxidation of furfural shows competitive results with petrochemical technologies. Nevertheless, the major environmental drawback of the new furfural‐to‐maleic anhydride production processes is detected on the environmental profile of the starting raw material. The results suggest that a better environmental footprint for maleic anhydride production in gas phase can be obtained if environmentally friendly furfural production technologies are used at the commercial scale.

Heterogeneously-catalyzed aerobic oxidation of furfural to furancarboxylic acid with CuO-Promoted MnO2

A cost-effective and sustainable noble-metal free catalyst system based on ubiquitously available Mn–Cu bimetallic oxides was served as efficient catalysts for furfural selective oxidation to furancarboxylic acid (FA). Interestingly, Mn2Cu1Ox exhibited an excellent furfural conversion of 99% with quantitative selectivity toward FA. Especially, we demonstrate the significant weakening of the Mn–O bonds with the incorporation of CuO into the Mn–Cu oxides, resulting in an improved OL reactivity of Mn2Cu1Ox, which brings about a higher catalytic activity for furfural oxidation. More importantly, Mn2Cu1Ox could exhibit YFA>90% over 5 cycles of reusability test. Through this study, the relationship between the morphology, surface chemistry, and catalytic activity of Mn–Cu bimetallic oxides are elucidated, providing a simple and environmentally friendly catalytic strategy and scientific basis for the development of Mn–Cu bimetallic oxides bioderived molecular aerobic oxidation materials.

Effect of poly(N-vinylpyrrolidone) ligand on catalytic activities of Au nanoparticles supported on Nb2O5 for CO oxidation and furfural oxidation

The development of green preparation methods for acidic metal oxide supported gold catalysts is of great importance for the extensive use of gold catalysts as well as for a comprehensive understanding of gold catalysts. In this study, poly(N-vinylpyrrolidone) (PVP) was used as the stabilizer of gold colloids to deposit gold nanoparticles on an acidic metal oxide, Nb2O5. The effects of the PVP ligand on the preparation of Au(-PVP)/Nb2O5 and on the catalytic activities for gas-phase CO oxidation and liquid-phase furfural oxidation were investigated. As removing more ligand PVP of Au(-PVP)/Nb2O5, the catalytic activities for both CO oxidation and furfural oxidation increased. The optimal calcination temperature for Au(-PVP)/Nb2O5 was determined to be 400 °C, and calcination at that temperature gave gold nanoparticles with an average size of 6.4 ± 2.5 nm and of the support of Nb2O5 remained as the original crystalline structure. The temperature for 50% CO conversion (T50%) of Au(-PVP)/Nb2O5 (calcined at 400 °C) was 81 °C. In addition, Au(-PVP)/Nb2O5 (calcined at 400 °C) presented 43% furfural conversion with 100% selectivity of furoic acid under a mild conditions (0.5 MPa O2, 40 °C) in the batch system. These results suggested that Au(-PVP)/Nb2O5 is a good catalyst for both gas-phase and liquid-phase reactions.

Efficient Synthesis of Biobased Furoic Acid from Corncob via Chemoenzymatic Approach

Valorization of lignocellulosic materials into value-added biobased chemicals is attracting increasing attention in the sustainable chemical industry. As an important building block, furoic acid has been commonly utilized to manufacture polymers, flavors, perfumes, bactericides, fungicides, etc. It is generally produced through the selective oxidation of furfural. In this study, we provide the results of the conversion of biomass-based xylose to furoic acid in a chemoenzymatic cascade reaction with the use of a heterogeneous chemocatalyst and a dehydrogenase biocatalyst. For this purpose, NaOH-treated waste shrimp shell was used as a biobased carrier to prepare high activity and thermostability of biobased solid acid catalysts (Sn-DAT-SS) for the dehydration of corncob-valorized xylose into furfural at 170 °C in 30 min. Subsequently, xylose-derived furfural and its derivative furfuryl alcohol were wholly oxidized into furoic acid with whole cells of E. coli HMFOMUT at 30 °C and pH 7.0. The productivity of furoic acid was 0.35 g furoic acid/(g xylan in corncob). This established chemoenzymatic process could be utilized to efficiently valorize biomass into value-added furoic acid.

Efficient and selective oxidation of furfural into high‐value chemicals by cobalt and nitrogen co‐doped carbon

AbstractSupported non‐noble metal catalysts for the selective oxidation of furfural into high‐value chemicals have attracted considerable attention. Herein, an atom‐level‐isolated, cobalt‐catalyst‐supported N‐doped carbon (Co SAs‐N@C) was synthesized through a metal cobalt–tannic acid coordination assembly strategy. The obtained Co SAs‐N@C with 7.68 wt% of Co content was qualitatively and quantitatively characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy, inductively coupled plasma optical emission spectrometer, and X‐ray absorption fine structure techniques. From the structural properties, potassium thiocyanate poisoning, and acid leaching, it was found that the atomic‐dispersed CoNx species of the catalyst acts as the active site and plays a vital role in its highly effective oxidative esterification activity. The catalytic mechanism of this reaction is involved in radical oxidation, as confirmed by electron paramagnetic resonance spectra. The density functional theory calculations revealed that the reaction pathway proceeds as a hemiacetal pathway. Interestingly, the Co SAs‐N@C catalyst also showed satisfactory catalytic activity for the aerobic oxidation of furfural. Unexpectedly, the Co SAs‐N@C catalyst still possessed excellent stability and recyclability without loss of activity after five reuses.

Insight into the catalytic mechanism of core–shell structured Ni/Ni-N/CN catalyst towards the oxidation of furfural to furancarboxylic acid

Developing low-cost and sustainable non-noble-metal catalysts for the efficient oxidation conversion of biomass-derived furfural to high value-added chemicals has evoked considerable interest. In this contribution, we report a facile and green core–shell structure N-doped carbon-supported nickel catalyst (Ni/Ni-N/CN), which exhibits excellent activity for the oxidation of furfural and other investigated aldehydes to corresponding carboxylic acid. Based on experimental studies, the synergy of Ni and Ni-N species in Ni/Ni-N-CN boosted the outstanding catalytic efficiency. The Ni site in Ni/Ni-N-CN contributes to the adsorption and activation of the aldehyde group in furfural, while the Ni-N site provides a stronger electron transfer ability and basicity of the Ni/Ni-N/CN catalyst, thus facilitates the activation of oxygen and abstraction of hydrogen during furfural oxidation process. Remarkably, Ni/Ni-N/CN-5 offered an outstanding FA formation rate of 4.13 molFA·molNi−1·h−1, which was far more than that of the ever-reported non-noble catalysts. More importantly, the as-prepared Ni/Ni-N/CN catalyst also presents great stability and reusability. The present work provides an efficient catalytic strategy toward selective oxidation reactions.

Transforming Electrocatalytic Biomass Upgrading and Hydrogen Production from Electricity Input to Electricity Output

Integrating biomass upgrading and hydrogen production in an electrocatalytic system is attractive both environmentally and in terms of sustainability. Conventional electrolyser systems coupling anodic biosubstrate electrooxidation with hydrogen evolution reaction usually require electricity input. Herein, we describe the development of an electrocatalytic system for simultaneous biomass upgrading, hydrogen production, and electricity generation. In contrast to conventional furfural electrooxidation, the employed low-potential furfural oxidation enabled the hydrogen atom of the aldehyde group to be released as gaseous hydrogen at the anode at a low potential of approximately 0 VRHE (vs. RHE). The integrated electrocatalytic system could generate electricity of about 2 kWh per cubic meter of hydrogen produced. This study may provide a transformative technology to convert electrocatalytic biomass upgrading and hydrogen production from a process requiring electricity input into a process to generate electricity.

Transforming Electrocatalytic Biomass Upgrading and Hydrogen Production from Electricity Input to Electricity Output

AbstractIntegrating biomass upgrading and hydrogen production in an electrocatalytic system is attractive both environmentally and in terms of sustainability. Conventional electrolyser systems coupling anodic biosubstrate electrooxidation with hydrogen evolution reaction usually require electricity input. Herein, we describe the development of an electrocatalytic system for simultaneous biomass upgrading, hydrogen production, and electricity generation. In contrast to conventional furfural electrooxidation, the employed low‐potential furfural oxidation enabled the hydrogen atom of the aldehyde group to be released as gaseous hydrogen at the anode at a low potential of approximately 0 VRHE (vs. RHE). The integrated electrocatalytic system could generate electricity of about 2 kWh per cubic meter of hydrogen produced. This study may provide a transformative technology to convert electrocatalytic biomass upgrading and hydrogen production from a process requiring electricity input into a process to generate electricity.

Catalytic Furfural/5-Hydroxymethyl Furfural Oxidation to Furoic Acid/Furan-2,5-dicarboxylic Acid with H2 Production Using Alkaline Water as the Formal Oxidant.

Furfural and 5-hydroxymethyl furfural (HMF) are abundantly available biomass-derived renewable chemical feedstocks, and their oxidation to furoic acid and furan-2,5-dicarboxylic acid (FDCA), respectively, is a research area with huge prospective applications in food, cosmetics, optics, and renewable polymer industries. Water-based oxidation of furfural/HMF is a lucrative approach for simultaneous generation of H2 and furoic acid/FDCA. However, this process is currently limited to (photo)electrochemical methods that can be challenging to control, improve, and scale up. Herein, we report well-defined ruthenium pincer catalysts for direct homogeneous oxidation of furfural/HMF to furoic acid/FDCA, using alkaline water as the formal oxidant while producing pure H2 as the reaction byproduct. Mechanistic studies indicate that the ruthenium complex not only catalyzes the aqueous oxidation but also actively suppresses background decomposition by facilitating initial Tishchenko coupling of substrates, which is crucial for reaction selectivity. With further improvement, this process can be used in scaled-up facilities for a simultaneous renewable building block and fuel production.

Solid Solution F-Mnxco3-Xo4 Ultrathin Nanosheets: Highly Active and Selective Catalyst for Oxidation of 5-Hydroxymethyl Furfural

Solid Solution F-Mnxco3-Xo4 Ultrathin Nanosheets: Highly Active and Selective Catalyst for Oxidation of 5-Hydroxymethyl Furfural

Influence of Pd and Pt Promotion in Gold Based Bimetallic Catalysts on Selectivity Modulation in Furfural Base-Free Oxidation

Furfural (FF) has a high potential to become a major renewable platform molecule to produce biofuels and bio-based chemicals. The catalytic performances of AuxPty and AuxPdy bimetallic nanoparticulate systems supported on TiO2 were studied in a base-free aerobic oxidation of furfural to furoic acid (FA) and maleic acid (MA) in water. The characterization of the catalysts was performed using standard techniques. The optimum reaction conditions were also investigated, including the reaction time, the reaction temperature, the metal ratio, and the metal loading. The present work shows a synergistic effect existing between Au, Pd, and Pt in the alloy, where the performances of the catalysts were strongly dependent on the metal ratio. The highest selectivity (100%) to FA was obtained using Au3-Pd1 catalysts, with 88% using 0.5% Au3Pt1 with about 30% of FF conversion at 80 °C. Using Au-Pd-based catalysts, the maximum yield of MA (14%) and 5% of 2(5H)-furanone (FAO) were obtained by using a 2%Au1-Pd1/TiO2 catalyst at 110 °C.

Environmental bio-oxidation of toxic furan by the co-recycling of waste fermented broth and rest cells

Furoic acid (FA) is used widely as raw material for bio-based resin, food, pharmaceutical and perfume products. The biocatalysis of Gluconobacter oxydans is on the spotlight of furfural oxidation to FA because of high selectivity, safety and environmental friendliness. However, like most bacterial fermentations, we have to treat a lot of waste fermented broth, especially containing toxic furans. An integrated bioprocess was developed to achieve the co-recycling of cells and waste broth during FA bioproduction. We found sorbitol performed a critical role during the co-recycling bioprocess and the cost of yeast extract was substituted entirely by cheaper corn extract. Here, FA bioproduction efficiency kept six rounds with the productivity of 10.3 g/L/h and 98% yield. The integrated bioprocess provides a novel idea for biotechnology developments not only on bioconversion of toxic furans but also on industrial fermentation, especially for the troublesome problems around the recycling of waste fermented broth.

Design of bimetallic Au/Cu nanoparticles in ionic liquids: Synthesis and catalytic properties in 5‐(hydroxymethyl)furfural oxidation

AbstractIn alloyed nanoparticles, synergistic electronic and/or geometric effects may enhance the catalytic properties compared to their monometallic counterparts. Herein, we address the synthesis of bimetallic Au/Cu nanoparticles with different compositions by wet chemical reduction in ionic liquids. The nanoparticles were successively supported on carbon. The ionic liquid could be recycled after synthesis. Annealing of the carbon‐supported NPs at 400 °C led to NPs of the ordered intermetallic L10 AuCu phase. The nanoparticle‐derived catalysts were characterized by X‐ray diffraction analysis, transmission electron microscopy, X‐ray photoelectron spectroscopy and optical emission spectroscopy with inductively coupled plasma. Oxidation of biomass‐derived furans is a prominent process for biomass transformation into value‐added chemicals. Herein, the oxidation of 5‐hydroxymethyl‐2‐furfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) was chosen as a model reaction to evaluate the effect of Cu addition and intermetallic structure on the catalytic performance. Particularly Au/Cu nanoparticles with an Au/Cu ratio of 3 : 1 showed very high conversion to FDCA.

Dual-functional paired photoelectrocatalytic system for the photocathodic reduction of CO2 to fuels and the anodic oxidation of furfural to value-added chemicals

The global warming and energy requirement have accentuated the need to convert atmospheric CO2 into fuels through a highly efficient photoelectrochemical cell (PEC) process. Typically, CO2 reduction at the cathode is accompanied by water oxidation at the anode to produce O2, which is not of significant value. Herein, we report the design of paired PEC to reduce CO2 to CH3OH and the oxidation of furfural (FF) to 2-furoic acid (2-FA) and 5-hydroxyfuroic acid (5-HFA). The paired PEC electrolyzer was constructed with Au/α-Fe2O3/RGO and Ru/RGO/Pt based asymmetric electrodes. The photocathode-driven PEC CO2 conversion test showed a high CH3OH yield of 63 μmol L−1 cm−2 at 21.5 % quantum efficiency with a Faradaic efficiency of 91 % at -0.6 V under visible light. The anodic furfural oxidation test demonstrated a higher FF conversion (82 %) with higher yields of 2-FA and 5-HFA. This study showed the potential of the paired PEC process to produce valuable products at both electrodes.