Constant temperature and humidity combined with vacuum-steam pulsed steaming of Polygonatum cyrtonema rhizome: Quality attribute and browning mechanism.

The quality of Polygonatum cyrtonema rhizome is considerably influenced by steaming, a post-harvest procedure; however, the mechanisms behind this quality formation are not well understood. This study explored two innovative streaming methods for Polygonatum cyrtonema rhizome: constant temperature and humidity steaming and drying (CTHSD) and constant temperature and humidity combined with vacuum-steam pulsed steaming and drying (CTH + VSPSD). Traditional atmospheric steaming, simmering, and drying (ASD) were also used. We evaluated the microstructure, colour and polysaccharide, reducing sugar, 5-hydroxymethylfurfural, amino acid, phenolics and diosgenin contents as well as its antioxidant capacity. Results indicated that all methods enhanced antioxidant activity, released phenolic compounds and disrupted the microscopic pore wall structure. The processed samples exhibited increased browning values owing to non-enzymatic browning reactions between amino acids and reducing sugars. Notably, the CTH + VSPSD method yielded the highest antioxidant capacity, better preservation of polysaccharides and lower levels of 5-hydroxymethylfurfural compared to other methods. Additionally, CTH + VSPSD reduced production time by 66.7 % while achieving a comparable colour profile to that of conventional ASD technology. Therefore, the CTH + VSPSD method shows great promise for producing high-quality Polygonatum cyrtonema rhizome products.

Inhibitory effects of polyphenols on the Maillard reaction in low lactose milk and the underlying mechanism.

In this study, low lactose milk (LLM) was heat-treated under different conditions and stored at 4, 25 and 37°C for 15 d, after which the changes in the Maillard reaction (MR) of LLM were investigated. The contents of α-dicarbonyl compounds and 5-hydroxymethylfurfural(5-HMF) in LLM after the addition of polyphenols were determined via HPLC, and the inhibitory effects of 3 different concentrations of epigallocatechin gallate (EGCG), dihydromyricetin (DMY), and procyanidin (PC) on the MR of LLM were studied. The fluorescence intensity of LLM was measured at 290, 300 and 310 K, the fluorescence quenching types and binding constants of PC on casein were investigated, and thermodynamic analysis was carried out. These results suggest that the optimal heat treatment conditions were 80°C for 15 s and that the optimal storage conditions were 4°C. In the α-dicarbonyl compound capture and 5-HMF inhibition tests, PC had the greatest inhibitory effect at a concentration of 0.2 mg/mL, with an inhibition rate of 48.19%. Therefore, PC is more stable than the other 2 polyphenols. The mechanism of inhibition involves the formation of matrix complexes between PC and casein in LLM, resulting in static quenching of the LLM and thus a reduction of the inhibitory effect. The thermodynamic analysis revealed that the binding of PC to casein was an exothermic reaction, and the combination of the 2 was driven mainly by hydrogen bonding and van der Waals forces. This study lays a theoretical foundation for the development of LLM.

Proton-Coupled Electron Transfer in Photoelectrochemical Alcohol Oxidation Enhanced by Nickel-based Cocatalysts.

Using biomass oxidation reactions instead of water oxidation reactions is optimal for accomplishing biomass conversion and effective hydrogen generation. Here, we report that Fe2O3 photoanodes with a NiOOH cocatalyst exhibit excellent performance for photoelectrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The conversion efficiency for HMF reaches 98.5%, while the selectivity for FDCA is 94.2%. We revealed that HMF is oxidized through a spontaneous proton-coupled electron transfer (PCET) process with the high-valent phase of the Ni-based catalyst. The dangling oxygen and bridging oxygen of the high-valent phase species serve as proton-accepting sites. Furthermore, we pointed out that the deprotonated bond dissociation free energy difference between the catalysts and alcohols is the thermodynamic trigger for the PCET process. This study provides a reasonable explanation for the alcohol oxidation reaction, which is beneficial for designing biomass conversion systems.

Enhancing 5-Hydroxymethylfurfural Production from Fructose Using Triethylbenzylammonium Chloride-Based Acidic Deep Eutectic Solvents: Optimization and Acidity Impact.

5-Hydroxymethylfurfural (5-HMF) is an important biomass-based platform compound that links biomass feedstocks with petrochemical refinery products. In this work, we developed a novel approach using TEBAC-based acidic deep eutectic solvents (ADESs) to synthesize 5-HMF through the dehydration of fructose. Our approach demonstrates significant improvements in both 5-HMF yield and process efficiency compared to conventional solvent systems. Under optimal experimental conditions (90°C, 4.5 h), a maximum 5-HMF yield of 97.77±3.20% was achieved at a TEBAC:acetic acid ratio of 2:3 with 1 wt% fructose loading.  Notably, our system inhibits the formation of by-products such as levulinic acid (LA) and formic acid (FA), which are commonly detected in other dehydration processes. Additionally, higher 5-HMF yields of 76.67±0.33% and 73.51±1.14% were achieved with 10 wt% and 20 wt% fructose loadings, respectively, further highlighting the scalability of the process. The  acidity of ADESs was found to significantly affect the dehydration rate and yield, as demonstrated through Hammett's acidity function analysis. The key innovation of our study lies in the strategic selection of hydrogen bond donors and acceptors in the DES, enabling both high efficiency and selectivity in 5-HMF production. These findings provide a promising pathway for large-scale biomass conversion with reduced by-product formation.

CO2-assisted Controllable Synthesis of PdNi Nanoalloys for Highly Selective Hydrogenation of Biomass-derived 5-Hydroxymethylfurfural.

The selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bishydroxymethyltetrahydrofuran (BHMTHF), a vital fuel precursor and solvent, is crucial for biomass refining. Herein, we report highly selective and stable PdNi nanoalloy catalysts for this deep hydrogenation process. A CO2-assisted green method was developed for the controllable synthesis of various bimetallic and monometallic catalysts. The PdNi/SBA-15 catalysts with various Pd/Ni ratios exhibited a volcano-like trend between BHMTHF yield and Pd/Ni ratio. Among all catalysts tested, Pd2Ni1/SBA-15 achieved the best performance, converting 99.0% of HMF to BHMTHF with 96.0% selectivity, surpassing previously reported catalysts. Additionally, the Pd2Ni1/SBA-15 catalyst maintained excellent stability even after five recycling runs. Catalyst characterizations (e.g., HAADF-STEM) and DFT calculations confirmed the successful formation of the alloy structure with electron transfer between Ni and Pd, which accounts for the remarkable performance and stability of the catalyst. This work paves the way for developing highly selective and stable alloy catalysts for biomass valorization.

Microwave-Assisted Conversion of 5-Hydroxymethylfurfural into 2,5-Furandicarboxylic Acid over CuCo Oxide.

A series of CuCo bimetallic catalysts were prepared via the co-precipitation method for the catalytic transformation of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA). FDCA acts as a precursor for biodegradable biopolymer polyethylene furanoate production, thereby achieving a carbon-neutral approach. Out of all the synthesized catalysts, CuCo(1:1) showed remarkable catalytic activity and yielded 70.67% FDCA while achieving 100% HMF conversion in 5 minutes at 50 ℃ temperature in the presence of tert-butyl hydroperoxide as an oxidant. Synergistic effects of the catalyst, such as adsorbed oxygen, relative oxygen vacancy, lesser pore size, and pore volume, were key factors attributed to the catalyst's excellent activity. The synthesized catalyst showed good recyclability with a minimal decrease in FDCA yield up to 5 cycles. Pre and post-characterization of catalysts such as BET, TEM, FE-SEM, XRD, H2-TPR, CO2 TPD, ICP-OES, and XPS were done to correlate the catalyst's properties with its activity. In addition, the effect of reaction parameters such as stirring speed, temperature reaction time, catalyst weight, base, and oxidant was studied to achieve optimum reaction conditions. The reaction products were analyzed quantitatively and qualitatively using HPLC and HR-MS.

Post-functionalized cellulose/metal-organic framework composite with sulfonic acid: An efficient, rapid and recyclable bio-based solid acid catalyst for the synthesis of 5-hydroxymethylfurfural.

A new acid catalyst derived from renewable sources was developed using an ultrasound-assisted approach. This involved the formation of a metal-organic framework called MIL-88(Fe) in the presence of carboxymethylated-cellulose (CMC). Subsequently, the catalyst underwent a post-synthetic modification to introduce further acidic -SO3H groups into the structure of the CMC/MIL-88(Fe) composite. Various examinations were carried out that validated the successful creation of the CMC/MIL-88(Fe)-SO3H catalyst. The effectiveness of the catalyst was assessed in the process of solid acid catalysis, specifically in the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF). Through the employment of Response Surface Method (RSM) optimization, it was determined that utilizing 34 wt% of the catalyst at a temperature of 90 °C for 30 min resulted in a remarkable 98 % HMF yield. The catalyst exhibited good reusability, as it retained its catalytic effectiveness throughout four consecutive cycles. Comparative catalytic investigations involving CMC and CMC/MIL-88(Fe) composite without sulfonation revealed the superior activity of CMC/MIL-88(Fe)-SO3H catalyst, emphasizing the collaborative effect of CMC, MIL-88(Fe), and the impact of post-functionalization with -SO3H on the performance of the catalyst.

Phase effects in zirconia catalysed glucose conversion to 5-hydroxy methylfurfural.

5-(hydroxymethyl)furfural (HMF) is a key biomass derived platform chemicals used to produce fuel precursors or additives and value-added chemicals, synthesised by the cascade isomerisation of glucose and subsequent dehydration of reactively formed fructose to HMF over Lewis and Bronsted acid catalysts respectively. Zirconia is a promising catalyst for such reactions; however, the impact of acid properties of different zirconia phases is poorly understood. In this work, we unravel the role of the zirconia crystalline phase in glucose isomerisation and fructose dehydration to HMF. The Lewis acidic monoclinic phase of zirconia is revealed to preferentially facilitate glucose isomerisation, while the nanoparticulate tetragonal phase possesses Brønsted acid sites which favour fructose dehydration. Synergy between both zirconia phases facilitates cascade HMF production, with both catalysts investigated as physical mixtures in batch and flow reactor configurations. Using a physical mixture of only 15 wt% m-ZrO2 with 85 wt% t-ZrO2 in either batch or packed bed reactor configuration is sufficient to reach equilibrium conversion of glucose for subsequent dehydration by the t-ZrO2 component. Under continuous flow, a six-fold increase in HMF production was obtained when operating with a physical mixture of m- and t-ZrO2 compared to that from a single bed of t-ZrO2.

The Stability Challenge of Furanic Platform Chemicals in Acidic and Basic Conditions.

The transition toward renewable resources is pivotal for the sustainability of the chemical industry, making the exploration of biobased furanic platform chemicals derived from plant biomass of paramount importance. These compounds, promising alternatives to petroleum-derived aromatics, face challenges in terms of stability under synthetic conditions, limiting their practical application in the fuel, chemical, and pharmaceutical sectors. Our study presents a comprehensive evaluation of the stability of furan derivatives in various solvents and under different conditions, addressing the significant challenge of their instability. Through systematic experiments involving GC‒MS, NMR, FT‒IR and SEM analyses, we identified key degradation pathways and conditions that either promote stability or lead to undesirable degradation products. These findings demonstrate the strong stabilizing effect of polar aprotic solvents, especially DMF, and reveal the dependence of furan stability on solvent and additive type. This research opens new avenues in the utilization of renewable furans by providing critical insights into their behavior under synthetic conditions, significantly impacting the development of sustainable materials and processes. The broad appeal of this study lies in its potential to guide the selection of conditions for the efficient and sustainable synthesis of furan-based chemicals, marking a significant advance in green chemistry and materials science.

Bifunctional MoNi4/nickel foam electro-catalyst for ultra-efficient oxidation of high-concentration 5-hydroxymethylfurfural and HER.

The electro-catalytic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) provides an attractive route to produce 2, 5-furandicarboxylic acid (FDCA) as a substitute for terephthalic acid used in the plastics industry. Herein, we prepared MoNi4 alloy on nickel foam (NF) using a simple hydrothermal method followed by hydrogen reduction. Applied MoNi4/NF as the bifunctional electrodes for the electro-catalytic HMF oxidation reaction (HMFOR) and HER, 98.7% FDCA yield and 97.3% Faraday efficiency (FE) can be achieved even with HMF concentration as high as 200 mM. Notably, no obvious deactivation was observed after ten consecutive cycles. In-situ Raman, XANES and EXAFS results show that the nickel species of MoNi4/NF is first oxidized to Ni3+ species under the applied voltage, and after undergoing the electro-catalytic HMFOR, then reduced to Ni2-δ state (with a valence between 0 and +2) due to the electron-donating effect from Mo. MoNi4/NF with more than one electron transfer between Ni3+ and Ni2-δ during the HMFOR enables it to have excellent electro-catalytic oxidation ability toward HMFOR.

Non-noble metal catalysts for electrooxidation of 5-hydroxymethylfurfural.

2,5-Furandicarboxylic acid (FDCA) is a class of valuable biomass-based platform compounds. The creation of FDCA involves the catalytic oxidation of 5-hydroxymethylfurfural (HMF). As a novel catalytic method, electrocatalysis has been utilized in the 5-hydroxymethylfurfural oxidation reaction (HMFOR). Common noble metal catalysts show catalytic activity, which is limited by price and reaction conditions. Non-noble metal catalyst is known for its environmental friendliness, affordability and high efficiency. The development of energy efficient non-noble metal catalysts plays a crucial role in enhancing the HMFOR process. It can greatly upgrade the demand of industrial production, and has important research significance for electrocatalytic oxidation of HMF. In this paper, the reaction mechanism of HMF undergoes electrocatalytic oxidation to produce FDCA are elaborately summarized. There are two reaction pathways and two oxidation mechanisms of HMFOR discussed deeply. In addition, the speculation on the response of the electrode potential to HMFOR is presented in this paper. The main non-noble metal electrocatalysts currently used are classified and summarized by targeting metal element species. Finally, the paper focus on the mechanistic effects of non-noble metal catalysts in the reaction, and provide the present prospects and challenges in the electrocatalytic oxidation reaction of HMF.

Boron-doped sulfonated graphitic carbon nitride as a highly efficient catalyst for the production of 5-hydroxymethylfurfural from carbohydrates.

The presence of humins during the conversion of concentrated fructose presents a major obstacle in the large-scale production of 5-hydroxymethylfurfural (HMF) from fructose. Herein, we reported a boron-doped graphitic carbon nitride sulfonated (BGCN-SO3H) as an excellent catalyst for the synthesis of HMF from fructose. The BGCN-SO3H catalyst structures were analyzed using various characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), elemental mapping analysis, and Fourier-transform infrared spectroscopy (FT-IR). The BGCN-SO3H catalyst was evaluated for the synthesis of HMF from fructose. We investigated the influence of catalyst performance, including solvent reactions, catalyst loading, substrates, and volume of solvent to optimize reaction conditions. As a result, the yield of HMF was obtained at 88 % within 5 h when using 30 mg of catalyst. The study of catalyst activity involved examining reactions that allowed recovery and reuse. The research findings offer a method for producing HMF with exceptional efficiency using solid catalysts.

The relationship between the deterioration of frying oil and the generation of hazards during frying.

Deep-fat frying gives food a desirable color and flavor but inevitably leads to oil deterioration and production of hazards. In this study, the simultaneous generation of multiple hazards under different frying conditions was investigated, the deterioration of frying oil was evaluated, and finally, their correlation was analyzed. The results showed that as the temperature of frying chicken wings increased from 150 to 190 °C, the levels of acrylamide (AA), heterocyclic amines (HCAs), and polycyclic aromatic hydrocarbons (PAHs) in the oil also increased proportionally. At 190 °C, the fried potato oil contained the highest AA content of 2.60 mg·kg-1, while the content of HCAs and PAHs was the highest in fried chicken wings oil, with values of 5.06 µg·kg-1 and 5.18 µg·kg-1, respectively. 5-Hydroxymethylfurfural was detected only in fried potato oil. Oil quality deteriorated gradually with increasing frying temperature and heating time, as indicated by increased acid value, carbonyl value, and levels of total polar compounds. Overall, the results indicated hazards were positively correlated with oil deterioration, suggesting that oil deterioration contributed to the generation of hazards. This work links hazards and oil deterioration, which is crucial for improving the quality and safety of fried foods, while reducing negative environmental impacts, and achieving clean production.

Unlocking the Anion Effect on Steerable Production of 5-Hydroxymethylfurfural.

Homogeneous metal salt catalysts play a pivotal role in industrial production of 5-hydroxymethylfurfural (HMF). Herein, we first proposed the anion effect on steerable production of HMF using metal salts with different anions as catalyst in a biphasic system of tetrahydrofuran (THF)/NaCl aqueous solution (NaCl aq). Notably, the anions affected the catalytic activity of the metal salts, leading to an order of magnitude difference in the HMF yields, i.e., AlBr3 (74.0 mol %)>AlCl3 (60.8 mol %)>Al2(SO4)3 (35.2 mol %)>Al(NO3)3 (14.9 mol %). The anion effect on steerable production of HMF could be attributed to the proximity effect and electron tension. Anions form close-range interactions with glucose molecules by proximity effect to promote electron transfer, facilitating the isomerization of glucose to fructose. Besides, anions induce a reduction of the electron cloud density of glucose carbon atoms, generating electron tension that rapidly transforms glucose from the ground state to the transition state, thereby increasing the HMF yield. Based on the revelation of anions effect and evaluation of techno-economic process, we expect to provides theoretical guidance for high-throughput screening of metal salt catalysts in industrial biorefinery.

Unilamellar MnO2 nanosheets confined Ru-clusters combined with pulse electrocatalysis for biomass electrooxidation in neutral electrolytes.

The electrochemical oxidation of 5-hydroxymethylfurfural (HMFOR) in alkaline electrolyte is a promising strategy for producing high-value chemicals from biomass derivatives. However, the disproportionation of aldehyde groups under strong alkaline conditions and the polymerization of HMF to form humic substances can impact the purity of 2,5-furandicarboxylic acid (FDCA) products. The use of neutral electrolytes offers an alternative environment for electrolysis, but the lack of OH- ions in the electrolyte often leads to low current density and low yields of FDCA. In this study, a sandwich-structured catalyst, consisting of Ru clusters confined between unilamellar MnO2 nanosheets (S-Ru/MnO2), was used in conjunction with an electrochemical pulse method to realize the electrochemical conversion of 5-hydroxymethylfurfural into FDCA in neutral electrolytes. Pulse electrolysis and the strong electron transfer between Ru clusters and MnO2 nanosheets help maintain Ru in a low oxidation state, ensuring high activity. The increased *OH generation led to a groundbreaking current density of 47 mA/cm2 at 1.55 V vs. reversible hydrogen electrode (RHE) and an outstanding yield rate of 98.7 % for FDCA in a neutral electrolyte. This work provides a strategy that combines electrocatalyst design with an electrolysis technique to achieve remarkable performance in neutral HMFOR.

Co@NC Chainmail Nanowires for Thermo- and Electrocatalytic Oxidation of 2,5-Bis(hydroxymethyl)furan to 2,5-Furandicarboxylic Acid.

2,5-Furandicarboxylic acid (FDCA) has emerged as an important bio-based furanic compound, which has broad application prospects in renewable energy and materials, especially in the preparation of polyethylene 2,5-furandicarboxylate (PEF). While the  conventional synthesis of FDCA involves oxidation of 5-hydroxymethylfurfural (HMF) as a substitute, the thermal and chemical instability of HMF due to its aldehyde group poses challenges. A more favorable alternative is the utilization of 2,5-bis(hydroxymethyl)furan (BHMF), a non-aldehyde and more stable precursor. This study pioneeringly reports nitrogen-doped-carbon encapsulated cobalt (Co@NC) chainmail nanowires for the thermal and electrocatalytic oxidation of BHMF to FDCA. The Co@NC/NF achieved a 97.9% conversion of BHMF with a 93.3% yield of FDCA  at 1.475 V vs. RHE, whereas thermal catalysis only obtained 14.9% FDCA yield after 10 hours. Kinetic studies indicated that the large electrochemically active surface area and excellent kinetic parameters contribute its superior electrochemical performance. Mechanistic analysis revealed that the migration of inner electrons to the exterior modified the electronic properties of the carbon layer, thereby facilitating the oxidation of BHMF. Furthermore, the in-situ generation of high-valent cobalt species markedly accelerated the BHMF oxidation. This research underscores the potential of carbon-encapsulated metal chainmail catalysts in thermal and electrochemical biomass conversion.

Biphasic Production of 5-hydroxymethylfurfural (HMF) in a Recyclable Deep Eutectic Solvent-based System Catalyzed by H4SiW12O40.

The reaction with in situ extraction to yield 5-hydroxymethylfurfural (HMF) from d-fructose (Fru) was investigated using a biphasic system based on a self-consuming deep eutectic solvent (DES) as reaction phase. The significance of choline chloride (ChCl), a cost-effective and safe quaternary ammonium salt, was evident in enhancing HMF yield through fructose dehydration and concurrently suppressing side reactions. The DES system demonstrated fast reactions with high selecivities and recyclability across five cycles. The observed decline in H4SiW12O40 activity, primarily due to proton leaching, was successfully restored with the addition of HCl. Furthermore, ChCl exhibited ease of recrystallization in the presence of acetonitrile. This research proposes an environmentally friendlier approach for HMF production through a reusable-biphasic process. The presented reaction system suppresses completely the formation of levulinic and formic acid leading to HMF yields of up to 84 % of selectivities of up to 88 % after 30 minutes at 80 °C. The system was recycled over 16 runs and after an initial slight loss of activity the system in the run 0-5, run 6-15 has shown a constant HMF output as in the first recycling run.

Furandicarboxylic Acid (FDCA): Electrosynthesis and Its Facile Recovery From Polyethylene Furanoate (PEF) via Depolymerization.

Replacing fossil fuels with renewable, bio-based alternatives is inevitable for the modern chemical industry, in line with the 12 principles of green chemistry. 2,5-Furandicarboxylic acid (FDCA) is a promising platform molecule that can be derived from 5-hydroxymethyl furfural (HMF) via sustainable electrochemical oxidation. Herein, we demonstrate TEMPO-mediated electrooxidation of HMF to FDCA in ElectraSyn 2.0 using inexpensive commercially available electrodes: graphite anode and stainless-steel cathode, thereby avoiding the often cumbersome electrode preparation. Key parameters such as concentration of HMF, KOH, and catalyst loading were optimized by experimental design. Under the optimized conditions, using only a low amount of TEMPO (5 mol %), high yield and Faradaic efficiency of 96 % were achieved within 2.5 h. Moreover, since FDCA is a monomer of the bio-based poly(ethylene furanoate), PEF, we aimed to investigate its recovery by depolymerization, which could be of paramount importance in the circular economy of the FDCA. For this, a new polar aprotic solvent, methyl sesamol (MeSesamol), was used, allowing the facile depolymerization of PEF at room temperature with high monomer yields (up to 85 %), while the cosolvent MeSesamol was recycled with high efficiency (95-100 %) over five reaction cycles.

Enhancing the Electrocatalytic Oxidation of 5-Hydroxymethylfurfural Through Cascade Structure Tuning for Highly Stable Biomass Upgrading.

Electrocatalytic 5-hydroxymethylfurfural oxidation reaction (HMFOR) provides a promising strategy to convert biomass derivative to high-value-added chemicals. Herein, a cascade strategy is proposed to construct Pd-NiCo2O4 electrocatalyst by Pd loading on Ni-doped Co3O4 and for highly active and stable synergistic HMF oxidation. An elevated current density of 800 mA cm-2 can be achieved at 1.5 V, and both Faradaic efficiency and yield of 2,5-furandicarboxylic acid remained close to 100% over 10 consecutive electrolysis. Experimental and theoretical results unveil that the introduction of Pd atoms can modulate the local electronic structure of Ni/Co, which not only balances the competitive adsorption of HMF and OH- species, but also promote the active Ni3+ species formation, inducing high indirect oxidation activity. We have also discovered that Ni incorporation facilitates the Co2+ pre-oxidation and electrophilic OH* generation to contribute direct oxidation process. This work provides a new approach to design advanced electrocatalyst for biomass upgrading.

Direct Reductive Amination of HMF to 5-(Aminomethyl)-2-furanmethanol Using Supported Iridium-based Catalysts.

In this work, partial reductive amination of 5-hydroxymethylfurfural (HMF) with gaseous ammonia over iridium supported on γ-Al2O3, TiO2, SiO2 and carbon has been studied. The influence of the support and pressure was investigated in the valorization under mild conditions of HMF to 5-(aminomethyl)-2-furanmethanol (AMFM). The catalysts were characterized by TEM, SEM-EDS, N2 sorption Isotherms, TGA, CO-Chemisorption, TPR, XRD, NH3-TPD, ICP-AES and XPS. The maximum activity and high rates were obtained for all catalytic systems. At 50 minutes of the reaction the Ir/C catalyst achieved 93 % of conversion and exhibited the highest yield and selectivity of 92 % and 99 % respectively, to the desired product 5-(aminomethyl)-2-furanmethanol. The main properties that influence activity and selectivity are related to the amount of iridium on the surface and catalyst acidity. After the third cycle, 63 % and 59 % of selectivity and yield to AMFM respectively at 93 % of conversion were obtained.