Hydrogenation Of 5-hydroxymethylfurfural Research Articles

Cu-based catalysts for hydrogenation of 5-hydroxymethylfurfural: Understanding of the coordination between copper and alkali/alkaline earth additives

This study investigated impacts of alkali or alkaline earth metals additives (Na, K, Mg, Ca, Sr or Ba) on the physicochemical properties and catalytic behaviors of Cu/Al2O3 catalyst in hydrogenation of 5-hydroxymethylfurfural (HMF). Na or K addition to Cu/Al2O3 led to the decreased specific area via merging of the small pores and the partial transformation of γ-Al2O3 into AlOOH phase. Na, K or Mg addition could drastically increase the activity for hydrogenation of HMF to 2,5-dihydroxy methyl furan (DHMF) at low temperatures (i.e. 60 °C), possibly attributing to the increased weak alkaline sites and the synergetic effects between the additives and copper. In addition, the additives could effectively suppress the hydrogenolysis or the opening of furan ring, retaining DHMF, the major initial product from HMF hydrogenation, in the reaction medium. The in situ DRIFTS of hydrogenation of HMF and in situ DRIFTS-MS of thermal treatment of HMF indicated the presence of the additives significantly impacted the reaction intermediates formed during the hydrogenation of HMF.

Complete Aqueous Hydrogenation of 5-Hydroxymethylfurfural at Room Temperature over Bimetallic RuPd/Graphene Catalyst

Aqueous hydrogenation of 5-hydroxymethylfurfural (HMF) was performed over the RuPd/graphene (RGO) bimetallic catalyst at room temperature (20 °C). The combination of Pd and Ru gave the best catalyt...

Selective hydrogenation of bio-based 5-hydroxymethyl furfural to 2,5-dimethylfuran over magnetically separable Fe-Pd/C bimetallic nanocatalyst

There is an ever increasing need to innovate and provide alternative energy sources to reduce the overdependence on conventional fossil fuels. 2, 5-Dimethylfuran (DMF), a bio-based chemical, has gained a lot of attention due to its potential application as a biofuel additive and is synthesized through hydrogenation of 5-hydroxymethylfurfural (HMF). Bimetallic nano-catalysts have gained importance in recent years due to their excellent selectivity and activity. In this paper, a magnetically separable Fe-Pd/C bimetallic nano-catalyst was developed which not only showed excellent selectivity to DMF but also helped reduce the noble metal consumption, thereby making the catalyst cheaper. Using XPS, XRD and TPR characterizarion techniques, the Fe-Pd/C catalyst was found to exist as bimetallic containing a partially oxidized Fe and reduced Pd atoms. It exhibited 85% selectivity towards DMF with 100% conversion of HMF. The reaction was conducted in a liquid-acid-free environment, thus making the process environmental friendly. The oxidized Fe imparts magnetic properties to the catalyst making it easy to recover. The catalyst was found to be robust and showed excellent activity on repeated use. Overall a highly efficient, economic and green process for DMF synthesis was developed based on biomass as feedstock.

The effect of potassium on Cu/Al2O3 catalysts for the hydrogenation of 5-hydroxymethylfurfural to 2,5-bis(hydroxymethyl)furan in a fixed-bed reactor

The highly efficient selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) was achieved in a fixed-bed reactor by using inexpensive potassium-doped Cu/Al2O3 catalysts.

A High‐Throughput Composite Catalyst based on Nickel Carbon Cubes for the Hydrogenation of 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran

AbstractA high‐throughput composite catalyst is prepared from porous carbon with an unconventional nanocube morphology decorated with nickel nanoparticles. Owing to the advantageous properties of the designed carbon support, the composite combines a high surface area and a hierarchical pore structure with high functionality. Furthermore, the regularly shaped nanocubes allow for a good packing of a fixed‐bed flow reactor, in which the internal transport pores cannot be blocked and stay open for efficient column performance. The composite is employed as a catalyst in the hydrogenation of 5‐hydroxymethylfurfural (HMF) to 2,5‐dimethylfuran (DMF), showing good catalytic performance and overcoming the conventional problem of column blocking.

Synergism studies on alumina-supported copper-nickel catalysts towards furfural and 5-hydroxymethylfurfural hydrogenation

The structure of alumina-supported copper-nickel catalysts prepared by impregnation method was studied by using a combination of various characterization techniques including XRD, N2-sorption, TEM, H2-TPR, NH3-TPD, XANES/EXAFS and CHNS methods. A series of characterizations revealed that dispersion of copper increases with an increase in nickel loading on ɣ-Al2O3 due to strong interaction between nickel and copper oxide particles. This also led to the formation of mixed copper-nickel oxides in calcined catalysts at the highest loading of nickel and copper (i.e. Cu/Ni=1). In catalytic activity, both the monometallic Cu/ɣ-Al2O3 and Ni/ɣ-Al2O3 showed lower activity and selectivity towards hydrogenation of both Furfural and 5-Hydroxymethylfurfural to 2-methylfuran (2-MF) and 2, 5-dimethylfuran (DMF), respectively. However, with increase in nickel loading, the activity and the selectivity of Cu/ɣ-Al2O3 drastically increased for both the cases and Cu-Ni/ɣ-Al2O3 (Cu/Ni=1) showed the highest catalytic activity. Furthermore, combination of Cu/Ni ratios and temperature plays a significant role in the product distribution, as in the case of furfural hydrogenation, at a lower temperature, furfuryl alcohol (FOL) appears as the main product while at a higher temperature, 2-methylfuran (2-MF) is found to be the dominant product over Cu-Ni/ɣ-Al2O3 (Cu/Ni=1) catalysts. Similarly, 2,5-bishydroxymethylfuran (BHF) is found to be the major product at a lower temperature and 2,5-dimethylfuran (DMF) is selectively produced at a higher temperature in the HMF hydrogenation. Furthermore, reaction pathways are discussed for both the reactions.

Effect of FeOx Modification of Al2O3 on Its Supported Au Catalyst for Hydrogenation of 5-Hydroxymethylfurfural

To enhance the hydrogenation activity of alumina supported Au (Au/Al2O3) catalyst for selective hydrogenation of 5-hydroxymethylfurfural (HMF), an important biomass-derived aldehyde, Al2O3 support was modified with iron oxide (FeOx). The apparent catalytic activity of the FeOx/Al2O3 supported Au (Au/FeOx/Al2O3) catalysts increased as an increase of Fe loading up to 10 wt % (3–4 times higher than Au/Al2O3). When the Fe loading was more than 10 wt %, the apparent catalytic activity decreased, and Au/α-Fe2O3 showed much lower activity than Au/Al2O3. The Fe K-edge X-ray absorption fine structure (XAFS) spectra and the atomic scale observation using aberration corrected scanning transmission electron microscopy (Cs-STEM) suggested positive and negative effects of FeOx support. As the positive effect, FeOx promotes formation of Au clusters by reduction of Au single atoms having low or no catalytic activity for the hydrogenation. On the other hand, as the negative effect, FeOx, more specifically, large α-Fe2O3, ...

Production of 2,5-dimethylfuran from 5-hydroxymethylfurfural over reduced graphene oxides supported Pt catalyst under mild conditions

Reduced graphene oxides supported platinum (Pt/rGO) is extremely active and selective for the production of 2,5-dimethylfuran (DMF) via hydrogenation of 5-hydroxymethylfurfural (HMF) among a series of supported Pt catalysts under mild conditions. The influence of varied reaction parameters, such as solvent, reaction temperature, H2 pressure, and HMF concentration were investigated with respect to the conversion of HMF and the yield of DMF. It was found that the yield of DMF reached 73.2% with a 100% conversion of HMF at 120°C, 3.0MPa H2 and 2.0h.

Electrocatalytic hydrogenation of 5-hydroxymethylfurfural in acidic solution.

Electrocatalytic hydrogenation of 5-hydroxymethylfurfural (HMF) is studied on solid metal electrodes in acidic solution (0.5 M H2 SO4 ) by correlating voltammetry with on-line HPLC product analysis. Three soluble products from HMF hydrogenation are distinguished: 2,5-dihydroxymethylfuran (DHMF), 2,5-dihydroxymethyltetrahydrofuran (DHMTHF), and 2,5-dimethyl-2,3-dihydrofuran (DMDHF). Based on the dominant reaction products, the metal catalysts are divided into three groups: (1) metals mainly forming DHMF (Fe, Ni, Cu, and Pb), (2) metals forming DHMF and DMDHF depending on the applied potentials (Co, Ag, Au, Cd, Sb, and Bi), and (3) metals forming mainly DMDHF (Pd, Pt, Al, Zn, In, and Sb). Nickel and antimony are the most active catalysts for DHMF (0.95 mM cm(-2) at ca. -0.35 VRHE and -20 mA cm(-2) ) and DMDHF (0.7 mM cm(-2) at -0.6 VRHE and -5 mA cm(-2) ), respectively. The pH of the solution plays an important role in the hydrogenation of HMF: acidic condition lowers the activation energy for HMF hydro-genation and hydrogenates the furan ring further to tetrahydrofuran.

Catalytic synthesis of 2,5-bis-methoxymethylfuran: A promising cetane number improver for diesel

Efficient hydrogenation of 5-hydroxymethylfurfural (HMF) into 2,5-bis-hydroxymethylfuran (BHMF) was performed using a Cu/SiO2 catalyst, obtaining as high as 97% BHMF yield. In the presence of acidic ZSM-5 zeolite (HZSM-5), the synthesized BHMF further reacted with methanol, leading to 70% yield of corresponding 2,5-bis-methoxymethylfuran (BMMF). The target product BMMF was an excellent cetane number improver for diesel, proved by its cetane number of 80 (much higher than that of the commercial diesel), high flash point (90°C) and low cold filter plugging point (<−37°C).

Selective Transformation of 5-Hydroxymethylfurfural into the Liquid Fuel 2,5-Dimethylfuran over Carbon-Supported Ruthenium

A simple and efficient process was presented for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) into the high-quality liquid fuel 2,5-dimethylfuran (DMF) in the presence of tetrahydrofuran (THF). Among the employed metal catalysts, the relatively inexpensive carbon-supported ruthenium (Ru/C) displayed the highest catalytic performance, which led to 94.7% DMF yield with 100% HMF conversion at a relatively mild reaction temperature of 200 °C for only 2 h. Although Ru/C had a little loss in the catalytic activity when it was used for five successive reaction runs, the partially deactivated Ru/C could be easily regenerated by heating at a mixed flow of H2 and N2. Moreover, the plausible mechanism involving an aldehyde group, a hydroxyl group, and a furan ring for the selective hydrogenation of HMF into DMF was also proposed. Subsequently, DMF was separated from the crude hydrogenation mixture according to their various boiling points by the combination of atmospheric distillation and vacuum distillation, and then, the chemical structures and physical properties of the separated DMF were confirmed to be consistent with the authentic DMF. More gratifyingly, Ru/C and THF were also found to be a good combination for the direct hydrogenation of carbohydrate-derived HMF into DMF, which is very important for the practical production of DMF from a variety of biomass-derived carbohydrates such as fructose, glucose, sucrose, maltose, cellobiose, starch, and cellulose.

Hydrogenation of 5-hydroxymethylfurfural in supercritical carbon dioxide–water: a tunable approach to dimethylfuran selectivity

The use of supercritical carbon dioxide–water on the hydrogenation of 5-hydroxymethylfurfural (HMF) was investigated over a Pd/C catalyst. It was possible to achieve a very high yield (100%) of DMF within the reaction time of 2 hours at 80 °C. A significant effect of CO2 pressure was observed on the product distribution. Simply by tuning the CO2 pressure it was possible to achieve various key compound, such as tetrahydro-5-methyl-2-furanmethanol (MTHFM) (<10 MPa), 2,5-dimethylfuran (DMF) (10 MPa) and 2,5-dimethyltetrahydrofuran (DMTHF) (>10 MPa) with very high selectivity. Optimization of other reaction parameters revealed that H2 pressure, temperature, as well as the CO2–water mole ratio, played an important role in the selectivity to the targeted DMF. It is interesting to note that a very high yield of DMF was achieved when a combination of CO2 and water was used. For instance, in the absence of water or CO2, the selectivity of DMF was low; similarly, an excess of water against the fixed pressure of CO2 reduced the selectivity to DMF. Hence, an optimized amount of water was mandatory in the presence of CO2 for the formation of DMF with high selectivity. This method was successfully extended to the hydrogenation of furfural, which could afford 100% selectivity to 2-methylfuran with complete conversion within a very short reaction time of 10 min. The studied catalyst could be recycled successfully without significant loss of catalytic activity.

Electrocatalytic Hydrogenation of 5‐Hydroxymethylfurfural in the Absence and Presence of Glucose

Electrocatalytic hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethylfuran (DHMF) or other species, such as 2,5-dimethylfuran, on solid metal electrodes in neutral media is addressed, both in the absence and in the presence of glucose. The reaction is studied by combining voltammetry with on-line product analysis by using HPLC, which provides both qualitative and quantitative information about the reaction products as a function of electrode potential. Three groups of catalysts show different selectivity towards: (1) DHMF (Fe, Ni, Ag, Zn, Cd, and In), (2) DHMF and other products (Pd, Al, Bi, and Pb), depending on the applied potential, and (3) other products (Co, Au, Cu, Sn, and Sb) through HMF hydrogenolysis. The rate of electrocatalytic HMF hydrogenation is not strongly catalyst-dependent because all catalysts show similar onset potentials (-0.5 ± 0.2 V) in the presence of HMF. However, the intrinsic properties of the catalysts determine the reaction pathway towards DHMF or other products. Ag showed the highest activity towards DHMF formation (up to 13.1 mM cm(-2) with high selectivity> 85%). HMF hydrogenation is faster than glucose hydrogenation on all metals. For transition metals, the presence of glucose enhances the formation of DHMF and suppresses the hydrogenolysis of HMF. On poor metals such as Zn, Cd, and In, glucose enhances DHMF formation; however, its contribution in the presence of Bi, Pb, Sn, and Sb is limited. Remarkably, in the presence of HMF, glucose hydrogenation itself is largely suppressed or even absent. The first electron-transfer step during HMF reduction is not metal-dependent, suggesting a non-catalytic reaction with proton transfer directly from water in the electrolyte.