Hydrogenation Of Furfuryl Alcohol Research Articles

Single-Step Hydrogenolysis of Furfuryl Alcohol to 1,2-Pentanediol by CoWO4 Catalyst

Furfuryl alcohol (FOL) is a biomass derivative used in polymer and fine chemical industries. Hydrogenation of FOL was reported to give tetrahydrofurfuryl alcohol (THFA), while its hydrogenolysis gave 1,2-pentanediol (1,2-PeD) and 1,5-pentanediol (1,5-PeD) in pressurized hydrogen by platinum group metals (e.g., Ru, Pd, and Pt). Herein, cobalt tungstate (CoWO4) catalyzed selective hydrogenation or hydrogenolysis of FOL to give THFA or 1,2-PeD in the absence of pressurized hydrogen. Crystalline CoWO4 was synthesized hydrothermally at a relatively lower temperature (<160 ​°C) and shorter time (<10 ​h) compared to reported procedures (180–200 ​°C, 15–24 ​h). Lower hydrothermal temperature (<150 ​°C) yields low-crystalline CoWO4. Catalytic differences of CoWO4 in crystalline and low-crystalline phases were observed in hydrogenolysis of FOL in alcohols. We found that 1,2-PeD of 67% was selectively achieved in 2-propanol at 160 ​°C for 7 ​h by low-crystalline CoWO4 (5 ​mol%), while the same reaction in ethanol gave 54% THFA. The reaction was proposed to be a pseudo first-order towards FOL with the experimental energy barrier of 107 ​kJ/mol and turnover frequency (TOF) up to 3.6 ​h−1.

The Effect of Support on Catalytic Performance of Ni-Doped Mo Carbide Catalysts in 2-Methylfuran Production

Ni-doped Mo carbide with Ni/Mo atomic ratio of 0.1 was supported on SiO2, Al2O3, and a porous carbon material (C), using a combination of gel combustion and impregnation methods. XRD, XPS, XANES, and EXAFS analyses indicated that the main active sites for the supported catalysts were metallic nickel and Mo carbides. The catalysts were evaluated in furfural hydrogenation to produce 2-methylfuran (2-MF) in a batch reactor at 150 °C under a hydrogen pressure of 6.0 MPa. The carbide materials supported on C showed the highest activity and selectivity towards 2-MF formation, with a yield of 61 mol.% after 3.5 h. Using furfuryl alcohol as the feedstock instead of furfural resulted in a high selectivity to 2-MF production. The carbon-supported sample was tested in a fixed-bed reactor at 160–260 °C with a pressure of 5.0 MPa in the hydrogenation of furfuryl alcohol, leading to the formation of up to 82 mol.% of 2-MF at 160–200 °C. The higher temperature (260 °C) resulted in the formation of C5 alcohols and hydrocarbons, while the hydrogenation of furfural at the same temperature led to 100 mol.% conversion, and up to an 86 mol.% yield of 2-MF.

Introduction of NiSO4 to Ni/SiO2 catalyst in hydrogenation of furfuryl alcohol: Tailoring metallic nickel sites to switch major product from tetrahydrofurfuryl alcohol to cyclopentanone

Nickel-based catalysts are widely used in hydrogenation of varied types of organics. However, the nickel catalyst, like Ni/SiO2, lacks selectivity for hydrogenation of C=C and C=O. This is undesirable in some scenarios, such as conversion of biomass-derived furfuryl alcohol (FA) to cyclopentanone (CPO), a fine chemical, in which the C=C in furan ring of FA needs to be retained. In this study, introduction of sulfur species to Ni/SiO2 catalyst via loading NiSO4 was adopted to inhibit hydrogenation of furan ring in FA, aiming to achieve conversion of FA to CPO via ring-opening route. The results indicated that NiSO4 was reduced to NixSy, which further reacted with metallic Ni, forming Ni3S2 species and introducing the acidic sites with high-strength. The co-existence of NixSy and metallic Ni species effectively hindered hydrogenation of furan ring in FA, reducing tetrahydrofurfuryl alcohol (THFA) yield from 97% over Ni/SiO2 to 0 over the NiSx/SiO2 catalysts and shifting the major product to CPO. Nonetheless, the enhanced acidic sites along with the introduction of NiSO4 catalyzed polymerization of reaction intermediates, competing with the production of CPO. The acidic sites, however, facilitated hydrogenolysis of vanillyl alcohol to selectively produce (yield: 94.3%) in hydrogenation of vanillin. Characterization of hydrogenation of FA with in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique suggested the oxygen-containing functionalities in FA, instead of furan ring, could strongly adsorb on the NiS10/SiO2 catalyst, enhancing rearrangement reaction to form CPO while suppressing hydrogenation of the furan ring.

Impacts of externally added Brønsted and Lewis acid on conversion of furfural to cyclopentanone over Ni/SiC catalyst

The conversion of furfural to cyclopentanone (CPO) involves not only hydrogenation but also acid-catalysis reactions. The step of the acid-catalysis might be catalyzed by Lewis acid or Brønsted acid or both, which was investigated in this study by employing Ni/SiC, a catalyst with “clean” surface containing negligible amounts of acidic sites. Lewis acid (nitrate salts and chloride salts) or Brønsted acid (D008, a solid acid resin catalyst) with externally added to the reaction medium. The results showed that both Lewis acid and Brønsted acid could catalyze the conversion of furfural to CPO. The further hydrogenation of furfuryl alcohol (FA) to tetrahydrofurfuryl alcohol was main side reaction, which could be suppressed more effectively with the Lewis acid like CrCl3. The yield of CPO could be up to ca. 88.1 % with the Ni/SiC-CrCl3 catalytic system. The chelation of CrCl3 with FA stabilized the CC bond in the furan ring and the hydroxyl group, preventing the side reactions while facilitating CPO formation. The synergistic effects between the cation and anion was essential for the conversion of FA to CPO as the varied nitrate salts or chloride salts chelated with furfural, FA or other reaction intermediates in distinct ways, determining distribution of the products.

Hydrogenation of Furfural with Nickel Nanoparticles Stabilized on Nitrogen-Rich Carbon Core-Shell and Its Transformations for the Synthesis of γ-Valerolactone in Aqueous Conditions.

In this article, we report the synthesis of nitrogen-rich carbon layer-encapsulated Ni(0) nanoparticles as a core-shell structure (Ni@N/C-g-800) for the catalytic hydrogenation of furfural to furfuryl alcohol. The nickel nanoparticles were stabilized by the nitrogen-rich graphitic framework, which formed during the agitation of nickel acetate-impregnated cucurbit[6]uril surface in a reducing atmosphere. Furthermore, the catalyst was characterized using various physicochemical methods such as powder X-ray diffraction, Raman, field emission-scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area, CO2-temperature-programmed desorption, inductive coupled plasma, and CHN analyses. The nitrogen-rich environment of the solid support with metallic Ni nanoparticles was found to be active and selective for the catalytic hydrogenation of furfural with molecular H2 in an aqueous medium at 100 °C. To understand the reaction mechanism, the diffuse reflectance infrared Fourier transform study was performed, which revealed that the C═O bond is activated in the presence of a catalyst. In addition, we have extended our methodology toward the synthesis of "levulinic acid" and "γ-valerolactone", by successive hydrolysis and hydrogenation of furfuryl alcohol and levulinic acid, respectively, in an aqueous medium. Moreover, the heterogeneous catalysts used in all of the three consecutive steps help in recovery and recycling of the catalyst and easy separation of products.

Furfural Hydrogenation to Furfuryl Alcohol over Bimetallic Ni–Cu Sol–Gel Catalyst: A Model Reaction for Conversion of Oxygenates in Pyrolysis Liquids

High metal loading NiCu-based catalyst of Picula™ series produced by sol–gel technique was applied to furfural hydrogenation in the presence of hydrogen. This reaction represents the stabilization of pyrolysis oil that involves the selective reduction of aldehydes and ketones to alcohols and unsaturated C–C double bonds of pyrolysis oils components. The catalysts were pre-reduced at 250 and 300 °C. According to XRD analysis results, copper is mainly in the metallic state, and Ni is mostly in the form of oxide and silicate. XPS measurements reveal that hydrogen treatment at 250 °C leads to the partial reduction of Ni to the metallic state (6 %) while further reduction at 300 °C leads to an increase in this proportion up to 39 %. A 100 % selectivity towards furfuryl alcohol was achieved at 130 °C and 5 MPa of hydrogen in a batch reactor using decyl alcohol as a solvent. In the experiments with i-propanol as a solvent at 110–170 °C the main product was furfuryl alcohol, but minor components traced back were tetrahydrofurfuryl alcohol, 2-methylfuran and isopropyl furfuryl ether. The lower catalyst reduction temperature promotes the formation of isopropyl ester, while a higher reduction temperature favors further furfuryl alcohol hydrogenation.

Preparation and Characterization of NiB Amorphous Alloy Modified Using Chitosan

NiB amorphous alloy catalyst (NiB-CS) was prepared by direct reduction using the chemical- reduction method with chitosan as a stabilizer. The amorphous structure, atomic composition, and particle size of the as-prepared catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma spectrometry (ICP), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The catalytic behavior during the hydrogenation of furfuryl alcohol (FA) to tetrafurfural alcohol (THFA) was studied and compared with the NiB catalyst prepared without chitosan. The amorphous NiB-CS catalyst was found to be more reactive than the NiB catalyst. The superior catalytic activity of the NiB-CS catalyst is attributed to the small NiB particles and the high surface content of Ni active species. (Article)

Preparation and Catalytic Performance of Ni-B Amorphous Alloy Supported by Chitosan/SiO 2

Ni-B amorphous catalyst supported by chitosan (CS)-modified silica (Ni-B/CS/SiO 2) was prepared using impregnation-reduction method. The as-prepared catalysts were characterized using X-ray powder diffraction (XRD), fourier transform infrared (FTIR) spetra, inductively coupled plasma (ICP) spectrometer, Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The results showed that the particle sizes, the surface content of Ni active species, and catalytic activity were improved by introducing chitosan to the surface of silica. In the hydrogenation of furfuryl alcohol (FA) to tetrahydrofurfuryl alcohol (THFA), the amorphous Ni-B/CS/SiO 2 catalyst exhibited superior catalytic activity to the corresponding traditional Ni-B/SiO 2 amorphous catalyst and Raney Ni.

Kinetics of Liquid-Phase Hydrogenation of Furfuryl Alcohol to Tetrahydrofurfuryl Alcohol over a Ru/TiO2 Catalyst

The kinetics of the liquid-phase hydrogenation of furfuryl alcohol (FA) to a green solventtetrahydrofurfuryl alcohol (THFA)over a 5% Ru/TiO2 catalyst was studied in a slurry reactor. Hydrogenation of furfuryl alcohol was carried out at a hydrogen pressure of 0.68−4.08 MPa and temperature in the range 313−363 K. The selectivity toward THFA was >97% at and below 333 K reaction temperature. Various Ru supported catalysts and solvents were screened during hydrogenation of furfuryl alcohol. Among the catalysts tested, 5% Ru/TiO2 was found to be the more active catalyst for the hydrogenation of FA using 2-propanol as a solvent. The kinetic data were analyzed using the power-law model. A single-site Langmuir−Hinshelwood-type model suggesting molecular adsorption (nondissociative) of hydrogen and surface reaction as the rate-controlling mechanism with the product inhibition step provided the best fit of the experimental data. Catalyst could be recycled with good selectivity.

Experimental study for liquid phase selective hydrogenation of furfuryl alcohol to tetrahydrofurfuryl alcohol on supported Ni catalysts

The liquid phase hydrogenation of furfuryl alcohol (FA) to tetrahydrofurfuryl alcohol (THFA) on a series of new special supported Ni catalyst was experimentally studied while the raw material and the product were analyzed by a set of on-line GC. The reactor used in the experiment was a continuous stirred autoclave with volume of 500 mL. The operating conditions studied in the experiments were opted as the following ranges: temperature within 433–453 K, pressure within 3.0–4.0 MPa, catalyst loading 20 g/L and the stirring rate at about 1000 rpm. The experimental results show that, under the operation conditions mentioned above, the hydrogenation of FA in the presence of the catalyst QD3 can lead to a high FA conversion above 99.9% and a high selectivity of THFA higher than 98.3% within 3.5 h.

Preparation and structure elucidation of 1,6,9,13-tetraoxadispiro(4.2.4.2)tetradecane

The tricyclic title compound, a symmetrical dispiro oxygen heterocycle, was isolated as a byproduct in the hydrogenation of furfuryl alcohol in the presence of hydrochloric acid. NMR studies and single crystal X-ray analysis have established the relative stereochemistry of the two ketal carbons. Formation of the observed trans stereoisomer under equilibrating conditions is attributed to the anomeric effect.

High selective production of tetrahydrofurfuryl alcohol: Catalytic hydrogenation of furfural and furfuryl alcohol

AbstractTetrahydrofurfuryl alcohol could be obtained by catalytic hydrogenation of either furfural or furfuryl alcohol using Pd‐, Ru‐, Rh‐ and Ni‐supported catalysts as well as their mixtures with a Cu‐supported catalyst. In the case of furfural hydrogenation, the best results (97 % yield, 100 % conversion, 98 % selectivity) were obtained in the presence of Ni and Cu. However, this catalytic mixture could not be recycled. In the case of furfuryl alcohol hydrogenation, Ni‐supported catalysts were the most active. Nickel‐onsilica‐alumina catalyst containing 59 % of metal lead to the best results (98–99 % yield, selectivity and conversion &gt;99 %). Moreover, it could be recycled. Hydrogenation of furfuryl alcohol in the presence of this catalyst was the best procedure for the production of tetrahydrofurfuryl alcohol.