Search Results (22)

Supported Pd-based catalysts have been widely applied in the hydrogenation of specific functional groups. Recent trends have focused on employing Pd-based heterogeneous catalysts supported on inorganic nanotubes, wherein inner surface functionalization modulates both palladium nanoparticle (Pd-NP) dispersion and the interaction between reactants and the catalyst surface, thereby influencing catalytic properties. This study aims to develop a catalytic system using amine-lumened halloysite nanotubes immobilizing Pd-NPs (Pd/HNTA) as catalysts for hydrogenation reactions. The formation of Pd-NPs within the organo-functionalized lumen—modified by 3-aminopropyltrimethoxysilane—is confirmed by transmission electron microscopy (TEM) imaging, which reveals a particle size of 2.2 ± 0.4 nm. For comparison, Pd-NPs supported on pristine halloysite (Pd/HNTP) were used as control catalysts, displaying a metal particle size of 2.8 ± 0.8 nm and thereby demonstrating the effect of organic functionalization on the halloysite nanotubes. Both catalysts were employed in the hydrogenation of furfural (FUR) and nitrobenzene (NB) as model reactions. Pd/HNTA demonstrated superior catalytic performance for both substrates, with TOF values of 880 h⁻¹ for FUR and 946 h⁻¹ for NB, and selectivities exceeding 98% for tetrahydrofurfuryl alcohol (THFOH) and aniline (AN), respectively. However, recyclability studies displayed that Pd/HNTA was deactivated at the 10 catalytic cycles during the hydrogenation of FUR, whereas, in the hydrogenation of NB, 5 catalytic cycles were achieved with maximum conversion and selectivity at 360 min. These results revealed that the liquid-phase environment plays a pivotal role in catalyst stability. In the hydrogenation of NB, the coproduction of H₂O adversely affects the interaction between the Pd particles and the inner amine-modified surface, increasing the deactivation of the catalyst with reuse. Thus, the Pd/HNTA catalyst holds significant promise for the development of noble-metal-based catalysts and their application in the transformation of other reducible organic functional groups via hydrogenation reaction. Full article

Tetrahydrofurfuryl alcohol, a cost-effective biomass derivative, offers a sustainable path for synthesizing 1,5-pentanediol through hydrogenolysis. To develop the efficient production of 1,5-pentanediol from this alcohol, we have prepared a series of MgAl₂O₄-modified Pt/WO_x/γ-Al₂O₃ catalysts with varying compositions via impregnation–calcination methods. The physicochemical properties of these catalysts were subsequently characterized using diverse techniques. Characterization revealed that magnesia–alumina spinel modification enhanced Pt particle dispersion, CO adsorption on Pt/WO_x/γ-Al₂O₃, reduced Pt particle reduction temperature, diminished the acid content in the catalysts, and increased the surface oxygen vacancy concentration. These alterations appear to influence the catalyst performance, though other factors cannot be ruled out. Catalytic activity tests demonstrated that magnesia–alumina spinel modification improved tetrahydrofurfuryl alcohol hydrogenolysis activity and the 1,5-pentanediol selectivity of Pt/WO_x/γ-Al₂O₃. Optimal performance was achieved at 12% magnesia–alumina spinel loading, with a tetrahydrofurfuryl alcohol conversion of 47.3% and 1,5-pentanediol selectivity of 88.4%. Full article

A series of bimetallic Ni_xCu_y catalysts with different metal molar ratios, supported on nitric acid modified rice husk-based porous carbon (RHPC), were prepared using a simple impregnation method for the liquid-phase hydrogenation of furfural (FFA) to tetrahydrofurfuryl alcohol (THFA). The Ni₂Cu₁/RHPC catalyst, with an average metal particle size of 9.3 nm, exhibits excellent catalytic performance for the selective hydrogenation of FFA to THFA. The 100% conversion of FFA and the 99% selectivity to THFA were obtained under mild reaction conditions (50 °C, 1 MPa, 1 h), using water as a green reaction solvent. The synergistic effect of NiCu alloy ensures the high catalytic activity. The acid sites and oxygen-containing functional groups on the surface of the modified RHPC can enhance the selectivity of THFA. The Ni₂Cu₁/RHPC catalyst offers good cyclability and regenerability. The current work proposes a simple method for preparing an NiCu bimetallic catalyst. The catalyst exhibits excellent performance in the catalytic hydrogenation of furfural to tetrahydrofurfuryl alcohol, which broadens the application of non-noble metal bimetallic nanocatalysts in the catalytic hydrogenation of furfural. Full article

Ni-Mg/Al mixed oxide catalysts (Ni₂A_l, Ni₂Mg₁Al, and Ni₁Mg₁Al) obtained from layered double hydroxides (LDHs) were tested on the one-pot production of tetrahydrofurfuryl alcohol (TFA) from furfural (FF). Upon calcination at 400 °C and reduction at 500 °C, the LDHs gave catalysts containing small nickel crystallites (<4 nm) dispersed on mixtures of metal oxides and spinel structures. Complete conversion of FF (>99.5%) was achieved on all the catalysts after 4 h at 190 °C and 5.0 MPa of H₂ using 5 wt.% FF in ethanol and a furfural-to-catalyst mass ratio of 7.44 g/g. TFA evolved from the sequential hydrogenation of FF to furfuryl alcohol (FA) to TFA. Competing reaction routes involved decarbonylation of FF to furan (FUR) followed by hydrogenation to tetrahydrofuran (THF) or hydrogenolysis to n-butane (BU) and the hydrogenation of the carbonyl group in FF to form 2-methyl furan (mFUR) and its hydrogenation to 2-methyltetrahydrofuran (mTHF). A third competing route consisted of the nucleophilic addition of FF with ethanol and with FA to form acetals (such as 2-(diethoxymethyl)furan, FDA), which were later converted to difurfuryl ether (DFE) and tetrahydrofurfuryl ethyl ether (TFEE) as final products. Hydrogen pressure favored the production of TFA and diminished the formation of acetals, while temperature reduced the capacity of the catalyst to hydrogenate the furan ring, thus reducing TFA and increasing FA and FUR. An 80% yield to TFA was achieved with the Ni₂Mg₁Al catalysts after 6 h at 190 °C and 50 bar H₂, but a variety of coproducts were present at low concentration. Testing of the catalysts in gas-phase hydrogenation conditions at atmospheric pressure revealed a poorer performance, with FA as the main product. Full article

Polar-functionalized polyolefins are high-value materials with improved properties. However, their feedstocks generally come from non-renewable fossil products; thus, it requires the development of renewable bio-based monomers to produce functionalized polyolefins. In this contribution, via the Pd-catalyzed telomerization of 1,3-butadiene and three types of bio-based alcohols (furfuryl alcohol, tetrahydrofurfuryl alcohol, and solketal), 2,7-octadienyl ether monomers including OC8-FUR, OC8-THF, and OC8-SOL were synthesized and characterized, respectively. The copolymerization of these monomers with ethylene catalyzed by phosphine–sulfonate palladium catalysts was further investigated. Microstructures of the resultant copolymers were analyzed by NMR and ATR-IR spectroscopy, revealing linear structures with incorporations of difunctionalized side chains bearing both allyl ether units and polar cyclic groups. Mechanical property studies exhibited better strain-at-break of these copolymers compared to the non-polar polyethylene, among which the copolymer E-FUR with the incorporation of 0.3 mol% displayed the highest strain-at-break and stress-at-break values of 940% and 35.9 MPa, respectively. Full article

A rational design of transition metal catalysts to achieve selective hydrogenation of furfural (FFR) to tetrahydrofurfuryl alcohol (THFA) under facile conditions is a promising option. In this work, a series of Ni catalysts were synthesized by controlled thermal treatment of Ni-based metal-organic frameworks (MOFs), with the purpose of modulating the interface of nickel nanoparticles by the reticular coordination in MOF precursors. The catalytic performance indicates that Ni/C catalyst obtained at 400 °C exhibits efficient conversion of FFR (>99%) and high selectivity to THFA (96.1%), under facile conditions (80 °C, 3 MPa H₂, 4.0 h). The decomposition of MOF at low temperatures results in highly dispersed Ni⁰ particles and interfacial charge transfer from metal to interstitial carbon atoms induced by coordination in MOF. The electron-deficient Ni species on the Ni surface results in an electropositive surface of Ni nanoparticles in Ni/C-400, which ameliorates furfural adsorption and enhances the hydrogen heterolysis process, finally achieving facile hydrogenation of FFR to THFA. Full article

Conversion of biomass-derived furfural (FFA) platform molecule to value-added tetrahydrofurfuryl alcohol (THFA) molecule is a sustainable route using an efficient non-noble metallic catalyst in water solvent. In this work, Ni in various loadings on mesoporous titanium dioxide (m-TiO₂) was synthesized in one pot by Evaporation-Induced Self-Assembly (EISA). The synthesised catalysts were evaluated for the hydrogenation of furfural to tetrahydrofurfuryl alcohol. The catalysts were characterised using a combination of spectroscopic techniques such as XRD, H₂-TPR, H₂-TPD, XPS, SEM-EDX, TEM, and HR-TEM. The characterization results show that the Ni/m-TiO₂ materials exhibit enhanced electron-rich active sites, facilitated hydrogen spillover, uniform dispersion of small Ni particles (~5 nm), and strong metal support interaction between Ni and TiO₂. Among the various Ni dopings, 7.5 wt.% Ni/m-TiO₂ catalyst exhibited the best performance and achieved 99.9% FFA conversion and 93.2% THFA selectivity in water solvent at 100 °C and under 2 MPa H₂. Additionally, detailed kinetic studies, process parameters, the stability and reusability of the catalyst were also studied. The results demonstrated that the 7.5 wt.% Ni/m-TiO₂ catalyst is highly active and stable. Full article

Lithium-ion batteries (LIBs) have been used as electrochemical energy storage devices in various fields, ranging from mobile phones to electric vehicles. LIBs are composed of a positive electrode, a negative electrode, an electrolyte, and a binder. Among them, electrolytes consist of organic solvents and lithium ion conducting salts. The electrolytes used in LIBs are mostly linear and cyclic alkyl carbonates. These electrolytes are usually based on their combinations to allow the use of Li as the anodic active component, resulting in the high power and energy density of batteries. However, these organic electrolytes have high volatility and flammability that pose a serious safety issue when exposed to extreme conditions such as elevated temperatures. At that time, these electrolytes can react with active electrode materials and release a considerable amount of heat and gas. In this study, a simultaneous thermal analysis-mass spectrometry analysis was performed on six different organic solvents to examine the effect of water on hydrogen fluoride (HF) generation temperature in the electrolyte of a LIB. The electrolytes used in the experiment were anhydrous diethyl carbonate, 1,2-dimethoxyethane, ethylene carbonate, 1,3-dioxolane, tetrahydrofurfuryl alcohol, and 2-methyl-tetrahydrofuran, each containing LiPF₆. The HF formation temperature was observed and compared with that when water entered the electrolyte exposed to high-temperature conditions such as fire. Full article

Changes in the structural and textural properties of NiAl-layered double hydroxides (LDHs) (with 2–4 molar ratios of metals) and state of nickel that occur in different steps of the synthesis of nickel catalysts were studied using XRD, thermal analysis, TPR, low-temperature nitrogen adsorption, XANES, EXAFS, and electron microscopy methods. Relations between nickel content, catalyst reduction conditions, state of nickel, and its catalytic properties were revealed. It was shown that the use of NiAl LDH as the catalyst precursor even at a high content of active metal allows for the obtaining of the dispersed particles of supported nickel that are active in the aqueous-phase hydrogenation of furfural. The catalyst activity and conversion of furfural were found to increase with elevation of the catalyst reduction temperature and the corresponding growth of the fraction of reduced nickel. However, a lower reduction temperature (500 °C) makes it possible to form smaller nickel particles with the size of 4–6 nm, and a high Ni content (Ni:Al = 4) can be used to obtain the active Ni@NiAlO_x catalyst. Under mild reaction conditions (90 °C, 2.0 MPa), the furfural conversion reached 93%, and furfuryl alcohol was formed with the selectivity of 70%. Under more severe reaction conditions (150 °C, 3.0 MPa), complete conversion of furfural was achieved, and cyclopentanol and tetrahydrofurfuryl alcohol were the main hydrogenation products. Full article

The hydrogenation of furfural is an important process in the synthesis of bio-based chemicals. Copper-based catalysts favor the hydrogenation of furfural to alcohols. Catalytic activity and stability were higher at a Ni-to-Cu atomic ratio of 1:1 and 1.5:0.5 compared to 0.5:1.5. Here, we prepared Ni-Cu/Al₂O₃ hydrogenation catalysts derived from layered double hydroxides (LDHs). Catalysts calcined at 673 K and reduced at 773 K with nominal Ni/Cu atomic ratios y/x = 1.5/0.5, 1/1 and 0.5/1.5 were characterized by XRD, FESEM-EDX, H₂-TPR, XPS, FAA and BET. Their activity was tested at 463 K and in a 0.05 g g⁻¹ furfural solution in ethanol, and the space velocity in a packed-bed reactor (PBR) was 2.85 g_FF g_cat⁻¹ h⁻¹. In a slurry reactor (SSR) at 5 MPa H₂ and a contact time of 4 h, conversion was complete, while it varied from 91 to 99% in the PBR. Tetrahydrofurfuryl alcohol (TFA) was the main product in the SSR, with a selectivity of 32%, 63% and 56% for Ni_0.5Cu_1.5Al₁, Ni₁Cu₁Al₁ and Ni_1.5Cu_0.5Al₁, respectively. The main product in the atmospheric PBR was furfuryl alcohol (FA), with a selectivity of 57% (Ni_0.5Cu_1.5Al₁), 61% (Ni₁Cu₁Al₁) and 58% (Ni_1.5Cu_0.5Al₁). Other products included furan, methylfuran, 1-butanol and 1,2-pentanediol. Ethyl tetrahydrofurfuryl ether and difurfuryl ether were also formed via the nucleophilic addition of furfural with ethanol and furfuryl alcohol. Full article

Exploiting biomass to synthesise compounds that may replace fossil-based ones is of high interest in order to reduce dependence on non-renewable resources. 1,2-pentanediol and 1,5-pentanediol can be produced from furfural, furfuryl alcohol or tetrahydrofurfuryl alcohol following a metal catalysed hydrogenation/C-O cleavage procedure. Colloidal ruthenium nanoparticles stabilized with polyvinylpyrrolidone in situ modified with different organic compounds are able to produce 1,2-pentanediol directly from furfural in a 36% of selectivity at 125 °C under 20 bar of H₂ pressure. Full article

Catalytic conversion of biomass-derived feedstock to high-value chemicals is of remarkable significance for alleviating dependence on fossil energy resources. MgAl spinel-supported Pt catalysts were prepared and used in furfuryl alcohol conversion. The approaches to tune the reaction selectivity toward pentanediols (PeDs) were investigated and the catalytic performance was correlated to the catalysts’ physicochemical properties based on comprehensive characterizations. It was found that 1–8 wt% Pt was highly dispersed on the MgAl₂O₄ support as nanoparticles with small sizes of 1–3 nm. The reaction selectivity did not show dependence on the size of Pt nanoparticles. Introducing LiOH onto the support effectively steered the reaction products toward the PeDs at the expense of tetrahydrofurfuryl alcohol (THFA) selectivity. Meanwhile, the major product in PeDs was shifted from 1,5-PeD to 1,2-PeD. The reasons for the PeDs selectivity enhancement were attributed to the generation of a large number of medium-strong base sites on the Li-modified Pt catalyst. The reaction temperature is another effective factor to tune the reaction selectivity. At 230 °C, PeDs selectivity was enhanced to 77.4% with a 1,2-PeD to 1,5-PeD ratio of 3.7 over 4Pt/10Li/MgAl₂O₄. The Pt/Li/MgAl₂O₄ catalyst was robust to be reused five times without deactivation. Full article

Glucose–carbon hybrids were synthetized with different carbon materials, namely carbon nanotubes, reduced graphene oxide, carbon black and activated carbon by a hydrothermal treatment. These carbon hybrids were used as Pt-supports (1 wt.%) for the furfural (FUR) hydroconversion in the gas phase at mild operating conditions (i.e., P = 1 atm and T = 200 °C). The physicochemical properties (porosity, surface chemistry, Pt-dispersion, etc.) were analyzed by different techniques. Glucose–carbon hybrids presented apparent surface areas between 470–500 m² g⁻¹, a neutral character and a good distribution of small Pt-nanoparticles, some large ones with octahedral geometry being also formed. Catalytic results showed two main reaction pathways: (i) FUR hydrogenation to furfuryl alcohol (FOL), and (ii) decarbonylation to furane (FU). The products distribution depended on the reaction temperature, FOL or FU being mainly produced at low (120–140 °C) or high temperatures (170–200 °C), respectively. At intermediate temperatures, tetrahydrofurfuryl alcohol was formed by secondary FOL hydrogenation. FUR hydroconversion is a structure-sensitive reaction, rounded-shape Pt-nanoparticles producing FU, while large octahedral Pt-particles favor the formation of FOL. Pt-catalysts supported on glucose–carbon hybrids presented a better catalytic performance at low temperature than the catalyst prepared on reference material, no catalyst deactivation being identified after several hours on stream. Full article

Poland is one of the leading producers of sugar from sugar beet in Europe. However, the production of sugar generates large amounts of lignocellulosic waste, in the form of beet pulp and leaves. Currently, this waste is not reutilized in the chemical industry, but is only used as food for farm animals. This paper assesses the potential of using bio-waste from the sugar industry as a raw material for the production of furfurals via acid hydrolysis. Further processing of furfural into derivatives such as furfuryl alcohol (FA) or tetrahydrofurfuryl alcohol (THFA) could increase the economic profitability of the initiative. Furfuryl alcohol can be used as a fuel additive in sugar factories. Tetrahydrofurfuryl alcohol can be used as a component in agricultural fertilizers, increasing the yield of sugar beet. This approach reduces the amount of post-production waste and brings the sugar industry closer to the concept of a circular economy. Full article

We investigated the effect of oxide supports on the hydrogenation of furfural over Pd catalysts on various supports (Al₂O₃, SiO₂, TiO₂, CeO₂, and ZrO₂). Pd catalysts (5 wt%) prepared by chemical reduction on various supports. The dispersion and uniformity of Pd were affected by the properties of the support and by the nucleation and growth of Pd. The conversion of furfural was enhanced by greater Pd dispersion. The selectivity for cyclopentanone and tetrahydrofurfuryl alcohol was affected by physicochemical properties of Pd catalyst and reaction parameters. High Pd dispersion and high acidity of the catalyst led to greater C=C hydrogenation, thereby, generating more tetrahydrofurfuryl alcohol. The Pd/TiO₂ catalyst showed the highest cyclopentanone yield than other catalysts. The Pd/TiO₂ catalyst exhibited the >99% furfural conversion, 55.6% cyclopentanone selectivity, and 55.5% cyclopentanone yield under the optimal conditions; 20 bar of H₂, at 170 °C for 4 h with 0.1 g of catalyst. Full article