Ethyl Levulinate Research Articles

Alkyl Levulinates and 2-Methyltetrahydrofuran: Possible Biomass-Based Solvents in Palladium-Catalyzed Aminocarbonylation

In this research, ethyl levulinate, methyl levulinate, and 2-methyltetrahydrofuran as bio-derived hemicellulose-based solvents were applied as green alternatives in palladium-catalyzed aminocarbonylation reactions. Iodobenzene and morpholine were used in optimization reactions under different conditions, such as temperatures, pressures, and ligands. It was shown that the XantPhos ligand had a great influence on conversion (98%) and chemoselectivity (100% carboxamide), compared with the monodentate PPh3. Following this study, the optimized conditions were used to extend the scope of substrates with nineteen candidates (various para-, ortho-, and meta-substituted iodobenzene derivatives and iodo-heteroarenes), as well as eight different amine nucleophiles.

Antibiotic residue derived solid acids for ethanolysis of furfuryl alcohol into ethyl levulinate

Antibiotic residue derived carbon-based solid acids were developed for the ethanolysis of furfuryl alcohol into ethyl levulinate, which highlighted a novel direction for the synthesis of value-added chemicals over organic waste derived materials.

Sc(OTf)3: An efficient homogeneous catalyst for microwave-assisted transfer hydrogenation of ethyl levulinate to γ-valerolactone under mild conditions

γ-Valerolactone (GVL) is considered as a versatile platform chemical obtained from biomass refinery. In this study, eco-friendly group III metal (Sc, Y, La) triflates were examined as homogeneous catalysts for microwave-assisted transfer hydrogenation of ethyl levulinate (EL) to GVL under mild conditions. Experimental results revealed that the selectivity of GVL has a positive relationship with the Lewis acidity of metal ion, which is related to effective charge density of the metal center (3.23, 2.81, 2.60 for Sc3+, Y3+, La3+, respectively). The stronger Lewis acidity of metal ion, the higher catalytic activity of MPV reduction. Among these catalysts, Sc(OTf)3 exhibited the best catalytic activity, achieving 98.4% EL conversion and 92.4% GVL yield at 140 °C in 3.0 h. Furthermore, Sc(OTf)3 showed high stability and recyclability for at least ten reaction cycles. In addition, a plausible reaction pathway and mechanism were proposed.

Thermophysical Properties of Biodiesel with Ethyl Levulinate, Ethyl Acetoacetate, and Ethyl Pyruvate + MgO Mixtures from 288.15 to 338.15 K

Thermophysical properties are important to design the fuel system components and to evaluate new alternative fuels in diesel engine tests. Also, experimental properties allow us to understand the type of interactions present in the studied mixtures. Densities, viscosities, and refractive indices of biodiesel + ethyl levulinate, + ethyl acetoacetate, and + ethyl pyruvate with MgO mixtures have been measured from 288.15 to 338.15 K at 0.1 MPa over the whole composition range and at a constant concentration of 5 × 10–6 in mass fraction for MgO. Our experimental properties for the pure ketoesters agree with data reported in the literature within an average absolute percentage deviation of 0.056, 3.140, and 0.027 % for density, viscosity, and refractive index, respectively. Vibrating tube densimeter, glass capillary viscosimeter, and Abbemat refractometer have been used to measure the properties. Densities and viscosities of the biodiesel mixtures have been compared with the biodiesel fuel standard EN 14214. Flash point, cetane index, and calorific value of the biodiesel mixtures that meet the EN 14214 norm have been measured. Excess molar volume, viscosity deviation, and refractive index deviation are obtained from experimental data and correlated using the Redlich–Kister equation. Equations reported in the literature are used to correlate the thermophysical properties of the investigated mixtures.

Catalytic Transfer Hydrogenation and Ethanolysis of Furfural to Ethyl Levulinate Using Sulfonated Hf- or Ni-Catalysts Prepared with Mixed Solvents

Catalytic Transfer Hydrogenation and Ethanolysis of Furfural to Ethyl Levulinate Using Sulfonated Hf- or Ni-Catalysts Prepared with Mixed Solvents

Kinetics and structural design of ZSM-5@SiC foam catalytic packing in RD column for ethyl levulinate synthesis

Reactive distillation (RD) column is one of the important equipment to improve the reaction conversion limited by the chemical equilibrium, however, the application in industrial scale is still challenging due to the lack of efficient catalytic packing with corresponding kinetics and separation performances. This work developed the novel catalytic packing consists of the structured ZSM-5@SiC foam catalyst and corrugated sheet, which is used in RD for the synthesis of ethyl levulinate (EL). The results of X-ray CT characterization revealed that the structure of ZSM-5@SiC has significant effects on the kinetics and performances of RD column. The kinetic of structured ZSM-5@SiC foam catalyst was measured, and a novel kinetic model was developed regarding the “structure factor” of ZSM-5@SiC catalyst. Furthermore, the structural design of ZSM-5@SiC in RD column has been firstly performed based on the developed kinetics that was incorporated into Aspen Plus embedded FORTRAN. The results demonstrated excellent performance of the designed ZSM-5@SiC (EL yield 37.65 % with energy consumption 3695 kJ/kg) are achieved. Such findings in this work could serve as a tool for further upgrading of structured catalyst and application of RD column with ZSM-5@SiC foam catalytic packing.

Conversion of Glucose and Xylose to 5-Hydroxymethyl furfural, Furfural, and Levulinic Acid Using Ethanol Organosolv Pretreatment under Various Conditions

The objective of this study was to understand the conversion characteristics of glucose and xylose using the major monosaccharide standards for lignocellulosic biomass. The acid-catalyzed organosolv pretreatment conducted using ethanol was significantly different from the acid-catalyzed process conducted in an aqueous medium. 5-hydroxymethylfurfural (5-HMF), levulinic acid and furfural were produced from glucose conversion. The maximum yield of 5-HMF was 5.5%, at 200°C, when 0.5% sulfuric acid was used. The maximum yield of levulinic acid was 21.5%, at 220°C, when 1.0% sulfuric acid was used. Furfural was produced from xylose conversion and under 0.5% sulfuric acid, furfural reached the maximum yield 48.5% at 210°C. Ethyl levulinate and methyl levulinate were also formed from the glucose standard following the esterification reaction conducted under conditions of the combined conversion method, which proceeded under both ethanol-rich and water-rich conditions.

Sustainable Ketalization of Glycerol with Ethyl Levulinate Catalyzed by the Iron(III)-Based Metal-Organic Framework MIL-88A.

The catalytic properties of a simple iron-containing MOF based on fumaric acid, MIL-88A, were investigated in the ketalization of ethyl levulinate with glycerol. The corresponding product is a component of current interest as a renewable building block for many uses. Under the following conditions (solventless, 120 °C, stoichiometric ratio, 1% cat.), the reaction proceeds with good yields (85%), and the catalyst can be recovered and recycled without loss of activity, despite some changes in the crystalline lattice and morphology. Moreover, the residual iron content in the product is in the order of units of ppm (≤2), which demonstrates the robustness of the MOF under the reaction conditions.

Catalytic Synthesis of Energy‐rich Fuel Additive Levulinate Esters from Levulinic Acid using Modified Ultra‐stable Zeolite Y

AbstractIn the present investigation, the esterification reaction of levulinic acid with ethanol was performed using sulfuric acid‐modified zeolite Y catalyst to synthesize ethyl levulinate. Characterization of zeolite catalysts was performed using SEM‐EDS, XRD, and FTIR techniques. The experiments were performed to find the optimum reaction parameters to obtain the maximum yield of 96 % of the product, levulinate ester by varying catalyst concentration (2–12 wt %), levulinic acid to ethanol mole ratio (1 : 1 to 1 : 13), reaction temperature (40 °C–100 °C). The esterification of levulinic acid with ethanol followed pseudo‐first‐order reaction kinetics. The activation energy for this reaction was found to be 19.570 KJmol−1.

Effective synthesis of ethyl levulinate via alcoholysis of furfuryl alcohol over simple nickel-titanium dioxide

A series of non-noble metals based titanium dioxide catalysts were synthesized following a facile sol-gel route. The catalytic performance for direct furfuryl alcohol (FAL) conversion to ethyl levulinate (EL) was investigated. Successful performance was confirmed by N2 physisorption analysis, XRD, XPS, SEM, EDS, TEM, ICP-OES, NH3-TPD, Pyridine-IR spectroscopy. 5 % Ni-TiO2 with the highest surface area, enhanced physical and textural characteristics exhibited better catalytic performance than other candidates. The strong Brönsted/Lewis acidity strength showed a pivotal role in defining product range. Ethoxymethylfuran (EMF), α-angelica lactone (AAL), 5-methyl-2(5 H)-furanone (β-angelica lactone, BAL) and other important intermediates were obtained, as well as the two routes mechanism was proposed. The ever reported highest EL productivity and TOF value (652.0 molFAL/molNih and 1018.1 molEL/molNih) achieved under the optimum condition. The differential charge density diagram demonstrated the loss of electrons promoted by Ni doping, and the route mainly transferred from the O and Ni to Ti.

Polyhedron-like Co-embedded carbon catalyst derived from ZIF-67 by surface confinement pyrolysis strategy for upgrading of ethyl levulinate to γ-valerolactone

Polyhedron-like Co-embedded carbon catalyst was constructed through a P123-assisted surface-confinement pyrolysis strategy using ZIF-67 as precursor in the present studies. The introduction of P123 resulted in a homogeneously distributed hierarchical pore structure of the catalyst, modulated the composition of different valence Co species and limited the agglomeration of cobalt nanoparticles, which improves the hydrogenation and dehydration ability of the catalyst, and thus endow it robust activity and long-term durability in conversion of ethyl levulinate to γ-valerolactone (Yield ≥98%, well stability for no less than 7 runs). The present work may supply a novel strategy for synthesis of polyhedron-like carbon materials for the transformation of biomass-plate molecular in the range hydrogenation.

Engineering oxygen vacancy and crystal surfaces for TiO2-based photocatalysts for enhanced photocatalytic hydrogenation of bio-based carbonyls to biofuels

Photocatalytic reductive conversion of bio-derivatives to biofuels and fine chemicals is an eco-friendly and energy-saving way for biomass valorization. Herein, we developed a new and high-performance protocol for control of activity/selectivity in photocatalytic reductive upgrading of biomass to biofuels at room temperature via engineering oxygen vacancy (Ov) and manipulating the exposed crystal surfaces of the TiO2-based catalysts, such as efficient cascade photocatalytic hydrogenation-cyclization of ethyl levulinate to γ-valerolactone in water (up to 96% yield, TOF: 112.1 h−1), and the selective conversion of 5-methylfurfural to 5-methylfurfuryl alcohol (90% yield) or long carbon-chain coupling products (86% yield) in methanol, respectively. The {101} crystal plane is prone to produce more Ov in situ than the {001} and {110} crystal planes. The formation of Ov was not only beneficial to the adsorption and activation of the bio-based carbonyls, but also could enhance the migration efficiency of the photo-generated carriers and effectively adjust the semiconductor band structure of the TiO2-based photocatalyst to promote the visible-light absorption, thus enhancing the overall reductive conversion process, as elucidated by DFT calculations. Also, the charge distribution and adsorption intensity of different exposed crystal surfaces of the photocatalyst were able to control the selectivity of the bioproducts. In addition, the optimal Ov-TiO2−x{101} catalyst had excellent reusability and could be reused at least five times with no obvious decrease in photocatalytic performance. The strategy of selectivity control via engineering the catalyst exposed crystal surfaces and loaded Ov provides an opportunity for multi-catalytic biomass conversion to biofuels.

Design and synthesis of SO3H-functionalized acidic ionic liquids for catalytic conversion of wheat straw to ethyl levulinate

Ethyl levulinate (EL) is a key platform compound for the catalytic conversion of biomass. Ionic liquids (ILs) have attracted much attention due to their unique tunable structures and wide range of applications, a series of SO3H-functionalized imidazole based acidic ILs were designed and synthesized. These SO3H-functionalized ILs were used as the catalyst to be applied to the conversion of the wheat straw to EL. Among them, SimIL-6 exhibited good catalytic performance for the conversion of wheat straw to EL in ethanol. When the concentration of SimIL-6 was 30 mmol/L, the yield of EL could reach 20.1 wt% at 180 ℃ for 2 h. Furthermore, SimIL-6 as the catalyst was reused at least six times without significant reduction in catalytic efficiency. This work shed light on a new approach towards the full utilization of biomass and efficient degradation of biomass to EL.

Performance Comparison of Polymeric and Silica-Based Multi-Bed Pervaporation Membrane Reactors during Ethyl Levulinate Production.

A detailed numerical study of ethyl levulinate (EtLA) production with levulinic acid (LA) and ethanol (Et) in a multi-bed traditional reactor (MB-TR) and a silica-based and polymeric multi-bed pervaporation membrane reactors (MB-PVMR) was conducted and the efficiency of each design was studied under different operation conditions. Due to water production in the EtLA production process, water removal by a pervaporation system may improve process performance. Our results showed that MB-PVMR had higher performance compared with MB-TR. In addition, the silica membrane was more effective in water removal compared with the polymeric membrane. Therefore, higher LA conversion was achievable by a silica-based multi-bed pervaporation membrane reactor (SMB-PVMR). All the results were evaluated for percentage of water removal and LA conversion, based on variations in the Et/LA molar ratio, feed molar flow, reaction zone temperature, and catalyst loading. The results showed that water removal was higher than 95% and LA conversion of about 95% was attained by SMB-PVMR.

Production of γ-valerolactone from ethyl levulinate over hydrothermally synthesized Sn-Beta under mild conditions

Production of γ-valerolactone (GVL) from ethyl levulinate (EL) was studied by catalytic transfer hydrogenation (CTH) strategy under mild conditions. Hydrothermally synthesized Sn-Beta zeolites with high crystallinity show high catalytic activity and selectivity. With isopropanol as hydrogen source, 97.1 % GVL yield with 100 % selectivity was given under 110 °C. Crystallization time for synthesis of Sn-Beta showed great effect on the catalytic performance. Sn-Beta-xd catalysts with longer crystallization time (≥7 days) have high crystallinity and better catalytic performance. Firstly, longer crystallization time is necessary for the formation of large amount of Lewis acid sites which catalyze the conversion of EL to GVL. Secondly, high level of silanol groups in Sn-Beta has negative effect on the catalytic performance. High crystallinity means the amount of silanol groups in Sn-Beta-xd at a low level which is favorable for this CTH reaction. Meanwhile, this is why hydrothermally synthesized Sn-Beta shows higher catalytic activity than post-synthesized Sn-Beta in the conversion of EL to GVL. Furthermore, the catalyst was reusable.

High Dispersion of Platinum Nanoparticles over Functionalized Zirconia for Effective Transformation of Levulinic Acid to Alkyl Levulinate Biofuel Additives in the Vapor Phase

In recent years, functionalized metal oxides have been gaining popularity for biomass conversion to fuels and chemicals due to the global energy crisis. This study reports a novel catalyst based on noble metal immobilization on functionalized zirconia that has been successfully used in the production of biofuel alkyl levulinates (ALs) from lignocellulosic biomass-derived levulinic acid (LA) under vapor-phase. The wet impregnation method was used to immobilize Pt-metal nanoparticles on zirconia-based supports (silicotungstic acid zirconia, STA-ZrO2; sulfated zirconia, S-ZrO2; and tetragonal zirconia, t-ZrO2). A variety of physicochemical techniques were used to characterize the prepared catalysts, and these were tested under atmospheric pressure in continuous flow esterification of LA. The order of catalytic activity followed when ethyl levulinate was produced from levulinic acid via esterification: Pt/STA-ZrO2 ≫ Pt/S-ZrO2 ≫ Pt/t-ZrO2. Moreover, it was found that ALs synthesis from LA with different alcohols utilizing Pt/STA-ZrO2 catalyst followed the order ethyl levulinate ≫ methyl levulinate ≫ propyl levulinate≫ butyl levulinate. This work outlines an excellent approach to designing efficient catalysts for biofuels and value-added compounds made from biomass.

Catalytic one-pot conversion of biomass-derived furfural to ethyl levulinate over bifunctional Nb/Ni@OMC

As one of the important chemical feedstocks and biofuels, ethyl levulinate (EL) can be produced from biomass-derived furfural by consecutive hydrogenation, etherification and ring-opening reactions. However, this process normally requires two separate steps in different reaction systems, which is complex and energy consumption. Herein, Nb–Ni bifunctional ordered mesoporous carbons (Nb/Ni@OMCs) were synthesized by a two-step process where Ni@OMC was firstly synthesized by a solvent evaporation induced self-assembly (EISA) process using F127 as a template agent, polyphenol gallic acid as carbon precursor and Ni2+ as cross-linker, following with the supporting of Nb species in the Ni@OMC by an incipient wetness impregnation method. The as-synthesized Nb/Ni@OMC samples were applied for the one-pot catalytic transformation of furfural to EL, and exhibited good activity with the highest EL yield of 83% under an optimized condition. Two possible pathways for the one-pot production of EL were proposed according to two intermediates: (1) hydrogenation of furfural to form furfuryl alcohol (FFA) that is then etherified with ethanol to form 2-(ethoxymethyl)furan (2-EMF); and (2) acetalization and etherification of furfural with ethanol to produce 2-(diethoxymethyl)furan (2-DMF). Then both 2-DMF and 2-EMF are converted to EL through acid catalyzed ring opening reaction. The dominant reaction pathway varied with the properties of the catalyst and the applied reaction conditions.

Separation of fuel additive levulinic acid using toluene, xylene, and octanol from water stream

Levulinic acid is an important fuel additive due to its multifunctionality with keto and carboxylic functional groups. It also carries the potential to produce some other fuel additives viz. γ-valerolactone, ethyl levulinate, and 2-methyl tetrahydrofuran. These substances can be combined with petroleum-derived transportation fuels similarly to bioethanol without modifying in engines. The wastewater and solid wastes from various industries contain organic acids in the downstreams. The recovery and separation of organic acids from wastewater is challenging due to its dilute concentrations and other issues. The presented study involves the separation of levulinc acid from the waste-water stream using various solvents such as toluene, xylene, and octanol at 25°C. The experimental results were described in terms of the partition constant (Pc), dimerization constant (Dc), distribution coefficients (KD), and extraction efficiency (Eη). The present study can significantly contribute to the recovery of levulinic acid as fuel additive levulinic with low-cost process.

Surface-active site engineering: Synergy of photo- and supermolecular catalysis in hydrogen transfer enables biomass upgrading and H2 evolution

The appropriate regulation of photocatalyst band structure by simultaneous introduction of active sites is an effective strategy in constructing efficient photocatalytic systems for biomass valorization. Herein, a renewed host–guest photocatalyst (Ov-WO3@CB[5]) prepared by anchoring cucurbit[5]uril on oxygen vacancy-rich WO3 was efficient for reductive upgrading of biomass derivatives using NH3-BH3, such as cascade photocatalytic hydrogenation-cyclization of ethyl levulinate to γ-valerolactone (up to 99 % yield) at 25 °C in 1 h, and quantitative production of primary/secondary bio-alcohols or arylamines from various aldehydes/ketones or nitroarenes, respectively. Also, the rate of H2 production by direct photocatalytic hydrolysis of NH3-BH3 could reach 5.75 mL h−1 g−1. The inclusion of cucurbit[5]uril effectively adjusted the semiconductor band structure and enhanced migration efficiency of photo-generated carriers, and the hydrophobic cavity of cucurbit[5]uril favored the entrance of NH3-BH3, as elaborated by theoretical calculations. Properly engineering supramolecular surface-active sites based on interface host–guest chemistry opens new avenues for reductive upgrading of biomass and hydrogen evolution.

Sustainable production of ethyl levulinate by levulinic acid esterification obtained from Colombian rice straw

E-fuels are synthetic fuels produced from renewable sources that have garnered attention because of their potential to reduce environmental impacts in the transport sector. Ethyl levulinate is a fuel additive that can address issues associated with traditional fuels. This product can be obtained from agro-industrial wastes such as rice straw. Therefore, the aim of this study was to assess the technical, economic, and environmental feasibility of producing ethyl levulinate from Colombian rice straw. Aspen Plus v12 and life cycle assessment methodology were used for evaluating the process through the cultivation to the biorefinery stage. A base scenario was analyzed, with an overall yield of 0.115 kg ethyl levulinate/kg rice straw and a total energy consumption of 133.2 kWh/kg of ethyl levulinate produced. A carbon footprint of 2.71 kg CO2-eq/kg Ethyl levulinate was observed, which primarily ascribed to the use of steam derived from fossil fuels. An alternative scenario was proposed by implementing two changes to reduce the environmental impacts. First, steam was generated by the solid hydrolyzed residue combustion, and second, the paddy rice yield was increased to 5.7 t/ha. Reductions of 58.5% and 25.4% in the carbon footprint and ozone depletion were respectively obtained from these improvements. A class V economic assessment is performed for the alternative scenario, yielding a net present value of 18.7 MUSD, payback period of 5 years, and return on investment of 19.6%. Hence, the production of Ethyl levulinate from rice straw is a feasible alternative to boost the e-fuel market while upgrading agro-industrial waste into valuable products.