Synthesis Of Levulinates Research Articles

Synthesis of Alkyl Levulinates from α-Angelica Lactone Using Methanesulfonic Acid as a Catalyst: A Sustainable and Solvent-Free Route

Synthesis of Alkyl Levulinates from α-Angelica Lactone Using Methanesulfonic Acid as a Catalyst: A Sustainable and Solvent-Free Route

The influence of catalyst structure on acidic strength of –SO3H groups for alkyl levulinate synthesis from biomass–derived feedstocks using sulfonic acid functionalized flexible MOF catalyst

A Brönsted acidic BUT−8(Cr)–SO3H metal–organic framework was used for the synthesis of ethyl levulinate from two different biomass–derived platform chemicals viz. furfuryl alcohol and levulinic acid. The catalyst was well characterized using various methods such as PXRD, FTIR spectroscopy, acid–base titration, NH3–TPD, TGA–DTA, SEM, TEM as well as the computational density functional theory (DFT) method. The performance of BUT–8(Cr)–SO3H catalysts was found to be superior to other catalysts (HZSM–5, H–Beta, and amberlyst –15) taken in this study. The sulfonic acid moieties bound to the aromatic naphthalene structure of BUT–8(Cr)–SO3H MOF were found to have a much stronger influence on the catalytic performance than the sulfonic acid moieties bound to the styrene framework of amberlyst–15. The key discoveries regarding the Brönsted acidic characteristics were computed via DFT incorporating the hydrogen removal energy, molecular electrostatic potential maps, and stability of the conjugate base of –SO3H moieties. The trend in the DFT–derived values was in the following order: BUT–8(Cr)–SO3H > Linker–naph –SO3H > Amberlyst–15. The results also indicate the influence of Cr metal on MOF structure to increase the acidic strength of the –SO3H group. The reaction optimization using DOE, recyclability, leaching study, and substrate scope study for both pathways using BUT–8(Cr)–SO3H were obtained.

Dual-Acidity Catalysts for Alkyl Levulinate Synthesis from Biomass Carbohydrates: A Review

Dual-Acidity Catalysts for Alkyl Levulinate Synthesis from Biomass Carbohydrates: A Review

Environmentally sustainable ethyl levulinate synthesis from delignified sugarcane bagasse using ternary eutectic solvent under MW-xenon irradiation: engine performance and emission assessment.

For the first time, a synergistic energy-efficient combination of microwave-xenon (MW-XE) irradiations in presence of photoactive ternary acidic deep eutectic solvents (TADES) has been applied for intensification of ethyl levulinate synthesis from delignified sugarcane bagasse (DSB) under mild (90min, 90°C) and environmentally benign process conditions. The Taguchi orthogonal designed optimized conditions (20 W/cm3 of MW specific irradiation power input, 1 mol/mol of FeCl3 to citric acid ratio, 90min of reaction time, 150 W of XE specific power input) rendered maximum 61.3mol% of EL yield (selectivity: 87.70 [Formula: see text] 0.5%). Remarkably, synergistic effect of MW and XE irradiation significantly enhanced the EL yield (61.3mol%) compared to the individual MW (34.52mol%) and XE (22.67mol%) irradiation at otherwise optimized reaction conditions. Moreover, the MWXE irradiated reactor (MWXER) exhibited a significant 79.10% increase in EL yield compared to the conventional thermal reactor (CTR), at the expense of 10% less energy consumption. The ethyl levulinate could be recovered efficiently through green protocol from reaction mix resulting in high purity (97 [Formula: see text] 0.5%) and TADES was sustainably reused in the process. The optimally generated product EL when blended (5 and 10 vol.%) with B10 and B20 (10% and 20% biodiesel-diesel blend) could provide 21-31% reduction in HC and 7.3-36% reduction in CO in comparison with petro-diesel. It was also explored that, at similar optimal parametric combinations, the TADES produced 29.5% greater EL yield in comparison with the standard ionic liquid BMIMCl. The life cycle environmental impact analysis (LCEIA) of the overall process revealed that the 5 vol.% EL blending with B10 contributed lowest environmental impacts mitigating marine ecotoxicity, human toxicity, fossil depletion, and climate change by 77.9%, 77.4%, 78.4% and 77.5%, respectively.

Effects of Ethanol: Water Ratio and Reaction Time on Ethyl Levulinate Synthesis from Oil Palm Empty Fruit Bunch (OPEFB)

World energy consumption continues to escalate annually in line with current world development. Meeting this burgeoning demand necessitates the exploration of renewable energy. Biofuel is one of the promising alternatives for renewable energy sources. However, biofuel has a disadvantage in its lower overall performance than fossil fuel. The application of additives such as ethyl levulinate emerges as a potential solution to enhance biofuel performance. This research aims to investigate the effect of ethanol:water ratio and reaction time on the formation of ethyl levulinate from Oil Palm Empty Fruit Bunch (OPEFB). The OPEFB to be utilized was pretreated with 3% NaOH at a solid-to-liquid ratio of 1:8. The reaction was conducted at 120oC, with varying ethanol:water ratio and reaction time in the presence of H2SO4 as the catalyst. The reaction products were extracted using ethanol and analyzed with gas chromatography–mass spectrometry. The optimum reaction conditions obtained were 90 minutes and ethanol:water ratio of 99.1:0.9, resulting in a yield of 1.01%.

Trifloaluminate Ionic Liquids Supported UIO‐67 as Lewis Acidic Catalyst for Excellent Synthesis of Alkyl Levulinates

AbstractHerein, levulinate acid esters (LAEs) were efficiently synthesized from the α‐angelica lactone (α‐AL) esterification with trifloaluminate ionic liquids supported UIO‐67 MOF as Lewis acidic catalyst. A series of UIO‐67 catalysts with varied trifloaluminate ionic liquids loading were prepared via the post‐modification method and exhibited excellent catalytic activity for α‐AL esterification. Remarkable α‐AL conversion (100 %) and LAEs selectivity (>99 %) were achieved by UIO‐67 catalysts (0.2 mol %) with 12.4 %, trifloaluminate ionic liquids loading (UIO‐67‐TFA) at 70 °C and 90 min. The UIO‐67‐TFA catalyst can be reused at least 5 cycles without significant loss of catalytic activity. The UIO‐67‐TFA catalysts were fully characterized by XRD, SEM, XPS, TGA, IR, N2 physisorption, etc. The results indicated that the well‐distributed active trifloaluminate Lewis acid catalytic sites, high BET surface area, and good thermal stability could contribute to its excellent catalytic activity.

Modification and characterization of Mordenite zeolite derived from waste coal fly ash and its application as a heterogeneous catalyst for the n-butyl levulinate synthesis

The thermal power plants produce huge quantity of fly ash as waste materials, and dumped in to the ash dykes, which occupies several acres of land and ultimately, spoil it. Researchers are looking for the reasonable treatment process to convert the fly ash into useful materials like zeolites. In this work, fly ash derived Mordenite zeolite has been synthesized with improved catalytic activity. The utility of this material is demonstrated as a solid acid catalyst for the synthesis of n-butyl levulinate from biomass derived levulinic acid. This study demonstrates successful cost effective transformation of fly ash into environmentally benign catalyst.

Methyl levulinate synthesis from rice husk employing e-waste derived silica supported nano CuO–CdSO4 photocatalyst: Assessment of production environmental impacts, engine performance and emissions

Applications of E-waste recovered silica (support) and copper citrate (precursor) for the synthesis of nano CuO–CdSO4 doped photocatalyst (NCCP) for subsequent employment in sustainable conversion of rice husk (RH) to drop-in biofuels viz. methyl levulinate (ML) have been explored. The prepared NCCP (low Eg = 2.0 eV) was employed for alcoholytic depolymerization (AD) to produce ML from holocellulose (HOC) extracted from RH through infrared assisted delignification. Taguchi orthogonal design predicted the optimal values of the AD viz. HOC: Water (1:5 w/w), NCCP concentration (1 wt%), HOC: methanol (1:30 w/w) and AD time (125 min) rendering 96.97% ML yield deploying combined ultrasonication-UV energies at 60 °C; saving 30% energy compared to conventional heating system. Noticeably, this is the first insightful investigation on the application of ML as a diesel additive demonstrating significant diminutions (25.92% and 83.33% for CO and HC) in harmful emissions. The LCA of the overall ML synthesis indicates remarkable reduction in environmental pollution with 63.63% and 66.66% mitigations in GWP and ecotoxicity respectively. Thus, a sustainable ML synthesis protocol encompassing the development of E-waste derived nanophotocatalyst through conversion of rice husk and its successful use as a diesel additive could be established.

Production of Alkyl Levulinates from Carbohydrate-Derived Chemical Intermediates Using Phosphotungstic Acid Supported on Humin-Derived Activated Carbon (PTA/HAC) as a Recyclable Heterogeneous Acid Catalyst

This work reports a straightforward and high-yielding synthesis of alkyl levulinates (ALs), a class of promising biofuel, renewable solvent, and chemical feedstock of renewable origin. ALs were prepared by the acid-catalyzed esterification of levulinic acid (LA) and by the alcoholysis of carbohydrate-derived chemical platforms, such as furfuryl alcohol (FAL) and α-angelica lactone (α-AGL). Phosphotungstic acid (PTA) was chosen as the solid acid catalyst for the transformation, which was heterogenized on humin-derived activated carbon (HAC) for superior recyclability. Using HAC as catalyst support expands the scope of valorizing humin, a complex furanic resin produced inevitably as a side product (often considered waste) during the acid-catalyzed hydrolysis/dehydration of sugars and polymeric carbohydrates. Under optimized conditions (150 °C, 7 h, 25 wt.% of 20%PTA/HAC-600 catalyst), ethyl levulinate (EL) was obtained in an 85% isolated yield starting from FAL. Using the general synthetic protocol, EL was isolated in 88% and 84% yields from LA and α-AGL, respectively. The 20%PTA/HAC-600 catalyst was successfully recovered from the reaction mixture and recycled for five cycles. A marginal loss in the yield of ALs was observed in consecutive catalytic cycles due to partial leaching of PTA from the HAC support.

One-pot method of recyclable lipase-nanocatalyst based on chitosan magnetic nanomaterial for ethyl levulinate synthesis

Carrier, immobilization method and conditions are the most important factors affecting the performance of immobilized lipase. In this study, MNP@CTS is successfully prepared via an improved hydrothermal method combined with ion condensation. Then, we creatively adopt one-pot method, combining electrostatic adsorption with chemical crosslinking, to prepare lipase-nanocatalyst with excellent performance under mild conditions. MNP@CTS and lipase-nanocatalyst are characterized by FTIR, SEM, HRTEM, CLSM, CD, etc, the optimal conditions are explored in detail too. Lipase-nanocatalyst is 189 nm, and the loading ratio of free lipase is up to 67.6%. Compared with free lipase, specific activity is increased by 2.9 times, and it also broadens toleration to pH, thermal, organic solvents. In addition, lipase-nanocatalyst exhibits high storage stability and reusability. The residual activity is approximately 92.3% after the 10th recycle, and the cumulative catalytic activity is 13.4 times than that of free lipase. Finally, lipase-nanocatalyst is used to synthesize ethyl levulinate, with a production ratio of 68.6% for the first recycle, and the total output of EL is 12.9 times than that of free lipase after ten cycles. Thus, our findings provide a foundation for lipase-nanocatalyst showing several attractive features, such as easy preparation, excellent catalytic activity, good stability and reusability.

DTAB Mediated Post Modification of Zeolite H-BEA, Its Characterization and Catalytic Application for n-Butyl Levulinate Synthesis

DTAB Mediated Post Modification of Zeolite H-BEA, Its Characterization and Catalytic Application for n-Butyl Levulinate Synthesis

Efficient synthesis of alkyl levulinates fuel additives using sulfonic acid functionalized polystyrene coated coal fly ash catalyst

In this study, sulfonic acid functionalized polystyrene coated coal fly ash catalyst (CFA@PS-SO3H) was designed and prepared by the post-synthesis method, which exhibited excellent catalytic performance for esterification of levulinic acid (LA) to afford alkyl levulinates. Four significant factors, including reaction time, catalyst dosage, alcohol-to-acid molar ratio and reaction temperature were evaluated systematically. Response surface methodology based on Box-Behnken design (BBD) was carried out to determine the optimal parameters. The maximum yield could reach 99.6% under the mild conditions. Furthermore, kinetics of the esterification reaction between levulinic acid and n-butanol were analyzed and the activation energies of the first and second step of esterification reaction were found to 52.18 and 59.81 kJ/mol, respectively. The CFA@PS-SO3H also showed high catalytic activity for the esterification of levulinic acid with other linear alcohols, which made it a low cost, environmentally friendly and promising solid catalyst for the synthesis of alkyl levulinates.

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.

Metal sulfate-catalyzed methanolysis of cellulose at high solid loadings: Heterogeneous degradation kinetics and levulinate synthesis

Increasing efforts have been devoted to the production of bio-based chemicals from high solid content of renewable biomass to pursue optimal process efficiency and economics. In this study, the preparation of methyl levulinate (ML) by metal sulfate-catalyzed methanolysis from high solid content of cellulose was investigated. When the cellulose loading was 15%, 38.67% of ML yield can be obtained under the optimum reaction conditions. Al2(SO4)3 can be reused more than five times while maintaining high activity in the process. The characterization of cellulose particles confirmed that cellulose particles shrunk over the reaction time. The heterogeneous degradation kinetics of high solid content of cellulose in methanol could be explained by a shrinking core model. High solid loadings led to a decrease of the reaction rate constants of methanolysis. Using cellulose with a small particle size can improve the methanolysis reaction rate. The study also proposed comprehensive reaction pathways for ML production from high solid content of cellulose. To elucidate the methanolysis mechanism, an assessment of density functional theories for the calculation of glucose methanolysis at the molecular level is presented. All these results can inspire the development of ML synthesis technology through methanolysis from renewable biomass with high solid loadings.

Propylsulfonic Acid-Functionalized Mesostructured Natural Rubber/Silica Nanocomposites as Promising Hydrophobic Solid Catalysts for Alkyl Levulinate Synthesis.

Organosulfonic acid-functionalized mesoporous silica is a class of heterogeneous acid catalysts used in esterification processes due to its high surface area, shape-selective properties, and strongly acidic sites. Since water is generated as a by-product of esterification, the surface of mesostructured silica is modified to enhance hydrophobicity and catalytic performance. In this study, a series of propylsulfonic acid-functionalized nanocomposites based on natural rubber and hexagonal mesoporous silica (NRHMS-SO3H) with different acidities were prepared via an in situ sol-gel process using tetraethyl orthosilicate as the silica source, dodecylamine as the nonionic templating agent, and (3-mercaptopropyl)trimethoxysilane as the acid-functional group precursor. Compared with conventional propylsulfonic acid-functionalized hexagonal mesoporous silica (HMS-SO3H), NRHMS-SO3H provided higher hydrophobicity, while retaining mesoporosity and high surface area. The catalytic activity of synthesized solid acids was then evaluated via batch esterification of levulinic acid (LA) with alcohols (ethanol, n-propanol, and n-butanol) to produce alkyl levulinate esters. NRHMS-SO3H exhibited higher catalytic activity than HMS-SO3H and ultra-stable Y (HUSY) zeolite owing to the synergistic effect between the strongly acidic-functional group and surface hydrophobicity. The activation energy of the reaction over the NRHMS-SO3H surface was lower than that of HUSY and HMS-SO3H, suggesting that tuning the hydrophobicity and acidity on a nanocomposite surface is a compelling strategy for energy reduction to promote catalysis.

One-pot two-step synthesis of alkyl levulinates directly from furfural by combining Ni3Sn2 alloy nanoparticles and montmorillonite K10

In this work, we developed a catalytic system comprising Ni3Sn2 alloy nanoparticles and montmorillonite K10 that is effective for the one-pot two-step synthesis of alkyl levulinates directly from furfural.

Lipase as a green and sustainable material for production of levulinate compounds: State of the art

Levulinate compounds are considered as a potential energy chemical and bio-lubricant of the present century due to extraordinary application in fuel blending which improves the performance and efficiency of fuel and engine. The traditional industrial synthesis of levulinate compounds involves the use of hazardous reagents/chemicals and harsh reaction temperature conditions which are considered as non-green methodologies that violate the green and sustainable chemistry principles. The recent literature survey suggested that enzyme (lipase) catalyzed synthesis of levulinate compounds may be a competent solution over the present traditional synthesis. However, there is need of extensive research efforts and reviewing of recent advances in this field to get the proficient synthesis of levulinates through enzyme catalysis. In view of this, the present review article highlights the current state of the art in this field along with major challenges for the proficient enzyme catalyzed scale-up production of levulinate compounds.

Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final conversion and separation efficiency of the system. The effects were described qualitatively, demonstrating that working at sufficiently low flow rates, LA was completely converted, while at moderate flow rates, only a partial conversion was achieved. The system worked properly even at room temperature (303 K), where LA was completely converted, an encouraging result as esterification reactions are normally performed at higher temperatures.

Alkyl Levulinates from Furfuryl Alcohol Using CT151 Purolite as Heterogenous Catalyst: Optimization, Purification, and Recycling

Commercially available Purolite CT151 demonstrated to be an efficient acid catalyst for the synthesis of alkyl levulinates via alcoholysis of furfuryl alcohol (FA) at mild temperatures (80–120 °C) and short reaction time (5 h). Reaction conditions were first optimized for the synthesis of ethyl levulinate and then tested for the preparation of methyl-, propyl-, isopropyl-, butyl, sec-butyl- and allyl levulinate. Preliminary scale-up tests were carried out for most of the alkyl levulinates (starting from 5.0 g of FA) and the resulting products were isolated as pure by distillation in good yields (up to 63%). Furthermore, recycling experiments, conducted for the preparation of ethyl levulinate, showed that both the Purolite CT151 and the exceeding ethanol can be recovered and reused for four consecutive runs without any noticeable loss in the catalyst activity.

Tungstophosphoric acid supported on metal/Si-pillared montmorillonite for conversion of biomass-derived carbohydrates into methyl levulinate

Biomass-derived carbohydrates exploited toward the synthesis of alkyl levulinates is very promising, but still limited by the applicable catalyst. In this study, novel metal/Si-pillared montmorillonite supported phosphotungstic acid catalysts (SG-HPW-XSiMt-y, where X = La3+, Ce3+, Er3+, Cu2+, Al3+, Ti4+, Zr4+) were synthesized by sol-gel method. The catalytic performance of SG-HPW-XSiMt-y were comprehensively studied for glucose methanolysis to methyl levulinate (ML), focusing on the effects of metal acidity, HPW contents and reaction conditions. The appropriate Lewis acidity of metal ions effectively facilitated the isomerization of glucose/methyl-glucoside to fructose/methyl-fructoside; the strong Brønsted acidity of incorporated HPW was capable of suppressing the side reactions; and the large specific surface area and hierarchical pores of the mesoporous structure allow the reaction to take place both on surface and inside the porous framework. Among these as-synthesized catalysts, the SG-HPW-ZrSiMt-20 showed the most superior activity and achieved 65.8% yield of ML from glucose at 170 °C for 4 h. Alternative biomass-derived carbohydrates, including fructose, sucrose and cellobiose, also gave excellent ML yields under such catalytic system. The SG-HPW-ZrSiMt-20 had impressively stable reusability with merely loss of catalytic activity after eight cycles, owing to the uniform dispersion and stable bonding of HPW with ZrSiMt support. Generally, this catalyst system realizes an efficient and sustainable conversion of biomass-derived carbohydrates to ML production.