Search Results (39)

The effect of water on the dynamics and ionic conductivity of the ionic liquids 1-ethyl-1-methylpyrrolidinium levulinate ([C₂C₁Pyr]Lev) and 1-butyl-1-methylpyrrolidinium levulinate ([C₄C₁Pyr]Lev) was investigated using differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS) over a wide temperature range. Although both ILs share the same levulinate anion, water induces markedly different dynamical responses depending on cation structure. In both systems, water acts as a plasticizer, lowering the glass transition temperature; however, the extent of plasticization and the resulting relaxation dynamics are cation-dependent. Stronger water–cation interactions are observed in [C₂C₁Pyr]Lev, whereas in [C₄C₁Pyr]Lev, water primarily disrupts alkyl-chain packing, enhancing ionic mobility. Increasing hydration shifts the main relaxation to higher frequencies and increases liquid fragility, while translational ionic motion remains decoupled from structural relaxation. These results demonstrate that water plays a cation-specific and mechanistically distinct role in levulinate-based ILs, providing new insights into hydration-controlled glassy dynamics and charge transport relevant to the design of IL-based electrolytes under non-anhydrous conditions. Full article

Gamma-valerolactone (GVL) can be used as a renewable solvent, flavoring agent, and precursor to produce liquid fuels and fine chemicals. GVL is mainly produced by the efficient hydrogenation of levulinic acid and its esters over a wide range of bifunctional catalysts under harsh conditions because high temperature is generally required for GVL formation. So far, the hydrogenation of levulinic acids/esters under mild conditions remains a great challenge. In this study, 2 wt.% Ru was loaded onto ZSM-5 zeolite (MFI) via a deposition–precipitation method and further wrapped by crystallization, forming a core–shell structure. Moreover, the wrapped Ru catalyst was coated with a petal-like layer of Mg₃Si₄O₉(OH)₄ (MgSiO₃) via a hydrothermal reaction in a Mg(NO₃)₂ solution, thereby introducing alkalinity and achieving spatial separation of Mg and Ru. This dual-functional catalyst reduces the inhibitory effect of Mg on the Ru active center and enables efficient preparation of GVL from ethyl levulinate (EL) under mild conditions, achieving 100% EL conversion and 98% GVL selectivity in the aqueous phase at 80 °C in 2 h under 0.5 MPa of H₂. Full article

The hydrogenation of the biomass platform compound, ethyl levulinate, for the synthesis of γ-valerolactone represents a highly promising pathway for biomass valorization. Transition metal phosphates are extensively utilized in biomass hydrogenation reactions due to their Brønsted and Lewis acid sites. In this study, we synthesized a series of transition metal (Ni, Co, and NiCo) phosphide catalysts using the liquid phase method. We investigated the effects of metal species and initial Co/Ni molar ratios on catalytic activity in hydrogenation of ethyl levulinate and optimized the reaction conditions. The NiCoP-1.00 sample, prepared with a Co/Ni molar ratio of 1, demonstrated high efficacy in the hydrogenation of ethyl levulinate to γ-valerolactone, achieving excellent selectivity (97.9%) under optimized conditions. Experimental findings indicate that the synergistic interaction between Ni and Co facilitates the hydrogenation of the intermediate ethyl 4-hydroxypentanoate to γ-valerolactone while inhibiting excessive hydrogenation. The catalytic performance of the NiCoP-1.00 catalyst remained stable over five recycling runs. Full article

Isobaric vapor-liquid equilibrium (VLE) data for binary mixtures of biomass–derived ethyl levulinate and ethanol were measured using an apparatus comprising a modified Rose-Williams still and a condensation system. Measurements were taken at temperatures ranging from 329.58 K to 470.00 K and pressures of 40.0, 60.0 and 80.0 kPa. The thermodynamic consistency of the VLE data was evaluated using the Redlich-Kister area test, the Fredenslund test and the Van Ness point-to-point test. The data was correlated using three activity coefficient models: Wilson, NRTL and UNIQUAC. The Gibbs energy of mixing of the VLE data was analyzed to verify the suitability of the binary interaction parameters of these models. The activity coefficients and excess Gibbs free energy, calculated from the VLE experimental data and model correlation results, were analyzed to evaluate the models’ fit and the non–ideality of the binary system. The accuracy of the regression results was also assessed based on the root mean square deviation (RMSD) and average absolute deviation (AAD) for both temperature and the vapor phase mole fraction of ethyl levulinate. The results indicate that the NRTL model provided the best fit to the experimental data. Notably, the experimental data showed strong correlation with the predictions of all three models, suggesting their reliability for practical application. Full article

In this study, a response surface methodology (RSM) using a central composite design (CCD) was implemented to investigate the influence of process variables on ethyl levulinate (EL) production from the ethanolysis of waste corn cob samples, using sulphuric acid as a catalyst. The effects of four independent variables, namely, the temperature (A), the corn cob content (B), corn cob/H₂SO₄ mass ratio (C) and the reaction time (D) on the yields of EL (Y₁), diethyl ether (DEE) (Y₂) and solid residue (Y₃) were explored. Using multiple regression analysis, the experimental results were fitted to quadratic polynomial models. The predicted yields based on the fitted models were well within the experimental uncertainties. Optimum conditions for maximising the EL yield were found to be 176 °C, 14.6 wt. %, 21:1 and 6.75 h for A to D, respectively. A moderate-to-high EL yield (29.2%) from corn cob was achieved in optimised conditions, a result comparable to those obtained from model C₆ carbohydrate compounds. Side products were also produced, including diethyl ether, furfural, levulinic acid, 5-hydroxymethyl furfural, ethyl acetate, ethyl formate and water. Total unknown losses of only 5.69% were reported after material balancing. The results suggest that lignocellulosic waste such as corn cob can be used as a potential feedstock for the production of ethyl levulinate by direct acid-catalysed ethanolysis, but that the treatment of side products will need to be considered. Full article

In this study, the palladium-catalyzed aminocarbonylation of 1-iodoisoquinoline was accomplished in the presence of various amines. While the reactions with simple primary and secondary amines were carried out by using the well-known Pd(OAc)₂/PPh₃ catalyst, the application of amines with lower basicity (e.g., aromatic amines) or more difficult structures (e.g., amino acid methyl esters, nortropine, diethyl (α-aminobenzyl)phosphonate) required the use of bidentate XantPhos ligand to achieve complete conversion in short reaction time (2–8 h). In this way, several valuable isoquinoline-1-carboxamides were synthesized in chemoselective carbonylation and isolated in good to high yields (55–89%). Furthermore, the aminocarbonylation of the model compound in the presence of several amines was also investigated in three biomass-derived solvents (GVL, ethyl levulinate, and 2-MeTHF). After comparing the outcome of the reactions in DMF and the above green solvents, similar reactivity was observed, justifying that they could be considered a feasible alternative reaction medium. Full article

As an important biomass resource, γ-valerolactone (GVL) shows considerable potential for applications in biofuel production, organic synthesis, polymer, and food industries. Herein, an effective method was presented for synthesizing GVL through the catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) under mild conditions. Using isopropanol as a hydrogen donor, a 100% conversion of ethyl levulinate and an 88.7% yield of GVL were achieved over 2%Zr-Beta-7d catalyst at 110 °C for 8 h. The acidic sites of synthesized Zr-Beta via hydrothermal methods easily adjusted and offered high catalytic activity and selectivity. The Lewis (L) acid sites on the zeolite serve as the active centers for the conversion of EL. Characterization results indicate that the amounts of L acid sites on Zr-Beta increased with the Zr content and crystallization time rose, thus enhancing the selectivity for GVL. Additionally, the influences of catalyst dosage, reaction temperature, and time on catalytic performance are studied, as well as calculations of kinetic parameters such as reaction rate constants and activation energies. The 2%Zr-Beta-7d catalyst retains its high performance after five cycles. The current research may present an efficient approach for the conversion of EL to GVL under mild conditions. Full article

Esterification of levulinic acid with ethanol was investigated using deep eutectic systems based on choline chloride and oxalic or p-toluenesulfonic acid as catalysts under conventional heating and alternative energy inputs, namely microwave, ultrasound, and mechanochemical treatment. The experiments were performed under varying operating conditions such as catalyst type and loading, alcohol to carboxylic acid molar ratio, temperature, or time. The obtained results demonstrate the overall better catalytic performance of the p-toluenesulfonic acid-based deep eutectic mixture in comparison with the oxalic acid-based analogue. The best results: levulinic acid conversion of 76% and 58%, for p-toluenesulfonic and oxalic acid containing deep eutectic systems, respectively, with 100% selectivity for both cases, were achieved for microwave-assisted synthesis with 5 wt.% of catalyst and excess alcohol to acid (molar ratio 5), at 413.15 K and for 10 min. The main advantage of all of the alternative activation methods studied (microwaves, ultrasounds, and ball mill processing) was the significant reduction in the reaction time. Full article

This study aims to reveal the evolution mechanism of odour and taste active compounds in cooked marinated pork knuckles via typical process steps; among them, the brine soup stage was the most important part due to spices’ enriching flavours. These results revealed that the content and diversity of volatile compounds increased due to the addition of spices and heating temperature, imparting a unique aroma. Aldehydes played the main role in the overall odour. Benzaldehyde, hexanal, 1-octen-3-ol, levulinic acid, hydroxyacetone, ethyl octanoate, and 2-pentyl-furan were identified as the most important odour-active compounds. The key taste-active amino acids were glutamine, leucine, valine, and lysine. The IMP, AMP, and GMP provided a strong umami taste. Taste nucleotides and Val, Leu, Ile, and Phe were important precursor substances for aldehydes. The high responses of the electronic nose indicated that the gas component contained alkanes, alcohols, and aldehydes. The synergistic effects between umami-free amino acids and nucleotides correlated well with umami, as assessed by the electronic tongue. These results could be a starting point for the manufacturing industry, contributing to a better understanding of product performance. Full article

This work presents the synthesis and characterization of materials that contain Sn metal clusters formed by ligands of trimesic acid (Sn-BTC) or 5-sulfobenzene-1,3-dicarboxylic acid (Sn-H₃-5-SIP). These catalysts were used to convert levulinic acid with ethanol to produce ethyl levulinate under mild reaction conditions. The characterization results confirmed that Sn is mainly present in the cassiterite crystalline phase with a tetragonal rutile structure in octahedral and tetrahedral coordination in the materials. The assembly of trimesic acid (a hard base) with metal species (Sn) results in the formation of acid and thermally stable metal–organic frameworks. The use of 5-sulfobenzene-1,3-dicarboxylic acid instead of trimesic acid in the synthesis incorporates sulfonic groups in the material, enhancing the total acidity of the Sn-H₃-5-SIP catalyst compared to the Sn-BTC material. The Sn-H₃-5-SIP catalyst exhibited the highest catalytic activity when converting levulinic acid with ethanol, resulting in a turnover frequency (TOF) of 0.0495 s⁻¹, which is a 50% increase compared to the TOF of the Sn-BTC catalyst (0.0329 s⁻¹). This result can be attributed to its higher concentration of acid sites (2.23 ± 0.05 mmol H⁺/g_cat) and specific area (139 m²/g). Thus, materials containing tin metal clusters and sulfonic groups are promising materials that could be used as catalysts for synthesizing ethyl levulinate under mild reaction conditions. Full article

Methyl ethyl ketone (MEK) is among the most extensively utilized solvents in various industrial applications. In this study, we present a highly efficient synthesis route for MEK via the decarboxylation of biomass-derived levulinic acid, using potassium persulfate (K₂S₂O₈) and silver nitrate (AgNO₃) as key reagents. The specific roles of AgNO₃ and K₂S₂O₈ were thoroughly investigated. Additional silver species, such as Ag₂O and AgO, were also detected during the reaction. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses provided evidence of the evolution of solid phases throughout the reaction. Based on these findings, we propose a radical decarboxylation mechanism initiated by the generation of sulfate radicals (SO₄•⁻) through the catalytic breakdown of K₂S₂O₈ by AgNO₃. This mechanistic understanding, combined with a parametric study, enabled us to achieve an unprecedented level of levulinic acid conversion (97.9%) and MEK yield (86.6%) with this system, surpassing all previously reported results in the literature. Full article

This study presents the synthesis and characterization of mesoporous silica using biobased silica recovered from rice husks (RHs) as an excellent example of the circular economy. Distinct hydrothermal methods were used, namely, the autoclave hydrothermal method and microwave irradiation. Furthermore, the microwave-synthesized SBA-15 material was subjected to post-functionalization with –SO₃H groups using the organosilane 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (CSPTMS). The structural and chemical properties of the prepared materials were rigorously characterized through several techniques, thereby confirming the successful preparation of this functionalized material. Subsequently, the functionalized SBA-15 (CSPTMS@SBA-15) was employed as a catalyst in the synthesis of ethyl levulinate (EL) from 5-hydroxymethylfurfural (5-HMF) using different methodologies: typical high-pressure batch reactor, conventional heating, and microwave irradiation. This investigation aimed to elucidate the influence of microwave and non-microwave heating methods on the efficient conversion of 5-HMF into EL. The findings revealed that the microwave reactor exhibited superior conversion rates and selectivity when compared to the non-microwave heating methods. The study also explored the effects of temperature and utilization of various alcohols as both solvents and reagents. The results demonstrated that higher temperatures favored the production of alkyl levulinate and that complete conversion of 5-HMF was attainable for all the alcohols employed. Specifically, for methanol and ethanol a 100% yield of alkyl levulinates was achieved, while for 1-propanol and butanol a reduction in the yield of alkyl levulinates was observed. These outcomes underscore the feasibility of achieving significant yields of various alkyl levulinates through the utilization of CSPTMS@SBA-15 as a catalyst. Full article

In this work, a novel sustainable approach was proposed for the integral valorisation of Arctium lappa (burdock) seeds and roots. Firstly, a preliminary recovery of bioactive compounds, including unsaturated fatty acids, was performed. Then, simple sugars (i.e., fructose and sucrose) and phenolic compounds were extracted by using compressed fluids (supercritical CO₂ and propane). Consequently, a complete characterisation of raw biomass and extraction residues was carried out to determine the starting chemical composition in terms of residual lipids, proteins, hemicellulose, cellulose, lignin, and ash content. Subsequently, three alternative ways to utilise extraction residues were proposed and successfully tested: (i) enzymatic hydrolysis operated by Cellulases (Thricoderma resei) of raw and residual biomass to glucose, (ii) direct ethanolysis to produce ethyl levulinate; and (iii) pyrolysis to obtain biochar to be used as supports for the synthesis of sulfonated magnetic iron-carbon catalysts (Fe-SMCC) to be applied in the dehydration of fructose for the synthesis of 5-hydroxymethylfurfural (5-HMF). The development of these advanced approaches enabled the full utilisation of this resource through the production of fine chemicals and value-added compounds in line with the principles of the circular economy. Full article

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) (B. dorsalis) is an important agricultural, major invasive, and quarantine pest that can cause significant damage to the economic value of the fruit and vegetable industry. Male bait is one of the most effective methods of surveying, monitoring, and controlling B. dorsalis. In our study, we constructed cDNA libraries using total RNA extracted independently from the antennae, mouthparts, and thoracic legs of male and female adults and the ovipositors of female adults and screened out four aldehyde-oxidase-related genes (AOX-related), C58800, C66700, C67485, and C67698. Molecular docking predictions showed that eight compounds, including 3,4-dimethoxycinnamyl alcohol, 3,4-dimethoxy-cinnamaldehyde, deet, ethyl N-acetyl-N-butyl-β-alaninate, n-butyl butyrate, n-butyl butyrate, ethyl butyrate, methyl eugenol, and ethyl acetate, could combine with proteins encoded by the four B. dorsalis AOX-related genes. Furthermore, QPCR was performed to confirm that four compounds, including 3,4-dimethoxy cinnamic aldehyde, butyl levulinic acid ethyl ester (mosquito repellent), butyl butyrate, and methyl eugenol, induced significant changes in the AOX-related genes of B. dorsalis. These results provide useful information and guidance for the batch screening of potentially useful compounds and the search for effective attractants of B. dorsalis. Full article

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. Full article