Search Results (74)

Alkyn-1,2-diones have gained great attention as useful building blocks in organic synthesis. Regioselective synthetic routes towards 3,5-disubstituted isoxazoles, containing the methylfuroyl or diterpenylfuroyl moiety at the C-3 or C-5 position from alkyne-1,2-diones 1, 2, 3, are reported. The reaction with hydroxylamine hydrochloride 6 in ethanol afforded the 1,2-addition products: 5-aryl-3-(methylfuran-2-carbonyl)isoxazoles (yield 61–94%) or 16-(5-arylisoxazole-3-carbonyl)labdatrienes (yield 48–97%). The reaction of alkynediones 1–3 with 6 in THF in the presence of triethylamine led to 5-hydroxy-4,5-dihydroisoxazoles and subsequent dehydration afforded regioisomeric 3-aryl-5-(methylfuran-2-carbonyl)isoxazoles or 16-(3-arylisoxazole-5-carbonyl)labda-trienes (yield 65–98%). New heterocyclic compounds exhibited significant analgesic action in acetic acid writhing and hot-plate tests, and the activity was comparable to reference drugs diclofenac sodium and celecoxib. Isoxazoles, which possessed the most analgesic activity, reduced the concanavalin A-induced inflammation by 34–51%; the effect was comparable to the drug indomethacin. The results of in vitro biological assays (MTT test) revealed that isoxazoles were non-toxic against the normal epithelial VERO cells, and 16-(3-aryl-5-hydroxyisoxazoline-5-carbonyl)labdatrienes 20–24 exhibited selective cytotoxicity against the breast adenocarcinoma MCF 7 (GI₅₀ = 4.7–8.3 μM) and cervical cancer cells C33 A (GI₅₀ = 3.4–4.7 μM). Molecular docking analysis to determine the binding potential of new molecules to the active site of human COX-1 and COX-2 enzymes was conducted. Full article

3-Acetyl-1-propanol (3-AP) is a key intermediate in the pharmaceutical and pesticide industries, which can be synthesized from the biomass derivative 2-methylfuran (2-MF) through a one-step hydrogenation process with significant economic and environmental benefits. Zeolite-supported metal catalysts showed feasible application, but simply regulating the acidic sites was difficult to break the activity–selectivity balance. Traditional single-metal Pd-based catalysts still suffer from low dispersion. This study constructed the PdZn/TS-1 catalyst for the efficient conversion of 2-MF into 3-AP. The low electronegativity of Zn facilitates the electron transfer from Zn to Pd, forming an electron-rich Pd active center. A small amount of Zn embedded in the Pd lattice causes lattice contraction, optimizing the spatial configuration of active sites. The synergy between the electronic and structural effects significantly improves catalytic performance. Under optimized conditions, the conversion rate of 2-MF reached 80.6%, and the yield of 3-AP reached 69.1%, providing a new paradigm for the design of catalysts for the directed hydrogenation of furan derivatives. Full article

The flavor and aroma of kiwifruit are largely influenced by the concentration of Volatile Organic Compounds (VOCs). To analyze the volatile profiles and identify characteristic aroma compounds, this study utilized Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) to analyze the aromatic compounds sourced from seven major production regions in China and New Zealand, covering red-, green-, and yellow-fleshed varieties. A total of 77 VOCs were identified, with esters, aldehydes, and ketones as the dominant classes. Significant regional and varietal differences were observed: red-fleshed kiwifruits from Yunnan exhibited high levels of 2-Vinyl-5-methylfuran, Ethyl formate, and 1-Penten-3-one; green-fleshed fruits from Shaanxi were rich in Limonene and Methyl hexanoate, and those from Yunnan were rich in 1-Propanol and 1-Hexanol; and yellow-fleshed fruits from Henan were characterized by Methyl salicylate and 3-Hydroxy-2-butanone. Orthogonal partial least squares discriminant analysis (OPLS-DA) successfully classified kiwifruits by origin and variety, confirming the stability and predictive power of the model (Q2Y > 0.97). This study also elucidated the key metabolic pathways—including lipid oxidation, amino acid degradation, and terpenoid metabolism—underlying the formation of these characteristic VOCs. These findings provide a theoretical foundation for the biochemical regulation of kiwifruit flavor and support the development of origin-tracing and quality-assessment tools based on VOC fingerprints. Full article

Biodiesel and 2-methylfuran (MF) exhibit significant potential as alternative fuels due to advancements in their production techniques. Despite this potential, the low cetane number (CN) of biodiesel–MF (BMF) blends limits their practical use in diesel engines due to poor auto-ignition characteristics and extended ignition delays. This study addresses this issue by investigating the impact of the cetane improver 2-ethylhexyl nitrate (2-EHN) on the performance and emissions of a BMF30 blend. The blend consists of 70% biodiesel and 30% MF, with 2-EHN added at concentrations of 1% and 1.5% to enhance ignition properties. The experiments were conducted on a four-cylinder, four-stroke, direct-injection compression ignition (DICI) engine at a constant speed of 1800 rpm with brake mean effective pressures (BMEP) ranging from 0.13 to 1.13 MPa. The results showed that 2-EHN improved the CN of the BMF30 blend, leading to earlier combustion initiation and longer combustion duration. At low BMEP (0.13 MPa), 2-EHN increased the peak rate of heat release and in-cylinder pressure, whereas at higher BMEP (0.88 MPa), these parameters decreased. The key findings include a reduction in brake-specific fuel consumption (BSFC) by 5.49–7.33% and an increase in brake thermal efficiency (BTE) by 3.30–4.69%. Additionally, NOx emissions decreased by 9.4–17.48%, with the highest reduction observed at 1.5% 2-EHN. CO emissions were reduced by 45.1–85.5% and soot emissions also declined. Hydrocarbon (HC) emissions decreased by 14.56–24.90%. These findings demonstrate that adding 2-EHN to BMF30 blends enhances engine performance, reduces key emissions, and offers a promising alternative fuel for diesel engines. Full article

Biomass, as a renewable carbon resource, holds broad application prospects. Among various bio-based platform molecules, furan derivatives play a significant role in green chemical production. Notably, the conversion of 2-methylfuran (2-MF) to 3-acetyl-1-propanol (3-AP) over bifunctional catalysts has attracted considerable interest. In this study, a Pd@PHZSM-5 catalyst was prepared by encapsulating Pd nanoparticles within P-doped HZSM-5 for 2-MF conversion. The encapsulation improved Pd dispersion and metal–acid synergy, enhancing both catalytic activity and 3-AP selectivity. Additionally, phosphorus doping increased HZSM-5 crystallinity, resulting in excellent stability. This work provides a feasible strategy for optimizing metal–acid cooperation, offering theoretical guidance for bifunctional catalysis and biomass valorization. Full article

With the advancement of new synthetic techniques, 5-Methyl-2-ethylfuran (5-MEF) has emerged as a promising renewable biofuel. In this study, the potential energy surfaces for the unimolecular dissociation reaction, H-addition reaction, and H-abstraction reaction of 5-MEF were mapped at the CBS-QB3 level. The temperature- and pressure-dependent rate constants for these reactions on the potential energy surfaces were determined by solving the master equation, using both transition state theory and Rice–Ramsperger–Kassel–Marcus theory. The results showed that the dissociation reaction of the C(6) site on the branched chain of 5-MEF has the largest rate constant and is the main decomposition pathway, while the dissociation reaction of the H atom on the furan ring has a lower rate constant and is not the main reaction pathway. In addition, the dissociation of H atoms on the branched chain and intramolecular H-transfer reactions also have high-rate constants and play an important role in the decomposition of 5-MEF. H-addition reactions mainly occur at the C(2) and C(5) sites, and the generation of the corresponding products through β-breakage becomes the main reaction pathway. With the increase in temperature, the H-addition reaction at the C(2) site gradually changes to a substitution reaction, dominating the formation of C₂H₅ and 2-methylfuran. Full article

The effects of furfural and 5-methyl-2-furfural produced by the Maillard reaction on PhIP formation were investigated in chemical models and roasted pork patties. In the chemical models, the results indicated that increasing levels of furfural (r = −0.7338, R² = 0.9557) and 5-methyl-2-furfural (r = −0.7959, R² = 0.9864) significantly reduced PhIP formation, displaying a strong linear correlation. The effects of furfural and 5-methyl-2-furfural on the precursors of phenylalanine (Phe) and phenylacetaldehyde showed a significant reduction in the Phe level, while the level of phenylacetaldehyde was not increased. In addition, neither furfural nor 5-methyl-2-furfural could significantly reduce creatinine or PhIP. Further mechanism studies showed that furfural (5-methyl-2-furfural) directly captured Phe to form the corresponding Schiff base compounds a (2-((furan-2-ylmethylene) amino)-3-phenylpropanoic acid) and b (2-(((5-methylfuran-2-yl)methylene)amino)-3-phenylpropanoic acid). This process reduced the production of phenylacetaldehyde, thereby inhibiting the PhIP formation pathway. More importantly, these two compounds were detected in roasted pork patties to which glucose was added. The above pathway was finally confirmed in roasted pork patties. These results revealed that furfural and 5-methyl-2-furfural, formed during the Maillard reaction, play a significant role in inhibiting the formation of PhIP by reacting with Phe. Full article

In this work, a new methodology for dispersing metal particles supported in clay has been described. For this purpose, a sepiolite has been modified by a microwave-assisted treatment to increase the surface area and pore volume due to the progressive leaching of the Mg²⁺-species located in the octahedral sheet. These materials have been used as support to incorporate Cu species on the surface by a precipitation-deposition process from the thermal decomposition of urea at 95 °C. Once calcined and reduced, the Cu-based catalysts showed a Cu⁰-particle size lower than 5 nm in the case of catalysts whose support is a sepiolite subjected to acid treatment. On the other hand, when raw sepiolite is used as a support, the Cu⁰-crystal size is much larger (15–20 nm). This difference in Cu⁰-crystal size showed a variable catalytic behavior for the hydrogenation reaction of furfural in gas-phase. Catalysts with larger particle size promote the hydrogenation reaction, obtaining a yield towards furfuryl alcohol close to 60% after 5 h at 190 °C. In contrast, catalysts with smaller particle size promote the hydrogenation reaction and subsequently the hydrogenolysis reaction, obtaining methylfuran as a product with a yield of 58% after 1 h of reaction at 190 °C; however, the sites where hydrogenolysis are involved are more prone to be deactivated. Full article

2-Methylfuran (2-MF) has emerged as a promising renewable alternative fuel, primarily due to its sustainable production processes and its potential to significantly reduce soot emissions. However, when blended with diesel, it presents challenges, including an increase in NOx emissions, which is attributed to the lower cetane number (CN) of the M30 blend. This study investigates the effect of adding 2-ethylhexyl nitrate (2-EHN), a cetane enhancer, to the M30 blend (30% 2-MF by volume), on combustion characteristics and exhaust emissions. Experiments were conducted using a modified four-cylinder, four-stroke, direct-injection compression ignition (DICI) engine featuring a common rail fuel injection system. The engine was evaluated under different load conditions, with brake mean effective pressure (BMEP) ranging from 0.13 to 1.13 MPa, while maintaining a constant engine speed of 1800 rpm. The incorporation of 1.5% and 2.5% 2-EHN into the M30 blend enhanced combustion performance, as indicated by a reduction in the maximum pressure rise rate, a shorter ignition delay (ID), and an extended combustion duration (CD). Furthermore, the brake-specific fuel consumption (BSFC) reduced by 2.78% and 5.7%, while the brake thermal efficiency (BTE) increased by 3.54% and 7.1%, respectively. Moreover, the inclusion of 2-EHN led to a significant reduction in Nox by 9.20–17.57%, with the most significant reduction observed at a 2.5% 2-EHN, where hydrocarbon (HC) decreased by 7.93–21.59%, and carbon monoxide (CO) reduced by 12.11–33.98% as compared to the M30 blend without 2-EHN. Although a slight increase in soot emissions was observed with higher concentrations of 2-EHN, soot levels remained significantly lower than those from pure diesel. The results indicate that the addition of 2-EHN can effectively mitigate the trade-off between NOx and soot emissions in low cetane number oxygenated fuels. Full article

Polyols such as 1,5-pentadiol, 1,6-hexanediol, and 1,2,6-hexanetriol are crucial chemicals, traditionally derived from non-renewable fossil sources. In the pursuit of sustainable development, exploring renewable and environmentally benign routes for their production becomes imperative. Furfural and 5-hydroxymethylfurfural are C₅ and C₆ biomass-derived platform molecules, which have potential in the synthesis of various polyols through hydrogenation and hydrogenolysis reactions. Currently, there is an extensive body of literature exploring the transformation of biomass-derived furan compounds. However, a comprehensive review of the transformation of furan compounds to polyols is lacking. We summarized the literature from recent years about the ring-opening reaction involved in converting furan compounds to polyols. This article reviews the research progress on the transformation of furfural, furfuryl alcohol, and 2-methylfuran to 1,2-pentadiol, 1,4-pentadiol, 1,5-pentadiol, and 1,2,5-pentanetriol, as well as the transformation of 5-hydroxymethylfurfural to 1,2-hexanediol, 1,6-hexanediol, and 1,2,6-hexanetriol. The effects of the supported Pd, Pt, Ru, Ni, Cu, Co, and bimetallic catalysts are discussed through examining the synergistic effects of the catalysts and the effects of metal sites, acidic/basic sites, hydrogen spillover, etc. Reaction parameters like temperature, hydrogen pressure, and solvent are considered. The ring opening catalytic reaction of furan rings is summarized, and the catalytic mechanisms of single-metal and bimetallic catalysts and their catalytic processes and reaction conditions are discussed and summarized. It is believed that this review will act as a key reference and inspiration for researchers in this field. Full article

Environmental contamination with xenobiotics affects organisms and the symbiotic relations between them. A convenient object to study relationships between parasites and their hosts is the host–parasite system “Tenebrio molitor Linnaeus, 1758 (Coleoptera, Tenebrionidae)—Gregarina polymorpha (Hammerschmidt, 1838) Stein, 1848 (Eugregarinorida, Gregarinidae)”. For this experiment, we took 390 T. molitor larvae and 24 organic compounds. Groups of mealworms, 15 in each, were subjected to those compounds for 10 days. Then, we recorded the vitality of both the larvae of T. molitor and G. polymorpha. To assess how G. polymorpha had affected the hosts’ wellbeing, we looked for changes in the larvae’s body mass and compared them to the number of gregarines in their intestines. The vitality of the larvae was inhibited by cyclopentanol and 2-naphthol. The intensity of gregarine invasion was reduced by diphenyl ether, benzyl alcohol, catechol, and 3-aminobenzoic acid. No effect on the number of gregarines was produced by 3,4,5-trihydroxybenzoic acid, cyclohexanemethanol, phenol, benzalkonium chloride, maleic anhydride, cyclohexanol, resorcin, benzoic acid, 2-methylfuran, terpinen-4-ol, 1-phenylethylamine, dibutyl phthalate, 3-furancarboxylic acid, 5-methyl furfural, 6-aminohexanoic acid, succinic anhydride, o-xylene, and benzaldehyde. In the infected T. molitor individuals, the mean number of G. polymorpha equaled 45 specimens per host. The groups of smaller mealworms had fewer gregarines. Positive correlation was seen between growth rates of T. molitor larvae and the intensity of invasion by gregarines. Full article

2-methylfuran is a significant organic chemical raw material which can be produced by hydrolysis, dehydration, and selective hydrogenation of biomass hemicellulose. 2-methylfuran can be converted into value-added chemicals and liquid fuels. This article reviews the latest progress in the synthesis of liquid fuel precursors through hydroxyalkylation/alkylation reactions of 2-methylfuran and biomass-derived carbonyl compounds in recent years. 2-methylfuran reacts with olefins through Diels–Alder reactions to produce chemicals, and 2-methylfuran reacts with anhydrides (or carboxylic acids) to produce acylated products. In the future application of 2-methylfuran, developing high value-added chemicals and high-density liquid fuels are two good research directions. Full article

Longjing tea is favored by consumers due to its refreshing and delicate aroma, as well as its fresh and sweet flavor. In order to study the processing technology of Longjing tea with ‘Baiye 1’ tea varieties, solid phase microextraction and gas chromatography–mass spectrometry were used to analyze the volatile components of Longjing tea in different process stages. The results revealed the identification of 275 aroma metabolites in the processing samples of Longjing tea. The sensory evaluation and principal component analysis revealed that the leaves of fresh (XY) and spreading (TF) were different from the leaves of first panning (YQ), second panning (EQ), final panning (HG), and fragrance enhancing (TX). The relative contents of geraniol (1199.95 and 1134.51), linalool (745.93 and 793.98), methyl salicylate (485.22 and 314.67), phenylethyl alcohol (280.14 and 393.98), 2-methylfuran (872.28 and 517.96), 2-butenal (56.01 and 154.60), and 2-hexenal (46.22 and 42.24), refreshing and floral substances in the XY and TF stages, were higher than other stages. The aroma contents of 2-methylfuran, furfural, 2-methyl-1-penten-3-one, 3-hexen-2-one, dodecane, hexanoyl hexanoate, 2,5-dimethyl-pyrazine, and methyl-pyrazine were found to be significantly positively correlated with the intensity of chestnut aroma. In conclusion, this study contributes to a better understanding of the composition and formation mechanism of chestnut-like aroma and provides new insights into the processing technology to improve the quality of albino green tea. Full article

Lignocellulosic biomass can uptake CO₂ during growth, which can then be pyrolysed into three major products, biochar (BC), syngas, and bio-oil. Due to the presence of oxygenated organic compounds, the produced bio-oil is not suitable for direct use as a fuel and requires upgrading via hydrodeoxygenation (HDO) and hydrogenation. This is typically carried out over a supported metal catalyst. Regarding circular economy and sustainability, the BC from the pyrolysis step can potentially be activated and used as a novel catalyst support, as reported here. A 15 wt% Ni/BC catalyst was developed by chemically modifying BC with sulfuric acid to improve mesoporous structure and surface area. When compared to the pristine Ni/BC catalyst, sulfuric activated Ni/BC catalyst has excellent mesopores and a high surface area, which increases the dispersion of Ni nanoparticles and hence improves the adsorptive effect and thus catalytic performance. A liquid phase hydrogenation of furfural to 2-methylfuran was performed over the developed 15 wt% Ni/BC catalyst. Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic type models for adsorption of dissociative H₂ were screened based on an R² value greater than 99%, demonstrating that the experimental data satisfactorily fit to three plausible models: competitive (Model I), competitive at only one type of adsorption site (Model II), and non-competitive with two types of adsorption sites (Model III). With a correlation coefficient greater than 99% between the experimental rates and the predicted rate, Model III, which is a dual-site adsorption mechanism involving furfural adsorption and hydrogen dissociative adsorption and surface reaction, is the best fit. The Ni/BC catalyst demonstrated comparative performance and significant cost savings over previous catalysts; a value of 24.39 kJ mol⁻¹ was estimated for activation energy, −11.43 kJ mol⁻¹ for the enthalpy of adsorption for H₂, and −5.86 kJ mol⁻¹ for furfural. The developed Ni/BC catalyst demonstrated excellent stability in terms of conversion of furfural (96%) and yield of 2-methylfuran (54%) at the fourth successive experiments. Based on furfural conversion and yield of products, it appears that pores are constructed slowly during sulfuric acid activation of the biochar. Full article

Furan and its derivatives are found in various heat-treated foods. Furan is classified as a possible human carcinogen. The European Union authorities recommend collecting data on the occurrence of these compounds, estimating consumer exposure, and taking measures to protect human health based on a scientific risk assessment. The aim of this study was to estimate the exposure of infants and toddlers to furan and its methyl derivatives—2-methylfuran, 3-methylfuran, and ∑2,5-dimethylfuran/2-ethylfuran—present in home-prepared foods and to characterize the associated health risks. The compounds of interest were determined using the HS-GC/MS. The risk was characterized by the calculation of the margin of exposure (MoE). Levels of furan and its derivatives in analyzed samples were in the range of <LOD ÷ 10 µg/kg and <LOD ÷ 80.3 µg/kg, respectively. The MoEs for neoplastic effects in most of the presumed scenarios indicate a risk associated with the intake of analyzed compounds in both age groups (MoE < 10,000; 331 to 6354 for 95th percentile, 3181–39,033 for median). The MoEs for non-neoplastic effects indicate a potential risk associated with the intake of 3-methylfuran and Σ2,5-dimethylfuran/2-ethylfuran for high exposure (95th percentile) only (MoE < 100; 16–47). The obtained results indicate the need for further research in this area. Full article