Unsaturated Groups Research Articles

Sustainable production of 2,5-diformylfuran via peroxymonosulfate-triggered mild catalytic oxidation of lignocellulosic biomass

Abstract The relentless depletion of fossil fuels accentuates the urgent necessity for the sustainable synthesis of chemicals from renewable biomass. 5-Hydroxymethylfurfural (HMF), extracted from lignocellulosic biomass, emerges as a beacon of hope for conversion into value-added chemicals. However, the inherent susceptibility of its unsaturated aldehyde groups to excessive oxidation often culminates in undesired reactions, compromising both the yield and specificity of the desired products. Here, we introduce a holistic methodology for the cost-effective and ecologically responsible generation of 2,5-diformylfuran (DFF), through the heterogeneously catalyzed oxidation of HMF utilizing peroxymonosulfate (PMS) under benign conditions. This strategy, characterized by the meticulous enhancement of surface ketone groups via a mixed-salt co-pyrolysis technique, achieves an unparalleled selective activation of PMS, engendering singlet oxygen to catalyze the oxidation of HMF into DFF with a selectivity surpassing 80%. Life cycle assessments underscore a negligible impact on human health, ecosystems, and natural resources, endorsing the holistic utilization of biomass. This integration of pyrolysis for the creation of functional carbonaceous materials within biomass conversion processes significantly enhances sustainability and economic viability, whilst paving new pathways for selective biomass oxidation and the production of high-value chemicals.

Boosting Adsorption and Selectivity of Acetylene by Nitro Functionalisation in Copper(II)-Based Metal-Organic Frameworks.

Purification and storage of acetylene (C2H2) are important to many industrial processes. The exploitation of metal -organic framework (MOF) materials to address the balance between selectivity for C2H2 vs carbon dioxide (CO2 ) against maximising uptake of C2H2 has attracted much interest. Herein, we report that the synergy between unsaturated copper (II) sites and functional groups, fluoro (-F), methyl (-CH3), nitro (-NO2) in a series of isostructural MOF materials MFM-190(R) that show exceptional adsorption and selectivity of C2H2 . At 298 K, MFM-190(NO2) exhibits an C2H2 uptake of 216 cm3 g-1 (320 cm3 g-1 at 273 K ) at 1.0 bar and a high selectivity for C2H2/CO2 (up to ~150 for v/v = 2/1) relevant to that in the industrial cracking stream. Dynamic breakthrough studies validate and confirm the excellent separation of C2H2/CO2 by MFM-190(NO2) under ambient conditions. In situ neutron powder diffraction reveals the cooperative binding, packing and selectivity of C2H2 by unsaturated Cu(II) sites and free -NO2 groups.

Boosting Adsorption and Selectivity of Acetylene by Nitro Functionalisation in Copper(II)‐Based Metal‐Organic Frameworks

Purification and storage of acetylene (C2H2) are important to many industrial processes. The exploitation of metal –organic framework (MOF) materials to address the balance between selectivity for C2H2 vs carbon dioxide (CO2 ) against maximising uptake of C2H2 has attracted much interest. Herein, we report that the synergy between unsaturated copper (II) sites and functional groups, fluoro (‐F), methyl (‐CH3), nitro (‐NO2) in a series of isostructural MOF materials MFM‐190(R) that show exceptional adsorption and selectivity of C2H2 . At 298 K, MFM‐190(NO2) exhibits an C2H2 uptake of 216 cm3 g−1 (320 cm3 g−1 at 273 K ) at 1.0 bar and a high selectivity for C2H2/CO2 (up to ~150 for v/v = 2/1) relevant to that in the industrial cracking stream. Dynamic breakthrough studies validate and confirm the excellent separation of C2H2/CO2 by MFM‐190(NO2) under ambient conditions. In situ neutron powder diffraction reveals the cooperative binding, packing and selectivity of C2H2 by unsaturated Cu(II) sites and free ‐NO2 groups.

Waste lithium-ion batteries for selective transfer hydrogenation of bio-based ethyl levulinate: Experiments, kinetics and economic assessment

The present research firstly developed the waste lithium-ion batteries as heterogenous catalysts for catalytic upgrading of bio-based ethyl levulinate (EL) into γ-valerolactone (GVL) using 2-propanol as both the hydrogen source and solvent. The existing acid and basic sites in waste lithium-ion batteries significantly favored the MPV reduction of bio-based EL, wherein 87.4 % GVL yield and low activation energy of 35.2 kJ/mol were achieved. Furthermore, the waste lithium-ion batteries contributed to H-transfer upgrading of a variety of building blocks containing unsaturated groups, such as aldehydes and esters. More gratifyingly, the economic assessment demonstrated that EL-to-GVL transformation via H-transfer manner was preferred as compared with the traditional hydrogenation, in which the total cost for converting 1 kg EL declined by 10.58 $ and overall profit increased by 12.35 $. In addition, the plausible mechanism for H-transfer upgrading of EL into GVL over waste lithium-ion batteries was proposed.

СУЛЬФУВАННЯ ТРИГЛЦЕРИДІВ НЕНАСИЧЕНИХ ЖИРНИХ КИСЛОТ ДЛЯ ОДЕРЖАННЯ ПОВЕРХНЕВО-АКТИВНИХ РЕЧОВИН

The paper describes the preparation of surface-active substances by sulfonation of unsaturated groups that are present in the composition of molecules of fatty unsaturated acids of triglycerides. Sunflower oil, chosen for its renewable and vegetable-based origin, served as the primary raw material. The method for producing sulfonated derivatives of fatty acid triglycerides is detailed, and the structures of the resulting products were verified using IR spectroscopy. We have demonstrated the effective surfactant properties of the compounds obtained by dispersing hydrophobic substances in an aqueous environment.

Room‐Temperature Synthesis, Characterization, and Protonation of Two Zinc Phthalocyanines With Unsaturated Groups

ABSTRACTTo explore the room‐temperature synthesis of metal phthalocyanines with unsaturated substituents, two zinc phthalocyanines with unsaturated alkoxy groups were synthesized in a reaction system composed of 4‐citronellol‐oxy‐phthalonitrile or 4‐geraniol‐oxy‐phthalonitrile, Zn(OAc)2⋅2H2O, DBU, and ethanol, at room temperature. The synthetic reactions lasted for 7 days and the yields of two phthalocyanine derivatives reached 21% and 18%, respectively, and they are inclined to protonation in a non‐coordinated organic solvent, for example, CHCl3. By the way, the phthalocyanine compounds with other metals, such as Cu, Ni, and Co, cannot be prepared. This work will provide preference for improving the synthetic method in the future, so as to synthesize many new phthalocyanine compounds in general laboratories.

Gas-phase preparation of silylacetylene (SiH3CCH) through a counterintuitive ethynyl radical (C2H) insertion.

Elementary reaction mechanisms constitute a fundamental infrastructure for chemical processes as a whole. However, while these mechanisms are well understood for second-period elements, involving those of the third period and beyond can introduce unorthodox reactivity. Combining crossed molecular beam experiments with electronic structure calculations and molecular dynamics simulations, we provide compelling evidence on an exotic insertion of an unsaturated sigma doublet radical into a silicon-hydrogen bond as observed in the barrierless gas-phase reaction of the D1-ethynyl radical (C2D) with silane (SiH4). This pathway, which leads to the D1-silylacetylene (SiH3CCD) product via atomic hydrogen loss, challenges the prerequisite and fundamental concept that two reactive electrons and an empty orbital are required for the open shell, unsaturated radical reactant to insert into a single bond.

Sulfur-bridged bis(2-indenyl) zirconocenes and their performance in olefin polymerization

A series of sulfur-bridged bis(2-indenyl) zirconocenes were synthesized and tested for ethylene/1-octene co- polymerization and 1-decene oligomerization. Zirconocene bearing two 5,6-positioned methyl substituents in indenyl moieties, distant from the metal center, appeared to be an active catalyst producing 1-decene oligomers with high content of unsaturated vinylidene end groups, which is preferable for post-functionalization.

Gold Catalysts for Selective Hydrogenations: The Role of Heterolytic H2 Dissociation

AbstractHydrogenations are fundamental transformations in organic synthesis, and the industrial applications span from food, petrochemical, fine chemicals to pharmaceuticals synthesis where hydrogenations of multifunctional molecules should be carried out in a chemoselective way. In this concept article we aim at providing an overview on the activation of molecular hydrogen (H2) via heterolytic dissociation, which is responsible to unlock high activity of gold catalysts for chemoselective hydrogenations. The key benefit of heterolytically dissociated H species is their preference for hydrogenating polar unsaturated groups like C=O, C=N, and C=S, as these polar bonds are ideal acceptors for proton and hydride pairs. We will provide examples on how to obtain enhanced chemoselectivity on alkynes, α, β‐unsaturated aldehydes and nitro‐compounds hydrogenations with gold catalysts.

A clean and novel drying method for bamboo colorization and in-situ surface wax utilization

Round bamboo is considered an environmentally friendly product, with surface color crucial to its value. Surface wax is crucial for the growth and development of bamboo, but can alter the color of round bamboo and easily detach under the influence of heat and humidity, leading to uneven colorization. By controlling the drying temperature at 90 ℃, the surface wax can be uniformly levelled on the bamboo’s surface, enhancing its color to a consistent deep red. Chromaticity measurements show L* values between 29.58 and 34.68 and a* values from 5.58 to 6.04 at 90 ℃. DSC test shows that the wax completely melted and levelled evenly at 90 ℃, solidifying uniformly on the bamboo surface upon drying, thus realising in-situ utilization of the wax. FTIR, GC-MS and XPS analyses reveal that drying at 90 ℃ leads to an increase in chromogenic substances within the wax and bamboo green, along with heightened intensity of unsaturated functional groups, and deepening of surface color, ultimately achieving the colorization of the round bamboo. Furthermore, the prepared round bamboo exhibits excellent pencil hardness (5 H), adhesion, and glossiness (5.38 GU), while maintaining its mechanical properties. This innovative method integrates drying, colorization, and wax utilization in one step, offering a novel strategy for enhancing round bamboo’s quality.

Comparison of Pb adsorption and transformation behavior induced by chicken manure and its DOM in contaminated soil

Organic fertilizer derived from animal manure can significantly improve soil fertility. However, limited research has investigated the capacity of exogenous organic fertilizer dissolved organic matter (DOM) to migration and transform heavy metals. In this study, the effect of chicken manure organic fertilizers with different maturity and their DOM on changes of Pb bioactivity was evaluated and the role of soil environmental factors driving the changes was determined through soil incubation, adsorption and leaching experiments. The FTIR results indicated that DOM derived from farmhouse chicken manure organic fertilizer (FCMD) contained more protein-like compounds and low maturity, while DOM from commercial chicken manure organic fertilizer (CCMD) contained more humic/fulvic acid and high maturity. FCMD and CCMD reduced the content of RES-Pb by 16.3–27.52 % and 6.66–13.98 %, respectively. And the effects of organic fertilizers and their DOM on Pb migration and activation follow the order of FCMD> CCMD> CK> commercial chicken manure organic fertilizer (CCM)> farmhouse chicken manure organic fertilizer (FCM). FTIR analysis showed that FCMD was primarily composed of aromatic unsaturated functional groups, and its adsorption capacity for Pb2+ was significantly lower than that of FCM. In addition, the application of FCMD significantly altered the physicochemical properties of soil and promoted the migration and leaching of Pb. FCMD not only causes the soil Pb2+ to be released into the effluent but also activates Pb from the stable form into the active form. In summary, animal manure with lower maturity has a risk to activate heavy metals and should be applied with cautions.

Harnessing the synergistic power of lignin-Ecoflex blends for enhanced performance in food packaging

In this study, a two-step chemical modification method was applied to lignin, enabling the thermal blending of lignin and Ecoflex® (PBAT) to produce films for food packaging applications. In the first step, 90 % of phenolic and carboxylic acid groups were converted into aliphatic hydroxy groups via hydroxyethylation, and in the second step, the aliphatic hydroxy groups were esterified with cinnamic acid, introducing abundant phenyl rings as well as unsaturated groups to the polymer. The modified lignin possessed an aliphatic–aromatic structure, similar to Ecoflex®, thereby enhancing the potential miscibility between these two materials. Subsequent experiments revealed that adding 20 % of modified lignin into Ecoflex® film resulted in the most significant improvement in mechanical properties, tripling the stiffness and doubling the strength. The addition of 30 % of modified lignin showed the best outcomes in UV absorption, barrier properties against oxygen and water vapor, and anti-oxidation ability. A strawberry ripening test indicated that the Ecoflex® film containing 30 % of modified lignin extended the shelf-life of strawberries from 2 days to 7 days, with better performance than the results of polyethylene bags and pure Ecoflex® films.

A convenient strategy for mitigating microplastics in wastewater treatment using natural light and ZnO nanoparticles as photocatalysts: A mechanistic study

Polypropylene microplastics (PPMPs) are one of the major emerging contaminants in the ecosystem due to their frequent usage and improper disposal practices. These PPMPs enter ecosystems via wastewater effluent plants and cause severe environmental health issues. In addition, quantifying PPMPs smaller than 50 μm in wastewater plant extraction is very difficult. Thus, the current study was designed to mitigate the PPMPs using zinc oxide nanoparticles (ZnONPs) as a photocatalyst under sunlight. The photocatalytic reaction was examined using spectroscopic techniques and microscopic imaging. The findings indicated that the weight loss percentage of PPMPs increased, and a decrease in UV–Vis DRS peak intensities was observed. The spectroscopic results elucidated the formation of free radicals, which affect the PPMPs and lead to the formation of carbonyl, allylic, and unsaturated groups. Further, EDS reports clarified that there is increased oxygen content due to the photooxidation process and the disintegration of the polymer chain owing to decreased carbon levels. Overall, ZnO photocatalyst absorbs photons from the visible spectrum of sunlight and forms free radicals, which affect the PPMPs to initiate polymer deterioration. Also, the current study revealed the mechanistic pathway of PPMP degradation under the photocatalytic reaction as proposed in the results obtained above.

Construction of MIL-100(Fe)-DMA material for efficient adsorption of Sr and Cs ions from radioactive wastewater

A novel metal-organic framework (MOF) material, MIL-100(Fe)-DMA, was synthesized using the solvothermal method. The structure of the MOF was characterized using scanning electron microscopy-energy dispersive X-ray spectroscopy, N2 adsorption–desorption isotherms, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy. Batch adsorption experiments were performed to investigate the effects of initial Sr2+ and Cs+ concentrations, adsorption time, pH, and coexisting cations on the adsorption performance of the material. The adsorption mechanism was further elucidated using adsorption kinetics and isotherm models. The results indicated that the adsorption of Sr2+ and Cs+ does not significantly affect the MOF material structure. As reaction time and initial ion concentration increased, the adsorption capacity of MIL-100(Fe)-DMA for Sr2+ and Cs+ increased rapidly and then gradually reached equilibrium. Optimal adsorption occurred under alkaline conditions, with maximum adsorption capacity observed at pH = 8. The adsorption process for Sr2+ and Cs+ was well described by the pseudo-second-order kinetic model, the Weber–Morris model, and the Langmuir adsorption isothermal model. The adsorption process was mainly identified as monolayer chemical adsorption, influenced by multiple factors. Characterization combined with density functional theory calculations revealed that the unsaturated carboxylic acid groups on the surface of the MOFs play a crucial role in the interaction with Sr2+ and Cs+.

Correlation between AFM characterizations and dynamic mechanical testing to assess the ductile-to-brittle transition during ABS photodegradation

The extensive use of Acrylonitrile Butadiene Styrene (ABS) raises challenges due to its vulnerability to oxidative degradation, primarily impacting its mechanical behavior. Photodegradation appears to be the pivotal driver in this degradation process. The main aim of the present study is to provide a comprehensive approach to the underlying mechanisms governing the transition from ductile to brittle behavior in ABS after exposure to UV-induced photodegradation. This study thus focuses on the multiphase nature of ABS, wherein polybutadiene (PB) nodules are dispersed within a matrix of styrene-acrylonitrile. Dynamic mechanical tensile tests have been employed to highlight aged layer mechanical impact by blocking the dissipative response of the matrix and applying a homogenous stress field, while atomic force microscopy (AFM) has been used to characterize the local mechanical properties of ABS finely. The evolution of global mechanical properties has been correlated with changes in microstructural behavior. One of the main contributions of the present work is the correlation between the formation of brittle layers with the brittle state of aged ABS. Mechanical testing using dynamical tensile test revealed a critical aging time marking the transition from a ductile to a brittle state of the 450 µm thick samples. Chemical analysis using infrared spectroscopy revealed evolutions in the material composition, especially in the carbonyl, hydroxyl, and PB unsaturation groups. Distinct thin oxidized layers on each exposed surface were observed using optical microscopy. Finally, AFM analysis on the exposed surface shows the stiffening of PB nodules, indicating the formation of brittle thin layers due to oxidation causing an apparent fragile behavior of ABS.

Effect of reactive fumes suppressant DOPO on the chemical composition and performance of asphalt

9,10-Dihydro-9-oxa-10-phosphorophenanthrene-10-oxide (DOPO), recognized for its role as an efficacious fume suppressant, has been shown to mitigate the emission of noxious vapors emanating from asphalt. However, the comprehensive influence of DOPO on the composition and properties of asphalt had remained unexplored. This study embarked on an in-depth examination of the effects of various DOPO dosages on the chemical composition of asphalt, employing hydrogen nuclear magnetic resonance spectroscopy (1H NMR) alongside an exhaustive analysis of asphalt components. Furthermore, the investigation elucidated the consequences of different DOPO dosages on the physical, rheological properties, and aging resistance of asphalt. The results of 1H NMR and component analysis of asphalt disclosed that DOPO engaged in chemical reactions with the unsaturated groups within the asphalt, catalyzing a metamorphosis of saturates into aromatics and resins. Such chemical transformations were instrumental in augmenting the softening point, viscosity, and rutting propensity of the asphalt while imposing a minimal impact on its penetration and ductility. Post exposure to the thin film oven test (TFOT), pressure aging vessel (PAV), and ultraviolet (UV) aging, the DOPO modified asphalt (DMA) exhibited a diminution in the increment of softening point and viscosity aging index relative to the control asphalt. Furthermore, the DMA showcased enhanced retention rates of penetration and ductility, coupled with substantially reduced shifts in complex modulus and phase angle post-aging, underlining its superior aging resistance. Fourier transform infrared spectroscopy analysis revealed a comparatively slower rate of change in carbonyl and sulfoxide groups in DMA after aging, as opposed to the control asphalt. Notably, DMA exhibited enhanced resistance to UV aging relative to TFOT and PAV aging scenarios, a trait attributable to remarkable UV absorption capabilities of DOPO. Fundamentally, DOPO enhanced the high-temperature performance and aging resistance of asphalt while simultaneously diminishing the emission of noxious fumes.

Pd0–Ov–Ce3+ Interfacial Sites with Charge Redistribution for Enhanced Hydrogenation of Methyl Oleate to Methyl Stearate

Improving the efficiency of metal/reducible metal oxide interfacial sites for hydrogenation reactions of unsaturated groups (e.g., C=C and C=O) is a promising yet challenging endeavor. In our study, we developed a Pd/CeO2 catalyst by enhancing the oxygen vacancy (OV) concentration in CeO2 through high-temperature treatment. This process led to the formation of an interface structure ideal for supporting the hydrogenation of methyl oleate to methyl stearate. Specifically, metal Pd0 atoms bonded to the OV in defective CeO2 formed Pd0–OV–Ce3+ interfacial sites, enabling strong electron transfer from CeO2 to Pd. The interfacial sites exhibit a synergistic adsorption effect on the reaction substrate. Pd0 sites promote the adsorption and activation of C=C bonds, while OV preferably adsorbs C=O bonds, mitigating competition with C=C bonds for Pd0 adsorption sites. This synergy ensures rapid C=C bond activation and accelerates the attack of active H* species on the semi-hydrogenated intermediate. As a result, our Pd/CeO2-500 catalyst, enriched with Pd0–OV–Ce3+ interfacial sites, demonstrated excellent hydrogenation activity at just 30 °C. The catalyst achieved a Cis–C18:1 conversion rate of 99.8% and a methyl stearate formation rate of 5.7 mol/(h·gmetal). This work revealed the interfacial sites for enhanced hydrogenation reactions and provided ideas for designing highly active hydrogenation catalysts.

3D-printed nanocomposites filled with untreated and surface-modified PTFE powders treated by a Na-naphthalene-system

This study focuses on the mechanical properties of DLP/LCD-type 3D-printed nanocomposites comprised of polyester acrylate resin with DPGDA reactive diluent filled with untreated PTFE and surface-modified PTFE powders by the Na-Naphtalenide system. To obtain the nanocomposites, untreated and surface-modified PTFE powders were incorporated into the resin systems at loading ratios ranging from 1% to 6%. The X-ray photoelectron spectroscopy (XPS) data following the Na-naphthalene system treatment demonstrated the existence of functional groups such as OH, carbonyl, and C=C unsaturation groups on the surface of the untreated PTFE powders. The study showed improvements for the nanocomposites obtained through a DLP/LCD type 3D printer up to a certain ratio in terms of tensile strength, Young's modulus, Izod impact resistance, and Shore D hardness values. Evaluating the promising samples, the nanocomposites with surface-modified PTFE powders of 2% and 1% showed increases of 5.1% and 7.6% in ultimate tensile strength and Izod impact resistance compared to the unfilled polyester acrylate sample. On the other hand, the nanocomposite with untreated PTFE powders of 1% only showed increases of 2.4% and 3.2% in ultimate tensile strength and Izod impact resistance. Moreover, Young’s modulus showed less decrease for surface-modified PTFE-filled nanocomposites.

The introduction of rich active sites on 0D@2D nanocarbon via light illuminating with high-efficient electrocatalytic H2O2 production

Two-dimensional (2D) carbon-based materials are high-quality electrocatalytic materials with high mass transfer interfaces. However, the intrinsic 2D surfaces often lack of abundant active sites and outstanding electron transport channels. Herein, a 0D@2D nanocarbon material with affluent unsaturated oxygen-containing groups (UOCGSs) active sites and excellent electron channels are constructed via a novel sodium ion-capping and light illuminating strategy. With the aid of the light illuminating, the final 0D@2D product exhibits a superior practical H2O2 production rate of up to 1109 mmol·gcatalyst−1 h−1 with a high level of onset potential 0.78V and 94 % H2O2 selectivity in H-cell. This improved performance arises from the introduction of UOCGSs and excellent charge transfer on the 0D@2D interface. Obviously, this work exhibits a new green stagey for the design of 0D@2D carbon-based structure via light illuminating.

A Sterically Accessible Monomeric Stibine Oxide Activates Organotetrel(IV) Halides, Including C-F and Si-F Bonds.

Phosphine oxides and arsine oxides are common laboratory reagents with diverse applications that stem from the chemistry exhibited by these monomeric species. Stibine oxides are, in contrast, generally dimeric or oligomeric species because of the reactivity-quenching self-association of the highly polarized stiboryl (Sb=O/Sb+-O-) group. We recently isolated Dipp3SbO (Dipp = 2,6-diisopropylphenyl), the first example of a kinetically stabilized monomeric stibine oxide, which exists as a bench-stable solid and bears an unperturbed stiboryl group. Herein, we report the isolation of Mes3SbO (Mes = mesityl), in which the less bulky substituents maintain the monomeric nature of the compound but unlock access to a wider range of reactivity at the unperturbed stiboryl group relative to Dipp3SbO. Mes3SbO was found to be a potent Lewis base in the formation of adducts with the main-group Lewis acids PbMe3Cl and SnMe3Cl. The accessible Lewis acidity at the Sb atom results in a change in the reactivity with GeMe3Cl, SiMe3Cl, and CPh3Cl. With these species, Mes3SbO formally adds the E-Cl (E = Ge, Si, C) bond across the unsaturated stiboryl group to form a 5-coordinate stiborane. The biphilicity of Mes3SbO is sufficiently potent to activate even the C-F and Si-F bonds of C(p-MeOPh)3F and SiEt3F, respectively. These results mark a significant contribution to an increasingly rich literature on the reactivity of polar, unsaturated main-group motifs. Furthermore, these results highlight the utility of a kinetic stabilization approach to access unusual bonding motifs with unquenched reactivity that can be leveraged for small-molecule activation.