MUF-n-Octadecane Phase-Change Microcapsules: Effects of Core pH and Core-Wall Ratio on Morphology and Thermal Properties of Microcapsules.

Phase change energy storage microcapsules were synthesized in situ by using melamine-formaldehyde-urea co-condensation resin (MUF) as wall material, n-octadecane (C18) as core material and styryl-maleic anhydride copolymer (SMA) as emulsifier. Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis were used to study the effects of emulsifier type, emulsifier dosage, core-wall ratio and pH on the morphology and thermal properties of microcapsules. The results show that the pH of core material and the ratio of core to wall have a great influence on the performance of microcapsules. SMA emulsifiers and MUF are suitable for the encapsulation of C18. When the pH is 4.5 and the core-wall ratio is 2/1, the latent heat and encapsulation efficiency of phase transition reaches 207.3 J g-1 and 84.7%, respectively. The prepared phase-change microcapsules also have good shape stability and thermal stability.

Structural Characteristics-Reactivity Relationships for Catalytic Depolymerization of Lignin into Aromatic Compounds: A Review.

Developing renewable biomass resources is an urgent task to reduce climate change. Lignin, the only renewable aromatic feedstock present in nature, has attracted considerable global interest in its transformation and utilization. However, the complexity of lignin's structure, uncertain linkages, stability of side chain connection, and inevitable recondensation of reaction fragments make lignin depolymerization into biofuels or platform chemicals a daunting challenge. Therefore, understanding the structural characteristics and reactivity relationships is crucial for achieving high-value utilization of lignin. In this review, we summarize the key achievements in the field of lignin conversion with a focus on the effects of the ß-O-4 content, S/G ratio, lignin sources, and an "ideal" lignin-catechyl lignin. We discuss how these characteristics influence the formation of lignin monomer products and provide an outlook on the future direction of lignin depolymerization.

Advances in Polyoxometalates as Electron Mediators for Photocatalytic Dye Degradation.

The increasing concerns over the environment and the growing demand for sustainable water treatment technologies have sparked substantial interest in the field of photocatalytic dye removal. Polyoxometalates (POMs), known for their intricate metal-oxygen anion clusters, have received considerable attention due to their versatile structures, compositions, and efficient facilitation of photo-induced electron transfers. This paper provides an overview of the ongoing research progress in the realm of photocatalytic dye degradation utilizing POMs and their derivatives. The details encompass the compositions of catalysts, catalytic efficacy, and light absorption propensities, and the photocatalytic mechanisms inherent to POM-based materials for dye degradation are exhaustively expounded upon. This review not only contributes to a better understanding of the potential of POM-based materials in photocatalytic dye degradation, but also presents the advancements and future prospects in this domain of environmental remediation.

Mechanistic Insights into the Oxidative Ring Expansion from Penicillin N to Deacetoxycephalosporin C Catalyzed by a Nonheme Iron(II) and α-KG-Dependent Oxygenase.

Deacetoxycephalosporin C synthase (DAOCS) is a nonheme iron(II) and 2-oxoglutarate (α-KG)-dependent oxygenase that catalyzes the oxidative ring expansion of penicillin N (penN) to deacetoxycephalosporin C (DAOC). Earlier reported crystal structures of DAOCS indicated that the substrate penicillin binds at the same site of succinate, leading to the proposal of the unusual "ping-pong" mechanism. However, more recent data provided evidence of the formation of ternary DAOCS·α-KG·penN complex, and thus DAOCS should follow the usual consensus mechanism of α-KG-dependent nonheme iron(II) oxygenases. Nevertheless, how DAOCS catalyzes the ring expansion is unknown. In this paper, on the basis of the crystal structure, we constructed two reactant models and performed a series of combined quantum mechanics/molecular mechanics (QM/MM) calculations to illuminate the catalysis of DAOCS. The binding mode of substrate was found to be crucial in determining which hydrogen atom in two methyl groups is first abstracted and whether the second H-abstraction to be abstracted in the final desaturation step locates in a suitable orientation. The highly reactive FeIV-oxo species prefers to abstract a hydrogen atom from one of two methyl groups in penN to trigger the ring arrangement. After the H-abstraction, the generated methylene radical intermediate can easily initiate the ring arrangement. First, the C-S bond cleaves to generate a thiyl radical, which is in concert with the formation of the terminal C═C double bond; the newly generated thiyl radical then rapidly shifts to the more stable tertiary C atom to complete ring expansion. In the final step, the FeIII-OH species abstracts the second hydrogen to give the desaturated DAOC product. During the catalysis, no active site residue is directly involved in the chemistry, which implies that the other pocket residues except the coordinate ones with iron play a role only in anchoring the substrate.

Reduction of N2O by H2 Catalyzed by Keggin-Type Phosphotungstic Acid Supported Single-Atom Catalysts: An Insight from Density Functional Theory Calculations.

In the present paper, the mechanisms of N2O reduction by H2 were systemically examined over various polyoxometalate-supported single-atom catalysts (SACs) M1/PTA (M = Fe, Co, Mn, Ru, Rh, Os, Ir, and Pt; PTA = [PW12O40]3-) by means of density functional theory calculations. Among these M1/PTA SACs, Os1/PTA SAC possesses high activity for N2O reduction by H2 with a relatively low rate-determining barrier. The favorable catalytic pathway involves the first and second N2O decomposition over the Os1/PTA SAC and hydrogenation of the key species after the second N2O decomposition. Molecular geometry and electronic structure analyses along the favorable reaction pathway indicate that a strong charge-transfer cooperative effect of metal and support effectively improves the catalytic activity of Os1/PTA SAC. The isolated Os atom not only plays the role of adsorption and activation of the N2O molecule but also works as an electron transfer medium in the whole reaction process. Meanwhile, the PTA support with very high redox stability has also been proven to be capable of transporting the electron to promote the whole reaction. We expect that our computation results can provide ideas for designing new SACs for N2O reduction by using H2 selective catalytic reduction technology.

[C_(19)-diterpenoid alkaloids from Aconitum austroyunnanense].

Eight C_(19)-diterpenoid alkaloids( 1-8) were isolated from the ethyl acetate soluble fraction of 95% ethanol extract of the ground roots of Aconitum austroyunnanense through various column chromatographies on silica gel,ODS,Sephadex LH-20 and MCI gel.Their structures were elucidated as 14α-benzoyloxy-13ß,15α-dihydroxy-1α,6α,8ß,16ß,18-pentamethoxy-19-oxoaconitan( 1),N-deethylaconitine( 2),spicatine B( 3),leucanthumsine A( 4),acofamine B( 5),macrorhynine B( 6),aconitilearine( 7),and ambiguine( 8) based on their chemical and physicochemical properties and spectroscopic data. Compound 1 was a new compound and alkaloids 2-8 were isolated from this plant for the first time. Some isolated alkaloids were tested in vitro for cytotoxic potential by employing the MTT method. As a result,alkaloid 1 exhibited weak cytotoxic activity against three tested tumor cell lines( A-549,He La,and Hep G2) with IC_(50) values less than 20 µmol·L~(-1).

Oxidative Rearrangement Mechanism of Pentalenolactone F Catalyzed by Cytochrome P450 CYP161C2 (PntM).

The CYP161C2 (PntM) from Streptomyces arenae is a member of the cytochrome P450 enzymes, which catalyzes the unusual oxidative rearrangement of pentalenolactone F (1) to the sesquiterpenoid antibiotic pentalenolactone (3). On the basis of the crystal structure of PntM bound with substrate, quantum mechanical/molecular mechanics (QM/MM) calculations have been performed to explore the detailed mechanism of PntM-catalyzed oxidative rearrangement. The conversion from pentalenolactone F (1) to pentalenolactone (3) involves the stereospecific removal of the H-1 si from 1, the syn-1,2-migration of the 2 si methyl group, and the antarafacial loss of H-3 re. The abstraction of H-1 si by Cpd I is calculated to be rate limiting with an energy barrier of 20.3 kcal/mol, which basically agrees with the estimated free energy barrier from experiments (18.6 kcal/mol). It is the unfavorable geometry of Fe-OH-C1 that blocks the oxygen rebound reaction, and the subsequent intramolecular syn-1,2-methyl migration is accompanied by an electron transfer from the substrate to the porphyrin ring via an Fe-OH group, generating the carbocation intermediate. Owing to the positive charge, the intermediate can easily lose a proton to form the final products. Our calculation results indicate that both the carboxyl group of porphyrin and Fe-OH can act as bases to accept the proton of the substrate. The target product pentalenolactone and the three isomeric byproducts correspond to four different modes of deprotonation.

[Amaryllidaceae alkaloids from Lycoris radiata].

Three aporphine-type alkaloids (1-3), three lycorine-type alkaloids (4-6), two crinane type alkaloids (7, 8) and one phenanthridine-type alkaloid (9) were isolated from the chloroform soluble fraction of 70% ethanol extract of the bulbs of Lycoris radiata through various column chromatographies over silica gel, ODS, Sephadex LH-20 and MCI. Their structures were elucidated as (+)-N-methoxylcarbonyl-1,2-methylenedioxyl-isocorydione (1), isocorydione (2), 8-demethyl-dehydrocrebanine (3), (+)-3-hydroxy-anhydrolycorine N-oxide (4), vasconine (5), pancratinine D (6), yemenine A (7), 11-O-acetylhaemanthamine (8), and 5,6-dihydro-5-methyl-2-hydroxyphenanthridine (9) based on their chemical and physicochemical properlies and spectroscopic data. Compound 1 was a new compound and alkaloids 2-9 were isolated and identified from this plant for the first time.

[Terpenoids isolated from Viburnum ternatum].

Four iridoids (1-4), five iridoid glucosides (5-9), and three triterpenoids (10-12) were isolated from the ethyl acetate soluble fraction of 70% Me2CO extract of the aerial parts of Viburnum ternatum through various column chromatographies over silica gel, ODS, Sephadex LH-20 and MCI. Their structures were elucidated as ternatumin A (1), 2,9-dioxatricyclo[4.3.1.03，7]decanes (2), 7,10,2'-triacetylsuspensolide F (3), 7,10,2',3'-tetraacetylsuspensolide F (4), viburtinoside IV (5), viburtinoside II (6), viburtinoside B (7), luzonoside A (8), luzonoside B (9), 2α,3ß,24-trihydroxy-12-ursen-28-oic acid (10), 6-hydroxy-20(29)-lupen-3-one (11), and pomalic acid (12) based on the their chromatographic properties, chemical and physicochemical methods, and spectroscopic data. Compound 1 was a new compound and compounds 3-12 were isolated from this plant for the first time. Furthermore, we note here the first isolation of compound 2 as a new natural product.

Biomedical molecular of woody extractives of Cunninghamia Lanceolata biomass.

Extractives, important compounds from wood, provide abundant resources for woody medicine. In this study, the three extractives from Cunninghamia lanceolata wood were removed by method of three-stage extraction with alcohol, petroleum ether, and alcohol/petroleum ether and their chemical components were analyzed by gas chromatography-mass spectrometry (GC-MS). Thirteen chemical components were discovered in the first-stage extractives, including: 4-((1e)-3-hydroxy-1-propenyl)-2-methoxyphenol (36.80%), α-(2-phenylethenyl)-1-piperidineacetonitrile (15.39%). One-hundred chemical components were discovered in the second-stage extractives, including: [1s-(1α,4aα,10aß)]-1, 2,3,4,4a,9,10,10a-octahydro-1,4a- dimethyl-7-(1-methylethyl)-1- phenanthrenecar-boxylic acid (15.16%), 1,3-dimethoxy-5-[(1e)-2- phenylethenyl]-benzene (6.99%). Seven chemical components were discovered in the third-stage extractives, including: 1,3-dimethoxy -5-[(1E)-2-phenylethenyl]-benzene (32.88%), stigmasta-4,6,22-trien-3α-ol (17.83%). And both the main retention time of the first-stage and which of third-stage extractives are 20-30 minutes, and the main retention time of the second-stage extractives is <10 minutes. Besides, the three extractives contained many biomedical molecular, such as [1s-(1α,4aα,10aß)]-1,2,3,4,4a,9,10,10a-octahydro-1,4a-dimethyl-7-(1-methylethyl)-1-phenanthrenecar-boxylic acid, squalene, stigmast-4-en-3-one and γ-sitosterol and so on, which means that the three extractives from Cunninghamia lanceolata wood have huge potential in biomedicine.

Sustainable depolymerization of lignin into aromatic compounds using amphiphilic Anderson-type polyoxometalate catalysts.

Lignin serves as a primary abundant source of renewable aromatic compounds. Achieving efficient breakdown of lignin and retaining its aromatic properties is highly desirable but remains a challenging task. To address this challenge, we synthesized Anderson-type polyoxometalate (POM) catalysts, particularly [CTAC]2[CoMo6]. We then investigated the effectiveness of the POM catalysts in the oxidative depolymerization of larch lignin. Under conditions of 160 °C, 1.0 MPa oxygen atmosphere, and a catalyst-to-substrate ratio of 1:5, we achieved a monomer yield of phenolic compounds at 12.43 wt%. The unsaturated coordination sites of Mo5+ within the catalysts were identified as active sites, facilitating enhanced O2 adsorption and activation. The enhanced O2 adsorption significantly influenced the production of aromatic monomers from lignin. We observed that the catalysts effectively cleaved CC bonds in ß-O-4 dimer compounds using lignin dimer model compounds. Notably, the [CTAC]2[CoMo6] catalyst exhibited excellent stability across five cycles, maintaining its high efficiency in lignin depolymerization. This indicates that Anderson-type POM-based catalysts exhibit potential for sustainable conversion of biomass into valuable compounds and for enhancing lignin valorization processes.

Ultrasound-assisted fungal self-growth and heteroatom doping for the preparation of high-performance lignocellulose-based supercapacitor electrodes.

Biomass materials are widely used as supercapacitor electrode materials due to their cost-effectiveness and eco-friendliness. In this work, ultrasound-assisted impregnation was employed for the thorough mixing of the liquid medium, and fungal treatment was conducted on the three main components of lignocellulose to prepare a fungi-modified heteroatom-doped lignocellulose-based carbon material (LCF-NP). The effects of heteroatom doping, the content of the three main components, and fungal modification on the electrochemical performance of lignocellulose-based carbon materials was investigated. The results revealed the synergistic effect of heteroatom doping and fungal treatment on the electrochemical performance. Compared with its counterpart free of fungal treatment, LCF-NP has a more reasonable pore structure and exhibits excellent electrochemical performance. LCF-NP porous carbon material has the highest specific surface area (792 m2/g), large pore volume (0.523 cm3/g), and ideal specific capacitance (1940 mF/cm2) under the conditions of 1.0 M Na2SO4 electrolyte and current density of 0.5 mA/cm2. After 10,000 cycles, there is almost no loss of capacitance. These results indicate that the joint utilization of heteroatom doping and fungal treatment has a promising application prospect in pore structure regulation and electrochemical performance improvement. This study provides a new strategy for the preparation of lignocellulose-based carbon electrode materials.

Multi-active photocatalysts of biochar-doped g-C3N4 incorporated with polyoxometalates for the high-efficient degradation of sulfamethoxazole.

Sulfamethoxazole (SMX) is one of major antibiotic contaminants in current aqueous environment. In this paper, waste loofah and melamine were co-carbonized to prepare biochar-doped g-C3N4 (CCN) by a one-pot method and then combined with Co2PMo11VO40 (CoPMoV) using a binder to obtain the novel polyoxometalates (POMs) photocatalytic composites (CCN/CoPMoV). The incorporation of CoPMoV dramatically reduced the photogenerated carrier recombination and led to a small band gap. Under visible light, the synergetic activation from biochar, g-C3N4 and POMs can remove 98.5% of SMX (k = 0.215 min-1) in the peroxymonosulfate (PMS) system within 20 min and keep its high stability with the degradation of 88.9% after five cycles. Multi-active sites from CCN/CoPMoV are contributed to develop the most active species of SO4-∙, ·OH, 1O2, and h+. The validity in the degradation of SMX makes CCN/CoPMoV a promising and potential material for the removal of aqueous pollutants in the future.

Effectiveness of Surface Treatment on Bonding Performance of Starch-Based Aqueous Polymer Isocyanate Wood Adhesive.

The surface of a bonding material plays a key role in the bonding performance of an adhesive. Herein, we evaluated the effect of substrate surface treatment methods (sandpaper polished, chemical oxidation, and coupling agent) on the adhesive properties of starch-based aqueous polymer isocyanate (API) wood adhesive during hygrothermal aging. The birch substrate was processed with three different surface treatments, and the change of surface was analyzed by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared spectroscopy (FT-IR), and Energy Dispersive Spectroscopy (EDS) methods. The results showed that the surface treatment had a great influence on the change of the shear strength of glued wood under hygrothermal conditions, and the silane coupling agent treatment could effectively reduce the decrease in the compressive shear strength of the adhesive. An XPS analysis indicated that the chemical oxidation modified wood surface polarity, and the coupling agent treatment in the wood surface formed a transition layer. After hygrothermal aging treatment, due to the different surface treatment of adhesive joint surface binding energy, the internal water absorption rate of starch-based API adhesives exhibited different failure modes of the adhesive joint. These findings indicate that the surface treatment effectively improved the durability of the adhesive joints.

Bimetallic polyoxometalates catalysts for efficient lignin depolymerization: Unlocking valuable aromatic compounds from renewable feedstock.

Lignin, a complex and abundant polymer present in lignocellulosic biomass, holds immense potential as a renewable source for the production of valuable aromatic compounds. However, the efficient depolymerization of lignin into these compounds remains a formidable challenge. Here, we present a promising solution by harnessing polyoxometalates (POMs) catalysts, which exhibit improved catalytic performance and selectivity. We synthesized a series of NixCoy@POMs catalysts (POMs: CsPW or CsPMo) and explored their application in the depolymerization of pine lignin, aiming to investigate the influence of different metal species and doping ratios of POMs on catalytic performance. Through meticulous optimization of reaction conditions, we achieved significant yields of valuable aromatic compounds, including methyl vanillate, vanillin, and 4-hydroxy-3-methoxyacetophenone. Furthermore, the Ni0.75Co0.75@CsPMo catalyst demonstrated exceptional efficacy in catalyzing the cracking process of C-C and/or C-O bonds in a ß-O-4 dimer model compound. Notably, our catalyst exhibited outstanding stability over five cycles, underscoring its suitability as an effective heterogeneous catalyst for cyclic lignin depolymerization. This study sheds light on the potential of POMs-based catalysts for advancing lignin valorization and offers new avenues for sustainable biomass conversion into valuable chemicals.

Recent Advances in Application of Polyoxometalates in Lignocellulose Pretreatment and Transformation.

Lignocellulose, composed of cellulose, hemicellulose, and lignin, holds immense promise as a renewable resource for the production of sustainable chemicals and fuels. Unlocking the full potential of lignocellulose requires efficient pretreatment strategies. In this comprehensive review, efforts were taken to survey the latest developments in polyoxometalates (POMs)-assisted pretreatment and conversion of lignocellulosic biomass. An outstanding finding highlighted in this review is that the deformation of the cellulose structure from I to II accompanied by the removal of xylan/lignin through the synergistic effect of ionic liquids (ILs) and POMs resulted in a significant increase in glucose yield and improved cellulose digestibility. Furthermore, successful integration of POMs with deep eutectic solvents (DES) or γ-valerolactone/water (GVL/water) systems has demonstrated efficient lignin removal, opening avenues for advanced biomass utilization. This review not only presents the key findings and novel approaches in POMs-based pretreatment but also addresses the current challenges and prospects for large-scale industrial implementation. By offering a comprehensive assessment of the progress in this field, this review serves as a valuable resource for researchers and industry professionals aiming to harness the potential of lignocellulosic biomass for sustainable chemical and fuel production.

Fabrication and application of amphiphilic polyoxometalate catalyst (CTA)nH5-nPMo10V2O40 for transformation of lignin into aromatic chemicals.

Conversion of renewable lignin into bio-aromatic chemicals offers a sustainable pathway to increase biorefinery profitability. However, the catalytic transformation of lignin into monomers remains a highly challenging task due to the complexity and stability of the lignin structure. In this study, a series of micellar molybdovanadophosphoric polyoxometalate (POM) catalysts, (CTA)nH5-nPMo10V2O40 (n = 1-5), were prepared by the ion exchange method and applied as oxidative catalysts for birch lignin depolymerization. These catalysts showed efficient cleavage of C-O/C-C bonds in lignin, and the introduction of an amphiphilic structure facilitated the generation of monomer products. The best catalytic activity was observed at 150 °C within 150 min under a 1.5 MPa oxygen atmosphere over (CTA)1H4PMo10V2O40, which yielded a maximum lignin oil yield of 48.7 % and lignin monomer yield of 13.5 %. We also employed phenolic and nonphenolic lignin dimer model compounds to explore the reaction pathway and demonstrated the selective cleavage of CC and/or CO lignin bonds. Moreover, these micellar catalysts have excellent recyclability and stability as heterogeneous catalysts, which can be used up to five times. The application of amphiphilic polyoxometalate catalysts facilitates the valorization of lignin, and we expect to develop a novel and practical strategy for harvesting aromatic compounds.

Research Progress on the Improvement of Flame Retardancy, Hydrophobicity, and Antibacterial Properties of Wood Surfaces.

Wood-based materials are multifunctional green and environmentally friendly natural construction materials, and are widely used in decorative building materials. For this reason, a lot of research has been carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as fire-retardancy, hydrophobicity, and antibacterial properties. To improve the performance of wood, more and more attention is being paid to the functioning of the surface. Understanding and mastering technology to improve the surface functionality of wood opens up new possibilities for developing multifunctional and high-performance materials. Examples of these techniques are ion crosslinking modification and coating modification. Researchers have been trying to make wooden surfaces more practical for the past century. This study has gradually gained popularity in the field of wood material science over the last 10 years. This paper provides an experimental reference for research on wood surface functionalization and summarizes the most current advancements in hydrophobic, antibacterial, and flame-retardant research on wood surfaces.

A Review of Composite Phase Change Materials Based on Biomass Materials.

Phase change materials (PCMs) can store/release heat from/to the external environment through their own phase change, which can reduce the imbalance between energy supply and demand and improve the effective utilization of energy. Biomass materials are abundant in reserves, from a wide range of sources, and most of them have a natural pore structure, which is a good carrier of phase change materials. Biomass-based composite phase change materials and their derived ones are superior to traditional phase change materials due to their ability to overcome the leakage of phase change materials during solid-liquid change. This paper reviews the basic properties, phase change characteristics, and binding methods of several phase change materials (polyethylene glycols, paraffins, and fatty acids) that are commonly compounded with biomass materials. On this basis, it summarizes the preparation methods of biomass-based composite phase change materials, including porous adsorption, microencapsulation based on biomass shell, and grafting by copolymerization and also analyzes the characteristics of each method. Finally, the paper introduces the latest research progress of multifunctional biomass-based composite phase change materials capable of energy storage and outlines the challenges and future research and development priorities in this field.

Rational fabrication of a new ionic imprinted carboxymethyl chitosan-based sponge for efficient selective adsorption of Gd(iii).

The selective recovery of Gd(iii) from wastewater is very meaningful for the prospective development of economics and the environment. To overcome disadvantages of poor adsorption capacity, low selectivity and complex preparation process in conventional adsorbents, herein a new ionic imprinted carboxymethyl chitosan (CMC) sponge functionalized by hyperbranched polyethyleneimine (PEI) with a 3D network structure (PEI-CMC-IIS) was successfully prepared and applied in the selective adsorption of Gd(iii). The PEI-CMC-IIS is endowed with lots of amino groups due to the combination of biomass CMC with highly branched PEI, which is helpful for the adsorption of Gd(iii). The imprinting sites are located at the surface of channels in PEI-CMC-IIS, which can achieve the adsorption specificity to Gd(iii) and improve adsorption capacity. It is found that the maximum adsorption capacity of PEI-CMC-IIS is 38.64 mg g-1 at pH = 7. Meanwhile, the selectivity tests suggest that the PEI-CMC-IIS presents preferential adsorption for Gd(iii) with a distribution coefficient of 437.5 mL g-1. Furthermore, the PEI-CMC-IIS displays excellent reusing and regeneration ability. Our findings will bring about potential application in fabrication of other high-efficiency adsorbents for selective adsorption of Gd(iii).