Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in br...Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in broad-spectrum(UVA and UVB)sunscreens.It could be partially and selectively acetylated in a simple,fast,and more reliable process.In this work,a composite film was prepared with UV-resistant properties through a casting method.Bio-based cellulose acetate(CA)was employed as a major matrix while nano-acetylated kraft lignin(AL-NPs)was used as filler during synthesizing UV-shielding films loaded with various amounts(1–5 wt.%)of AL-NPs.Kraft lignin was acetylated through a simple and fast microwave-assisted process using acetic acid as a solvent and acetylating agent.The physicochemical and morphological characteristics of the prepared films were evaluated using different methods,including scanning electron microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),X-ray diffraction analysis(XRD),mechanical testing and contact angle measurement.The UV-Vis spectroscopy optical investigation of the prepared films revealed that AL-NPs in the CA matrix showed strong UV absorption.This feature demonstrated the effectiveness of our research in developing UV-resistant bio-based polymer films.Hence,the prepared films can be considered as successful candidates to be applied in packaging applications.展开更多
Two novel substituted phenyl isoxazole benzoxazine formamide derivatives were designed and synthesized with substituted o-aminophenol,1,2-dibromoethane and different phenyl substituted isoxazole formyl chloride as the...Two novel substituted phenyl isoxazole benzoxazine formamide derivatives were designed and synthesized with substituted o-aminophenol,1,2-dibromoethane and different phenyl substituted isoxazole formyl chloride as the raw materials via microwave assistant synthesis.The target compounds were characterized by IR,^(1)H NMR,^(13)C NMR and HRMS.Both single-crystal structures were further determined by X-ray diffraction.3-(2’-Chloro-6’-fluoro-phenyl)-4-(2’,3’-dihydro-1’,4’-benzoxazine)-5-methyl-isoxazole formamide (4a) crystallizes in orthorhombic system,P2_(1) space group with a=8.9414(18),b=10.834(2),c=17.706(4)A,V=1715.1(6)A^(3),D_(c)=1.444 Mg/m^(3),Z=4,F(000)=768,μ(Mo Kα)=0.255 mm^(-1),R=0.0406 and wR=0.1171.3-Phenyl-4-(6-methyl-2’,3’-dihydro-1’,4’-benzoxazine)-5-methyl-isoxazole formamide (4b) is of triclinic system,space group PI with a=7.7659(16),b=8.3626(17),c=13.484(3)A,α=76.04(3)°,β=100.63(3)°,γ=82.01(3)°,V=841.6(3)A^(3),D_(c)=1.319 Mg/m^(3),Z=2,F(000)=352,μ(Mo Kα)=0.090 mm^(-1),R=0.0672 and wR=0.2671.Both crystals are packed through C–H···O hydrogen bonding interaction.There is C–H···F hydrogen bond between 4a molecules,and C–H···N between 4b molecules.Bioassay results showed that compounds 4a and 4b exhibited detoxification on maize and restored maize growth index.展开更多
At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a ...At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a microwave-assisted fast synthesis approach to obtain a Sm^(3+)-activated borotellurate Na_(2)Y_(2)TeO_(4)(BO_(3))_(2)(NYTB)red phosphor with high crystallinity,excellent thermostability,and low chromaticity shift.For the NYTB-based phosphor,in contrast to the conventional solid-state synthesis,the microwave-assisted synthesis method involves lower synthesis temperature and shorter processing time.Additionally,the concentration quenching mechanism was determined.The w-LED device packaged with the studied phosphor exhibits a near-standard white light with proper CCT and high Ra parameters.展开更多
Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to ...Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to study its effect on the oxidation resistance, apparent porosity, bulk density, elastic modulus, and modulus of rupture. It is found that Al_(4)SiC_(4) can be synthesized by microwave sintering at 1 300 ℃ and the addition of Al_(4)SiC_(4)-containing material as an antioxidant can enhance the oxidation resistance of the magnesia carbon refractory brick.展开更多
This paper describes mass-based energy phase-space projection of microwave-assisted synthesis of transition metals (zinc oxide, palladium, silver, platinum, and gold) nanostructures. The projection uses process energy...This paper describes mass-based energy phase-space projection of microwave-assisted synthesis of transition metals (zinc oxide, palladium, silver, platinum, and gold) nanostructures. The projection uses process energy budget (measured in kJ) on the horizontal axes and process density (measured in kJg−1) on the vertical axes. These two axes allow both mass usage efficiency (Environmental-Factor) and energy efficiency to be evaluated for a range of microwave applicator and metal synthesis. The metrics are allied to the: second, sixth and eleventh principle of the twelve principle of Green Chemistry. This analytical approach to microwave synthesis (widely considered as a useful Green Chemistry energy source) allows a quantified dynamic environmental quotient to be given to renewable plant-based biomass associated with the reduction of the metal precursors. Thus allowing a degree of quantification of claimed “eco-friendly” and “sustainable” synthesis with regard to waste production and energy usage.展开更多
Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge....Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.展开更多
Fe-N-C endowed with inexpensiveness,high activity,and excellent anti-poisoning power have emerged as promising candidate catalysts for oxygen reduction reaction(ORR).Single-atom Fe-N-C electrocatalysts derived from Fe...Fe-N-C endowed with inexpensiveness,high activity,and excellent anti-poisoning power have emerged as promising candidate catalysts for oxygen reduction reaction(ORR).Single-atom Fe-N-C electrocatalysts derived from Fe-doped ZIF-8 represent the top-level ORR performance.However,the current fabrication of Fe-doped ZIF-8 relies on heavy consumption of time,energy,cost and organic solvents.Herein,we develop a rapid and solvent-free method to produce Fe-doped ZIF-8 under microwave irradiation,which can be easily amplified in combination with ball-milling.After rational pyrolysis,Fe-N-C catalysts with atomic FeN4 sites well dispersed on the hierarchically porous carbon matrix are obtained,which exhibit exceptional ORR performance with a half-wave potential of 0.782 V(vs.reversible hydrogen electrode(RHE))and brilliant methanol tolerance.The assembled direct methanol fuel cells(DMFCs)endow a peak power density of 61 mW cm^(-2) and extraordinary stability,highlighting the application perspective of this strategy.展开更多
Two-dimensional(2D)transition metal borides(MBenes)have emerged as a rising star and hold great potential promise for catalysis and metal ion batteries owing to a well-defined layered structure and ex-cellent electric...Two-dimensional(2D)transition metal borides(MBenes)have emerged as a rising star and hold great potential promise for catalysis and metal ion batteries owing to a well-defined layered structure and ex-cellent electrical conductivity.Unlike well-studied graphene,perovskite and MXene materials in various fields,the research about MBene is still in its infancy.The inadequate exploration of efficient etching methods impedes their further study.Herein,we put forward an efficient microwave-assisted hydrother-mal alkaline solution etching strategy for exfoliating MoAlB MAB phase into 2D MoB MBenes with a well accordion-like structure,which displays a remarkable electrochemical performance in sodium ion batter-ies(SIBs)with a reversible specific capacity of 196.5 mAh g^(-1)at the current density of 50 mA g^(-1),and 138.6 mAh g^(-1)after 500 cycles at the current density of 0.5 A g^(-1).The underlying mechanism toward excellent electrochemical performance are revealed by comprehensive theoretical simulations.This work proves that MBene is a competitive candidate as the next generation anode of sodium ion batteries.展开更多
The increasing global demand for clean and potable water underscores the need for advanced pollutant remediation technologies in wastewater,such as the degradation of azo dyes,which are known to be harmful to human he...The increasing global demand for clean and potable water underscores the need for advanced pollutant remediation technologies in wastewater,such as the degradation of azo dyes,which are known to be harmful to human health.To address this issue,heterogeneous photocatalysis emerges as a promising strategy for breaking down recalcitrant molecules.However,efforts are required to develop efficient and stable photocatalysts capable of operating under visible light.This study explores the photocatalytic potential of Fe-doped RE_(2)Zr_(2)O_(7-δ)(RE=Pr,Sm,Nd,Y)compositions,synthesized through the microwaveassisted solvothermal method,for the degradation of methylene blue.Characterizations,such as X-ray diffraction(XRD)and Raman spectroscopy,reveal the obtention of single-phase ordered pyrochlore for RE=Pr,Sm and Nd or defect fluorite structures for Y.Photocatalytic tests under visible light demonstrate efficient dye degradation for all Fe-doped samples,Y_(2)Zr_(1.9)Fe_(0.1)O_(6.95)(YZF)defect fluorite being the one that exhibits the highest efficiency.Radical scavenging experiments identify hydroxyl radicals as key contributors to the degradation process,along with photoinduced holes.These materials exhibit minimal leaching of iron ions,confirming their stability,and the best material,YZF,demonstrates effective reusability.The results highlight the potential of Fe-doped RE_(2)Zr_(2)O_(7)compositions as an efficient alternative for application as photocatalysts for the degradation of azo dyes under visible light.展开更多
In order to optimize the microwave-assisted extraction technology of polyphenols from Loropetalum chinense （R. Br.） Oliv., the effects of microwave power, ethanol concentration, solid to liquid ratio and extraction ...In order to optimize the microwave-assisted extraction technology of polyphenols from Loropetalum chinense （R. Br.） Oliv., the effects of microwave power, ethanol concentration, solid to liquid ratio and extraction time on polyphenols extraction rate were investigated. On the basis of single-factor test, a four-factor and three-level orthogonal test was designed by response surface method to establish a mathematical model between the response value and various factors. The results showed that the intensity of effect of different influencing factor on polyphenols ex- traction rate ranked as microwave power＇s〉solid to liquid ratio＇s〉extraction time＇s〉 ethanol concentration＇s. The optimum microwave-assisted extraction conditions for polyphenols from L. chinense were as follows： extraction power 254 W, ethanol concentration 60%, extraction time 12.5 rain and solid to liquid ratio 1：17. Under the optimum extraction conditions, the extraction rate of polyphenols from L. chinense was 19.17%.展开更多
Microwave-assisted rock-breaking technology,as a novel hybrid approach,is anticipated to facilitate the efficient excavation of complex rock formations.It is therefore crucial to understand the damage and failure mech...Microwave-assisted rock-breaking technology,as a novel hybrid approach,is anticipated to facilitate the efficient excavation of complex rock formations.It is therefore crucial to understand the damage and failure mechanisms of rocks that have been subjected to irradiation.In this study,uniaxial compression experiments were conducted on granite specimens after 1.4 kW microwave irradiation for varying durations.Furthermore,a numerical method was proposed to solve electromagnetic-thermal-mechanical coupling problems by integrating finite and discrete elements.The results demonstrated a differential temperature distribution(high temperature in the middle and low-temperature areas at the ends)in the granite specimens under microwave irradiation,which resulted in a notable reduction in their physical and mechanical properties.As the duration of irradiation increased,the rate of heating and the extent of strength reduction both diminished,while the morphology and distribution of cracks at ultimate failure became increasingly complex.The numerical method effectively addresses the simulation challenges associated with the electromagnetic selective heating of granite containing multiple polar minerals under microwave irradiation.This approach accounted for the non-uniform thermal expansion of the minerals and provided a comprehensive model of damage progression under compression.展开更多
Designing catalysts with high reaction efficiency is essential for reducing heavy metal Cr(VI)ions in wastewater via microwave induction.In this paper,a unique microwave-responsive lychee-like Ni/C/ZnFe_(2)O_(4) compo...Designing catalysts with high reaction efficiency is essential for reducing heavy metal Cr(VI)ions in wastewater via microwave induction.In this paper,a unique microwave-responsive lychee-like Ni/C/ZnFe_(2)O_(4) composite catalyst with a double-shell hollow porous heterojunction structure was constructed for the efficient reduction of Cr(VI).Benefiting from the novel hollow porous structure and“carbon nanocage”structure of the Ni/C/ZnFe_(2)O_(4),coupled with excellent electromagnetic wave absorption ability,the prepared lychee-like Ni/C/ZnFe_(2)O_(4) com-posite catalyst could remove up to 98%of Cr(VI)(50 mg L 1,50 mL)after 40 min of microwave irradiation,even in nearly neutral water conditions.Additionally,density functional theory calculations indicated that the heterojunction interface between Ni/C and ZnFe_(2)O_(4) enhances electron transfer from ZnFe_(2)O_(4) to Ni/C,ultimately facilitating the removal of Cr(VI).Furthermore,the incorporation of Ni/C facilitated the 2 acceleration of H ion transfer to*Cr_(2)O_(7),thereby expediting the conversion kinetics of the latter.This research aims to establish a theoretical and experimental foundation for the effective and stable microwave-assisted catalytic reduction of heavy metal Cr(VI)ions,presenting new insights and methods to combat heavy metal contamination.展开更多
The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concen...The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concentration of ethanol, ammonia and cation (M+), pH of extraction solution, different kinds of organic solvent etc. The results show that 50%-60%(v/v) ethanol can reach high percentage extraction of GA. If 1% (v/v) ammonia solution was added into 60%(v/v) ethanol, the percentage extraction can be increased from 2.0% to 2.31%. Without ammonia, 50mmol/L [M+] (M+ = K+, NH4+) was added into 60%(v/v) ethanol, percentage extraction of GA can reach about 2.26%. If pH of solution (60% ethanol) was adjust to pH=4.0, it can reach high percentage extraction. If pH of solution (60% ethanol + 50mmol [M+], pH=6.1) was adjust tO PH=4.0, especially M+ is K+ or NH4+, it can reach almost same extraction efficiency as that of 1% ammonia solution + 60% ethanol, and the operation environment can be greatly improved.展开更多
An optimized approach for the synthesis of N^1-ethoxymethyl-substituted cyclic inosine diphosphoribose（cIDPRE）,an analogue of cyclic adenosine diphosphoribose（cADPR）,has been developed via microwave-assisted intra...An optimized approach for the synthesis of N^1-ethoxymethyl-substituted cyclic inosine diphosphoribose（cIDPRE）,an analogue of cyclic adenosine diphosphoribose（cADPR）,has been developed via microwave-assisted intramolecular cyclization. The target compound has been successfully obtained through N^1-substitution,phosphorylation,cyclization and deprotection.By using this method,8-amino and bromo-substituted cIDPRE analogues were successfully obtained in good yield.The new approach has greatly shortened the synthetic route and enhanced the overall efficiency.展开更多
Microwave heating contributes to coal fracturing and gas desorption. However, problems of low penetration depth, local overheating and fracture closure exist. Coal demineralisation by acids has advantages in coal unbl...Microwave heating contributes to coal fracturing and gas desorption. However, problems of low penetration depth, local overheating and fracture closure exist. Coal demineralisation by acids has advantages in coal unblocking and permeability improvement, while it is difficult for acid to enter microcracks.Microwave-asisted acidification may offer an alternative. In this work, XRD,^(1)H-NMR, and SEM were used to evaluate the effect of microwave-assisted acidification on the microstructure of coal. Results show that kaolinite, calcite, and dolomite can be dissolved by acid. After microwave irradiation, the graphitization of microcrystalline structure of carbon improves. Microwave-assisted acidification erodes minerals in coal and enhances the graphitization degree of microcrystalline structure. Compared to individual microwave irradiation or acidification, the pore volume and pore connectivity can be greatly enhanced by microwave-assisted acidification. The NMR permeability of coal increased by 28.05%. This study demonstrates the potential of microwave-assisted acidification for coalbed methane recovery.展开更多
A highly active ZrO x /ZnO catalyst for microwave-assisted photocatalytic （MW/PC） degradation of endocrine disruptor dimethyl phthalate （DMP） has been prepared via cetyltrimethylammonium assisted hydrothermal meth...A highly active ZrO x /ZnO catalyst for microwave-assisted photocatalytic （MW/PC） degradation of endocrine disruptor dimethyl phthalate （DMP） has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrO x /ZnO was characterized by XPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences （＋2, ＋3, ＋4） co-existed in ZrO x /ZnO. By using the ZrO x /ZnO （0.1 g）, the TOC removal efficiency of DMP （100 mL of 50 mg/L） was 88% after 30 min reaction, which was about 15% higher than P25 TiO 2 . It was found that the removal process of DMP by MW/PC followed pseudo first-order kinetics in all cases, and ZrO x /ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP was shortened 45% compared with P25 TiO 2 . A possible catalytic mechanism was proposed based on microwave response and interfacial charge transfer. ZrO x /ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insights into designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation.展开更多
The microwave-assisted method was used to extract polysaccharides from solanum nigrum. The optimum experimental parameters, mechanism of the extraction and the effect of microwave-assisted extraction process on the st...The microwave-assisted method was used to extract polysaccharides from solanum nigrum. The optimum experimental parameters, mechanism of the extraction and the effect of microwave-assisted extraction process on the structures of polysaccharides were investigated. The extract was analyzed by the modified phenol-sulfuric acid method at 490nm. The optimum experimental parameters were obtained by orthogonal experiments as follows: extraction time 15min, microwave radiation power 455W and the process ratio of materials mass to solvent volume 1∶20. The results show that compared with the conventional reflux extraction, the microwave-assisted extraction has a higher yield in shorter time, with no effect on the finally obtained polysaccharides as seen from the FT-IR spectra. The scanning electron microscopy images reveal that the mechanism of the extraction is related to the structural changes of the plant cells in different extracting conditions.展开更多
Microwave-assisted extraction （MAE） of isoflavones from Belamcanda chinensis was studied using ethanol as the solvent. The single factor experiment and the orthogonal method were used to optimize the MAE condition. ...Microwave-assisted extraction （MAE） of isoflavones from Belamcanda chinensis was studied using ethanol as the solvent. The single factor experiment and the orthogonal method were used to optimize the MAE condition. It was concluded that two doses of intermittent microwave power radiation, 300 W each for 4 rain, were needed for extraction. The mass ratio of solvent to material was 8：1 and the alcohol mass fraction was 80%. The extracted liquor was then concentrated under vacuum and degreased with petroleum ether. The yield of total isofiavones was about 8.8% and the contents of tectoridin and iridin were 67.6% and 16.3% respectively. Compared with direct-heating extraction （DHE）, MAE may shorten extracting duration, reduce solvent consumption, and improve yield and purity of isoflavones from Belamcanda chinensis.展开更多
Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved b...Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved by soaking the sample with 70% methanol（1∶15,v/v）for 30 min,and then microwave irradiation for 11 min at a power of 600 W.Coupling the extraction process with HPLC-fluorescence presented good recovery,satisfactory precision,and good linear relation.Compared with a method from the Chinese Pharmacopoeia,the proposed method enables higher extraction efficiency and more accurate analytical results.It can be of potential value in quality assessment of Radix Puerariae thomsonii medicinal materials.展开更多
Hydrothermal methods are widely used in chemical synthesis of target products with specific morphology and nanostructure.Those methods are very efficient for the preparation of well-controlled structures but the react...Hydrothermal methods are widely used in chemical synthesis of target products with specific morphology and nanostructure.Those methods are very efficient for the preparation of well-controlled structures but the reaction time is usually long.The assistance of microwave makes the reaction system heat up faster,more uniformly and reactions are accelerated,it also can be utilized to change the morphology or structure of materials,which improves the physic-chemical properties of synthesized products and influences its gas-sensing performance.Copper oxide(CuO)is widely applied in semiconductor gas sensors because of its good reactivity and stability.This review article briefly introduces the principle,mechanism and recent development of CuO nanostructures obtained by microwave-as sis ted hydrothermal synthesis(MWHS)process.It also discussed the relation between endopathic factors of material and its gas-sensitive performance.The technical challenges and prospective solutions for highperformance CuO-based gas-sensitive materials with unique nanostructure are proposed.It is pointed out that the hierarchical CuO-based nanostructures and their composite materials prepared by MWHS process are efficacious methods to improve the gas-sensitive performance of the materials.On the basis of the morphology,the materials are divided into nanorods,nanoflowers,nanosheets,nanospheres and other nanostructures.The influence of microwave parameters on the properties of synthetic products is analyzed.The influence followed by metal element loading on the structure and properties of CuO-based materials by MWHS process is further discussed.Then this review summarizes the research progress of graphene-CuO and metal oxide-CuO composites prepared by MWHS process in recent years.展开更多
文摘Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in broad-spectrum(UVA and UVB)sunscreens.It could be partially and selectively acetylated in a simple,fast,and more reliable process.In this work,a composite film was prepared with UV-resistant properties through a casting method.Bio-based cellulose acetate(CA)was employed as a major matrix while nano-acetylated kraft lignin(AL-NPs)was used as filler during synthesizing UV-shielding films loaded with various amounts(1–5 wt.%)of AL-NPs.Kraft lignin was acetylated through a simple and fast microwave-assisted process using acetic acid as a solvent and acetylating agent.The physicochemical and morphological characteristics of the prepared films were evaluated using different methods,including scanning electron microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),X-ray diffraction analysis(XRD),mechanical testing and contact angle measurement.The UV-Vis spectroscopy optical investigation of the prepared films revealed that AL-NPs in the CA matrix showed strong UV absorption.This feature demonstrated the effectiveness of our research in developing UV-resistant bio-based polymer films.Hence,the prepared films can be considered as successful candidates to be applied in packaging applications.
基金the National Natural Science Foundation of China(No.31801784 and 31572042)Undergraduate SIPT program of Northeast Agricultural University(No.202010224112)。
文摘Two novel substituted phenyl isoxazole benzoxazine formamide derivatives were designed and synthesized with substituted o-aminophenol,1,2-dibromoethane and different phenyl substituted isoxazole formyl chloride as the raw materials via microwave assistant synthesis.The target compounds were characterized by IR,^(1)H NMR,^(13)C NMR and HRMS.Both single-crystal structures were further determined by X-ray diffraction.3-(2’-Chloro-6’-fluoro-phenyl)-4-(2’,3’-dihydro-1’,4’-benzoxazine)-5-methyl-isoxazole formamide (4a) crystallizes in orthorhombic system,P2_(1) space group with a=8.9414(18),b=10.834(2),c=17.706(4)A,V=1715.1(6)A^(3),D_(c)=1.444 Mg/m^(3),Z=4,F(000)=768,μ(Mo Kα)=0.255 mm^(-1),R=0.0406 and wR=0.1171.3-Phenyl-4-(6-methyl-2’,3’-dihydro-1’,4’-benzoxazine)-5-methyl-isoxazole formamide (4b) is of triclinic system,space group PI with a=7.7659(16),b=8.3626(17),c=13.484(3)A,α=76.04(3)°,β=100.63(3)°,γ=82.01(3)°,V=841.6(3)A^(3),D_(c)=1.319 Mg/m^(3),Z=2,F(000)=352,μ(Mo Kα)=0.090 mm^(-1),R=0.0672 and wR=0.2671.Both crystals are packed through C–H···O hydrogen bonding interaction.There is C–H···F hydrogen bond between 4a molecules,and C–H···N between 4b molecules.Bioassay results showed that compounds 4a and 4b exhibited detoxification on maize and restored maize growth index.
基金Project supported by the National Natural Science Foundation of China(22165031,21761034)NationalUndergraduate Innovation and Entrepreneurship Foundation(202210673034)Scientific Research Foundation of Education Departmentof Yunnan province(2022Y001)。
文摘At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a microwave-assisted fast synthesis approach to obtain a Sm^(3+)-activated borotellurate Na_(2)Y_(2)TeO_(4)(BO_(3))_(2)(NYTB)red phosphor with high crystallinity,excellent thermostability,and low chromaticity shift.For the NYTB-based phosphor,in contrast to the conventional solid-state synthesis,the microwave-assisted synthesis method involves lower synthesis temperature and shorter processing time.Additionally,the concentration quenching mechanism was determined.The w-LED device packaged with the studied phosphor exhibits a near-standard white light with proper CCT and high Ra parameters.
基金This work was funded by Luoyang Major Science and Technology Innovation Project(2301009A)Henan Province Key Research and Development Project(231111230200)。
文摘Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to study its effect on the oxidation resistance, apparent porosity, bulk density, elastic modulus, and modulus of rupture. It is found that Al_(4)SiC_(4) can be synthesized by microwave sintering at 1 300 ℃ and the addition of Al_(4)SiC_(4)-containing material as an antioxidant can enhance the oxidation resistance of the magnesia carbon refractory brick.
文摘This paper describes mass-based energy phase-space projection of microwave-assisted synthesis of transition metals (zinc oxide, palladium, silver, platinum, and gold) nanostructures. The projection uses process energy budget (measured in kJ) on the horizontal axes and process density (measured in kJg−1) on the vertical axes. These two axes allow both mass usage efficiency (Environmental-Factor) and energy efficiency to be evaluated for a range of microwave applicator and metal synthesis. The metrics are allied to the: second, sixth and eleventh principle of the twelve principle of Green Chemistry. This analytical approach to microwave synthesis (widely considered as a useful Green Chemistry energy source) allows a quantified dynamic environmental quotient to be given to renewable plant-based biomass associated with the reduction of the metal precursors. Thus allowing a degree of quantification of claimed “eco-friendly” and “sustainable” synthesis with regard to waste production and energy usage.
基金supported by National Natural Science Foundation of China(52302034,52402060,52202201,52021006)Beijing National Laboratory for Molecular Sciences(BNLMS-CXTD202001)+1 种基金Shenzhen Science and Technology Innovation Commission(KQTD20221101115627004)China Postdoctoral Science Foundation(2024T170972)。
文摘Graphdiyne(GDY)is a two-dimensional carbon allotrope with exceptional physical and chemical properties that is gaining increasing attention.However,its efficient and scalable synthesis remains a significant challenge.We present a microwave-assisted approach for its continuous,large-scale production which enables synthesis at a rate of 0.6 g/h,with a yield of up to 90%.The synthesized GDY nanosheets have an average diameter of 246 nm and a thickness of 4 nm.We used GDY as a stable coating for potassium(K)metal anodes(K@GDY),taking advantage of its unique molecular structure to provide favorable paths for K-ion transport.This modification significantly inhibited dendrite formation and improved the cycling stability of K metal batteries.Full-cells with perylene-3,4,9,10-tetracarboxylic dianhydride(PTCDA)cathodes showed the clear superiority of the K@GDY anodes over bare K anodes in terms of performance,stability,and cycle life.The K@GDY maintained a stable voltage plateau and gave an excellent capacity retention after 600 cycles with nearly 100%Coulombic efficiency.This work not only provides a scalable and efficient way for GDY synthesis but also opens new possibilities for its use in energy storage and other advanced technologies.
基金financially supported by the Key Program of the Chinese Academy of Sciences(KFZD-SW-419),Chinathe Major Research Plan of the National Natural Science Foundation of China(91834301),China。
文摘Fe-N-C endowed with inexpensiveness,high activity,and excellent anti-poisoning power have emerged as promising candidate catalysts for oxygen reduction reaction(ORR).Single-atom Fe-N-C electrocatalysts derived from Fe-doped ZIF-8 represent the top-level ORR performance.However,the current fabrication of Fe-doped ZIF-8 relies on heavy consumption of time,energy,cost and organic solvents.Herein,we develop a rapid and solvent-free method to produce Fe-doped ZIF-8 under microwave irradiation,which can be easily amplified in combination with ball-milling.After rational pyrolysis,Fe-N-C catalysts with atomic FeN4 sites well dispersed on the hierarchically porous carbon matrix are obtained,which exhibit exceptional ORR performance with a half-wave potential of 0.782 V(vs.reversible hydrogen electrode(RHE))and brilliant methanol tolerance.The assembled direct methanol fuel cells(DMFCs)endow a peak power density of 61 mW cm^(-2) and extraordinary stability,highlighting the application perspective of this strategy.
基金supported by the National Key Re-search and Development Program of China(No.2020YFC1909604)SZIIT Startup Fund(No.SZIIT2022KJ072)+1 种基金Shenzhen Peacock Project Startup Fund(No.RC2023-002)Shenzhen Steady General Projects(No.KJ2024C010).
文摘Two-dimensional(2D)transition metal borides(MBenes)have emerged as a rising star and hold great potential promise for catalysis and metal ion batteries owing to a well-defined layered structure and ex-cellent electrical conductivity.Unlike well-studied graphene,perovskite and MXene materials in various fields,the research about MBene is still in its infancy.The inadequate exploration of efficient etching methods impedes their further study.Herein,we put forward an efficient microwave-assisted hydrother-mal alkaline solution etching strategy for exfoliating MoAlB MAB phase into 2D MoB MBenes with a well accordion-like structure,which displays a remarkable electrochemical performance in sodium ion batter-ies(SIBs)with a reversible specific capacity of 196.5 mAh g^(-1)at the current density of 50 mA g^(-1),and 138.6 mAh g^(-1)after 500 cycles at the current density of 0.5 A g^(-1).The underlying mechanism toward excellent electrochemical performance are revealed by comprehensive theoretical simulations.This work proves that MBene is a competitive candidate as the next generation anode of sodium ion batteries.
基金Project supported by the Spanish Government and the Ministerio de Ciencia e Innovacion(PID2020-116149 GB-I00)Generalitat Valenciana(GRISOLIA/2019/054)the Brazilian National Council for Scientific and Technological Development(306567/2021-0)。
文摘The increasing global demand for clean and potable water underscores the need for advanced pollutant remediation technologies in wastewater,such as the degradation of azo dyes,which are known to be harmful to human health.To address this issue,heterogeneous photocatalysis emerges as a promising strategy for breaking down recalcitrant molecules.However,efforts are required to develop efficient and stable photocatalysts capable of operating under visible light.This study explores the photocatalytic potential of Fe-doped RE_(2)Zr_(2)O_(7-δ)(RE=Pr,Sm,Nd,Y)compositions,synthesized through the microwaveassisted solvothermal method,for the degradation of methylene blue.Characterizations,such as X-ray diffraction(XRD)and Raman spectroscopy,reveal the obtention of single-phase ordered pyrochlore for RE=Pr,Sm and Nd or defect fluorite structures for Y.Photocatalytic tests under visible light demonstrate efficient dye degradation for all Fe-doped samples,Y_(2)Zr_(1.9)Fe_(0.1)O_(6.95)(YZF)defect fluorite being the one that exhibits the highest efficiency.Radical scavenging experiments identify hydroxyl radicals as key contributors to the degradation process,along with photoinduced holes.These materials exhibit minimal leaching of iron ions,confirming their stability,and the best material,YZF,demonstrates effective reusability.The results highlight the potential of Fe-doped RE_(2)Zr_(2)O_(7)compositions as an efficient alternative for application as photocatalysts for the degradation of azo dyes under visible light.
基金Supported by Open Funds for Innovation Platforms of Colleges and Universities in Hunan Province(15K066)National College Students'Innovative Entrepreneuria Training Program(201510553003)Research Study and Innovative Experiment Plan Project for College Students in Hunan Province(2015-499)~~
文摘In order to optimize the microwave-assisted extraction technology of polyphenols from Loropetalum chinense （R. Br.） Oliv., the effects of microwave power, ethanol concentration, solid to liquid ratio and extraction time on polyphenols extraction rate were investigated. On the basis of single-factor test, a four-factor and three-level orthogonal test was designed by response surface method to establish a mathematical model between the response value and various factors. The results showed that the intensity of effect of different influencing factor on polyphenols ex- traction rate ranked as microwave power＇s〉solid to liquid ratio＇s〉extraction time＇s〉 ethanol concentration＇s. The optimum microwave-assisted extraction conditions for polyphenols from L. chinense were as follows： extraction power 254 W, ethanol concentration 60%, extraction time 12.5 rain and solid to liquid ratio 1：17. Under the optimum extraction conditions, the extraction rate of polyphenols from L. chinense was 19.17%.
基金funded by the Postgraduate Research and Practice Innovation Program of Jiangsu Province(Grant No.KYCX23_2744)the Fundamental Research Funds for the Central Universities(Grant No.2023XSCX051)the Graduate Innovation Program of China University of Mining and Technology(Grant No.2023WLKXJ182).
文摘Microwave-assisted rock-breaking technology,as a novel hybrid approach,is anticipated to facilitate the efficient excavation of complex rock formations.It is therefore crucial to understand the damage and failure mechanisms of rocks that have been subjected to irradiation.In this study,uniaxial compression experiments were conducted on granite specimens after 1.4 kW microwave irradiation for varying durations.Furthermore,a numerical method was proposed to solve electromagnetic-thermal-mechanical coupling problems by integrating finite and discrete elements.The results demonstrated a differential temperature distribution(high temperature in the middle and low-temperature areas at the ends)in the granite specimens under microwave irradiation,which resulted in a notable reduction in their physical and mechanical properties.As the duration of irradiation increased,the rate of heating and the extent of strength reduction both diminished,while the morphology and distribution of cracks at ultimate failure became increasingly complex.The numerical method effectively addresses the simulation challenges associated with the electromagnetic selective heating of granite containing multiple polar minerals under microwave irradiation.This approach accounted for the non-uniform thermal expansion of the minerals and provided a comprehensive model of damage progression under compression.
基金financially supported by National Natural Science Foundation of China(Grant No.52272021,52232002 and U23A20559)Natural Science Foundation of Wuhan(2024040701010051)+1 种基金Program for Innovative Teams of Outstanding Young and Middle-aged Researchers in the Higher Education Institutions of Hubei Province(T201602)The work was supported by the Open Fund of the Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Ministry of Ecology and Environment of the People's Republic of China(No.HB202402)。
文摘Designing catalysts with high reaction efficiency is essential for reducing heavy metal Cr(VI)ions in wastewater via microwave induction.In this paper,a unique microwave-responsive lychee-like Ni/C/ZnFe_(2)O_(4) composite catalyst with a double-shell hollow porous heterojunction structure was constructed for the efficient reduction of Cr(VI).Benefiting from the novel hollow porous structure and“carbon nanocage”structure of the Ni/C/ZnFe_(2)O_(4),coupled with excellent electromagnetic wave absorption ability,the prepared lychee-like Ni/C/ZnFe_(2)O_(4) com-posite catalyst could remove up to 98%of Cr(VI)(50 mg L 1,50 mL)after 40 min of microwave irradiation,even in nearly neutral water conditions.Additionally,density functional theory calculations indicated that the heterojunction interface between Ni/C and ZnFe_(2)O_(4) enhances electron transfer from ZnFe_(2)O_(4) to Ni/C,ultimately facilitating the removal of Cr(VI).Furthermore,the incorporation of Ni/C facilitated the 2 acceleration of H ion transfer to*Cr_(2)O_(7),thereby expediting the conversion kinetics of the latter.This research aims to establish a theoretical and experimental foundation for the effective and stable microwave-assisted catalytic reduction of heavy metal Cr(VI)ions,presenting new insights and methods to combat heavy metal contamination.
基金Supported by the National Natural Science Foundation of China(No.29836130).
文摘The property of extraction solution is an important factor influencing the extraction efficiency. In the present work, the effect of the property of solution on extraction of GA was studied, which including the concentration of ethanol, ammonia and cation (M+), pH of extraction solution, different kinds of organic solvent etc. The results show that 50%-60%(v/v) ethanol can reach high percentage extraction of GA. If 1% (v/v) ammonia solution was added into 60%(v/v) ethanol, the percentage extraction can be increased from 2.0% to 2.31%. Without ammonia, 50mmol/L [M+] (M+ = K+, NH4+) was added into 60%(v/v) ethanol, percentage extraction of GA can reach about 2.26%. If pH of solution (60% ethanol) was adjust to pH=4.0, it can reach high percentage extraction. If pH of solution (60% ethanol + 50mmol [M+], pH=6.1) was adjust tO PH=4.0, especially M+ is K+ or NH4+, it can reach almost same extraction efficiency as that of 1% ammonia solution + 60% ethanol, and the operation environment can be greatly improved.
基金National Natural Science Foundation of China (Grant No.20910094) Ministry of Education of China(Grant No.200800010078)
文摘An optimized approach for the synthesis of N^1-ethoxymethyl-substituted cyclic inosine diphosphoribose（cIDPRE）,an analogue of cyclic adenosine diphosphoribose（cADPR）,has been developed via microwave-assisted intramolecular cyclization. The target compound has been successfully obtained through N^1-substitution,phosphorylation,cyclization and deprotection.By using this method,8-amino and bromo-substituted cIDPRE analogues were successfully obtained in good yield.The new approach has greatly shortened the synthetic route and enhanced the overall efficiency.
基金supported by the National Natural Science Foundation of China (Nos. 52274195, 52274196, 51904103, and 52174180)the Science and Technology Innovation Program of Hunan Province (No. 2022RC1178)+1 种基金Hunan Provincial Natural Science Foundation of China (Nos. 2022JJ20024, and 2021JJ30254)Scientific Research Foundation of Hunan Provincial Education Department (No. 21B0465)。
文摘Microwave heating contributes to coal fracturing and gas desorption. However, problems of low penetration depth, local overheating and fracture closure exist. Coal demineralisation by acids has advantages in coal unblocking and permeability improvement, while it is difficult for acid to enter microcracks.Microwave-asisted acidification may offer an alternative. In this work, XRD,^(1)H-NMR, and SEM were used to evaluate the effect of microwave-assisted acidification on the microstructure of coal. Results show that kaolinite, calcite, and dolomite can be dissolved by acid. After microwave irradiation, the graphitization of microcrystalline structure of carbon improves. Microwave-assisted acidification erodes minerals in coal and enhances the graphitization degree of microcrystalline structure. Compared to individual microwave irradiation or acidification, the pore volume and pore connectivity can be greatly enhanced by microwave-assisted acidification. The NMR permeability of coal increased by 28.05%. This study demonstrates the potential of microwave-assisted acidification for coalbed methane recovery.
基金supported by the National Natural Science Foundation of China(No.50678045,50821002)
文摘A highly active ZrO x /ZnO catalyst for microwave-assisted photocatalytic （MW/PC） degradation of endocrine disruptor dimethyl phthalate （DMP） has been prepared via cetyltrimethylammonium assisted hydrothermal method. The ZrO x /ZnO was characterized by XPS, XRD, UV-Vis, BET and SEM techniques. The XPS result showed that Zr oxides with different valences （＋2, ＋3, ＋4） co-existed in ZrO x /ZnO. By using the ZrO x /ZnO （0.1 g）, the TOC removal efficiency of DMP （100 mL of 50 mg/L） was 88% after 30 min reaction, which was about 15% higher than P25 TiO 2 . It was found that the removal process of DMP by MW/PC followed pseudo first-order kinetics in all cases, and ZrO x /ZnO significantly accelerated the degradation of DMP. The degradation half-life time of DMP was shortened 45% compared with P25 TiO 2 . A possible catalytic mechanism was proposed based on microwave response and interfacial charge transfer. ZrO x /ZnO could be reused for six times without obvious decrease in catalytic activity. The study offers new insights into designing highly efficient catalysts for MW/PC process and is applicable for MW/PC environmental remediation.
文摘The microwave-assisted method was used to extract polysaccharides from solanum nigrum. The optimum experimental parameters, mechanism of the extraction and the effect of microwave-assisted extraction process on the structures of polysaccharides were investigated. The extract was analyzed by the modified phenol-sulfuric acid method at 490nm. The optimum experimental parameters were obtained by orthogonal experiments as follows: extraction time 15min, microwave radiation power 455W and the process ratio of materials mass to solvent volume 1∶20. The results show that compared with the conventional reflux extraction, the microwave-assisted extraction has a higher yield in shorter time, with no effect on the finally obtained polysaccharides as seen from the FT-IR spectra. The scanning electron microscopy images reveal that the mechanism of the extraction is related to the structural changes of the plant cells in different extracting conditions.
文摘Microwave-assisted extraction （MAE） of isoflavones from Belamcanda chinensis was studied using ethanol as the solvent. The single factor experiment and the orthogonal method were used to optimize the MAE condition. It was concluded that two doses of intermittent microwave power radiation, 300 W each for 4 rain, were needed for extraction. The mass ratio of solvent to material was 8：1 and the alcohol mass fraction was 80%. The extracted liquor was then concentrated under vacuum and degreased with petroleum ether. The yield of total isofiavones was about 8.8% and the contents of tectoridin and iridin were 67.6% and 16.3% respectively. Compared with direct-heating extraction （DHE）, MAE may shorten extracting duration, reduce solvent consumption, and improve yield and purity of isoflavones from Belamcanda chinensis.
基金the National Natural Science foundationof China(No.20875060) for financial support
文摘Microwave-assisted extraction was optimized with response surface methodology for HPLC-fluorescence determination of puerarin and daidzein in Radix Puerariae thomsonii.The optimized extraction procedure was achieved by soaking the sample with 70% methanol（1∶15,v/v）for 30 min,and then microwave irradiation for 11 min at a power of 600 W.Coupling the extraction process with HPLC-fluorescence presented good recovery,satisfactory precision,and good linear relation.Compared with a method from the Chinese Pharmacopoeia,the proposed method enables higher extraction efficiency and more accurate analytical results.It can be of potential value in quality assessment of Radix Puerariae thomsonii medicinal materials.
基金financially supported by the National Key Research and Development Program of China(No.2017YFE0115900)the Natural Science Foundation of China(No.51872254)Yangzhou City-Yangzhou University Cooperation Foundation(No.YZU201801)。
文摘Hydrothermal methods are widely used in chemical synthesis of target products with specific morphology and nanostructure.Those methods are very efficient for the preparation of well-controlled structures but the reaction time is usually long.The assistance of microwave makes the reaction system heat up faster,more uniformly and reactions are accelerated,it also can be utilized to change the morphology or structure of materials,which improves the physic-chemical properties of synthesized products and influences its gas-sensing performance.Copper oxide(CuO)is widely applied in semiconductor gas sensors because of its good reactivity and stability.This review article briefly introduces the principle,mechanism and recent development of CuO nanostructures obtained by microwave-as sis ted hydrothermal synthesis(MWHS)process.It also discussed the relation between endopathic factors of material and its gas-sensitive performance.The technical challenges and prospective solutions for highperformance CuO-based gas-sensitive materials with unique nanostructure are proposed.It is pointed out that the hierarchical CuO-based nanostructures and their composite materials prepared by MWHS process are efficacious methods to improve the gas-sensitive performance of the materials.On the basis of the morphology,the materials are divided into nanorods,nanoflowers,nanosheets,nanospheres and other nanostructures.The influence of microwave parameters on the properties of synthetic products is analyzed.The influence followed by metal element loading on the structure and properties of CuO-based materials by MWHS process is further discussed.Then this review summarizes the research progress of graphene-CuO and metal oxide-CuO composites prepared by MWHS process in recent years.
