Background:Corchorus olitorius L.(Malvaceae)is a green leafy vegetable widely consumed in the Middle East and valued for its rich nutritional content.Its essential oils,an important class of secondary metabolites,are ...Background:Corchorus olitorius L.(Malvaceae)is a green leafy vegetable widely consumed in the Middle East and valued for its rich nutritional content.Its essential oils,an important class of secondary metabolites,are of growing interest for potential use in cosmetics and fragrance industries due to their bioactive properties.Methods:Leaves of C.olitorius cultivated in Egypt were extracted using microwave-assisted hydrodistillation(MAHD)and conventional hydrodistillation(HD).The oils were analyzed by gas chromatography-mass spectrometry(GC-MS)to characterize their chemical profiles.In vitro assays were conducted to evaluate their anti-elastase and anti-collagenase activities,and in silico studies were performed to predict the pharmacokinetic and pharmacodynamic properties of major constituents.Results:GC-MS analysis showed that aldehydes,alkanes,fatty alcohols,fatty acids,and their derivatives were the predominant compound classes in both oils.Notably,oxygenated diterpenes(11.22%)were present exclusively in the MAHD oil,while triterpenoids(16.37%)were found only in the HD oil.The MAHD oil demonstrated stronger In vitro anti-elastase(IC_(50)=42.5μg/mL)and anti-collagenase(IC_(50)=131.5μg/mL)activities compared to the HD oil(IC_(50)=66.7 and 206.8μg/mL,respectively),reflecting an approximate 36.3%improvement in elastase inhibition and 36.4%improvement in collagenase inhibition.In silico docking indicated that the triterpenoidβ-amyrin acetate showed the highest predicted binding affinity for porcine pancreatic elastase(PDB ID:6QEO,ΔG=−8.1 kcal/mol)and collagenase(PDB ID:456C,ΔG=−9.1 kcal/mol)among the major compounds analyzed.Conclusion:These findings demonstrate that MAHD is a greener and more efficient extraction method,yielding oil with enhanced enzyme inhibitory activity compared to conventional HD.The promising anti-elastase and anti-collagenase properties suggest that C.olitorius MAHD oil could serve as a potential candidate for anti-aging cosmetic formulations,following further validation.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
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
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
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
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
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
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
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
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
Three microwave-assisted extraction(MAE) procedures were studied. The first procedure was household microwave oven dynamic extraction(HMODE). The second procedure was special microwave oven bath extraction(SMOBE). The...Three microwave-assisted extraction(MAE) procedures were studied. The first procedure was household microwave oven dynamic extraction(HMODE). The second procedure was special microwave oven bath extraction(SMOBE). The third procedure was microwave resonant cavity dynamic extraction(MRCDE). The results obtained by the three microwave-assisted extraction procedures were compared with those obtained by using traditional Soxhlet extraction. The results indicate that the MAE not only took a shorter time, but also simplified the procedure, and made the extraction a higher yield. At the same time the results obtained by the three MAE procedures were also compared with each other.展开更多
A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides...A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides in grains including rice,maize and millet.Twelve samples can be processed simultaneously in the method.During the extraction process,10%acetonitrile-water solutions containing 110μL of n-hexadecane were used to extract organochlorine pesticides.Subsequently,1.0 g sodium chloride was placed in the extract,and then centrifuged and cooled.The n-hexadecane drops containing the analytes were solidifi ed and transferred for determination by gas chromatography-electron capture detector without any further filtration or cleaning process.Limits of detection for organochlorine pesticides were 0.97–1.01μg/kg and the RSDs were in the range of 2.6%–8.5%.The developed technology has succeeded in analyzing six real grains samples and the recoveries of the organochlorine pesticides were 72.2%–94.3%.Compared with the published extraction methods,the developed method was used to analyze organochlorine pesticides in grains,being more environmentally friendly,which is suitable for the daily determination of organochlorine pesticides.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
Coals consist of some molecules trapped within an organic matrix from which some organic compounds can be extracted by solvents. The Soxhlet technique has been widely used for extracting organic compounds. Microwave h...Coals consist of some molecules trapped within an organic matrix from which some organic compounds can be extracted by solvents. The Soxhlet technique has been widely used for extracting organic compounds. Microwave heating methods may be successfully applied in the field of coal science. Acetone extraction yields and the chemical composition of the extract were investigated using a typical Chinese coal, Shenfu coal, with microwave-assisted extraction. The acetone extract and residue were analyzed by GC/MS and carbon-13 nuclear magnetic resonance spectroscopy respectively. The carbon spectra were converted into several numerical parameters, fa, Ha, Xb, which indicate the difference in macromolecular structure between Shenfu coal and its residue. Furthermore, a hybrid genetic algorithm was employed using these parameters to approximate a coal macromolecule by assembling the structural fragments or functional groups into a large and complicated structure.展开更多
This study was aimed at evaluating the physicochemical properties and oxidation stability of castor oil using microwave-assisted solvent extraction(MAE). MAE was performed using 5% ethanol in hexane as solvent at diff...This study was aimed at evaluating the physicochemical properties and oxidation stability of castor oil using microwave-assisted solvent extraction(MAE). MAE was performed using 5% ethanol in hexane as solvent at different extraction times, power intensities and solvent-to-feed(S/F, ml of solvent to gram of feed) ratios.The process parameters were optimized by statistical approach using historical data design of response surface method(RSM). The oils were characterized for yield, physicochemical properties, dielectric properties and oxidation stability, and comparison was also made with oil extracted using Soxhlet method. Results show that the maximum oil yield of 37% was obtained at 20 min with microwave power intensity of 330 W and S/F ratio of 20. The main fatty acid composition of castor oil is ricinoleic acid. The density, refractive index, dielectric properties and oxidation stability of oils are not affected by the extraction methods and extraction parameters of MAE. However, the MAE-extracted oil is more viscous compared to that by Soxhlet method. With extra caution on oil oxidation, MAE could be a promising solvent extraction method with an 86% less in processing time and a higher yield.展开更多
A comparison between conventional pyrolysis and a novel developed low-temperature microwave-assisted pyrolysis methodology has been performed for the valorisation of a range of biomass feedstocks including waste resid...A comparison between conventional pyrolysis and a novel developed low-temperature microwave-assisted pyrolysis methodology has been performed for the valorisation of a range of biomass feedstocks including waste residues. Microwave pyrolysis was found to efficiently deliver comparable evolution of bio-gases in the system as compared with conventional pyrolysis at significantly reduced temperatures （120-180 ℃vs 250-400 ℃）. The gas obtained from microwave-assisted pyrolysis was found to contain CO2, CH4 and CO as major components as well展开更多
A facile microwave-assisted procedure for synthesis of novel fluorinated pyrazolo[3,4-d]pyrimidine derivatives containing 1,3,4-thiadiazole is described. This protocol presented such advantages as short reaction time,...A facile microwave-assisted procedure for synthesis of novel fluorinated pyrazolo[3,4-d]pyrimidine derivatives containing 1,3,4-thiadiazole is described. This protocol presented such advantages as short reaction time, high yields, simple purification and environmentally benign procedures. Their antitumor activities were evaluated against HL-60 by an MTT assay. The preliminary results indicated that some title compounds exhibit more potent antitumor inhibitory activity than doxorubicin （DOX）.展开更多
Microwave-assisted extraction (MAE) for active ingredients in Ciwujia was studied by using ethanol as the extractant. Comparing MAE with conventional methods, the former can save the extracting time and increase the c...Microwave-assisted extraction (MAE) for active ingredients in Ciwujia was studied by using ethanol as the extractant. Comparing MAE with conventional methods, the former can save the extracting time and increase the content of the active ingredients in product. As to the operation in MAE, the continuous radiation process is more convenient for the extraction for traditional Chinese medicine than the intermittent radiation process. Optimized by uniform design, MAE was proved to be an effective and novel process for extracting active ingredients in Ciwujia. The optimized MAE conditions are as follows: the microwave power is 510W, the radiation time 30min, the alcohol concentration at 80%, the ratio of solvent to solid material being 5:1, the soaking time 0.5h, and the herbal particle size is (520±19)μm.展开更多
基金Egyptian Science and Technology and Innovation Fund(STIFA)for the support of the study through grant No.46667 entitled“Sustainability of Lab Capacities of the Center of Drug Discovery Research and Development”.
文摘Background:Corchorus olitorius L.(Malvaceae)is a green leafy vegetable widely consumed in the Middle East and valued for its rich nutritional content.Its essential oils,an important class of secondary metabolites,are of growing interest for potential use in cosmetics and fragrance industries due to their bioactive properties.Methods:Leaves of C.olitorius cultivated in Egypt were extracted using microwave-assisted hydrodistillation(MAHD)and conventional hydrodistillation(HD).The oils were analyzed by gas chromatography-mass spectrometry(GC-MS)to characterize their chemical profiles.In vitro assays were conducted to evaluate their anti-elastase and anti-collagenase activities,and in silico studies were performed to predict the pharmacokinetic and pharmacodynamic properties of major constituents.Results:GC-MS analysis showed that aldehydes,alkanes,fatty alcohols,fatty acids,and their derivatives were the predominant compound classes in both oils.Notably,oxygenated diterpenes(11.22%)were present exclusively in the MAHD oil,while triterpenoids(16.37%)were found only in the HD oil.The MAHD oil demonstrated stronger In vitro anti-elastase(IC_(50)=42.5μg/mL)and anti-collagenase(IC_(50)=131.5μg/mL)activities compared to the HD oil(IC_(50)=66.7 and 206.8μg/mL,respectively),reflecting an approximate 36.3%improvement in elastase inhibition and 36.4%improvement in collagenase inhibition.In silico docking indicated that the triterpenoidβ-amyrin acetate showed the highest predicted binding affinity for porcine pancreatic elastase(PDB ID:6QEO,ΔG=−8.1 kcal/mol)and collagenase(PDB ID:456C,ΔG=−9.1 kcal/mol)among the major compounds analyzed.Conclusion:These findings demonstrate that MAHD is a greener and more efficient extraction method,yielding oil with enhanced enzyme inhibitory activity compared to conventional HD.The promising anti-elastase and anti-collagenase properties suggest that C.olitorius MAHD oil could serve as a potential candidate for anti-aging cosmetic formulations,following further validation.
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.
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 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(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.
基金the Science and Technology Developing Fellowship Program(No.2 0 0 30 5 5 1- 7) by Jilin Province
文摘Three microwave-assisted extraction(MAE) procedures were studied. The first procedure was household microwave oven dynamic extraction(HMODE). The second procedure was special microwave oven bath extraction(SMOBE). The third procedure was microwave resonant cavity dynamic extraction(MRCDE). The results obtained by the three microwave-assisted extraction procedures were compared with those obtained by using traditional Soxhlet extraction. The results indicate that the MAE not only took a shorter time, but also simplified the procedure, and made the extraction a higher yield. At the same time the results obtained by the three MAE procedures were also compared with each other.
基金The study was financially supported by the National Science and Technology Support Program of China(Grant No.2013BAD16B08).
文摘A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides in grains including rice,maize and millet.Twelve samples can be processed simultaneously in the method.During the extraction process,10%acetonitrile-water solutions containing 110μL of n-hexadecane were used to extract organochlorine pesticides.Subsequently,1.0 g sodium chloride was placed in the extract,and then centrifuged and cooled.The n-hexadecane drops containing the analytes were solidifi ed and transferred for determination by gas chromatography-electron capture detector without any further filtration or cleaning process.Limits of detection for organochlorine pesticides were 0.97–1.01μg/kg and the RSDs were in the range of 2.6%–8.5%.The developed technology has succeeded in analyzing six real grains samples and the recoveries of the organochlorine pesticides were 72.2%–94.3%.Compared with the published extraction methods,the developed method was used to analyze organochlorine pesticides in grains,being more environmentally friendly,which is suitable for the daily determination of organochlorine pesticides.
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Project 40472082 supported by the National Natural Science Foundation of China
文摘Coals consist of some molecules trapped within an organic matrix from which some organic compounds can be extracted by solvents. The Soxhlet technique has been widely used for extracting organic compounds. Microwave heating methods may be successfully applied in the field of coal science. Acetone extraction yields and the chemical composition of the extract were investigated using a typical Chinese coal, Shenfu coal, with microwave-assisted extraction. The acetone extract and residue were analyzed by GC/MS and carbon-13 nuclear magnetic resonance spectroscopy respectively. The carbon spectra were converted into several numerical parameters, fa, Ha, Xb, which indicate the difference in macromolecular structure between Shenfu coal and its residue. Furthermore, a hybrid genetic algorithm was employed using these parameters to approximate a coal macromolecule by assembling the structural fragments or functional groups into a large and complicated structure.
基金Supported by Universiti Teknologi Malaysia through 415 Flagship(Grant No.03G70)
文摘This study was aimed at evaluating the physicochemical properties and oxidation stability of castor oil using microwave-assisted solvent extraction(MAE). MAE was performed using 5% ethanol in hexane as solvent at different extraction times, power intensities and solvent-to-feed(S/F, ml of solvent to gram of feed) ratios.The process parameters were optimized by statistical approach using historical data design of response surface method(RSM). The oils were characterized for yield, physicochemical properties, dielectric properties and oxidation stability, and comparison was also made with oil extracted using Soxhlet method. Results show that the maximum oil yield of 37% was obtained at 20 min with microwave power intensity of 330 W and S/F ratio of 20. The main fatty acid composition of castor oil is ricinoleic acid. The density, refractive index, dielectric properties and oxidation stability of oils are not affected by the extraction methods and extraction parameters of MAE. However, the MAE-extracted oil is more viscous compared to that by Soxhlet method. With extra caution on oil oxidation, MAE could be a promising solvent extraction method with an 86% less in processing time and a higher yield.
基金supported by the Gobierno de Espaa for the Provision of a Ramon y Cajal Contract (RYC-2009-04199),Projects P10 FQM-6711(Consejeria de Ciencia e Innovacion,Junta de Andalucia) and CTQ2011 28954-C02-02 (MICINN)
文摘A comparison between conventional pyrolysis and a novel developed low-temperature microwave-assisted pyrolysis methodology has been performed for the valorisation of a range of biomass feedstocks including waste residues. Microwave pyrolysis was found to efficiently deliver comparable evolution of bio-gases in the system as compared with conventional pyrolysis at significantly reduced temperatures （120-180 ℃vs 250-400 ℃）. The gas obtained from microwave-assisted pyrolysis was found to contain CO2, CH4 and CO as major components as well
基金the National Nature Science Foundation of Hubei Province(No.2008CDB016)the Scientific Research Fund of Hubei Provincial Education Department(No.D20111904)
文摘A facile microwave-assisted procedure for synthesis of novel fluorinated pyrazolo[3,4-d]pyrimidine derivatives containing 1,3,4-thiadiazole is described. This protocol presented such advantages as short reaction time, high yields, simple purification and environmentally benign procedures. Their antitumor activities were evaluated against HL-60 by an MTT assay. The preliminary results indicated that some title compounds exhibit more potent antitumor inhibitory activity than doxorubicin （DOX）.
文摘Microwave-assisted extraction (MAE) for active ingredients in Ciwujia was studied by using ethanol as the extractant. Comparing MAE with conventional methods, the former can save the extracting time and increase the content of the active ingredients in product. As to the operation in MAE, the continuous radiation process is more convenient for the extraction for traditional Chinese medicine than the intermittent radiation process. Optimized by uniform design, MAE was proved to be an effective and novel process for extracting active ingredients in Ciwujia. The optimized MAE conditions are as follows: the microwave power is 510W, the radiation time 30min, the alcohol concentration at 80%, the ratio of solvent to solid material being 5:1, the soaking time 0.5h, and the herbal particle size is (520±19)μm.
