A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under m...A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.展开更多
This study is a part of an overall research project on the effects of microwave(MW)irradiation on rocks for assisted rock breaking systems as well as mineral processing at McGill University.For the first time,this pap...This study is a part of an overall research project on the effects of microwave(MW)irradiation on rocks for assisted rock breaking systems as well as mineral processing at McGill University.For the first time,this paper highlights a comprehensive investigation on the effects of microwave irradiation on Canadian kimberlites.Potential contribution to the continuous rock excavation and rock weakening effect prior to implementation of mechanical techniques was explored.Two different kimberlite rocks,i.e.volcaniclastic kimberlite(VK)and hypabyssal kimberlite(HK),and granite samples were studied.Some important physical properties of the rock samples were measured including rock quality designation(RQD),specific gravity,porosity,and specific heat capacity.Rock samples were treated for various exposure times using a multi-mode MWunit at different power levels ranging from 2 kW to 15 kW.The effect of MW irradiation on rock samples was investigated.The results indicate that the mechanical properties including unconfined compressive strength(UCS)and Brazilian tensile strength(BTS)were significantly dropped as a result of MWirradiation.Finally,the effect on rock abrasivity using the Cerchar abrasivity index(CAI)has also been discussed.展开更多
Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO) random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL) and p-dioxanone(PDO) under microwave irradiation.The eff...Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO) random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL) and p-dioxanone(PDO) under microwave irradiation.The effects of irradiation time and different CL/PDO molar feed ratios on the microwave-assisted ring-opening polymerization(MROP) of PCDO have been discussed.The resultant products were characterized by ~1H NMR,GPC and DSC.It was found that the polymerization was completed within 20 min at 140℃.In...展开更多
A facile method of preparation of benzimidazoles by microwave irradiation was described. The mixtures of o-phenylenediamine and carboxylic acids were heated by microwave irradiation, to give 2-substituted benzimidazol...A facile method of preparation of benzimidazoles by microwave irradiation was described. The mixtures of o-phenylenediamine and carboxylic acids were heated by microwave irradiation, to give 2-substituted benzimidazoles with yields of 49%～93%. The reaction time was shortened to 3～6 min. However, the reaction of ethylenediamine with carboxylic acids did not give imidazoles but the N,N-diacyl ethylenediamines. The alphatic diamines lacked the activity to form imidazole ring. With adipic acid, intermolecular acylation took place to afford poly(ethylene adipamide).展开更多
A microwave irradiated magnetically separable nano cobalt ferrite catalyzed green method for the synthesis of 4-phenyl-4H-pyrano[3,2-h]quinolin-2-amine and 2-amino-4-phenyl-4H-pyrano[3,2-h] quinoline-3-carbonitrile de...A microwave irradiated magnetically separable nano cobalt ferrite catalyzed green method for the synthesis of 4-phenyl-4H-pyrano[3,2-h]quinolin-2-amine and 2-amino-4-phenyl-4H-pyrano[3,2-h] quinoline-3-carbonitrile derivatives through cyclization of aromatic aldehyde, acetonitrile/malononitrile and 8-hydoxyquinoline is developed and presented in this paper. The cubic magnetic cobalt ferrite nano particles were synthesized by sol-gel citrate precursor method and characterized by FT-IR, XRD, SEM and TEM techniques and the structures of the synthesized pyranoquinoline derivatives were assigned by IR, MASS and 1</sup>H NMR techniques. The reaction is carried out in a domestic microwave oven with a heat-resistant microwave safe glass container with a lid.展开更多
2-Carbonyl propionic acid-4-methyl benzoyl hydrazone(PAMH) has been synthesized by using 4-methyl benzoyl hydrazine and pyruvic acid as the chemicals and acetic acid as phase transfer catalyst under microwave radiatio...2-Carbonyl propionic acid-4-methyl benzoyl hydrazone(PAMH) has been synthesized by using 4-methyl benzoyl hydrazine and pyruvic acid as the chemicals and acetic acid as phase transfer catalyst under microwave radiation. Then the PAMH and Tb Cl3·6 H2 O are placed in the methanol/acetone/water(3:2:4) mixture for coordination reaction, getting the Schiff complex Tb(PAMH)3. The crystal structure is characterized by elemental analysis, X-ray Diffraction(XRD) and infrared spectrum. The compound crystallizes in the monoclinic space group P21/n, with a = 1.4770(4), b = 1.2864(3), c = 1.9287(5) nm, β = 92.06(3)o, V = 3.6623(15) nm3 and Z = 4. Tb(III) ion is nona-coordinated by three completely deprotonated PAMH ligands in a tricapped trigonal prism geometry, leaving a zero-dimensional mononuclear configuration. The optical properties and thermal stability are studied by ultraviolet spectrum, fluorescence spectra and thermogravimetric analysis(TGA). The antibacterial activities of the ligand and rare-earth complex are preliminarily studied, and found they have certain antibacterial activity on fusarium solani, and the complex is obviously more effective in suppressing fusarium solani than the ligand.展开更多
Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and...Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.展开更多
A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na_(2)TeO_(3) as the Te source in an aqueous environment.The synthesis paramete...A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na_(2)TeO_(3) as the Te source in an aqueous environment.The synthesis parameters of this simple and rapid approach,including the reaction temperature and time,the pH of the reaction solution and the molar ratio of the 3-mercaptopropionic acid(MPA)stabilizer to Cd^(2+),have considerable influence on the particle size and photoluminescence quantum yield of the CdTe quantum dots.The photoluminescence quantum yield of CdTe quantum dots prepared using relatively short reaction times(1040 min)reached 40%60%(emission peaks at 550640 nm).Furthermore,the resulting products could be used as fl uorescent probes to detect Hg^(2+)ions in aqueous media.The response was linearly proportional to the concentration of Hg^(2+)ion in the range 8.0×10^(9)mol/L to 2.0×10^(6)mol/L with a detection limit of 2.7×10^(9)mol/L.展开更多
In this work we prepared several CeO2-TiO2 catalysts for the NH3-SCR reactionusing co-precipitation with assistance of microwave irradiation.The catalytic NH3-SCR activities over CeO2-TiO2 catalysts at low temperature...In this work we prepared several CeO2-TiO2 catalysts for the NH3-SCR reactionusing co-precipitation with assistance of microwave irradiation.The catalytic NH3-SCR activities over CeO2-TiO2 catalysts at low temperatures are largely enhanced by the treatment of microwave irradiation,the operation temperature window is also broadened.For better understanding the promotion mechanism,the catalyst prepared by conventional co-precipitation with and without microwave irradiation treatment was characterized with H2-TPR,NH3-TPD,XPS,XRD and BET.Microwave irradiation treatment accelerates the crystallite rate of CeO2-TiO2 catalysts,and greatly enlarges their surface area by adjusting their microstructures.The resistance to SO2 and H2O is also improved via regulating the hierarchical pore structure by the microwave irradiation.Microwave irradiation treatment can also improve the redox property and increase the acid sites over the catalyst surfaces.The result of in situ DRIFTS suggests that the microwave irradiation treatment generates more Br?nsted acid sites on CeO2-TiO2-2 h catalyst,helpful in SCR reactions.XPS results show that after microwave irradiation on the CeO2-TiO2 catalysts,the surface demonstrates an elevated concentration of chemisorbed oxygen,consequently leading to better oxidation of NO to NO2.Additionally,the molar ratio of Ce3+/Ce4+has been elevated after being treated by microwave irradiation,a vital factor in enhancing the NH3-SCR activities.展开更多
Thermal hydrolysis was an effective pretreatment for the sewage sludge by improving dewatering and anaerobic digestion but the heating was a time-consuming process.This study focused on the effects of the microwave ir...Thermal hydrolysis was an effective pretreatment for the sewage sludge by improving dewatering and anaerobic digestion but the heating was a time-consuming process.This study focused on the effects of the microwave irradiation by using high temperature and pressured system on sewage sludge hydrolysis.The results obtained in current research showed that sludge could absorb microwave energy with high efficiency and then be hydrolyzed fast.The solubilization of suspended solid(SS),volatile suspended solids(VSS)and the increasing of the level of soluble chemical oxygen demand(SCOD)in liquid fraction showed that the microwave irradiation could be shortened to 5 min under a temperature range of 80℃-170℃.The highest value of VSS dissolution ratio(36.4%)was obtained at 170℃for 30 min.The COD dissolution ratio was about 25%at 170℃.The improvement of the biogas production from both mixture sludge and waste activated sludge was 20.2%and 25.9%respectively at 170℃for 10 min.The dewaterability of sludge was greatly improved.Subsequently,the sludge volume could be reduced by 60%with microwave irradiation.展开更多
Cu/ZnO/Al_(2)O_(3) catalysts with Cu/Zn/Al ratios of 6/3/1 were precipitated and aged by conventional and microwave heating methods and tested in the slurry phase reactor for methanol synthesis.The effect of technolog...Cu/ZnO/Al_(2)O_(3) catalysts with Cu/Zn/Al ratios of 6/3/1 were precipitated and aged by conventional and microwave heating methods and tested in the slurry phase reactor for methanol synthesis.The effect of technological condition of precipitation and aging process under microwave irradiation on the catalytic performance was investigated to optimize the preparing condition of Cu/ZnO/Al_(2)O_(3) catalyst.The results showed that the microwave irradiation during precipitation process could improve the activity of the catalyst,but had little effect on the stability.While the microwave irradiation during aging process has a great benefit to both the activity and stability of the catalyst,the catalyst aged at 80℃ for 1 h under microwave irradiation possessed higher methanol space time yield(STY)and more stable catalytic activity.The activity and stability of the catalyst was further enhanced when microwave irradiation was used in both precipitation and aging processes;the optimized condition for the catalyst precursor preparation was precipitation at 60℃ and aging at 80℃ under microwave irradiation.展开更多
The microwave-assisted rock fragmentation has been proven to be a promising approach in reducing cutting tools wear and improving efficiency in rock crushing and excavation.Thus,understanding the influence of damage i...The microwave-assisted rock fragmentation has been proven to be a promising approach in reducing cutting tools wear and improving efficiency in rock crushing and excavation.Thus,understanding the influence of damage induced by microwave irradiation on rock fragmentation is necessary.In this context,cylindrical Fangshan granite(FG)specimens were exposed to microwave irradiation at a power of 6 kW for different durations up to 4.5 min.The damages of the specimens induced by irradiation were quantified by using both X-ray micro-CT scanning and ultrasonic wave measurement.The CT value and Pwave velocity decreased with increase of irradiation duration.The irradiated specimens were then tested using a split Hopkinson pressure bar(SHPB)system to simulate rock fragmentation.A momentum-trap technique was utilized to ensure single-pulse loading on the specimen in SHPB tests,enabling valid fragment size distribution(FSD)analysis.The dependence of dynamic uniaxial compressive strength(UCS)on the irradiation duration and loading rate was revealed.The dynamic UCS increased with increase of loading rate while decreased with increase of irradiation duration.Using the sieve analysis,three fragmentation types were proposed based on FSD,which were dictated by both loading rate and irradiation duration.In addition,an average fragment size was proposed to quantify FSD.The results showed that the average fragment size decreased with increase of loading rate.A loading rate range was identified,where a dramatic reduction of the average fragment size occurred.The dependence of fragmentation on the irradiation duration and loading rate was also discussed.展开更多
A microwave-assisted solid phase synthesis for endothelin 1 is presented.Reduced endothelin 1 was synthesized efficiently on Wang resin under microwave irradiation using Fmoc/tBu orthogonal protection strategy.The who...A microwave-assisted solid phase synthesis for endothelin 1 is presented.Reduced endothelin 1 was synthesized efficiently on Wang resin under microwave irradiation using Fmoc/tBu orthogonal protection strategy.The whole peptide was cleaved from the resin and two disulphide bridges were formed under air oxidation at room temperature.The purity and efficiency of synthesizing the peptide is much higher than other methods used before.展开更多
The various methods for microwave processing of materials exhibit numerous advantages,such as short processing times,high yield,expanded reaction conditions,high reproducibility,and high purity of products.Microwave-a...The various methods for microwave processing of materials exhibit numerous advantages,such as short processing times,high yield,expanded reaction conditions,high reproducibility,and high purity of products.Microwave-assisted synthesis strategies have been widely adopted for the preparation of highperformance graphene-based materials for supercapacitor electrodes.Metal oxides,mixed metal oxides,metal hydroxides,layered double hydroxides,carbon nanotubes and conducting polymers are some of the main materials which have been added to graphene derivatives for advanced composite/hybrid electrodes.This review article first provides a brief introduction and an overview of microwave heating and its advantages for processing graphene-based electrode materials.After that,a systematic survey of recently published research on microwave irradiation-assisted processing is presented,focusing on:(i)transformation of graphite/graphite oxide into graphene/graphene oxide by exfoliation and reduction;(ii)formation of graphene derivatives in various liquid and gaseous media;(iii)modification of graphene derivatives with various metal oxides/hydroxides,carbon nanotubes,and conducting polymers for use in supercapacitors.Major challenges and future perspectives for microwave-assisted processing of graphene-based materials for cutting-edge supercapacitor electrode applications are also summarized in the conclusion.展开更多
Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst.The resulting esters were characterized...Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst.The resulting esters were characterized by melting point,hydrophilic-lipophilic balance,thin-layer chromatography,ultraviolet spectroscopy,Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR)spectroscopy.Inulin acetate demonstrated a high degree of acetylation(2.5-3.0)and presented a white,water-insoluble substance with bitter taste.The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone.Swelling capacity,water holding,oil-holding capacities,the foamability,foam stability and emulsifying properties were also evaluated.Inulin acetate showed promising foam stability 52%for 60 min and formed stable emulsions at concentration 0.2 g/L with 50 and 80%oil phases.Its water holding capacity was lower than the oil holding capacity.In addition to this,for the first time,the antimicrobial potential of inulin acetate was tested against seventeen microorganisms(Gram-positive and Gram-negative bacteria,yeasts and fungi).Inulin acetate(10 mg/ml)inhibited the growth of Bacillus cereus,Escherichia coli ATCC 8739,Salmonella abony,Candida albicans and Penicillium sp.However,inulin acetate demonstrated antimicrobial activity at concentration 1 mg/ml against Listeria monocytogenes 863,Escherichia coli 3398,Candida albicans 8673,Fusarium oxysporum and Aspergillus niger.The current study demonstrated the applications of“green”synthesized inulin acetate as a foaming agent,oil-in-water emulsion stabilizer and antimicrobial substance in pharmaceutical,agricultural and cosmetic preparations.展开更多
Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source forinulin production. “Green” method was performed for accelerated inulin extraction from Helianthus tuberosu...Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source forinulin production. “Green” method was performed for accelerated inulin extraction from Helianthus tuberosus L.tubers by the application of microwave irradiation. Further pretreatment of the water extract with acetone andethanol yielded inulin (20%) with purity 89% and degree of polymerization 18. Jerusalem artichoke inulin wascharacterized by FTIR and NMR spectroscopy. For the first time eco-friendly synthesis of acetylated Jerusalemartichoke inulin was performed by the reaction with acetic anhydride, without toxic solvent, but only withsodium acetate as catalyst under microwave irradiation for 60 s. The degree of acetylation (DA=2.1) and thestructure of inulin esters were confirmed by 1H and 13C NMR. The suggested microwave acetylation shortenssignificantly the esterification reaction.展开更多
A series of Pt/C catalysts for proton exchange membrane fuel cells(PEMFCs) with various metal loadings is synthesized by a microwave-assisted polyol process via mixing an extremely stable platinum colloid(> 3 month...A series of Pt/C catalysts for proton exchange membrane fuel cells(PEMFCs) with various metal loadings is synthesized by a microwave-assisted polyol process via mixing an extremely stable platinum colloid(> 3 months’ shelf life) from single batch preparation with activated carbon ethylene glycol suspension.21 wt%, 42 wt% and 61 wt% Pt loadings are employed to showcase the advantages of the improved polyol process. The ultraviolet(UV)–visible spectra and ζ-potential measurements are conducted to monitor the wet chemistry process during catalyst preparation. The powder X-ray diffraction(XRD), transmission electron microscopy(TEM) and thermogravimetric analysis(TGA) characterizations are carried out on catalysts. The catalyst activities are investigated using electrochemical and single cell tests. The stability of Pt nanoparticle colloid is explored by ORR, cyclic voltammetry(CV) and ζ-potential measurements. The TEM results show the Pt particle sizes of the colloid, and the sizes of the 21 wt%, 42 wt% and 61 wt%Pt/C samples are 2.1–3.9 nm. Because of the high Pt dispersion, the Pt/C catalysts exhibit superior electroactivity toward ORR. In addition, four 61 wt% Pt/C catalysts made from the Pt colloid with 0–3 months’ shelf life show almost the same performance, which exhibits superior stability of the Pt colloid system without surfactant protection.展开更多
Background: To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study...Background: To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method: The oat grains were kept as raw(control) or heated in an air-draft oven(dry roasting: DO) at 120 °C for 60 min and under microwave irradiation(MIO) for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results: The results showed that rumen degradability of dry matter, protein and starch was significantly lower(P <0.05) for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation(-0.99, P < 0.01)was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation(0.99, P < 0.01) was found between protein β-sheet and crude protein.Conclusion: The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.展开更多
The efficient, facile and green synthesis of 4-bromo pyrazolone by using N-bromo saccharine as valuable green reagent encouraged us to prepare some new fused heterocycles as furopyrazole, pyranopyrazole, imidazopyrazo...The efficient, facile and green synthesis of 4-bromo pyrazolone by using N-bromo saccharine as valuable green reagent encouraged us to prepare some new fused heterocycles as furopyrazole, pyranopyrazole, imidazopyrazole, pyrazolothiazole, pyrazol thiazolopyrimidine, pyrazolothiazine, oxathinopyrazole, pyrazolobenzooxazine, and pyrazoloquinoxaline. The synthesis was carried out by a basic condensation of bromo pyrazolone 2 and a suitable reagent in a one-pot reaction using chitosan as a green basic catalyst. The reactions were carried out by microwave irradiation technique as a green source of energy as well as the conventional heating. The antioxidant activity of the prepared compounds was studied using 1,1-phenyl-2-picrylhydrazyl (DPPH) assay and their antibacterial activity against Gram-positive, Gram-negative bacteria and antifungal activity was evaluated.展开更多
Hydrodesulfiirization(HDS)of thiophene,as a gasoline model oil,over an industrial Ni-Mo/Al2O3 catalyst was investigated in a continuous system under microwave irradiation.The HDS efficiency was much higher(5%-14%)unde...Hydrodesulfiirization(HDS)of thiophene,as a gasoline model oil,over an industrial Ni-Mo/Al2O3 catalyst was investigated in a continuous system under microwave irradiation.The HDS efficiency was much higher(5%-14%)under microwave irradiation than conventional heating.It was proved that the reaction was enhanced by both microwave thermal and non-thermal effects.Microwave selective heating caused hot spots inside the catalyst,thus improved the reaction rate.From the analysis of the non-thermal effect,the molecular collisions were significantly increased under microwave irradiation.However,instead of being reduced,the apparent activation energy increased.This may be due to the microwave treatment hindering the adsorption though upright S-bind(η1)and enhancing the parallel adsorption(η5),both adsorptions were considered to favor to the direct desulfurization route and the hydrogenation route respectively.Therefore,the HDS process was considered to proceed along the hydrogenation route under microwave irradiation.展开更多
基金the National Basic Research Program(No.2003CB515400),administered by the Ministry of Science and Technology of China.
文摘A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.
基金The financial support from the Natural Sciences and Engineering Research Council of Canada(NSERC)and our industrial partners,DeBeers,Metso,and Argex companies as well as PhD scholarship to Mr.Samir Deyab from the department of mining engineering,Tripoli University are gratefully acknowledged.
文摘This study is a part of an overall research project on the effects of microwave(MW)irradiation on rocks for assisted rock breaking systems as well as mineral processing at McGill University.For the first time,this paper highlights a comprehensive investigation on the effects of microwave irradiation on Canadian kimberlites.Potential contribution to the continuous rock excavation and rock weakening effect prior to implementation of mechanical techniques was explored.Two different kimberlite rocks,i.e.volcaniclastic kimberlite(VK)and hypabyssal kimberlite(HK),and granite samples were studied.Some important physical properties of the rock samples were measured including rock quality designation(RQD),specific gravity,porosity,and specific heat capacity.Rock samples were treated for various exposure times using a multi-mode MWunit at different power levels ranging from 2 kW to 15 kW.The effect of MW irradiation on rock samples was investigated.The results indicate that the mechanical properties including unconfined compressive strength(UCS)and Brazilian tensile strength(BTS)were significantly dropped as a result of MWirradiation.Finally,the effect on rock abrasivity using the Cerchar abrasivity index(CAI)has also been discussed.
文摘Biodegradable poly(epsilon-caprolactone-co-p-dioxanone)(PCDO) random copolymers have been synthesized by ring-opening polymerization of epsilon-caprolactone(CL) and p-dioxanone(PDO) under microwave irradiation.The effects of irradiation time and different CL/PDO molar feed ratios on the microwave-assisted ring-opening polymerization(MROP) of PCDO have been discussed.The resultant products were characterized by ~1H NMR,GPC and DSC.It was found that the polymerization was completed within 20 min at 140℃.In...
文摘A facile method of preparation of benzimidazoles by microwave irradiation was described. The mixtures of o-phenylenediamine and carboxylic acids were heated by microwave irradiation, to give 2-substituted benzimidazoles with yields of 49%～93%. The reaction time was shortened to 3～6 min. However, the reaction of ethylenediamine with carboxylic acids did not give imidazoles but the N,N-diacyl ethylenediamines. The alphatic diamines lacked the activity to form imidazole ring. With adipic acid, intermolecular acylation took place to afford poly(ethylene adipamide).
文摘A microwave irradiated magnetically separable nano cobalt ferrite catalyzed green method for the synthesis of 4-phenyl-4H-pyrano[3,2-h]quinolin-2-amine and 2-amino-4-phenyl-4H-pyrano[3,2-h] quinoline-3-carbonitrile derivatives through cyclization of aromatic aldehyde, acetonitrile/malononitrile and 8-hydoxyquinoline is developed and presented in this paper. The cubic magnetic cobalt ferrite nano particles were synthesized by sol-gel citrate precursor method and characterized by FT-IR, XRD, SEM and TEM techniques and the structures of the synthesized pyranoquinoline derivatives were assigned by IR, MASS and 1</sup>H NMR techniques. The reaction is carried out in a domestic microwave oven with a heat-resistant microwave safe glass container with a lid.
基金supported by the National Natural Science Foundation of China(21273171)Natural Science Foundation of Shangluo University(16SKY005)Special Scientific Research Project of Education Department of Shaanxi Province Government(17JK0242)
文摘2-Carbonyl propionic acid-4-methyl benzoyl hydrazone(PAMH) has been synthesized by using 4-methyl benzoyl hydrazine and pyruvic acid as the chemicals and acetic acid as phase transfer catalyst under microwave radiation. Then the PAMH and Tb Cl3·6 H2 O are placed in the methanol/acetone/water(3:2:4) mixture for coordination reaction, getting the Schiff complex Tb(PAMH)3. The crystal structure is characterized by elemental analysis, X-ray Diffraction(XRD) and infrared spectrum. The compound crystallizes in the monoclinic space group P21/n, with a = 1.4770(4), b = 1.2864(3), c = 1.9287(5) nm, β = 92.06(3)o, V = 3.6623(15) nm3 and Z = 4. Tb(III) ion is nona-coordinated by three completely deprotonated PAMH ligands in a tricapped trigonal prism geometry, leaving a zero-dimensional mononuclear configuration. The optical properties and thermal stability are studied by ultraviolet spectrum, fluorescence spectra and thermogravimetric analysis(TGA). The antibacterial activities of the ligand and rare-earth complex are preliminarily studied, and found they have certain antibacterial activity on fusarium solani, and the complex is obviously more effective in suppressing fusarium solani than the ligand.
文摘Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.
基金Helpful discussion with Prof.Yitai Qian and financial support from the National Natural Science Foundation of China(NSFC,20501014)Program for New Century Excellent Talents in University(NCET)National Basic Research Program of China(973 Program,2005CB623601,2007CB936602)is gratefully acknowledged.
文摘A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na_(2)TeO_(3) as the Te source in an aqueous environment.The synthesis parameters of this simple and rapid approach,including the reaction temperature and time,the pH of the reaction solution and the molar ratio of the 3-mercaptopropionic acid(MPA)stabilizer to Cd^(2+),have considerable influence on the particle size and photoluminescence quantum yield of the CdTe quantum dots.The photoluminescence quantum yield of CdTe quantum dots prepared using relatively short reaction times(1040 min)reached 40%60%(emission peaks at 550640 nm).Furthermore,the resulting products could be used as fl uorescent probes to detect Hg^(2+)ions in aqueous media.The response was linearly proportional to the concentration of Hg^(2+)ion in the range 8.0×10^(9)mol/L to 2.0×10^(6)mol/L with a detection limit of 2.7×10^(9)mol/L.
基金Project supported by the National Natural Science Foundation of China(21577005)the National Key Research and Development Program of China(2016YFB0600400)
文摘In this work we prepared several CeO2-TiO2 catalysts for the NH3-SCR reactionusing co-precipitation with assistance of microwave irradiation.The catalytic NH3-SCR activities over CeO2-TiO2 catalysts at low temperatures are largely enhanced by the treatment of microwave irradiation,the operation temperature window is also broadened.For better understanding the promotion mechanism,the catalyst prepared by conventional co-precipitation with and without microwave irradiation treatment was characterized with H2-TPR,NH3-TPD,XPS,XRD and BET.Microwave irradiation treatment accelerates the crystallite rate of CeO2-TiO2 catalysts,and greatly enlarges their surface area by adjusting their microstructures.The resistance to SO2 and H2O is also improved via regulating the hierarchical pore structure by the microwave irradiation.Microwave irradiation treatment can also improve the redox property and increase the acid sites over the catalyst surfaces.The result of in situ DRIFTS suggests that the microwave irradiation treatment generates more Br?nsted acid sites on CeO2-TiO2-2 h catalyst,helpful in SCR reactions.XPS results show that after microwave irradiation on the CeO2-TiO2 catalysts,the surface demonstrates an elevated concentration of chemisorbed oxygen,consequently leading to better oxidation of NO to NO2.Additionally,the molar ratio of Ce3+/Ce4+has been elevated after being treated by microwave irradiation,a vital factor in enhancing the NH3-SCR activities.
基金the projects of National Key Technology R&D Program of China(2014BAC24B01)Environmental Development Center of Ministry of Environmental Protection(ZZ-2016-01).
文摘Thermal hydrolysis was an effective pretreatment for the sewage sludge by improving dewatering and anaerobic digestion but the heating was a time-consuming process.This study focused on the effects of the microwave irradiation by using high temperature and pressured system on sewage sludge hydrolysis.The results obtained in current research showed that sludge could absorb microwave energy with high efficiency and then be hydrolyzed fast.The solubilization of suspended solid(SS),volatile suspended solids(VSS)and the increasing of the level of soluble chemical oxygen demand(SCOD)in liquid fraction showed that the microwave irradiation could be shortened to 5 min under a temperature range of 80℃-170℃.The highest value of VSS dissolution ratio(36.4%)was obtained at 170℃for 30 min.The COD dissolution ratio was about 25%at 170℃.The improvement of the biogas production from both mixture sludge and waste activated sludge was 20.2%and 25.9%respectively at 170℃for 10 min.The dewaterability of sludge was greatly improved.Subsequently,the sludge volume could be reduced by 60%with microwave irradiation.
基金supported by the National Basic Research Program of China(Grant No.2005CB221204).
文摘Cu/ZnO/Al_(2)O_(3) catalysts with Cu/Zn/Al ratios of 6/3/1 were precipitated and aged by conventional and microwave heating methods and tested in the slurry phase reactor for methanol synthesis.The effect of technological condition of precipitation and aging process under microwave irradiation on the catalytic performance was investigated to optimize the preparing condition of Cu/ZnO/Al_(2)O_(3) catalyst.The results showed that the microwave irradiation during precipitation process could improve the activity of the catalyst,but had little effect on the stability.While the microwave irradiation during aging process has a great benefit to both the activity and stability of the catalyst,the catalyst aged at 80℃ for 1 h under microwave irradiation possessed higher methanol space time yield(STY)and more stable catalytic activity.The activity and stability of the catalyst was further enhanced when microwave irradiation was used in both precipitation and aging processes;the optimized condition for the catalyst precursor preparation was precipitation at 60℃ and aging at 80℃ under microwave irradiation.
基金This research was supported by the National Natural Science Foundation of China(Nos.51704211 and 51879184).
文摘The microwave-assisted rock fragmentation has been proven to be a promising approach in reducing cutting tools wear and improving efficiency in rock crushing and excavation.Thus,understanding the influence of damage induced by microwave irradiation on rock fragmentation is necessary.In this context,cylindrical Fangshan granite(FG)specimens were exposed to microwave irradiation at a power of 6 kW for different durations up to 4.5 min.The damages of the specimens induced by irradiation were quantified by using both X-ray micro-CT scanning and ultrasonic wave measurement.The CT value and Pwave velocity decreased with increase of irradiation duration.The irradiated specimens were then tested using a split Hopkinson pressure bar(SHPB)system to simulate rock fragmentation.A momentum-trap technique was utilized to ensure single-pulse loading on the specimen in SHPB tests,enabling valid fragment size distribution(FSD)analysis.The dependence of dynamic uniaxial compressive strength(UCS)on the irradiation duration and loading rate was revealed.The dynamic UCS increased with increase of loading rate while decreased with increase of irradiation duration.Using the sieve analysis,three fragmentation types were proposed based on FSD,which were dictated by both loading rate and irradiation duration.In addition,an average fragment size was proposed to quantify FSD.The results showed that the average fragment size decreased with increase of loading rate.A loading rate range was identified,where a dramatic reduction of the average fragment size occurred.The dependence of fragmentation on the irradiation duration and loading rate was also discussed.
基金supported by the key project of Chinese Ministry of Education(No.109086)
文摘A microwave-assisted solid phase synthesis for endothelin 1 is presented.Reduced endothelin 1 was synthesized efficiently on Wang resin under microwave irradiation using Fmoc/tBu orthogonal protection strategy.The whole peptide was cleaved from the resin and two disulphide bridges were formed under air oxidation at room temperature.The purity and efficiency of synthesizing the peptide is much higher than other methods used before.
基金Science and Engineering Research Board(SERB),Department of Science&Technology(DST),New Delhi,India for providing research fund under Ramanujan Fellowship/Award(SB/S2/RJN-159/2017)。
文摘The various methods for microwave processing of materials exhibit numerous advantages,such as short processing times,high yield,expanded reaction conditions,high reproducibility,and high purity of products.Microwave-assisted synthesis strategies have been widely adopted for the preparation of highperformance graphene-based materials for supercapacitor electrodes.Metal oxides,mixed metal oxides,metal hydroxides,layered double hydroxides,carbon nanotubes and conducting polymers are some of the main materials which have been added to graphene derivatives for advanced composite/hybrid electrodes.This review article first provides a brief introduction and an overview of microwave heating and its advantages for processing graphene-based electrode materials.After that,a systematic survey of recently published research on microwave irradiation-assisted processing is presented,focusing on:(i)transformation of graphite/graphite oxide into graphene/graphene oxide by exfoliation and reduction;(ii)formation of graphene derivatives in various liquid and gaseous media;(iii)modification of graphene derivatives with various metal oxides/hydroxides,carbon nanotubes,and conducting polymers for use in supercapacitors.Major challenges and future perspectives for microwave-assisted processing of graphene-based materials for cutting-edge supercapacitor electrode applications are also summarized in the conclusion.
基金financially supported by Fund Science Contract No 1805С,Technical University of Gabrovo,Gabrovo,Bulgaria.
文摘Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst.The resulting esters were characterized by melting point,hydrophilic-lipophilic balance,thin-layer chromatography,ultraviolet spectroscopy,Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR)spectroscopy.Inulin acetate demonstrated a high degree of acetylation(2.5-3.0)and presented a white,water-insoluble substance with bitter taste.The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone.Swelling capacity,water holding,oil-holding capacities,the foamability,foam stability and emulsifying properties were also evaluated.Inulin acetate showed promising foam stability 52%for 60 min and formed stable emulsions at concentration 0.2 g/L with 50 and 80%oil phases.Its water holding capacity was lower than the oil holding capacity.In addition to this,for the first time,the antimicrobial potential of inulin acetate was tested against seventeen microorganisms(Gram-positive and Gram-negative bacteria,yeasts and fungi).Inulin acetate(10 mg/ml)inhibited the growth of Bacillus cereus,Escherichia coli ATCC 8739,Salmonella abony,Candida albicans and Penicillium sp.However,inulin acetate demonstrated antimicrobial activity at concentration 1 mg/ml against Listeria monocytogenes 863,Escherichia coli 3398,Candida albicans 8673,Fusarium oxysporum and Aspergillus niger.The current study demonstrated the applications of“green”synthesized inulin acetate as a foaming agent,oil-in-water emulsion stabilizer and antimicrobial substance in pharmaceutical,agricultural and cosmetic preparations.
文摘Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source forinulin production. “Green” method was performed for accelerated inulin extraction from Helianthus tuberosus L.tubers by the application of microwave irradiation. Further pretreatment of the water extract with acetone andethanol yielded inulin (20%) with purity 89% and degree of polymerization 18. Jerusalem artichoke inulin wascharacterized by FTIR and NMR spectroscopy. For the first time eco-friendly synthesis of acetylated Jerusalemartichoke inulin was performed by the reaction with acetic anhydride, without toxic solvent, but only withsodium acetate as catalyst under microwave irradiation for 60 s. The degree of acetylation (DA=2.1) and thestructure of inulin esters were confirmed by 1H and 13C NMR. The suggested microwave acetylation shortenssignificantly the esterification reaction.
基金financial supports from National Key R&D Plan of China (2017YFB0102803)the National Natural Science Foundation of China (21676135)+8 种基金Scientific Instrument Develop Major Project of National Natural Science Foundation of China (51627810)Joint Funds of the National Natural Science Foundation and Liaoning of China (U1508202)Key R&D programs in Jiangsu (BE2018051)“333” project of Jiangsu Province (BRA2018007)Natural Science Foundation of Jiangsu Province (BK20161273, BK20181199)the Graduate Innovation Foundation of Nanjing university (2017ZDL05)support of PAPD of Jiangsu Higher Education Institutions“Six Talent Peaks Program” of Jiangsu ProvinceFundamental Research Funds for the Central Universities, China。
文摘A series of Pt/C catalysts for proton exchange membrane fuel cells(PEMFCs) with various metal loadings is synthesized by a microwave-assisted polyol process via mixing an extremely stable platinum colloid(> 3 months’ shelf life) from single batch preparation with activated carbon ethylene glycol suspension.21 wt%, 42 wt% and 61 wt% Pt loadings are employed to showcase the advantages of the improved polyol process. The ultraviolet(UV)–visible spectra and ζ-potential measurements are conducted to monitor the wet chemistry process during catalyst preparation. The powder X-ray diffraction(XRD), transmission electron microscopy(TEM) and thermogravimetric analysis(TGA) characterizations are carried out on catalysts. The catalyst activities are investigated using electrochemical and single cell tests. The stability of Pt nanoparticle colloid is explored by ORR, cyclic voltammetry(CV) and ζ-potential measurements. The TEM results show the Pt particle sizes of the colloid, and the sizes of the 21 wt%, 42 wt% and 61 wt%Pt/C samples are 2.1–3.9 nm. Because of the high Pt dispersion, the Pt/C catalysts exhibit superior electroactivity toward ORR. In addition, four 61 wt% Pt/C catalysts made from the Pt colloid with 0–3 months’ shelf life show almost the same performance, which exhibits superior stability of the Pt colloid system without surfactant protection.
基金supported by grants from the Prairie Oat Grower Association(POGA)Natural Sciences and Engineering Research Council of Canada(NSERC-federal government)Ministry of Agriculture Strategic Research Chair(PY)Program
文摘Background: To our knowledge, there is little study on the interaction between nutrient availability and molecular structure changes induced by different processing methods in dairy cattle. The objective of this study was to investigate the effect of heat processing methods on interaction between nutrient availability and molecular structure in terms of functional groups that are related to protein and starch inherent structure of oat grains with two continued years and three replication of each year.Method: The oat grains were kept as raw(control) or heated in an air-draft oven(dry roasting: DO) at 120 °C for 60 min and under microwave irradiation(MIO) for 6 min. The molecular structure features were revealed by vibrational infrared molecular spectroscopy.Results: The results showed that rumen degradability of dry matter, protein and starch was significantly lower(P <0.05) for MIO compared to control and DO treatments. A higher protein α-helix to β-sheet and a lower amide I to starch area ratio were observed for MIO compared to DO and/or raw treatment. A negative correlation(-0.99, P < 0.01)was observed between α-helix or amide I to starch area ratio and dry matter. A positive correlation(0.99, P < 0.01) was found between protein β-sheet and crude protein.Conclusion: The results reveal that oat grains are more sensitive to microwave irradiation than dry heating in terms of protein and starch molecular profile and nutrient availability in ruminants.
文摘The efficient, facile and green synthesis of 4-bromo pyrazolone by using N-bromo saccharine as valuable green reagent encouraged us to prepare some new fused heterocycles as furopyrazole, pyranopyrazole, imidazopyrazole, pyrazolothiazole, pyrazol thiazolopyrimidine, pyrazolothiazine, oxathinopyrazole, pyrazolobenzooxazine, and pyrazoloquinoxaline. The synthesis was carried out by a basic condensation of bromo pyrazolone 2 and a suitable reagent in a one-pot reaction using chitosan as a green basic catalyst. The reactions were carried out by microwave irradiation technique as a green source of energy as well as the conventional heating. The antioxidant activity of the prepared compounds was studied using 1,1-phenyl-2-picrylhydrazyl (DPPH) assay and their antibacterial activity against Gram-positive, Gram-negative bacteria and antifungal activity was evaluated.
基金This work was supported by the National Natural Science Foundation of China(Grant No.21476258).
文摘Hydrodesulfiirization(HDS)of thiophene,as a gasoline model oil,over an industrial Ni-Mo/Al2O3 catalyst was investigated in a continuous system under microwave irradiation.The HDS efficiency was much higher(5%-14%)under microwave irradiation than conventional heating.It was proved that the reaction was enhanced by both microwave thermal and non-thermal effects.Microwave selective heating caused hot spots inside the catalyst,thus improved the reaction rate.From the analysis of the non-thermal effect,the molecular collisions were significantly increased under microwave irradiation.However,instead of being reduced,the apparent activation energy increased.This may be due to the microwave treatment hindering the adsorption though upright S-bind(η1)and enhancing the parallel adsorption(η5),both adsorptions were considered to favor to the direct desulfurization route and the hydrogenation route respectively.Therefore,the HDS process was considered to proceed along the hydrogenation route under microwave irradiation.
