microwave irradiation

摘要： 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.

摘要： 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.

摘要： 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.

摘要： 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 1H NMR techniques. The reaction is carried out in a domestic microwave oven with a heat-resistant microwave safe glass container with a lid.

摘要： A type of exfoliated kaolinite was produced by urea-intercalation and original microwave irradiation assisted method. The product was investigated by Fourier trans-formation infrared (FT-IR) spectroscopy, X-ray diffraction(XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET) and laser particle analysis techniques.FT-IR spectra show that NHCO molecule exists in the intercalated kaolinite. XRD analyses indicate that the kao-linite sheet-like structure was disordered after microwave irradiation. The urea decomposition process and explosion effect between the sheet-like structures of kaolinite under microwave irradiation were discussed. The SEM and BET analyses reveal that the end product is exfoliated kaolinite with thin particles and increased surface area. Size and zeta potential analyses show that the particle size distribution is between 250 nm and 550 nm with normal distribution and the particle is negatively charged. In comparison with the conventional grind method, the process adopted appears to be economic and the exfoliated kaolinite end product may display a significantly enhanced performance in industrial applications.

摘要： Polyaspartic acid (PASP) is suitable for the inhibition of scale deposition from water.To enhance its inhibition efficiency, PASP was modified by reacting aspartic acid (Asp) with glutamic acid (Glu) to provide Asp-Glu copolymer under microwave irradiation.The influence of reaction parameters on conversion, molecular weight and inhibition of CaCOa precipitation was investigated Infra-red.(IR),1H nuclear magnetic resonance (1H NMR) and 13C nuclear magnetic resonance (13C NMR) spectroscopies were used to characterize the copolymer.The results show that copolymerization of aspartic acid and glutamic acid is catalyzed by a small amount of phosphorous acid (H3PO4) in solvent, the product conversion is 98.05% under the following conditions: the molar ratio of glutamic acid to reactant [Glu/(Asp+Glu)] is 0.3 and that of catalyst (Cat) to reactant [Cat/(Glu+Asp)] is 0.05 (0.65ml H3PO4), the volume of solvent dimethylformamide is 16ml, the microwave power used is 720W and the reaction for 3 rnin.The weight average molecular weight of copolymer synthesized under these conditions is 2709 and the inhibition rate for CaCO3 is 97.75%.

摘要： In this paper, the characteristics of the preparation of novolacs for the shell process under microwave irradiation are investigated. Both polymerization and dehydration of the resins under microwave irradiation are compared with those under conventional heating and further analysis is made. The results show that compared with those under conventional heating, the polymerization and dehydration time under microwave irradiation are shortened by 85.2% and 80.7% respectively; On the other hand, the polymerization and dehydration under microwave irradiation lead to a remarkable increase in flow distance of the resins. Furthermore, the polymerization under microwave irradiation leads to reduced cure time, while the dehydration under microwave irradiation causes a slight increase in cure time.

摘要： The title compound (C25H24N4O3) has been prepared by the cyclocondensation of 5-amino-3-methyl-1-phenypyrazol, m-nitrobenaldehyde and dimedone in glycol under microwave irradiation without catalyst. The crystal structure was determined by single-crystal X-ray diffraction to be orthorhombic, space group Pbca with a = 16.3331(10), b = 13.8329(9), c = 19.4163(12) (A), V= 4386.8(5) (A)3, Z = 8, Dc = 1.298 g/cm3,μ = 0.087 mm-1, F(000) = 1808, Mr = 428.48, the final R =0.0519 and wR = 0.1019. X-ray analysis revealed that the pyridine ring is of boat conformation and the six-membered ring fused with it adopts twist boat conformation.

摘要： The title compound (C19H29NO4) has been synthesized by the reaction of propaldehyde with dimedone and hydroxylamine hydrochloride in glycol under microwave irradiation, and its structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 12.533(1), b = 13.184(2), c = 11.883(2)(A), ц = 109.06(1)°, V = 1856.0(5)(A)3, Mr = 335.43, Z = 4, Dc = 1.201 g/cm3, λ = 0.71073 (A), ц(MoKаа = 0.083 mm-1 and F(000) = 728. The structure was refined to R = 0.0488 and Wr = 0.1456 for 2306 observed reflections with I > 2б(I). X-ray analysis reveals that the pyridine ring adopts a boat conformation, while two cyclohexanone rings have envelope conformations.