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Wyniki wyszukiwania dla: MICROWAVE ASSISTED SYNTHESIS
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Microwave-assisted synthesis of zinc derivatives of potato starch
PublikacjaZincatated potato starch was prepared in a solid-state, microwave-assisted reaction using generated in situ sodium tetrahydroxozincate [Na2Zn(OH)4]. For comparison, zincatation of starch was also carriedout on convectional heating. Depending on the irradiation conditions, the products of either mono- or crosslinking esterification were formed. Higher power applied at shorter exposition offered products ofmonoesterification, and...
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Microwave-assisted synthesis of a TiO2-CuO heterojunction with enhanced photocatalytic activity against tetracycline
PublikacjaA microwave method was used for the synthesis of TiO2-CuO oxide systems. A detailed investigation was made of the effect of the molar ratio of components (TiO2:CuO=9:1, 7:3, 5:5, 3:7, 1:9) on the crystalline structure and morphology. Transmission electron microscopy (TEM) confirmed the presence of octahedral and rod-shaped titania particles and sheet copper(II) oxide particles; moreover, HRTEM analysis indicated the presence of...
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Design and Microwave-Assisted Synthesis of TiO2-Lanthanides Systems and Evaluation of Photocatalytic Activity under UV-LED Light Irradiation
PublikacjaThe TiO2-Eu and TiO2-La systems were successfully synthesized using the microwave method. Based on the results of X-ray diffraction analysis, it was found that regardless of the analyzed systems, two crystal structures were noted for the obtained samples: anatase and rutile. The analysis, such as XPS and EDS, proved that the doped lanthanum and europium nano-particles are present only on the TiO2 surface without disturbing the...
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Microwave-assisted hydrothermal synthesis and electrochemical studies of α- and h-MoO3
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Microwave-assisted silication of potato starch
PublikacjaSilication of potato starch was performed by microwave irradiation and convectional heating of starch with sodium metasilicate. The study has shown that microwaves offered more selective silication thanconvectional heating. Depending on the dose of metasilicate products of either monoesterification or crosslinking esterification were formed. Increase in the amount of the silicating agent favoured crosslinking of starch. In the...
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Microwave-assisted boration of potato starch
PublikacjaZiarnistą skrobię ziemniaczaną boranowano za pomocą kwasu borowego i dziesięciowodnego tetraboranu sodu (boraksu) w reakcji wspomaganej mikrofalami. Określono wpływ stosunku substratów oraz czasu trwania i mocy naświetlania na stopień estryfikacji (DE) produktów. Maksymalna wartość DE w próbkach skrobi boranowanej kwasem wyniosła 0,27, a boranowanej boraksem 0,18. Ustalono, że chociaż zmodyfikowana skrobia, o strukturze estrów...
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Synthesis of Titanium Dioxide via Surfactant-Assisted Microwave Method for Photocatalytic and Dye-Sensitized Solar Cells Applications
PublikacjaIn this study, titania nanoparticles were obtained using the microwave-assisted technique. Moreover, different surfactants (PEG (Mn = 400), Pluronic P123 and Triton X−100) were used during the synthesis in order to determine their impact on the crystallinity and morphology of the final products. Subsequently, techniques such as XRD, SEM and TEM (performed in high contrast and high-resolution mode), diffuse reflectance spectroscopy...
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Synthesis of amides under microwave irradiation
PublikacjaAmides belong to the most important carboxylic acid derivatives. They are constituents of natural compounds like peptides and proteins. They found applications in many branches of science and industry, especially in pharmaceutical and polymer science. Conventional procedures for amide preparation involve reaction between amine and carboxylic acid or their more active derivatives such as acid chlorides, acid anhydrides or esters....
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Rheology of potato starch chemically modified with microwave-assisted reactions
PublikacjaNative potato starch was sulfated, selenated, borated, silicated and zincatated by means of microwave-assisted reactions with varying doses of relevant reagents. Resulting products were characterized involving rheological behavior of pastes, their weight-average molecular weight (Mw), and radius of gyration (Rg). Most of the pastes showed shear-thinning behavior, with the flow behavior index (n) below unity. The pastes of starch...
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublikacjaApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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Microwave radiation in the synthesis of urethane prepolymers
PublikacjaThis paper describes the use of microwave radiation in the synthesis of urethane prepolymers in bulk (without solvent). The prepolymers were synthesized using 1,6-hexamethylene diisocyanate (HDI) and poly (ε-caprolactone) diol (PCL) at a molar ratio of 4:1. The reaction was carried out without a catalyst in the reactor with a conventional heating system (oil bath) or in the microwave reactor (MW Reactor NOVA 09) at temperatures...
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A review of amide bond formation in microwave organic synthesis
PublikacjaMicrowave-Assisted Organic Synthesis (MAOS) is one of the most current trends in organic chemistry. Herein, both the most popular and new approaches in microwave-syntheses of very important linkage in Nature - amide bond - are overviewed and compared with conventional synthetic routes.
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Fast surrogate-assisted simulation-driven design of compact microwave hybrid couplers
PublikacjaThis work presents a robust methodology for expedited simulation-driven design optimization of compact microwave hybrid couplers. The technique relies on problem decomposition, and a bot-tom–up design strategy, starting from the level of basic building blocks of the coupler, and finishing with a tuning procedure that exploits a fast surrogate model of the entire structure. The latter is constructed by cascading local response surface...
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Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles
PublikacjaNowadays, more than ever, environmental awareness is being taken into account when it comes to the design of novel materials. Herein, the pathway to the creation of a colloid of spherical, almost purely metallic nickel nanoparticles (NPs) through pulsed laser ablation in ethanol is presented. A complex description of the colloid is provided through UV-vis spectroscopy and dynamic light scattering analysis, ensuring insight into...
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Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles
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Microwave Assisted Liquefaction with Crude Glycerol as a Potential Method of Brewer’s Spent Grain Utilization
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Microwave assisted liquefaction with crude glycerol as a potential method of brewer's spent grain utylization
PublikacjaBrewer's spent grain was applied as a low-cost industrial type of lignocellulose biomass in a liquefaction and solvent: biomass ratio on the efficiency of the process, chemical structure and basic properties of obtained prepared polyols and soil residues shed light on the biomass degradation mechanism through application of microwaves and further reaction of degradation products with solvent particles.
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Microwave-assisted preparation of Li3V2(PO4)3/C composite with high-rate capacity
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Effect of Microwave Radiation Power on the Size of Aggregates of ZnO NPs Prepared Using Microwave Solvothermal Synthesis
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Biopolyols obtained via microwave-assisted liquefaction of lignin: structure, rheological, physical and thermal properties
PublikacjaThe present study examined the application of polyols obtained via microwave-assisted liquefaction of lignin in the production of rigid polyurethane foam. Lignin was liquefed in crude glycerol and 1,4-butanediol at diferent temperatures (130–170 °C), without a catalyst and using various biomass concentrations (15 and 30 wt%). The physicochemical properties, process yield, and FTIR-based identifcation of the obtained polyols were...