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Current Microwave Chemistry - Current Issue
Volume 11, Issue 1, 2024
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A Review of Ultrasonic Wave Propagation through Liquid Solutions
Authors: Rajalaxmi Panda, Subhraraj Panda and Susanta Kumar BiswalUnderstanding the molecular interactions in liquids or liquid mixtures of binary or ternary liquids is crucial for various applications. Numerous methods and tools exist to elucidate how atoms interact in such mixtures. This review examines multiple research papers investigating molecular interactions, focusing on the acoustic/ultrasonic technique. This technique employs ultrasonic waves to probe molecular interactions. Researchers utilized an ultrasonic interferometer to measure ultrasonic wave velocity, liquid density can be determined by using a specific gravity bottle, and employed the Ostwald viscometer for viscosity measurements. Researchers derived several acoustic and thermodynamic parameters by evaluating ultrasonic wave velocity, liquid density, and viscosity. This comprehensive study dramatically contributes to understanding the molecular interactions within specific samples, with detailed explanations provided for the observed parameters. Ultrasonic wave propagation influences the medium's physical characteristics; it includes knowledge of the physics of liquid and solution. How frequency and temperature affect thermo acoustical characteristics has been investigated. The nature of forces between molecules, including hydrogen bonds, charge transfer complexes, hydrogen bond breaking, and complexes, has been deduced from the investigations above.
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QbD Assisted Optimization of Microwave-assisted Synthesis of Polyacrylamide Grafted Tragacanth: Characterization and Instrumental Analysis
Authors: Mahesh Namballa, Anilkumar Adimulapu and Rajesh E JesudasanBackground: Polysaccharides have recently attracted a lot of attention in the designing of drug delivery systems due to their wide availability, lack of toxicity, and numerous ways that their nature, structure, and functionality can be altered. Methods: Microwave-assisted synthesis of graft copolymer of tragacanth (TRA) is done with polyacrylamide (PAM) by free radical polymerization using ceric ammonium nitrate (CAN) as initiator. Grafting polymer concentration, CAN concentration, and exposure time were selected as independent variables, and their effect is studied for Grafting Efficiency (GE) and Intrinsic viscosity (IV) using Box- Behnken optimization design. Results: A quadratic model was suggested by the software for further statistical evaluation. On the basis of the desirability approach, optimized parameters for microwave-assisted synthesis were demonstrated, and further grafted TRA (Gr-TRA) was synthesized. Gr-TRA was studied for various characterization and elemental analysis. Gr-TRA showed the highest swelling index and least weight loss during the chemical resistance test. Further instrumental analyses like FTIR, XRD, and elemental analysis confirmed the formation of Gr-TRA. Conclusion: Based on all of the above findings, the synthesis of PAM-grafted TRA has been optimized and could be used as a new pharmaceutical excipient in designing different dosage forms.
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Microwave-assisted Green Synthetic Approach towards Water Dispersible Luminescent PVP-coated Tb3+ and Ce3+/Tb3+-doped KZnF3 Nanocrystals
By Shyam SarkarBackground: Perovskite fluoride nanomaterials are an interesting research topic in material science due to their exciting properties like high-temperature superconductivity, magnetic behaviour, piezoelectric behaviour, etc. Doping of lanthanide ions into the perovskite fluoride nanomaterials makes them more promising as they have applications from biological labelling to multicolor optical devices. Objective: This study aimed to carry out the synthesis of perovskite KZnF3 nanocrystals in an ecofriendly environment with the help of a microwave-assisted route in a shorter reaction time and at low temperatures. Moreover, it aimed to make the nanocrystals water dispersible, illuminating brighter photoluminescence, which was achieved by coating nanocrystals surface with poly(N-vinyl- 2-pyrrolidone) and doping of different lanthanide ions (Ln= Tb3+ and Ce3+/Tb3+) respectively, into the KZnF3 nanocrystals matrix. Methods: The synthesis of nanocrystals was performed in an environment-friendly microwave-assisted way and under green conditions. For example, in the preparation of Tb3+(5mol%)-doped KZnF3 nanocrystals, 0.95 mmol of Zn(NO3)2 and 0.05 mmol of Tb(NO3)3 were dissolved in 8 mL of distilled water. Then, an 8 mL aqueous solution of KF (3 mmol) was added to it. The entire mixture was stirred well for 15 minutes. About 60 mg of PVP was added to the mixture and stirred for another 15 minutes. Then, a microwave reaction vessel was made by transferring the final reaction mixture into it and kept under microwave irradiation at 90°C temperature for 15 minutes. Finally, the product was cooled to room temperature and collected by centrifugation. Results: Both Tb3+(5mol%)-doped and Ce3+(15mol%)/Tb3+(5mol%) co-doped KZnF3 nanocrystals exhibit very strong green photoluminescence. The structural and optical properties of as-obtained nanocrystals were characterized by PXRD, field emission scanning electron microscopy, Fourier infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, and photoluminescence spectra. Conclusion: The nanocrystals with uniform cubical morphology having ~60 nm sizes were successfully synthesized. The high photoluminescence efficiency, together with the water dispersibility of the nanocrystals, makes the material useful in many fields of optical devices and offers several biological applications. Moreover, this method could be used to make other lanthanide-doped perovskite fluoride nanocrystals.
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Microwave Assisted Groebke-Blackburn-Bienayme Multicomponent Reaction to Synthesis of Imidazo[1,2-a]pyridine-furan Hybrids as Possible Therapeutic Option for Leukemia, Colon Cancer and Prostate Cancer
Authors: Parth Manvar, Dharmesh Katariya, Amita Vyas, Pooja Bhanderi and Ranjan KhuntAims: Microwave assisted Groebke-Blackburn-Bienayme multicomponent reaction to synthesis imidazo[1,2-a]pyridine-furan hybrids as anticancer agents. Background: Microwave synthesis has emerged as a potent tool for the more economical and environmental friendly synthesis of organic compounds, such as derivatives of imidazo[1,2- a]pyridine. Compared to traditional synthesis, microwave radiation causes molecules to be excited and distributes thermal energy evenly in a shorter amount of time. Objective: The primary objective of the work presented in this article was to prepare imidazo[1,2- a]pyridine-furan hybrids via Groebke-Blackburn-Bienayme multicomponent reaction using PEG 400 in microwave irradiation as green approach. Characterized it and evaluated their anticancer activities. Methods: In a sealed microwave glass vial, 5-methylfuran-2-carbaldehyde 1, 2-aminoazines 2ag, isocyanides 3a-c in presence of 20mol% acetic acid were dissolved in PEG 400 (polyethylene glycol 400) reaction solvent. The glass vial was sealed and irradiate in microwave with stirring at temperature of 75°C for 10 min. This method is an efficient alternative approach to synthesizing imidazo[1,2-a]pyridine-furan hybrids via Groebke-Blackburn-Bienayme multicomponent reaction. Results: We have successfully synthesised the imidazo[1,2-a]pyridine-furan hybrids via Groebke-Blackburn-Bienayme multicomponent reaction using PEG 400 in microwave irradiation as green approach. The structures of the compounds were confirmed through various spectroscopic techniques and evaluated their anticancer activities. Conclusion: The reported protocol is advantageous over conventional methods of imidazo[1,2- a]pyridine derivatives. The time required for the reaction is much less as compared to the usual requirements of reflux. Compound 4e, 4f, 4n and 4o shows the most increased activity against cell line RPMI-8226, HCT-116 and PC-3 of Leukemia, Colon cancer and Prostate cancer respectively. By using the potential of imidazo[1,2-a]pyridine-furan based compounds via sustainable green approach, more effective and accurate cancer treatments can be designed in future.
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Enhancing Intrinsic Electrocatalytic Activity of Pt/C Nanoparticles for Oxygen Reduction Reaction in Acidic Media by Microwave-Assisted Synthesis
This study is focused on the enhancement of the intrinsic electrocatalytic activity of Pt nanoparticles supported on C (Pt/C NPs) towards Oxygen Reduction Reaction (ORR) in acidic media. The goal was to investigate the effect of microwave-assisted synthesis on the electrocatalytic performance of Pt/C NPs towards ORR. Thus, Pt/C NPs were synthesized using a microwave-assisted method and by a conventional heating method; structural and morphological characteristics were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical studies were performed using the rotating disk electrode technique to evaluate the ORR performance. Microwave-assisted synthesis produced Pt/C NPs with a smaller particle size (6.3 ± 0.2 nm) than conventionally synthesized nanoparticles (8.6 ± 0.3 nm). Electrochemical analysis showed that the microwave-synthesized Pt/C NPs exhibited higher mass activity (4.6 ± 0.8 mA g-1Pt) for ORR compared to conventionally synthesized nanoparticles (1.9 ± 0.4 mAmAg-1Pt). These results demonstrate that microwave-assisted synthesis enhances the intrinsic electrocatalytic activity of Pt/C NPs for ORR in acidic media. These findings have important implications for the development of efficient electrocatalysts for fuel cell applications. Background: The synthesis and characterization of platinum nanoparticles on C are crucial for advancing electrocatalysis, particularly in the context of potential applications in fuel cells. This study builds on previous research, focusing on two distinct synthesis methods to enhance our understanding of their impact on nanoparticle properties and electrocatalytic performance. Objective: To investigate the synthesis efficiency, structural characteristics, and electrocatalytic activities of platinum nanoparticles on C using microwave-assisted heating and conventional synthesis reactor heating. The objective is to discern any significant differences in particle size, structure, and electrocatalytic performance between the two synthesis methods. Methods: The synthesis involved a comparative analysis of platinum nanoparticles using microwaveassisted and conventional heating methods. Chemical composition analysis verified the synthesis efficiency, and structural and morphological characterizations were performed using X-ray Diffraction and Transmission Electron Microscopy. Electrochemical studies employed the rotating disk electrode technique, with activation and evaluation conducted through cyclic voltammetry, and the oxygen reduction reaction studied via linear sweep voltammetry in an acidic media (0.5 molL-1 H2SO4). Results: Well-supported platinum nanoparticles with a face-centered cubic structure were obtained on C using both synthesis methods. However, microwave-synthesized particles (6.3 ± 0.2 nm) exhibited a smaller size compared to conventionally synthesized particles (8.6 ± 0.3 nm). Electrochemical assessment revealed superior mass activity for microwave-synthesized material (4.6 ± 0.8 mA g-1Pt), outperforming commercial Pt nanoparticles (3.0 ± 0.3 mA g-1Pt) and conventionally synthesized material (1.9 ± 0.4 mA mA g-1Pt). Conclusion: This study concludes that microwave-assisted synthesis yields platinum nanoparticles on C with enhanced electrocatalytic performance, as evidenced by the smaller particle size and superior mass activity compared to conventionally synthesized material and commercial Pt nanoparticles. These findings highlight the potential of microwave-synthesized Pt nanoparticles for applications in fuel cells.
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Recent Advances in Using Microwaves to Prepare Chemicals at the Industrial Level
More LessMicrowave-assisted synthesis has faced challenges in implementing its use at the industrial level in recent decades, including scaling up the processes. While microwave-assisted synthesis is established on a laboratory scale, there are some drawbacks associated with it, including the equipment and operational costs of the specialized microwave reactors, safety concerns due to high temperatures and pressures, reaction selectivity, capacity to control the rapid heating and cooling rates associated with the kinetics of some reactions, and optimization of reproducibility in the results. This manuscript discusses the relevant and recent news in the last ten years about the application of industrial reactors for producing chemicals at the industrial level.
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