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This review presents a summary of reactions performed using microwave irradiation. This green processes have resulted through use of less or no catalyst, readily recyclable solvents and yield that are often higher than conventional method. It also focus on the principle of microwave activation, various types of Microwave Reactor and its characteris...
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... is worth stressing that microwaves, in contrast to conventional heating methods, are means of volumetric heating of materials( Figure:5), which causes more extensive heating inside the material in comparison with outer layers of the material, which in turn makes hard a proper measurements of the reaction temperature. Temperature measurement under microwaves Smita Jauhari et al ...
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... Dipolar polarization and ionic conduction are the two basic ways by which the electric component of an electromagnetic field generates heat. The sample's ions or dipoles align in the applied electric field when exposed to MW radiation [11]. As the applied field oscillates, the dipole or ion field strives to realign itself with the alternating electric field. ...
... 24 Recently, a newer method utilizing a low-energy source such as microwave irradiation has been intensively studied in chemical synthesis, including for hydrogel preparation due to its safety profile, low cost, and ease of operation compared to high-energy radiation sources. 25,26 Moreover, microwave-assisted irradiation provides several advantages in chemical reactions, such as reduced catalyst and organic solvent use, reaction time, waste products, and an improved reaction yield. 25,27 Microwave irradiation is therefore a promising choice of an energy source for the PVA/ PVP-based hydrogel synthesis compared to gamma irradiation 17,28 because gamma radiation sources are not widely available due to its relatively high costs. ...
A simple and economical method for polyvinyl alcohol/polyvinylpyrroli-done/citric acid (PVA/PVP/CA) hydrogel preparation using microwave-assisted irradiation was presented. The synthesized hydrogels embedded with berberine or chlorogenic acid were investigated as a wound dressing agent. This study showed that the optimum condition for the hydrogel synthesis based on gel fraction and a degree of swelling values was 6:6:3% (w/v) of PVA/PVP/CA under 600 W at 120°C for 3 min of microwave irradiation. Herbal active compounds, berberine and chlorogenic acid, were loaded onto the hydrogel (4% (w/v)), and both were able to inhibit the growth of Staphylococcus aureus. Additionally, the anti-inflammatory study revealed that 700 μg/mL berberine and 2500 μg/ mL chlorogenic acid could inhibit protein degradation equivalent to a 200 μg/mL aspirin solution. The drug release study demonstrated that both compounds showed a more sustained release into PBS than water. The mechanism for the three-dimensional network formation based on esterification and the hydrogen-bonding interaction was also proposed. The ionic liquid-like structure of PVP-CA possibly played an important role in the cross-linking process. In addition, sodium bicarbonate applied to the synthesized hydrogel also had a significant effect in enhancing gel formation. The proposed approach showed a potential of the loaded hydrogels to protect wounds from infection and enhance the healing process.
... 21,28 Toxicity and daily metal requirements are the main criteria considered in the selection of candidate cations during the preparation of bio-MOFs. Several factors are considered when evaluating toxicity, including the median lethal dose (LD 50 ), which is the quantity of a compound capable of removing 50% of a sample within a determined period. It is most appropriate to construct bio-MOFs from metals that have a given fatal dose over oral prescription to mice (LD 50 , mg kg À1 ), such as Fe 3+ (LD 50 FeCl 3 = 450), Fe 2+ (LD 50 FeCl 2 = 984), Ca 2+ (LD 50 CaCl 2 = 1940), Zn 2+ (LD 50 Zn (OAc) 2 = 100-600), and Mg 2+ (LD 50 MgSO 4 = 5000). ...
... Several factors are considered when evaluating toxicity, including the median lethal dose (LD 50 ), which is the quantity of a compound capable of removing 50% of a sample within a determined period. It is most appropriate to construct bio-MOFs from metals that have a given fatal dose over oral prescription to mice (LD 50 , mg kg À1 ), such as Fe 3+ (LD 50 FeCl 3 = 450), Fe 2+ (LD 50 FeCl 2 = 984), Ca 2+ (LD 50 CaCl 2 = 1940), Zn 2+ (LD 50 Zn (OAc) 2 = 100-600), and Mg 2+ (LD 50 MgSO 4 = 5000). Daily dosage is another important issue as the human body requires a few essential trace elements. ...
... It is noteworthy that even slight changes in the mentioned factors could morphologically transform MOFs. 49,50 Recently, the microwave approach has been applied to the process of MOF synthesis. In a study by Jhung et al., 51 10 ]Á38H 2 O was conducted using NiCl 2 Á6H 2 O, glutaric acid, KOH, isopropyl alcohol (IPA), as well as water for 1 min microwave irradiation at 220 1C. ...
Biological metal-organic frameworks (bio-MOFs) constitute a growing subclass of MOFs composed of metals and bio-ligands derived from biology, such as nucleobases, peptides, saccharides, and amino acids. Bio-ligands are more abundant than other traditional organic ligands, providing multiple coordination sites for MOFs. However, bio-MOFs are typically prepared using hazardous or harmful solvents or reagents, as well as laborious processes that do not conform to environmentally friendly standards. To improve biocompatibility and biosafety, eco-friendly synthesis and functionalization techniques should be employed with mild conditions and safer materials, aiming to reduce or avoid the use of toxic and hazardous chemical agents. Recently, bio-MOF applications have gained importance in some research areas, including imaging, tumor therapy, and targeted drug delivery, owing to their flexibility, low steric hindrances, low toxicity, remarkable biocompatibility, surface property refining, and degradability. This has led to an exponential increase in research on these materials. This paper provides a comprehensive review of updated strategies for the synthesis of environmentally friendly bio-MOFs, as well as an examination of the current progress and accomplishments in green-synthesized bio-MOFs for drug delivery aims and tumor treatments. In conclusion, we consider the challenges of applying bio-MOFs for biomedical applications and clarify the possible research orientation that can lead to highly efficient therapeutic outcomes.
... This mechanism depends, among other factors, on the ion concentration, ionic size, the dielectric constant of the medium, the MW frequency, and the viscosity of the reacting medium [80]. The ions present in a solution are influenced by an electric field resulting in their migration throughout the polar liquid as the electric field changes, which causes them to move back and forth through the solvent, generating friction as well as increasing the rates of collision, ultimately expending their kinetic energy as heat energy (Figure 7) [59,83,89]. ...
The effective exploitation of lignin, the world’s largest renewable source of aromatics, is alluring for the sustainable production of chemicals. Microwave-assisted depolymerisation (MAD) of lignin using hydrogen-donating solvents (HDS) is a promising technique owing to its effective volumetric heating pattern and so-called “non-thermal effects.” However, lignin is a structurally complex bio-polymer, and its degradation produces a myriad of products; consequently, MAD reaction mechanisms are generally complex and poorly understood. This review aims to provide a perspective of current research into MAD reaction mechanisms involving HDS, with the goal to give researchers an overall understanding of MAD mechanisms and hopefully inspire innovation into more advanced methods with better yields and selectivity of desired aromatics. Most reaction mechanisms were determined using characterisation methods such as GC-MS, MALDI-TOF, 2D-NMR, GPC, and FT-IR, supported by computational studies in some instances. Most mechanisms generally revolved around the cleavage of the β–O–4 linkage, while others delved into the cleavage of α–O–4, 4–O–5 and even C–C bonds. The reactions occurred as uncatalysed HDS reactions or in combination with precious metal catalysts such as Pt/C, Pd/C and Ru/C, although transition metal salts were also successfully used. Typical MAD products were phenolic, including syringol, syringaldehyde, vanillin and guaiacol.
... In the game of soccer, there are several techniques that a soccer player must master in order to play well and correctly. The basic techniques are: 1) kicking, 2) dribbling, 3) passing, 4) holding, and 5) shooting (Ashfahany et al., 2017;Sudarmono et al., 2013;Surati et al., 2012). From these five basic techniques, the author intends to conduct research on passing using the inside of the foot. ...
The low learning outcomes for passing in class body weight position is not forward. The aim of this research is to find out whether the use of the command learning method can improve the learning outcomes of basic passing techniques for mentally retarded children. The population and sample in this study were students with intellectual disabilities in class X SMALB, totaling 4 students. This research is Classroom Action Research. The data collection techniques used were performance tests, student and teacher observation sheets. Data were analyzed by exposure between cycles. Based on the initial data results, the average student score was 65.25. Learning improvements in cycle I, the average student score rose to 75.5 or 10.25%. Learning improvements in cycle II saw an increase in the average student score by 81 or an increase of 5.5%. The research results in cycle II showed that there was a significant increase in classical completeness compared to cycle I with scores having reached the Minimum Completeness Criteria (KKM 75).
... The use of reactant heating using microwaves can reduce energy consumption because it can accelerate the reaction and improve product yield (Badgujar et al. 2016). Microwaves will directly couple with molecules in the entire reaction mixture system, causing a rapid temperature rise and resulting in better heat homogeneity than conventional heating (Surat et al. 2012). The even heating of the reaction system caused the product yield of nitrobenzene to be quite good in just 2.5 h. ...
Natural zeolite and sulfated natural zeolite catalyst materials have been successfully prepared, characterized, and applied as a replacement for the role of a sulfuric acid catalyst in the synthesis of nitrobenzene. Natural zeolites were prepared into uniform-sized powders and then refluxed with H 2 SO 4 with varying concentrations of 0, 1, 2, 3, and 4 M, proceeded by calcination with N 2 gas flow (labeled as NZ, SNZ-1, SNZ-2, SNZ-3, and SNZ-4). Nitrobenzene was synthesized in a batch microwave reactor using natural zeolite and sulfated natural zeolite catalysts with the best acidity value. The results showed that the sulfuric acid treatment of natural zeolite caused changes in its physical and chemical characteristics. The NZ catalyst has an acidity value of 1.742 mmol g −1 , and the 2 M concentration variation resulted in the sulfated natural zeolite with the best acidity value of 1.625 mmol g −1. The optimal amount of catalyst required is 1.0 g. Both catalysts are selective toward the nitration reaction of benzene. The average benzene conversion produced for each catalyst was 41.53 ± 3.61% and 58.92 ± 1.37%. Furthermore, the SNZ-2 catalyst has better reusability for three reaction runs.
... Following the cleavage both homo and hetero oligomers are produced with adequate yields varying between 43% and 95%. It is then thought that this could give the explanation of why microwave heating in SPPS often does not only make the reaction faster but is also responsible for the availability of higher peptide purities compared to conventional room temperature [24]. ...
... Due to the extremely high thermal conductivity and effusivity (the ability of exchanging thermal energy with the surrounding) of this SiC ceramic, the heat flow from the reactor to the reaction vessel is very fast and therefor fast heating occurs. At the same time, a fast stirring rate is also applied to transfer the heat homogeneously throughout the reaction solution (Surati et al., 2012). Several organic reactions used by nonmicrowave instant heating have been reported (Kappe, 2004;Chen et al. 2018;Surati et al., 2012;Kappe, 2018). ...
... At the same time, a fast stirring rate is also applied to transfer the heat homogeneously throughout the reaction solution (Surati et al., 2012). Several organic reactions used by nonmicrowave instant heating have been reported (Kappe, 2004;Chen et al. 2018;Surati et al., 2012;Kappe, 2018). ...
Cesium in-cooperated in Mobile Composite Matter Number 41 (CsMCM-41) was synthesized via hydrothermal synthesis. The material used involve Ludox AS-40 as silica (SiO2) source, aluminum isoproxide as alumina (Al2O3) source, Cesium hydroxide (CeOH) as mineralizer. CsMCM-41 was characterized using X-ray diffraction (XRD), N2 adsorption-desorption isotherms and X-ray fluorescence (XRF) spectroscopy. The sample shows a high surface area (685 m2 g-1), large pore volume (0.99 m2g-1), and 20.7 Ao as its pore size. The basicity of the sample was determine using back titration to obtained 101.57 mmol g-1. CsMCM-41 was used as heterogeneous solid base catalyst which is more environmentally friendly to synthesize jasminaldehyde via an aldol condensation reaction between benzaldehyde and heptanal at different temperature and reaction time. This replace the homogeneous base (NaOH, KOH) catalyst that produce corrosive bases as a waste. Four different heating methods were studied. Microwave, non-microwave instant heating, oven and refluxing method. The microwave heating method gave higher conversion (78.2%) and higher selectivity (70.2%) to jasminaldehyde at 180oC in 45 min. as a result of minimized heat loss displayed by the apparatus. Oven synthesis method gave lower conversion (29.4%) and lower selectivity (53.1%), at 180oC at a longer reaction time (24 hours), which resulted due to heat loss to the surrounding. Microwave irradiation was found to be the best heating method for jasminaldehyde synthesis. The catalyst (Cs-MCM-41) is environmentally friendly and can be recycled number of times (up to 5 times), without catalyst deactivation at the same time no waste generated.
... MWI induces friction and rotation of polar molecules, enabling direct and uniform internal heating, which has been considered an eco-friendly and high-efficiency heating method. MWI is effective in the manufacturing of various materials and in organic synthesis [18,19]. Furthermore, MWI provides more benefits than traditional heat treatment methods as it can selectively heat samples with a high heat transfer efficiency, a short processing time, low energy consumption, and cost-effectiveness [20][21][22]. ...
This study proposes a high-performance organic-inorganic hybrid memristor for the development of neuromorphic devices in the memristor-based artificial synapse. The memristor consists of a solid polymer electrolyte (SPE) chitosan layer and a titanium oxide (TiOx) layer grown with a low-thermal-budget, microwave-assisted oxidation. The fabricated Ti/SPE-chitosan/TiOx/Pt-structured memristor exhibited steady bipolar resistive switching (BRS) characteristics and demonstrated excellent endurance in 100-cycle repetition tests. Compared to SPE-chitosan memristors without a TiOx layer, the proposed organic-inorganic hybrid memristor demonstrated a higher dynamic range and a higher response to pre-synaptic stimuli such as short-term plasticity via paired-pulse facilitation. The effect of adding the TiOx layer on the BRS properties was examined, and the results showed that the TiOx layer improved the chemical and electrical superiority of the proposed memristor synaptic device. The proposed SPE-chitosan organic-inorganic hybrid memristor also exhibited a stable spike-timing-dependent plasticity, which closely mimics long-term plasticity. The potentiation and depression behaviors that modulate synaptic weights operated stably via repeated spike cycle tests. Therefore, the proposed SPE-chitosan organic-inorganic hybrid memristor is a promising candidate for the development of neuromorphic devices in memristor-based artificial synapses owing to its excellent stability, high dynamic range, and superior response to pre-synaptic stimuli.
... In 1986, the first application of microwave irradiation in chemical synthesis was published [37]. Microwavesupported synthesis has transformed chemical synthesis, where microwave irradiation is generally used as a heat source in chemical synthesis [38]. ...
... The fundamental mechanisms observed in microwave-supported syntheses were conduction and dipolar polarization [38]. Microwavesupported synthesis offers better selectivity, cleaner synthesis with improved reaction rates, higher yields, and more economical for synthesis of large quantity of organic molecules, when compared with conventional heating [37,38]. Numerous materials have diverse responses when subjected to microwave radiation; therefore, not all the materials are liable to microwave heating [37,38]. ...
... Microwavesupported synthesis offers better selectivity, cleaner synthesis with improved reaction rates, higher yields, and more economical for synthesis of large quantity of organic molecules, when compared with conventional heating [37,38]. Numerous materials have diverse responses when subjected to microwave radiation; therefore, not all the materials are liable to microwave heating [37,38]. In line with this, materials liable to microwaves (i) absorb microwaves, such as water, (ii) reflect microwaves, such as copper, or (iii) are transparent to microwave, such as sulfur [38]. ...
This study reports how to overcome the challenges experienced in achieving successful synthesized Schiff base via types of Schiff base (chiral and achiral), synthesis, nature of products, and its antibacterial applications. Schiff base is a versatile ligand which is useful in asymmetric reactions to prepare chiral catalysts. It is also used in symmetric reactions to prepare achiral compounds. In line with the achiral compounds, conventional (room temperature and refluxing) and microwave irradiation methods are the two main types of methods to synthesize achiral Schiff base as reported in this review. Among various experimental approaches, this study supports the green chemistry microwave approach to synthesize Schiff base because of its benefits environmental sustainability. Problems relating to the nature of products formed from the synthesized Schiff bases were examined and resolved. Herein, the products could either be solid (crystals, powder, and precipitate), oily, or viscous (sticky) products. Some familiar characterization techniques used to identify and confirm the successful syntheses of Schiff bases, such as solubility test, melting point (MP), Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis), and nuclear magnetic resonance (NMR, 1 H NMR, and 13 C NMR), were discussed. In addition, the antibacterial studies on Schiff base and corresponding metal complexes confirmed their biological relevance to the human.
