Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
7.4
4.2
Journals
Molecules
Special Issues
The Application of Microwave-Assisted Technology in Chemical Reaction
molecules-logo
Submit to Molecules Review for Molecules Propose a Special Issue

Journal Menu

► Journal Menu

Journal Browser

► Journal Browser
share announcement

The Application of Microwave-Assisted Technology in Chemical Reaction

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Microwave Chemistry".

Deadline for manuscript submissions: closed (31 January 2025) | Viewed by 16867

Special Issue Editors

Prof. Dr. Yong Nie

E-Mail Website
Guest Editor
College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
Interests: microwave; biomass energy; process intensification; biodiesel; reactor development
Dr. Qinglong Xie

E-Mail Website
Guest Editor
College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China
Interests: process intensification; microwave; biodiesel; glycerol; fixed-bed reactor; numerical simulation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Compared with conventional heating, microwave heating offers many advantages, including rapid and uniform heating, ease of set-up and operation, and low cost. The microwave-assisted technology has been applied in various organic and inorganic reactions, which can enhance the processes. An exploration of the thermal and non-thermal intensification effects of the microwave irradiation, especially at the molecular scale, will help us understand the microwave technology more deeply and promote its applications. This Special Issue aims to collect original research papers and review articles focused on the abovementioned aspects of microwave-assisted chemical reactions. Manuscripts presenting research on the application of microwave technology in chemical reactions, heat and mass transfer in microwave-assisted reactions, numerical simulation of microwave-heated processes, and intensification mechanism of microwave irradiation are all welcome.

Prof. Dr. Yong Nie
Dr. Qinglong Xie
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • microwave
  • process intensification
  • numerical simulation
  • thermal effect
  • non-thermal effect
  • reaction kinetics
  • heat transfer
  • microwave catalysis

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (10 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review

8 pages, 3452 KiB  
Communication
Solvent-Free and Microwave-Assisted Synthesis Enables Formation of Imidazole and Pyrazole Derivatives Through Epoxide Ring Opening
by MaryGrace McAfee, Joshua Pack and Brian Walker
Molecules 2025, 30(8), 1760; https://doi.org/10.3390/molecules30081760 - 14 Apr 2025
Viewed by 510
Abstract
A solvent-free, microwave-assisted approach for the ring-opening reactions of phenyl glycidyl ether with a series of commercially available imidazoles and pyrazoles is described. Microwave irradiation allows reactions to proceed rapidly. This straightforward approach efficiently generated adducts with competitive yields compared to traditional methods [...] Read more.
A solvent-free, microwave-assisted approach for the ring-opening reactions of phenyl glycidyl ether with a series of commercially available imidazoles and pyrazoles is described. Microwave irradiation allows reactions to proceed rapidly. This straightforward approach efficiently generated adducts with competitive yields compared to traditional methods that use conventional heating or organic solvents. This technique is particularly suited for high-throughput screening in drug discovery, offering a significant reduction in time and resource consumption. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

16 pages, 5851 KiB  
Article
Microwave-Assisted Doping Engineering Construction of Spinel-Structured Nonstoichiometric Manganese Cobaltite with Mixed 1D/2D Morphology for Supercapacitor Application
by Yuxuan Sheng, Yin Sun, Jin Yan, Wei Wang, Shuhuang Tan, Yuchen Lin, Haowei Wang, Yichen Liu, Baotong Xie and Xiaoran Sun
Molecules 2025, 30(4), 873; https://doi.org/10.3390/molecules30040873 - 14 Feb 2025
Viewed by 426
Abstract
High-performance electrode materials are fundamental to improving supercapacitor performance, serving as key factors in developing devices with high energy density, high power density, and excellent cyclic stability. Non-stoichiometric spinels with phase deficiencies can achieve electrochemical performance that surpasses that of stoichiometric materials, owing [...] Read more.
High-performance electrode materials are fundamental to improving supercapacitor performance, serving as key factors in developing devices with high energy density, high power density, and excellent cyclic stability. Non-stoichiometric spinels with phase deficiencies can achieve electrochemical performance that surpasses that of stoichiometric materials, owing to their unique structural characteristics. In this study, we used a microwave-assisted method to synthesize a high-performance non-stoichiometric spinel material with phase deficiencies, Mn0.5Co2.5O4, which displayed a wide potential window (1.13 V in a traditional aqueous three-electrode system) and high specific capacitance (716.9 F g−1 at 1 A g−1). More critically, through microwave-assisted doping engineering, nickel was successfully doped into the phase-deficient Mn0.5Co2.5O4, resulting in a spinel material, Ni−Mn0.5Co2.5O4, with significant lattice defects and a mixed 1D/2D morphology. The doping of nickel effectively promoted the high-state conversion of manganese valence states within the manganese cobaltite material, substantially increasing the quantity of highly active Co3+ ions. These changes led to an increase in the density of reactive sites, effectively promoting synergistic interactions, thereby significantly enhancing the material’s conductivity and energy storage performance. The specific capacitance of Ni−Mn0.5Co2.5O4 reached 1180.6 F g−1 at 1 A g−1, a 64.7% improvement over the original Mn0.5Co2.5O4; at a high current density of 10 A g−1, the capacitance increased by 14.3%. Notably, the charge transfer resistance was reduced by a factor of 41.6. After 5000 cycles of testing, the capacity retention stood at 79.2%. This work reveals the effectiveness of microwave-assisted doping engineering in constructing high-performance non-stoichiometric spinel-type bimetallic oxide materials, offering advanced strategies for the development of high-performance electrode materials. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

14 pages, 2101 KiB  
Article
Microwave Irradiation as a Powerful Tool for Isolating Isoflavones from Soybean Flour
by Sanja Đurović, Bogdan Nikolić, Boris Pisinov, Dušan Mijin and Zorica Knežević-Jugović
Molecules 2024, 29(19), 4685; https://doi.org/10.3390/molecules29194685 - 2 Oct 2024
Cited by 1 | Viewed by 1143
Abstract
The use of microwave irradiation energy for isolating bioactive compounds from plant materials has gained popularity due to its ability to penetrate cells and facilitate extraction of intracellular materials, with the added benefits of minimal or no use of organic solvents. This is [...] Read more.
The use of microwave irradiation energy for isolating bioactive compounds from plant materials has gained popularity due to its ability to penetrate cells and facilitate extraction of intracellular materials, with the added benefits of minimal or no use of organic solvents. This is particularly significant due to the possibility of using extracts in the food and pharmaceutical industries. The aim of this work is to examine the effect of microwave irradiation on the extraction of three of the most important isoflavones from soybean flour, glycitin, genistin, and daidzin, as well as their aglycones, glycitein, genistein, and daidzein. By varying the extraction time, temperature, and microwave power, we have established the optimal parameters (irradiation power of 75 W for 5 min) for the most efficient extraction of individual isoflavones. Compared to conventional maceration and ultrasound-assisted extraction, the total phenol content of the extracts increased from 3.66 to 9.16 mg GAE/g dw and from 4.67 to 9.16 mg GAE/g dw, respectively. The total flavonoid content increased from 0.38 to 0.83 mg CE/g dw and from 0.48 to 0.83 mg CE/g dw, and the antioxidant activity increased from 96.54 to 185.04 µmol TE/g dw and from 158.57 to 185.04 µmol TE/g dw, but also from 21.97 to 37.16 µmol Fe2+/g dw and from 30.13 to 37.16 µmol Fe2+/g dw. The positive correlation between microwave extraction and increased levels of total phenols, flavonoids, and antioxidant activity demonstrates the method’s effectiveness in producing bioactive compounds. Considering the growing recognition of glycitein’s potential role in medical and pharmaceutical applications, microwave-assisted extraction under optimized conditions has proven highly efficient. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

11 pages, 1665 KiB  
Article
Optimisation of Interfacial Modification by Two-Stage Microwave Irradiation
by Yusuke Asakuma, Yusuke Watanabe, Anita Hyde and Chi Phan
Molecules 2024, 29(15), 3673; https://doi.org/10.3390/molecules29153673 - 2 Aug 2024
Viewed by 790
Abstract
Microwave-assisted de-emulsification is attractive in the processes of petroleum production and refining. The main advantage of microwaves is their direct influence on the surfactant layer at the oil/water interface. Previously, an effective interfacial modification was demonstrated by pulsed microwave irradiation. However, the effect [...] Read more.
Microwave-assisted de-emulsification is attractive in the processes of petroleum production and refining. The main advantage of microwaves is their direct influence on the surfactant layer at the oil/water interface. Previously, an effective interfacial modification was demonstrated by pulsed microwave irradiation. However, the effect of the modification diminished during the off interval of the pulse irradiation. In this study, two-stage microwave irradiation with different powers and durations was applied as a method to maintain an interfacial effect. The power of the second stage was changed to optimise the modification. Quick modification was obtained by high-power irradiation followed by low-power irradiation. It was confirmed a sustained modification was maintained by a moderate power of the second irradiation. This observation indicates a re-adsorption or re-structure process after the first irradiation is suppressed by the second irradiation. The results open new opportunities to optimise microwave operation in oil/water systems. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

14 pages, 8192 KiB  
Article
Effects of TiO2 Nanoparticles Synthesized via Microwave Assistance on Adsorption and Photocatalytic Degradation of Ciprofloxacin
by Debora Briševac, Ivana Gabelica, Davor Ljubas, Arijeta Bafti, Gordana Matijašić and Lidija Ćurković
Molecules 2024, 29(12), 2935; https://doi.org/10.3390/molecules29122935 - 20 Jun 2024
Cited by 4 | Viewed by 1645
Abstract
In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol [...] Read more.
In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol was used as a solvent; acetylacetone was used as a complexation moderator; and nitric acid was used as a catalyst. Four samples of titanium dioxide were synthesized from the prepared colloidal solution in a microwave reactor at a temperature of 150 °C for 30 min and at a temperature of 200 °C for 10, 20, and 30 min. The phase composition of the TiO2 samples was determined by X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR). Nitrogen adsorption/desorption isotherms were used to determine the specific surface area and pore size distributions using the Brunauer–Emmett–Teller (BET) method. The band-gap energy values of the TiO2 samples were determined by diffuse reflectance spectroscopy (DRS). The distribution of Ti and O in the TiO2 samples was determined by SEM-EDS analysis. The effects of adsorption and photocatalytic activity of the prepared TiO2 samples were evaluated by the degradation of ciprofloxacin (CIP) as an emerging organic pollutant (EOP) under UV-A light (365 nm). The results of the photocatalytic activity of the synthesized TiO2 nanoparticles were compared to the benchmark Degussa P25 TiO2. Kinetic parameters of adsorption and photocatalysis were determined and analyzed. It was found that crystalline TiO2 nanoparticles with the highest specific surface area, the lowest energy band gap, and the highest photocatalytic degradation were the samples synthesized at 200 °C for 10 min. The results indicate that CIP degradation by all TiO2 samples prepared at 200 °C show a synergistic effect of adsorption and photocatalytic degradation in the removal process. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

14 pages, 1411 KiB  
Article
Microwave Heating for Synthesis of Carbonaceous Adsorbents for Removal of Toxic Organic and Inorganic Contaminants
by Aleksandra Bazan-Wozniak, Katarzyna Machelak, Agnieszka Nosal-Wiercińska and Robert Pietrzak
Molecules 2023, 28(19), 6825; https://doi.org/10.3390/molecules28196825 - 27 Sep 2023
Cited by 4 | Viewed by 1173
Abstract
The residues obtained from the extraction of Inonotus obliquus fungus were used to produce carbonaceous adsorbents. The initial material was subjected to pyrolysis in a microwave oven. The adsorbents were characterized through elemental analysis, low-temperature nitrogen adsorption/desorption isotherms, and Boehm titration. The carbonaceous [...] Read more.
The residues obtained from the extraction of Inonotus obliquus fungus were used to produce carbonaceous adsorbents. The initial material was subjected to pyrolysis in a microwave oven. The adsorbents were characterized through elemental analysis, low-temperature nitrogen adsorption/desorption isotherms, and Boehm titration. The carbonaceous adsorbents were tested for the removal of NO2, methylene blue, and malachite green. The results indicated that the obtained carbonaceous adsorbents exhibited basic characteristics and possessed specific surface areas of 372 and 502 m2/g. The adsorption process of liquid contaminants was modeled using the single-layer Langmuir model. The maximum adsorption capacities were found to be 101 and 109 mg/g for methylene blue, and 75 and 77 mg/g for malachite green. The kinetic study demonstrated that the adsorption of methylene blue and malachite green was better described by a pseudo-second order model. The study affirmed that the adsorption of organic dyes onto the resultant carbonaceous adsorbents was both spontaneous and endothermic. The study also demonstrated that the presence of an air stream during the NO2 adsorption process and prehumidization of the adsorbent with humid air had a beneficial effect on the obtained sorption capacities. In conclusion, the study demonstrated that pyrolysis of the extraction residues from the fungus Inonotus obliquus yields highly effective, environmentally friendly, and cost-efficient carbonaceous adsorbents for the removal of both gaseous and liquid pollutants. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

16 pages, 5277 KiB  
Article
Efficient Treatment of Oily Sludge via Fast Microwave-Assisted Pyrolysis, Followed by Thermal Plasma Vitrification
by Qinglong Xie, Zhen Chen, Yuqiang Zhou, Tongbo Pan, Ying Duan, Shangzhi Yu, Xiaojiang Liang, Zhenyu Wu, Weirong Ji and Yong Nie
Molecules 2023, 28(10), 4036; https://doi.org/10.3390/molecules28104036 - 11 May 2023
Cited by 9 | Viewed by 2321
Abstract
Oily sludge, as a critical hazardous waste, requires appropriate treatment for resource recovery and harmfulness reduction. Here, fast microwave-assisted pyrolysis (MAP) of oily sludge was conducted for oil removal and fuel production. The results indicated the priority of the fast MAP compared with [...] Read more.
Oily sludge, as a critical hazardous waste, requires appropriate treatment for resource recovery and harmfulness reduction. Here, fast microwave-assisted pyrolysis (MAP) of oily sludge was conducted for oil removal and fuel production. The results indicated the priority of the fast MAP compared with the MAP under premixing mode, with the oil content in solid residues after pyrolysis reaching below 0.2%. The effects of pyrolysis temperature and time on product distribution and compositions were examined. In addition, pyrolysis kinetics can be well described using the Kissinger-Akahira-Sunose (KAS) and the Flynn-Wall-Ozawa (FWO) methods, with the activation energy being 169.7–319.1 kJ/mol in the feedstock conversional fraction range of 0.2–0.7. Subsequently, the pyrolysis residues were further treated by thermal plasma vitrification to immobilize the existing heavy metals. The amorphous phase and the glassy matrix were formed in the molten slags, resulting in bonding and, hence, immobilization of heavy metals. Operating parameters, including working current and melting time, were optimized to reduce the leaching concentrations of heavy metals, as well as to decrease their volatilization during vitrification. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Graphical abstract

11 pages, 10211 KiB  
Communication
Effect of Europium Addition on the Microstructure and Dielectric Properties of CCTO Ceramic Prepared Using Conventional and Microwave Sintering
by Gecil Evangeline T, Raja Annamalai A and Pavel Ctibor
Molecules 2023, 28(4), 1649; https://doi.org/10.3390/molecules28041649 - 8 Feb 2023
Cited by 12 | Viewed by 2261
Abstract
In this work, Eu2O3-doped (CaCu3Ti4O12)x of low dielectric loss have been fabricated using both conventional (CS) and microwave sintering (MWS), where x = Eu2O3 = 0.1, 0.2, and 0.3, [...] Read more.
In this work, Eu2O3-doped (CaCu3Ti4O12)x of low dielectric loss have been fabricated using both conventional (CS) and microwave sintering (MWS), where x = Eu2O3 = 0.1, 0.2, and 0.3, respectively. According to X-ray diffraction (XRD) and scanning electron microscope (SEM) reports, increasing the concentration of Eu3+ in the CCTO lattice causes the grain size of the MWS samples to increase and vice versa for CS. The X-ray photoelectron spectroscopy (XPS) delineated the binding energies and charge states of the Cu2+/Cu+ and Ti4+/Ti3+ transition ions. Energy dispersive spectroscopy (EDS) analysis revealed no Cu-rich phase along the grain boundaries that directly impacts the dielectric properties. The dielectric characteristics, which include dielectric constant (ε) and the loss (tan δ), were examined using broadband dielectric spectrometer (BDS) from 10 to 107 Hz at ambient temperature. The dielectric constant was >104 and >102 for CS and MWS samples at x > 0.1, respectively, with the low loss being constant even at high frequencies due to the effective suppression of tan δ by Eu3+. This ceramic of low dielectric loss has potential for commercial applications at comparatively high frequencies. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Figure 1

7 pages, 235 KiB  
Communication
Degree of Coupling in Microwave-Heating Polar-Molecule Reactions
by Xingpeng Liu, Heping Huang, Linsen Yang and Kama Huang
Molecules 2023, 28(3), 1364; https://doi.org/10.3390/molecules28031364 - 31 Jan 2023
Cited by 3 | Viewed by 1629
Abstract
Microwave-assisted chemical reactions have been widely used, but the overheating effect limits further applications. The aim of this paper is to investigate the coupling degree of the electromagnetic field and thermal field in microwave-heating chemical reactions whose polarization changes as the reactions proceed. [...] Read more.
Microwave-assisted chemical reactions have been widely used, but the overheating effect limits further applications. The aim of this paper is to investigate the coupling degree of the electromagnetic field and thermal field in microwave-heating chemical reactions whose polarization changes as the reactions proceed. First, the entropy-balance equation of microwave-heating polar-molecule reactions is obtained. Then, the coupling degree of the electromagnetic field and the thermal field in microwave-heating polar-molecule reactions is derived, according to the entropy-balance equation. Finally, the effects of reaction processes on the degree of coupling are discussed. When the time scale of the component-concentration variation is much greater than the wave period during the chemical processes, the degree of coupling is sufficiently small, and the electric and thermal fields are considered as weakly coupled. On the other hand, the degree of coupling may change during the reactions. If the absolute value of the coupling degree becomes larger, due to the change in component concentration, this will lead to a transition from weak coupling to strong coupling. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)

Review

Jump to: Research

23 pages, 1350 KiB  
Review
A Systematic Review on Biomass Treatment Using Microwave-Assisted Pyrolysis under PRISMA Guidelines
by Neyha Rubab Syed, Bo Zhang, Stephen Mwenya and Awsan Shujaa Aldeen
Molecules 2023, 28(14), 5551; https://doi.org/10.3390/molecules28145551 - 20 Jul 2023
Cited by 7 | Viewed by 3985
Abstract
Biomass as a renewable energy resource is a major topic on a global scale. Several types of biomass heat treatment methods have been introduced to obtain useful byproducts via pyrolysis. Microwaves are a practical replacement for conventional stoves and ovens to perform pyrolysis [...] Read more.
Biomass as a renewable energy resource is a major topic on a global scale. Several types of biomass heat treatment methods have been introduced to obtain useful byproducts via pyrolysis. Microwaves are a practical replacement for conventional stoves and ovens to perform pyrolysis of biomass. Their rapid heating rate and user-friendliness make them a good choice for the pyrolysis process over conventional methods. The current study reviewed research articles that used microwaves for the pyrolysis process on different types of biomass. This study primarily provides comprehensive details about the pyrolysis process, especially microwave-assisted pyrolysis (MAP) and its feasibility for treating biomass. A systematic literature review, according to the PRISMA guidelines, was performed to find research articles on biomass treatment using MAP technology. We analyzed various research studies (n = 32), retrieved from different databases, that used MAP for pyrolysis on various types of biomass, and we achieved good results. The main goal of this study was to examine the usefulness of the MAP technique, comparing its effects on distinguished types of biomass. We found MAP’s effective parameters, namely, temperature, concentration of microwave absorber, moisture percentage of starting material and flow rate, microwave power and residence time of the initial sweep gas that control the pyrolysis process, and effect quality of byproducts. The catalytic agent in MAP pyrolysis was found to be useful for treating biomass, and that it has great potential to increase (nearly double) the production yield. Although MAP could not be used for all types of materials due to some challenges, it produced good results compared to conventional heating (pyrolysis) methods. We concluded that MAP is an effective method for reducing pyrolysis reaction time and improving the quality of value-added products. Also, MAP eliminates the shredding requirement for biomass and improves heating quality. Therefore, it is a viable method for reducing pyrolysis processing costs and should be applied on a larger scale than lab scale for commercialization. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
►▼ Show Figures

Graphical abstract

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-10
Back to TopTop