Green Chemical Synthesis with Microwaves and Ultrasound E-Book
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- Herausgeber: Wiley-VCH GmbH
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
- Veröffentlichungsjahr: 2024
The book provides the reader with advancements of microwave and ultrasound irradiations as green and eco-friendly methods for synthesis and recent industrial applications in the fields of organic chemistry and material science. It is a valuable reference for scientists, chemists, biochemists, pharmacists and engineers to learn about fundamentals, reactions and catalytic mechanisms. Also, benefits the reader by introducing the equipment and the classes of organic reactions, convenient, and reproducible techniques.
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Table of Contents
Cover
Table of Contents
Title Page
Copyright
About the Editors
Preface
1 Ultrasound Irradiation: Fundamental Theory, Electromagnetic Spectrum, Important Properties, and Physical Principles
1.1 Introduction
1.2 Cavitation History
1.3 Application of Ultrasound Irradiation
1.4 Conclusion
Acknowledgments
References
2 Fundamental Theory of Electromagnetic Spectrum, Dielectric and Magnetic Properties, Molecular Rotation, and the Green Chemistry of Microwave Heating Equipment
2.1 Introduction
2.2 Fundamental Concepts of the Electromagnetic Spectrum Theory
2.3 Electrical, Dielectric, and Magnetic Properties in Microwave Irradiation
2.4 Microwave Irradiation Molecular Rotation
2.5 Fundamentals of Electromagnetic Theory in Microwave Irradiation
2.6 Physical Principles of Microwave Heating and Equipment
2.7 Green Chemistry Through Microwave Heating: Applications and Benefits
2.8 Conclusion
References
3 Conventional Versus Green Chemical Transformation: MCRs, Solid Phase Reaction, Green Solvents, Microwave, and Ultrasound Irradiation
3.1 Introduction
3.2 A Brief Overview of Green Chemistry
3.3 Multicomponent Reactions
3.4 Solid Phase Reactions
3.5 Microwave Induced Synthesis
3.6 Ultrasound Induced Synthesis
3.7 Green Chemicals and Solvents
3.8 Conclusions and Outlook
References
4 Metal‐Catalyzed Reactions Under Microwave and Ultrasound Irradiation
4.1 Ultrasonic Irradiation
4.2 Microwave‐Assisted Reactions
4.3 Conclusion
Acknowledgments
References
5 Microwave‐ and Ultrasonic‐Assisted Coupling Reactions
5.1 Introduction
5.2 Microwave
5.3 Conclusion
References
6 Synthesis of Heterocyclic Compounds Under Microwave Irradiation Using Name Reactions
6.1 Introduction
6.2 Classical Methods for Heterocyclic Synthesis Under Microwave Irradiation
6.3 Conclusion
Acknowledgments
References
7 Microwave‐ and Ultrasound‐Assisted Enzymatic Reactions
7.1 Introduction
7.2 Influence Microwave Radiation on the Stability and Activity of Enzymes
7.3 Principle of Ultrasonic‐Assisted Enzymolysis
7.4 Applications of Ultrasonic‐Assisted Enzymolysis
7.5 Enzymatic Reactions Supported by Ultrasound
7.6 Biodiesel Production via Ultrasound‐Supported Transesterification
7.7 Conclusions
Acknowledgments
References
8 Microwave‐ and Ultrasound‐Assisted Synthesis of Polymers
8.1 Introduction
8.2 Microwave‐Assisted Synthesis of Polymers
8.3 Ultrasound‐Assisted Synthesis of Polymers
8.4 Conclusion
References
9 Synthesis of Nanomaterials Under Microwave and Ultrasound Irradiation
9.1 Introduction
9.2 Synthesis of Metal Nanoparticles
9.3 Synthesis of Carbon Dots
9.4 Synthesis of Metal Oxides
9.5 Synthesis of Silicon Dioxide
9.6 Conclusion
References
10 Microwave‐ and Ultrasound‐Assisted Synthesis of Metal‐Organic Frameworks (MOF) and Covalent Organic Frameworks (COF)
10.1 Introduction
10.2 Principles
10.3 MOF Synthesis by Microwave and Ultrasound Method
10.4 Factors That Affect MOF Synthesis
10.5 Application of MOF
10.6 COF Synthesis by Microwave and Ultrasound Method
10.7 Factors Affecting the COF Synthesis
10.8 Applications of COFs
10.9 Future Predictions
10.10 Summary
Acknowledgments
References
11 Solid Phase Synthesis Catalyzed by Microwave and Ultrasound Irradiation
11.1 Introduction
11.2 Wastewater Treatment
11.3 Biodiesel Production
11.4 Oxygen Reduction Reaction
11.5 Alcoholic Fuel Cells
11.6 Conclusion and Future Plans
References
12 Comparative Studies on Thermal, Microwave‐Assisted, and Ultrasound‐Promoted Preparations
12.1 Introduction
12.2 Fundamentals of Thermal, Microwave‐Assisted, and Ultrasound‐Assisted Reactions
12.3 Case Studies in Organic Synthesis
12.4 Scope and Limitations
12.5 Future Directions and Emerging Trends
12.6 Identification of Potential Areas for Further Exploration and Improvement
12.7 The Role of Artificial Intelligence and Computational Approaches in Optimizing Preparative Techniques
References
Index
End User License Agreement
List of Tables
Chapter 5
Table 5.1 Microwave‐assisted reactions.
Chapter 7
Table 7.1 Various applications of ultrasonic‐assisted enzymolysis.
Table 7.2 Applications of ultrasound‐assisted enzymatic reactions.
Table 7.3 Bibliographic collection of common parameters in homogeneous acid...
Table 7.4 Bibliographic compilation of typical parameters for homogeneous b...
Table 7.5 Bibliographic list of common variables in transesterifications th...
Table 7.6 Bibliographic list of typical transesterification parameters usin...
Table 7.7 Bibliographic list of common transesterification parameters using...
Chapter 8
Table 8.1 Loss tangents of frequently used solvents in microwave‐assisted r...
Chapter 10
Table 10.1 MOFs synthesized by the microwave technique at different reactio...
Table 10.2 Different MOFs synthesized by ultrasound at different reaction c...
Table 10.3 Applications of MOFs with name and synthesis method.
Table 10.4 Different 2D‐COFs synthesized by microwave method under differen...
Table 10.5 Different applications of COFs in different fields.
Chapter 11
Table 11.1 A list of the detected concentration of removed pollutants, the ...
Table 11.2 A list of some employed catalysts for the transesterification re...
Table 11.3 A list of microwave irradiated nanocatalysts for fuel cell appli...
Chapter 12
Table 12.1 The comparison of a conventional heating and microwave heating [...
Table 12.2 Overview of conventional, microwave and ultrasound heating.
Table 12.3 Comparative study of conversions reaction to 5‐HMF and LA.
Table 12.4 Comparison of reaction times using microwave versus conventional...
Table 12.5 Comparison of energy consumption per unit biodiesel production u...
Table 12.6 Hydrazinolysis of methyl salicylate using different methods.
Table 12.7 Cross‐coupling reactions meaning.
Table 12.8 Cross‐coupling reactions applications from literature study.
Table 12.9 Comparison between microwave and ultrasound differences.
Table 12.10 Comparison of methods for synthesis Pb(OH)Br nanowires [98].
Table 12.11 Comparison of conventional heating, MW, US, and SMUI in the syn...
List of Illustrations
Chapter 1
Figure 1.1 Schematic representation of the mechanism of generation of acoust...
Figure 1.2 Mechanism of cavitation growth and collapse in liquid medium.
Figure 1.3 Types of cavitation based on technique used.
Figure 1.4 The abdominal sonography of the brain of a 21‐week‐old fetus.
Figure 1.5 Schematic illustration for sonophotocatalytic mechanism.
Chapter 2
Figure 2.1 Scheme of the 12 principles of green chemistry.
Figure 2.2 Illustration showcasing the transformative impact of microwave an...
Figure 2.3 (a) Electromagnetic radiation and (b) electromagnetic spectrum.
Figure 2.4 Translational motions with changing electric field.
Figure 2.5 Microwave heating with green chemistry in environmentally friendl...
Figure 2.6 Microwave irradiation ‐based synthetic routes of various thiazoli...
Figure 2.7 The role of microwave radiation in microwave chemistry.
Figure 2.8 Microwave‐promoted synthesis of N‐based heterocycles.
Chapter 3
Figure 3.1 Schematic of MCRs facilitated using microwave and ultrasound irra...
Figure 3.2 Examples of some MCR reactions. (a), (b), (c), (d)...
Figure 3.3 Schemes for the solvent‐free synthesis of (a) dibenzalacetone....
Figure 3.4 Examples of some MW‐facilitated synthesis. (a), (b), (c)...
Figure 3.5 Examples of some US‐facilitated synthesis. (a) Triazines.. (b...
Figure 3.6 Some of the greener chemicals used for diverse applications.
Figure 3.7 Greenness of some commonly used analytical solvents.
Chapter 4
Figure 4.1 Synthesis of 1,4‐DHP derivatives, co‐catalyzed by Fe
3
O
4
/SiO
2
‐PDA ...
Figure 4.2 Synthesis of 1,4‐DHPs analogs by Fe
3
O
4
@g‐C
3
N
4
‐SA nanocatalyst....
Figure 4.3 Sonochemical preparation of benzimidazoloquinazolines mediated by...
Figure 4.4 Synthesis of tetrahydrobenzo[
b
]pyrans under US irradiation and Fe
Figure 4.5 A simple protocol for the preparation of 1,4‐DHPs mediated by inn...
Figure 4.6 Synthesis of pyridoimidazoisoquinolines‐imidazoles under US irrad...
Figure 4.7 Sonicated protocol for the synthesis of propargylamines mediated ...
Figure 4.8 Protocol for the preparation of 1,4‐DHPs mediated by green solven...
Figure 4.9 One‐pot synthesis of substituted imidazoles mediated by ultrasoun...
Figure 4.10 Sonicated synthesis of dihydropyrimidinone derivatives mediated ...
Figure 4.11 Sonicated synthesis of acridine derivatives mediated by heteroge...
Figure 4.12 Platinum carbon nanotube/NPs hybrid catalyzed one‐pot US‐assiste...
Figure 4.13 Ultrasound‐promoted preparation of dihydroquinazolinones catalyz...
Figure 4.14 Ultrasound‐mediated MCR for the synthesis of tetrahydropyranquin...
Figure 4.15 On water preparation of thiazoloquinolines using SBA‐15/[AubpyCl
Figure 4.16 Synthesis of substituted imidazoles mediated by MgAl
2
O
4
/NP and U...
Figure 4.17 Sonochemical preparation of imidazoles catalyzed by NiFe
2
O
4
/FMNP...
Figure 4.18 Montmorillonite K‐10 assisted condensation reaction assisted by ...
Figure 4.19 Montmorillonite KSF catalyzed cross‐aldol condensation reaction ...
Figure 4.20 Montmorillonite K‐10 assisted condensation reaction assisted by ...
Figure 4.21 Chitosan beads assisted condensation reaction under microwave ir...
Figure 4.22 Resin‐assisted condensation reaction by microwave irradiation....
Figure 4.23 Montmorillonite K‐10 assisted condensation reaction under microw...
Figure 4.24 Montmorillonite K‐10 catalyzed amidation under microwave irradia...
Figure 4.25 Na‐zeolite assisted cyclization reaction under microwave irradia...
Figure 4.26 HY‐zeolite assisted cyclization reaction under microwave irradia...
Figure 4.27 Montmorillonite K‐10 assisted cyclization reaction under microwa...
Figure 4.28 Montmorillonite K‐10 assisted cyclization reaction under microwa...
Figure 4.29 Montmorillonite K‐10 assisted cyclization reaction under microwa...
Figure 4.30 Montmorillonite K‐10 assisted cyclization reaction under microwa...
Figure 4.31 Montmorillonite K‐10 assisted cyclization reaction under microwa...
Figure 4.32 Montmorillonite K‐10, NaNO
2
assisted cyclization under microwave...
Figure 4.33 Montmorillonite K‐10 assisted MCR reaction under microwave irrad...
Figure 4.34 Chitosan‐SO
3
H assisted MCR reaction under microwave irradiation....
Figure 4.35 CoFe
2
O
4
/GO‐SO
3
H assisted MCR reaction under microwave irradiatio...
Figure 4.36 Nano MgAl
2
O
4
assisted MCR reaction under microwave irradiation....
Figure 4.37 PTSA‐Montmorillonite assisted Friedel–Crafts reaction under micr...
Figure 4.38 H‐beta‐zeolites assisted Friedel–Crafts reaction under microwave...
Figure 4.39 MPBOS‐assisted transformation reaction under microwave irradiati...
Figure 4.40 Zeolite Beta assisted transformation reaction under microwave ir...
Figure 4.41 Ca‐based catalyst‐assisted transformation reaction under microwa...
Figure 4.42 Cu/TiO
2
catalyst‐assisted reduction reaction under microwave irr...
Figure 4.43 Nano‐NiO catalyst assisted reduction reaction under microwave ir...
Figure 4.44 Ni/Cg catalyst assisted reduction reaction under microwave irrad...
Figure 4.45 FeCr
2
O
4
or CoCr
2
O
4
or CuCr
2
O
4
catalyst‐assisted oxidation reacti...
Figure 4.46 Cu/Cellulose (20%) catalyst‐assisted oxidation reaction under MW...
Figure 4.47 Pd/C (5 mol%) catalyst‐assisted oxidation reaction under microwa...
Figure 4.48 Sn‐polymer catalyst assisted oxidation reaction under microwave ...
Figure 4.49 Si‐based Pd
0
(0.5 mol%) catalyst‐assisted coupling reaction unde...
Figure 4.50 PdNPs/H
2
P‐CMP (0.5 mol%) catalyst‐assisted coupling reaction und...
Figure 4.51 Chitosan/Pd(II) catalyst‐assisted coupling reaction under microw...
Figure 4.52 NHC‐Pd catalyst assisted Suzuki–Mayaura coupling with microwave ...
Figure 4.53 Pd catalyzed Suzuki–Miyaura coupling reaction under microwave ir...
Figure 4.54 Chitosan/cellulose‐Pd(II) catalyzed Suzuki–Miyaura coupling with...
Figure 4.55 Pd/C (2 mol%) catalyzed Suzuki–Miyaura with microwave irradiatio...
Figure 4.56 SiO
2
catalyst Pd(0) assisted Suzuki–Miyaura coupling with microw...
Figure 4.57 Cu‐Pd (1 mol%) catalyzed Suzuki–Miyaura coupling with microwave ...
Figure 4.58 SS‐Rh catalyzed Suzuki–Miyaura coupling under microwave irradiat...
Figure 4.59 Pd/SiO
2
(2 mol%) catalyst Heck coupling with microwave irradiati...
Figure 4.60 CβCAT catalyst assisted heck coupling reaction...
Figure 4.61 Glass/polystyrene‐supported Pd(II) catalyst‐assisted heck coupli...
Figure 4.62 CuLDH‐3 catalyst assisted Ullmann coupling under microwave irrad...
Figure 4.63 NiCl
2
·6H
2
O catalyzed Buch...
Figure 4.64 CβCAT (0.01 mol%) catalyzed carbonylation/ca...
Figure 4.65 Pd@PS (2 mol%) catalyst‐assisted carbonylation/carboxylation rea...
Figure 4.66 CeCl
3
·7H
2
O‐SiO
2
catalyzed...
Figure 4.67 SiO
2
/CuCl
2
catalyst‐assisted multicomponent reaction under micro...
Figure 4.68 NiO catalyst‐assisted multicomponent reaction under microwave ir...
Figure 4.69 Co/SBA‐15 (1 mol%) catalyst assisted MCR under microwave irradia...
Figure 4.70 H
4
[SiW
12
O
40
] catalyst assisted multi‐component reaction under mi...
Figure 4.71 Cu‐HAP (25 wt%) catalyst assisted click reaction under microwave...
Figure 4.72 SiO
2
·Lm Cu(I) catalyst assisted c...
Figure 4.73 Cu(OCH
3
)
2
/porous glass catalyzed click reaction under microwave ...
Chapter 5
Figure 5.1 Diagram of continuous flow of microwave reaction.
Scheme 5.1 One‐pot synthesis of coumarins‐containing pyrrole.
Scheme 5.2 One‐pot multicomponent method.
Scheme 5.3 SMC reaction for the formation of biaryls.
Scheme 5.4 Pathway to design 3,5‐dibenzyl‐4‐amino1,2,4‐triazole deriv...
Scheme 5.5 Synthesis of dihydropyridine derivatives.
Scheme 5.6 Synthesis of 2‐aminopyrimidine.
Scheme 5.7 Synthesis of triazolothiadizepinylquinolines.
Scheme 5.8 Synthesis of Au(II) complex.
Scheme 5.9 Synthesis of hydroxy methyl xanthine derivatives.
Scheme 5.10 Synthesis of hydroxylated β‐carboline derivatives.
Scheme 5.11 Synthesis of pyrrole‐imidazole.
Scheme 5.12 Synthesis of the formamidine‐based ligand.
Scheme 5.13 Synthesis of coumarin‐3‐yl‐1,2,4‐triazolin‐3‐ones.
Scheme 5.14 Synthesis of 4‐hydroxy‐3[aryl(piperidin‐1‐yl/morpholino/p...
Scheme 5.15 C–S cross‐coupling reaction from thiols and 2‐(4‐bromo ph...
Scheme 5.16 Fe
3
O
4
@CNF@Cu catalyzed the Ullmann reaction of various ha...
Scheme 5.17 Heck reaction of different substrates with methyl acrylat...
Scheme 5.18 Coupling of Iodobenzene, aniline, and phenol with Ph
3
SnCl...
Scheme 5.19 Coupling reaction of Benzylamine.
Scheme 5.20 Suzuki reaction of 4‐methylbromobenzene with phenyl boron...
Scheme 5.21 Synthesis of 3‐heteroarylmethylene substituted isoindolin...
Scheme 5.22 Ultrasound‐assisted synthesis of rosuvastatin‐based azain...
Scheme 5.23 Cu‐catalyzed one‐pot synthesis of 11
H
‐pyrido[2,1‐
b
]quinaz...
Scheme 5.24 Synthesis of 3‐Br‐indazoles.
Scheme 5.25 Synthesis of 2‐aryl benzimidazoles.
Scheme 5.26 Synthesis of pyridine‐linked hydrazinylimidazoles.
Scheme 5.27 One‐pot synthesis of 1,2‐diaryl azaindoles under Pd/C–Cu ...
Scheme 5.28 Ultrasonication assisted reaction of 2,3‐dichloroquinoxal...
Scheme 5.29 Schematic illustration for the formation of DODHAs using ...
Scheme 5.30 Synthesis of Indeno[2′,1′:5,6]pyrido[2,3‐
d
]pyrimidines.
Chapter 6
Scheme 6.1 Piloty–Robinson pyrrole synthesis under microwave irradia...
Scheme 6.2 Clauson–Kaas synthesis of 1‐phenylpyrrole (
7
) under microw...
Scheme 6.3 Clauson–Kaas pyrrole synthesis under microwave irradiation...
Scheme 6.4 Paal–Knorr pyrrole synthesis under microwave irradiation a...
Scheme 6.5 Paal–Knorr pyrrole synthesis under microwave irradiation....
Scheme 6.6 Paal–Knorr furan synthesis under microwave irradiation.
Scheme 6.7 Paal–Knorr thiophene synthesis under microwave irradiation...
Scheme 6.8 Gewald reaction under microwave irradiation and convention...
Scheme 6.9 Cyclohexanone (
20
) in Gewald reaction under microwave irra...
Scheme 6.10 Microwave‐assisted Fisher indole synthesis.
Scheme 6.11 Bischler–Möhlau indole synthesis under microwave irradiat...
Scheme 6.12 Hemetsberger–Knittel indole synthesis under microwave irr...
Scheme 6.13 Leimgruber–Batcho indole synthesis under microwave irradi...
Scheme 6.14 Cadogan–Sundberg indole synthesis under microwave irradia...
Scheme 6.15 Pechmann pyrazole synthesis under microwave irradiation a...
Scheme 6.16 Microwave‐assisted synthesis of Lepidiline B (
43
).
Scheme 6.17 Debus–Radziszewski reaction under microwave irradiation f...
Scheme 6.18 Synthesis of tetrasubstituted imidazole
48
using the micr...
Scheme 6.19 van Leusen imidazole synthesis under microwave irradiatio...
Scheme 6.20 van Leusen oxazole synthesis under microwave irradiation ...
Scheme 6.21 Robinson–Gabriel reaction under microwave irradiation.
Scheme 6.22 Robinson–Gabriel under microwave irradiation for the alka...
Scheme 6.23 Hantzsch thiazole synthesis under microwave irradiation a...
Scheme 6.24 Einhorn–Brunner reaction under microwave irradiation and ...
Scheme 6.25 One‐pot synthesis of 1,2,4‐triazole
62
under microwave ir...
Scheme 6.26 Pellizzari reaction under microwave irradiation.
Scheme 6.27 Huisgen reaction under microwave irradiation and conventi...
Scheme 6.28 Huisgen reaction of benzyl azide (
70
) and vinyl acetate (
Scheme 6.29 Intramolecular Huisgen reaction under microwave irradiati...
Scheme 6.30 Huisgen reaction benzyl azide (
70
) and phenylacetylene (
7
...
Scheme 6.31 Finnegan tetrazole synthesis under microwave irradiation....
Scheme 6.32 One‐pot synthesis of 5‐phenyltetrazole (
80
) under microwa...
Scheme 6.33 Four‐component Ugi‐azide reaction under microwave irradia...
Scheme 6.34 Kröhnke pyridine ring annelation under microwave irradiat...
Scheme 6.35 Kröhnke pyridine synthesis under microwave irradiation an...
Scheme 6.36 Bohlmann–Rahtz pyridine synthesis under microwave irradia...
Scheme 6.37 Higher efficiency of the Bohlmann–Rahtz pyridine synthesi...
Scheme 6.38 Boger pyridine synthesis under microwave irradiation and ...
Scheme 6.39 Skraup reaction of aniline (
6
) under microwave irradiatio...
Scheme 6.40 Skraup reaction of nitrobenzene (
103
) under microwave irr...
Scheme 6.41 Gould–Jacobs reaction under microwave irradiation.
Scheme 6.42 Friedländer quinoline synthesis under microwave irradiati...
Scheme 6.43 Friedländer reaction under microwave irradiation.
Scheme 6.44 Povarov reaction under microwave irradiation and conventi...
Chapter 8
Figure 8.1 Various types of microwave‐assisted synthesis of polymer.
Chapter 9
Figure 9.1 Chemical and ultrasonic reduction of chloroauric acid. (A) Ligand...
Figure 9.2 (a) Effect of ultrasonic power on the synthesis of AgNPs. (b) Tem...
Figure 9.3 Sonochemical synthesis of C‐dots, Sn@C‐dots, and Sn@C‐dots@Sn NPs...
Figure 9.4 Formation of SnO
2
NPs under varying microwave conditions.
Figure 9.5 Field‐emission FESEM images of ZnO nanostructures produced via MW...
Figure 9.6 Fabrication of ZnO using chemical precipitation and ultrasonic ir...
Chapter 10
Figure 10.1 Mechanism of microwave heating.
Figure 10.2 Cavitation phenomenon under ultrasound.
Figure 10.3 Different MOFs synthesized by using different SBUs.
Figure 10.4 Schematic representations of the microwave‐assisted synthesis of...
Figure 10.5 Schematic representation of MOF‐74‐Ni synthesized by the microwa...
Figure 10.6 Schematic representation of MOF‐525 and MOF‐545 synthesized usin...
Figure 10.7 SEM images of MIL‐53 (Fe) synthesized at 70...
Figure 10.8 Schematic details and scheme of synthesis of the F‐MOFs.
Figure 10.9 Schematic diagram of the synthesis conditions and topologies for...
Figure 10.10 Video capture images of (a) COF‐1 and (b) COF‐5 by ultrasonicat...
Figure 10.11 Topology diagrams representing a general basis for the construc...
Figure 10.12 Topology diagrams representing a general basis for COF design a...
Figure 10.13 Scanning electron micrograph of COF‐102 synthesized in a sealed...
Chapter 11
Figure 11.1 SEM images of Ag
2
S nanoparticles after their preparation using m...
Figure 11.2 SEM pictures of CNTs before (a) and after (b) adsorbing crystal ...
Figure 11.3 Plots of decayed concentration of ibuprofen and diclofenac insid...
Figure 11.4 EDX charts and their corresponding mapping pictures of MgO/MgFe
2
Figure 11.5 Effect of varying the transesterification reaction parameters of...
Figure 11.6 SEM pictures of (a) Ca‐BTC and (b–d) Ca‐800N nanocatalysts. The ...
Figure 11.7 The durability test of phosphomolybdic acid/chitosan.
Figure 11.8 Arrhenius plot of oleic acid transesterification reaction using ...
Figure 11.9 TEM pictures of PtCu/PVP nanocatalysts after their heat treatmen...
Figure 11.10 (a) Rotating disk electrode measurements of doped graphene supp...
Figure 11.11 Steps of preparing ZnO@Zn/Fe‐ZIF15 and M
15
‐FeNC‐NH
3
.
Figure 11.12 Fabrication steps of CuCo‐N/C nanocatalyst.
Figure 11.13 (a) Linear sweep voltammograms of modified WS
2
electrode using ...
Figure 11.14 (a) Tafel plots of Fe
3
O
4
@CNTs nanomaterial and (b) its linear s...
Figure 11.15 Synthesis steps of FeWO
4
/Fe
3
O
4
@NrGO nanocatalyst.
Figure 11.16 Repeated cyclic voltammograms of (a) Pt
4.5
Sn
1.5
Rh1USNP/C, (b) P...
Figure 11.17 SEM pictures of Pd‐NrGO nanocatalyst using various magnificatio...
Figure 11.18 Chronoamperograms of (a) p‐CNO, ox‐CNO and N–CNO nanopowders as...
Figure 11.19 Nyquist plots of (a) bare CC, rGO/CC and rGO‐SnO
2
/CC nanocataly...
Chapter 12
Figure 12.1 Comparison between microwave heating and conventional heating. S...
Figure 12.2 Schematic diagram of the reaction mechanism of Ni/Al materials (...
Figure 12.3 Reaction mechanism of ultrasound assisted synthesis method. Sour...
Figure 12.4 Effect of temperature on esterification of FFA. Source: Ferdous ...
Figure 12.5 Dehydration of alcohols. Source: Jeffrey [63].
Figure 12.6 Aqueous aldehyde reforming under neutral conditions.
Figure 12.7 Cyclization‐methylation reaction. Source:...
Guide
Cover Page
Table of Contents
Title Page
Copyright
About the Editors
Preface
Begin Reading
Index
End User License Agreement
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Green Chemical Synthesis with Microwaves and Ultrasound
Edited by Dakeshwar Kumar Verma, Chandrabhan Verma, and Paz Otero Fuertes
Editors
Dr. Dakeshwar Kumar VermaGovt. Digvijay Autonomous Postgraduate CollegeDepartment of ChemistryRajnandgaon 491441ChhattisgarhIndia
Dr. Chandrabhan VermaKhalifa University of Science and TechnologyDepartment of Chemical EngineeringP.O. Box 127788Abu DhabiUnited Arab Emirates
Dr. Paz Otero FuertesUniversity of VigoFaculty of Food Science and TechnologyAnalytical and Food Chemistry DepartmentNutrition and Bromatology GroupOurense 32004Spain
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About the Editors
Dr. Dakeshwar Kumar Verma holds a PhD in chemistry and serves as Assistant Professor of Chemistry at Government of Digvijay Autonomous Postgraduate College in Rajnandgaon, Chhattisgarh, India. He is driven by a profound passion for scientific exploration, and his research focuses primarily on the preparation and design of organic compounds for diverse applications. With an impressive track record, Dr. Verma has authored more than 100 research articles, review articles, and book chapters that have found their places in esteemed peer‐reviewed international journals, including those published in Nature and by ACS, RSC, Wiley, Elsevier, Springer, and Taylor & Francis, among others. This extensive body of work showcases his dedication to contributing to the collective knowledge of the scientific community. Beyond his role as an author, Dr. Verma is an active and valued participant in the peer‐review process. As a testament to his academic influence, Dr. Verma has taken on editorial/authored responsibilities for various published and upcoming books, slated to be published by renowned publishers such as ACS, RSC, Wiley, Springer, Taylor & Francis, Elsevier, and De Gruyter. This role highlights his dedication to shaping and disseminating knowledge in various scientific domains. With a cumulative citation count of more than 1850, an h‐index of 26, and an i‐10 index of 34, Dr. Verma's impact is evident through the recognition and relevance of his work in the scientific community. His commitment to fostering the growth of future scholars is also evident in his supervision of two full‐time PhD research scholars. Dr. Verma's dedication to research excellence has been acknowledged through prestigious awards such as the Council of Scientific and Industrial Research Junior Research Fellowship award in 2013. During his PhD journey in 2013, he also achieved the MHRD National fellowship, further solidifying his commitment to academic growth and advancement. His multifaceted role as a researcher, reviewer, editor, invited speaker, resource person, and mentor underscores his substantial impact on the academic landscape.
Chandrabhan Verma works at the Department of Chemical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates. Dr. Verma obtained BSc and MSc degrees from Udai Pratap Autonomous College, Varanasi (UP), India. He received his PhD from the Department of Chemistry, Indian Institute of Technology (Banaras Hindu University) Varanasi, under the supervision of Prof. Mumtaz A. Quraishi in Corrosion Science and Engineering. He is a member of the American Chemical Society (ACS) and a lifetime member of the World Research Council (WRC). He is a reviewer and editorial board member of various internationally recognized journals from ACS, RSC, Elsevier, Wiley, and Springer. Dr. Verma has published numerous research and review articles with ACS, Elsevier, RSC, Wiley and Springer, etc., in different areas of science and engineering. His current research focuses on designing and developing industrially applicable corrosion inhibitors. Dr. Verma has edited a few books for the ACS, Elsevier, RSC, Springer, and Wiley. He has received several awards for his academic achievements, including a gold medal in MSc (Organic Chemistry; 2010) and Best Publication awards from the Global Alumni Association of IIT‐BHU (Second Prize 2013).
Dr. Paz Otero Fuertes received her bachelor's degree in food science from the University of Santiago de Compostela (USC), Spain. After that, she completed her PhD at the Pharmacology Department of the Veterinary Faculty in the same University and was awarded with the distinction Cum Laude and the Special PhD Award. Dr. Paz Otero has held postdoctoral research positions in Limerick Institute of Technology, Ireland (2014–2017), and The Institute of Food Science Research, CIAL (2017–2018) at the Autonomous University of Madrid. She has published extensively in the field of food chemistry, toxicology, analytical chemistry, pharmacology, nutrition, and phycotoxin biology with more than 56 authored research articles, 70 contributions to international congress, and 12 book chapters to date. Her h‐index is 28, and her total citation is 1550 in Google Scholar database. Dr. Paz Otero Fuertes also serves as invited reviewer for several research journals, editorial board member for online free‐access journals, and guest editor for special issues.
Preface
Chemical transformations mediated by ultrasound (US) and microwaves (MW) benefit different chemical processes. The following are some of the main advantages of each approach: Green chemistry principles are often employed in assessing the environmental impact of chemical reactions, particularly those facilitated by ultrasound and microwave radiation. Green chemistry aims to create and construct procedures that use less energy, produce fewer dangerous compounds, and are as efficient as possible. Reaction mixtures can be heated quickly and precisely using microwave heating, as is well known. Comparing this to traditional heating techniques can result in quicker reaction times and lower energy usage. Through the acceleration of chemical reactions and the promotion of effective mass transfer, ultrasonic waves can also increase reaction rates. This may lead to lower energy needs and more general efficiency. The use of large volumes of solvents is frequently reduced or eliminated when reactions may be conducted under milder circumstances, thanks to the capabilities of both microwave and ultrasonic technologies. This is consistent with the green chemistry idea of reducing the amount of hazardous or environmentally damaging solvents used. Specific reactions can be more selective than others due to the cavitation effects of ultrasound and the selective heating created by microwaves. Doing so can decrease waste and byproduct production, making the process more environmentally friendly. Reaction times are frequently shortened by the faster reaction rates associated with ultrasound and microwave techniques. This can save time and energy in producing a given amount of goods, positively affecting the environment and the economy. By reducing the possibility of thermal runaway or adverse reactions, the mechanical impacts of ultrasonic waves and the regulated and targeted heating offered by microwaves can help provide safer reaction conditions. Specific reactions mediated by microwaves and ultrasonography might be readily scaled up, enabling more significant, environmentally friendly operations.
This book explores the fundamentals, contemporary trends, obstacles, and potential future applications of microwave- and ultrasound‐assisted chemical transformation irradiations, demonstrating their worth and range. Each of the 12 chapters in this book covers a distinct facet of nonconventional chemical reactions. The fundamental theories and principles of ultrasound‐mediated reactions are covered in Chapter 1, along with the opportunities and problems that exist today. The theory and fundamentals of microwave‐mediated reactions are covered in Chapter 2. Chapter 3 compares the challenges and prospects of conventional and MW‐/US‐mediated chemical transformation. Metal‐catalyzed and coupling processes under MW and US irradiation are covered in Chapters 4 and 5, respectively. The synthesis of bioactive heterocycles, enzymatic processes, polymers, and nanomaterials under MW and US irradiation are covered in Chapters 6, 7, 8, and 9, respectively. The synthesis of covalent organic frameworks (COFs) and metal–organic frameworks (MOFs) mediated by MW and US is covered in Chapter 10. The benefits of MW and US irradiation in solid‐phase syntheses are discussed in Chapter 11. Chapter 12 concludes with a comparison of chemical changes facilitated by thermal, microwave, and ultrasonic heating.
We are very thankful to the authors of all chapters for their outstanding and passionate efforts in making this book. Special thanks to the Wiley staff Dr. Sakeena Quraishi (Commissioning Editor), Judit Anbu Hena (Content Refinement Specialist), Shwathi Srinivasan (Managing Editor, Advanced Chemistry and Chemical Engineering), and Tanya Domeier for their dedicated support and help during this project. In the end, all thanks to Wiley for publishing the book.
March 2024
Dakeshwar Kumar Verma
Chhattisgarh, India
Chandrabhan Verma
Abu Dhabi, United Arab Emirates
Paz Otero Fuertes
Ourense, Spain
1Ultrasound Irradiation: Fundamental Theory, Electromagnetic Spectrum, Important Properties, and Physical Principles
Sumit Kumar1, Amrutlal Prajapat2, Sumit K. Panja2, and Madhulata Shukla3
1Magadh University, Department of Chemistry, Bodh Gaya 824234, Bihar, India
2Uka Tarsadia University, Tarsadia Institute of Chemical Science, Maliba Campus, Gopal Vidyanagar, Bardoli, Mahuva Road, Surat 394350, Gujarat, India
3Veer Kunwar Singh University, Gram Bharti College, Department of Chemistry, Ramgarh, Kaimur 821110, Bihar, India
1.1 Introduction
US, also referred to as ultrasonic treatment or sonication, employs high frequency sound waves to agitate particles in a liquid or solid medium [1]. This process relies on the phenomenon of cavitation, which happens when high‐intensity sound waves create small bubbles in a liquid. These bubbles rapidly expand and collapse, producing pressure and temperature gradients that can break down particles and disrupt chemical bonds. This is known as acoustic cavitation, and it can be utilized for various purposes, including emulsification, dispersion, mixing, and extraction. Additionally, US can increase the surface area of reactants and enhance chemical reactions by promoting mass transfer between phases. It can also induce the formation of free radicals, which can react with target compounds and break them down. US is widely used in a range of fields, such as wastewater treatment, food processing, pharmaceuticals, and materials science [2–4]. The effectiveness of US depends on several factors, such as the frequency and intensity of the sound waves, the duration of exposure, and the characteristics of the medium being treated. Cavitation can be generated either by passing ultrasonic energy in the liquid medium or by utilizing alterations in the velocity/pressure in hydraulic systems. The intensity of cavitation, and hence the net chemical/physical effects, relies heavily on the operating and design parameters, including reaction temperature, hydrostatic pressure, irradiation frequency, acoustic power, and ultrasonic intensity. To increase the extent or rate of reaction, cavitation can be combined with one or more irradiations or some additives can be utilized, which can be solids or gases and can sometimes have catalytic effects. The free radicals generated during the oxidation process consist of hydroxyl (⋅OH), hydrogen (⋅H), and hydroperoxyl (HO2⋅) radicals. Overall, the theory behind US is based on the principles of acoustic cavitation, which can be harnessed to achieve a variety of physical, chemical, and biological effects.
US refers to the application of high‐frequency sound waves to a target material or medium. Here are some properties of US:
Frequency
: Ultrasound waves have frequencies above the upper limit of human hearing, typically between 20 kHz and several MHz (megahertz). The frequency determines the energy and penetration depth of the ultrasound waves.
Wavelength
: The wavelength of ultrasound waves is inversely proportional to the frequency. Higher frequencies result in shorter wavelengths. This property allows ultrasound waves to interact with small‐scale structures and particles.
Intensity
: Ultrasound intensity refers to the amount of energy carried by the sound waves per unit area. It determines the strength of the ultrasound waves and their effect on the target material. Ultrasound intensity is typically measured in units of watts per square centimeter (W/cm
2
).
Propagation
: Ultrasound waves propagate through materials as longitudinal waves, causing the particles of the medium to vibrate in the direction of wave propagation. This enables the transmission of energy and information through the medium.
Absorption
: Ultrasound waves can be absorbed by materials they pass through. The extent of absorption depends on the properties of the material, such as its density, viscosity, and composition. Absorption leads to the conversion of ultrasound energy into heat, which can be utilized in various applications.
Reflection and refraction
: When ultrasound waves encounter an interface between two different media, such as air and a solid object, some of the waves are reflected back and some are transmitted into the new medium. The angles of reflection and refraction obey the laws of physics similar to those governing light waves.
Cavitation
: US can induce a phenomenon known as cavitation, where the rapid changes in pressure cause the formation and implosion of tiny bubbles in a liquid medium. Cavitation can generate localized high temperatures and pressures, which can be utilized in processes like sonochemistry and ultrasonic cleaning.
Noninvasiveness
: Ultrasound waves can be transmitted through the body noninvasively, making them useful in medical imaging techniques like ultrasound scans and sonograms. They provide real‐time visualization of internal organs, tissues, and structures without the need for surgery or ionizing radiation.
Doppler effect
: The Doppler effect occurs when there is relative motion between the source of ultrasound waves and the target. This effect causes a shift in the frequency of the reflected waves, enabling the measurement of blood flow, velocity, and direction in medical applications like Doppler ultrasound [
5
,
6
].
Safety
: US is generally considered safe for medical and industrial applications, as it does not involve ionizing radiation like X‐rays or gamma rays. However, high‐intensity ultrasound can cause thermal effects, and prolonged exposure to certain intensities may have biological effects. Safety guidelines and standards are in place to ensure the safe use of ultrasound in different applications.
1.2 Cavitation History
The phenomenon of cavitation was first observed by Thornycroft and Barnaby in 1895 when the propeller of their submarine became pitted and eroded over a short operating period. This was due to collapsing bubbles caused by hydrodynamic cavitation, which generated intense pressure and temperature gradients in the surrounding area [7]. In 1917, Rayleigh published the first mathematical model describing a cavitation event in an incompressible fluid [8]. It was not until 1927, when Loomis reported the first chemical and biological effects of ultrasound, that researchers realized the potential of cavitation as a useful tool in chemical reaction processes [9]. One of the earliest applications of ultrasound‐induced cavitation was the degradation of a biological polymer [10]. Since then, the use of acoustic cavitation has become increasingly popular, particularly as a novel alternative to traditional methods for polymer production, enhancing chemical reactions, emulsifying oils, and degrading chemical or biological pollutants [11]. The advantage of utilizing acoustic cavitation for these applications is that it allows for much milder operating conditions compared to conventional techniques, and many reactions that may require toxic reagents or solvents are not necessary.
1.2.1 Basics of Cavitation
Ultrasound is a type of sound wave with a frequency above 20 kHz, and when it propagates through a liquid medium, it can create conditions for cavitation. Ultrasound has been extensively used as an intensifying approach in various fields, including chemical synthesis, electrochemistry, food technology, environmental engineering, materials, and nanomaterial science, biomedical engineering, biotechnology, sonocrystallization, and atomization [2, 12–21]. The use of ultrasound can lead to greener intensified processing with significant economic savings [22, 23]. Ultrasound‐induced cavitation, also known as acoustic cavitation, is mainly due to the alternate compression and rarefaction cycles that drive the various stages of cavity inception, growth, and final collapse, as shown in Figure 1.1[12].
When cavities collapse, a significant amount of energy is released, leading to the formation of acoustic streaming associated with turbulence resulting from the continuous generation and collapse of cavities in the system. Moreover, chemical effects, such as the occurrence of local hotspots in the interfacial region between the bubble and adjacent liquid, can generate free radicals [24]. The primary reactions that occur during sonication can be considered the initiator of a series of radical reactions depending on the species:
Figure 1.1 Schematic representation of the mechanism of generation of acoustic cavitation.
Source: Reproduced from Gogate et al. [12]/John Wiley & Sons.
When ultrasound is applied to water, it causes the generation of ⋅OH and H⋅ radicals, which subsequently leads to the production of hydrogen peroxide (H2O2). Both of these agents are strong oxidizing agents. As the cavitation bubble collapses, it generates tremendous local pressure gradients, temperature, and microjets in the liquid at the collapse point [25]. The release of the accumulated energy during bubble collapse in the form of shock waves and hot spots can significantly enhance the reaction rate [26]. In large‐scale sonochemical reactors, the two most important features of cavity dynamics are the maximum size reached before the violent collapse and the intensity of the collapse. Maximizing both of these effects in large‐scale designs is necessary to achieve the desired processing efficacy.
The chemical changes associated with cavitation induced by the passage of sound waves are referred to as sonochemistry [1]. Ultrasound's chemical effects do not arise from direct interaction with molecular species but rather from acoustic cavitation, which involves the formation, growth, and implosive collapse of bubbles in a liquid, resulting in very high energy densities of 1–1018 kW/m3 [1, 27]. Figure 1.2 depicts the mechanism of cavitation growth and collapse in liquid. The collapse takes place in microseconds and can be considered adiabatic. Cavitation can occur at millions of locations in a reactor simultaneously and generate conditions of very high temperatures and pressures (a few thousand atmospheres of pressure and a few thousand Kelvin of temperature) locally, while the overall environment remains at ambient conditions. As a result, chemical reactions that require stringent conditions can be effectively carried out using cavitation at ambient conditions.
Figure 1.2 Mechanism of cavitation growth and collapse in liquid medium.
Acoustic cavitation is the process of nucleus growth and collapse of micro‐gas bubbles or cavities in a liquid. This occurs rapidly, releasing large amounts of energy over a small area and creating extreme temperature and pressure gradients [23, 28, 29]. Cavitation generates high temperatures (between 1000 and 15 000 K) and pressures (between 500 and 5000 bar) locally and can occur at millions of locations within the reactor. Additionally, cavitation leads to acoustic streaming, intense shear stress near the collapsing bubble, and the formation of micro‐jets. The local effects of cavitation are advantageous for reactions, including the generation of free radicals due to the dissociation of vapors trapped in the cavitating bubbles, which can intensify chemical reactions or cause unexpected reactions. The collapse of cavities also creates acoustic streaming and turbulence, promoting reaction rates [1, 13, 30]. Therefore, cavitation is useful for generating local turbulence and liquid micro‐circulation and enhancing transport processes.
1.2.2 Types of Cavitation
Cavitation is a physical process that can happen when ultrasound is applied to a liquid medium, causing the formation, growth, and subsequent collapse of bubbles or voids in the liquid. The effects of ultrasound on the liquid medium can either be beneficial or detrimental, depending on the type of cavitation. Ultrasound radiation can stimulate various types of cavitation, such as stable cavitation, transient cavitation, inertial cavitation, and acoustic cavitation, depending on the properties of the liquid medium and the intensity and frequency of the ultrasound. To optimize ultrasound‐based processes and minimize potential harmful effects, it is crucial to understand the different types of cavitation that can occur during US. The following are the various types of cavitation that can occur during US:
Stable cavitation
: Stable cavitation occurs when bubbles are formed and oscillate in a liquid medium under the influence of ultrasound. Unlike other types of cavitation, the bubbles in stable cavitation do not collapse completely but rather oscillate at a specific frequency. The oscillation of these bubbles can generate acoustic streaming and microstreaming, which can enhance the mixing and mass transfer of the liquid medium. Stable cavitation has been utilized in several applications such as ultrasound‐assisted emulsification, sonochemistry, and ultrasound‐assisted extraction [
31
,
32
].
Transient cavitation
: Transient cavitation occurs when bubbles are formed, grow, and rapidly collapse in a liquid medium under the influence of ultrasound
[33]
. The collapse of these bubbles can produce high‐pressure waves and shock waves, which can cause mechanical damage to cells and tissues. Although transient cavitation can be useful in applications such as sonoporation, which involves the temporary formation of pores in cell membranes to enhance drug delivery, excessive or prolonged exposure to it can result in tissue damage and cell death.
Inertial cavitation
: Inertial cavitation occurs when bubbles in a liquid medium grow and collapse violently due to ultrasound exposure. The collapse of the bubbles produces high‐pressure waves and shock waves that may result in mechanical damage to cells and tissues. Inertial cavitation can also create high temperatures and pressures that can trigger chemical reactions in the liquid medium
[34]
. This type of cavitation is usually unwanted in many applications due to the risk of tissue damage and chemical degradation.
Acoustic cavitation
: Acoustic cavitation is a physical phenomenon that involves the formation and collapse of bubbles in a liquid medium under the influence of ultrasound. The type of cavitation can either be stable or transient, depending on the intensity of the ultrasound. Acoustic cavitation can produce high temperatures and pressures that can induce chemical reactions in the liquid medium, as well as generate free radicals and other reactive species that can cause chemical degradation.
Furthermore, cavitation can be categorized into four principal types, which are acoustic, hydrodynamic, optic, and particle cavitation, as illustrated in Figure 1.3. Acoustic and hydrodynamic cavitation is the result of tensions that exist in a liquid, while optic and particle cavitation arise from the local deposition of energy. The classification of cavitation based on the method of technique used and the process of cavity generation is important for understanding the effects of ultrasound on a liquid medium and for optimizing ultrasound‐based processes.
Acoustic cavitation
: Acoustic cavitation is the process of forming and collapsing bubbles in a liquid medium through the use of sound waves, particularly ultrasound with frequencies ranging from 16 kHz to 100 MHz. The phenomenon of chemical changes induced by acoustic cavitation is commonly known as sonochemistry
[35]
. It involves the combination of ultrasound and chemistry.
Figure 1.3 Types of cavitation based on technique used.
Hydrodynamic cavitation
: Hydrodynamic cavitation is a type of cavitation that is produced by pressure variations created through the geometry of the system, which creates velocity variation. For instance, by leveraging the system's geometry, the interchange of pressure and kinetic energy can be achieved, leading to the formation of cavities, as seen in the case of flow through an orifice, venturi, and other similar systems.
Optic cavitation
: Optic cavitation involves the use of high‐intensity light, typically from a laser, to create cavitation in a liquid medium. The photons of the light can rupture the liquid continuum and generate bubbles or voids.
Particle cavitation
: Particle cavitation is induced by a stream of elementary particles, such as a neutron beam, disrupting a liquid medium. This type of cavitation is commonly observed in devices like bubble chambers.
When it comes to cavitation, two types are frequently employed due to their efficacy in generating the necessary intensities for chemical or physical transformations: acoustic and hydrodynamic cavitation. The extent of cavitational impact hinges on both the turbulence intensity and the number of cavities formed. In essence, ultrasound wave propagation through medium results in acoustic cavitation, whereas hydrodynamic cavitation occurs as the flow's velocity changes due to alterations in the flow path geometry.
1.3 Application of Ultrasound Irradiation
US has a wide range of applications across various fields. Here are some notable applications of US:
Medical sciences
: Ultrasound imaging is commonly used in medical diagnostics to visualize internal organs, tissues, and structures in real‐time
[36]
. It is a noninvasive and radiation‐free imaging technique that is particularly useful for examining the abdomen, pelvis, heart, blood vessels, and developing fetus during pregnancy (see
Figure 1.4
). There are some other applications, which are explained below.
Diagnostic imaging
: One of the most common uses of ultrasound in medicine is diagnostic imaging. Ultrasound imaging allows noninvasive visualization of internal organs, tissues, and structures in real‐time. It is used to examine various body parts, including the abdomen, pelvis, heart, blood vessels, musculoskeletal system, and the developing fetus during pregnancy [
38
,
39
].
Obstetrics and gynecology
: Ultrasound is extensively used in obstetrics and gynecology to monitor the progress of pregnancy, assess fetal development, determine the position of the fetus, and detect any abnormalities. It is also used for evaluating the female reproductive system, such as examining the uterus, ovaries, and fallopian tubes.
Cardiology
: Ultrasound plays a crucial role in cardiology for evaluating the structure and function of the heart. Echocardiography, a type of ultrasound imaging, allows visualization of the heart's chambers, valves, and blood flow patterns. It helps in diagnosing and monitoring various heart conditions, such as heart valve disorders, congenital heart defects, and heart muscle abnormalities.
Figure 1.4 The abdominal sonography of the brain of a 21‐week‐old fetus.
Source: Reproduced with permission from Pilu et al. [37]/John Wiley & Sons.
Vascular imaging
: Ultrasound is used to examine blood vessels and assess blood flow patterns. Doppler ultrasound is particularly valuable in measuring the velocity and direction of blood flow, detecting blockages, or narrowing of vessels (such as in cases of deep vein thrombosis or arterial stenosis), and evaluating vascular abnormalities.
Interventional procedures
: Ultrasound guidance is employed during certain minimally invasive procedures to enhance accuracy and safety. For example, ultrasound can be used to guide the insertion of needles for biopsies, aspirations, or injections. It helps in precisely targeting the intended area and avoiding damage to surrounding structures.
Sonography‐guided therapies
: Ultrasound is utilized in various therapeutic procedures.
High‐intensity focused ultrasound
(
HIFU
) is used to precisely deliver focused energy to treat tumors or ablate abnormal tissues, such as uterine fibroids or prostate tumors, without the need for surgery. Additionally, ultrasound can be used for targeted drug delivery or gene therapy by utilizing microbubbles that enhance the permeability of cell membranes.
Guidance for minimally invasive surgeries
: During minimally invasive surgeries, such as laparoscopic or robotic procedures, ultrasound can be used to provide real‐time imaging guidance. It helps surgeons visualize and navigate internal structures, locate tumors or lesions, and ensure precise surgical instrument placement.
Therapeutic treatments
: HIFU is utilized for therapeutic purposes. It involves focusing ultrasound waves on specific target tissues to generate heat or mechanical effects, leading to tissue ablation, tumor destruction, and targeted drug delivery. HIFU is used in the treatment of various conditions, including uterine fibroids, prostate cancer, liver tumors, and pain management.
Physiotherapy and rehabilitation
: Ultrasound therapy is used in physiotherapy to provide deep tissue heating and promote healing. It is employed to treat conditions like muscle strains, sprains, joint inflammation, and sports injuries. The thermal effects of ultrasound can increase blood flow, relax muscles, and alleviate pain.
Dental applications
: Ultrasound is utilized in dentistry for various procedures. It is commonly used for dental imaging, such as imaging the teeth and supporting structures. Ultrasonic scalers are also employed for dental cleanings and the removal of plaque and tartar from teeth.
Scaling and root planning, endodontic treatment, periodontal treatment, implantology, restorative dentistry, and dental prosthetics are important procedures to employ the ultrasonic iterations. Ultrasonic scalers are commonly used in dental hygiene for scaling and root planning procedures. These devices use ultrasonic vibrations to remove tartar, plaque, and bacterial deposits from the teeth and gums. The high‐frequency vibrations generated by the ultrasonic scaler help to break down and dislodge the deposits, making the cleaning process more efficient and comfortable for the patient.
Ultrasonic instruments are utilized in endodontics, which involves the treatment of the tooth's pulp and root canal system. Ultrasonic tips, such as ultrasonic files or ultrasonic irrigators, are employed to remove infected or necrotic pulp tissue, clean and shape the root canals, and facilitate the irrigation of disinfectants or irrigation solutions. Ultrasonic vibrations aid in the removal of debris, disinfection of the canals, and better penetration of irrigants into complex root canal anatomy.
Ultrasonic devices are utilized in periodontal therapy to treat gum diseases and perform various procedures. Ultrasonic scalers and tips are used for subgingival debridement, which involves removing calculus and bacteria from below the gum line. The ultrasonic vibrations help to disrupt and remove the biofilm and tartar from periodontal pockets, promoting better healing and reduced pocket depths. Ultrasonic instruments are also employed in implant dentistry for the placement and maintenance of dental implants. During implant surgery, ultrasonic tips can be used for site preparation, osteotomy, and socket cleaning. Ultrasonic instruments are also useful for implant maintenance and cleaning around implant surfaces, removing plaque and calculus without damaging the implant or surrounding tissues.
The applications of ultrasonic irradiation in restorative dentistry procedures are as well. Ultrasonic instruments can be used for the removal of old restorative materials, such as amalgam or composite fillings, by gently vibrating and loosening the material for easier removal. Ultrasonic tips can also aid in the cleaning and preparation of the tooth structure before placing restorations like dental crowns or veneers.
1.3.1 Sonoluminescence and Sonophotocatalysis
Sonoluminescence refers to the emission of light from collapsing bubbles in a liquid medium under the influence of ultrasound. It is a fascinating phenomenon with potential applications in fields such as chemistry, physics, and materials science. Sonophotocatalysis (see Figure 1.5) involves combining ultrasound with photocatalytic reactions to enhance the efficiency of photocatalysts for water treatment, pollution remediation, and energy production.
Figure 1.5 Schematic illustration for sonophotocatalytic mechanism.
Source: Reproduced with permission from Wang and Cheng [40]/MDPI/Licensed under CC BY 4.0.
When used in conjunction with light and a photocatalyst, the sonophotocatalytic process can have a synergistic impact that speeds up the breakdown of organic contaminants in wastewater. The increased generation of reactive free radicals as well as the enhanced mass transfer of the contaminants to the photocatalyst surface are two reasons for the synergistic impact [40]. The enhanced creation of reactive radicals like ⋅OH (see Figure 1.5), which are particularly effective at destroying organic pollutants, is one of the main benefits of sonophotocatalysis. Ultrasonic waves have the ability to cause cavitation, which produces high‐energy bubbles that burst and emit shockwaves and heat, leading reactive radicals to develop.
Yun et al. [41] have developed an efficient catalyst that can produce H2O2 and destroy refractory pollutants. This study uses an in situ precipitation technique to rationally construct a number of new Ag6Si2O7/SmFeO3 (ASF) heterojunction catalysts. Several characterization procedures were used to confirm the characteristics of the manufactured ASF nanocomposites. With an adequate concentration of ciprofloxacin (CIP) of 10 mg/l at 400 W US power, 0.6 g/l catalyst dosage, pH of 5.0, as well as 40 kHz US frequency during irradiation time of 60 minutes, the ASF‐1.5 sample in particular displays high efficiency (94.9%) of sonophotocatalytic.
1.3.2 Industrial Cleaning
US is applied in industrial cleaning processes such as ultrasonic cleaning [42, 43]. It involves immersing objects in a cleaning solution and subjecting them to high‐frequency sound waves. The cavitation effect generated by ultrasound helps remove dirt, contaminants, and deposits from the surfaces of objects, making it useful for cleaning delicate or intricate items.
Ultrasonic cleaning systems consist of a cleaning tank filled with a suitable cleaning solution or solvent. The object to be cleaned is immersed in the liquid, and ultrasonic transducers located in the tank generate high‐frequency sound waves. These sound waves create alternating high‐ and low‐pressure zones in the liquid, leading to the formation and collapse of cavitation bubbles near the object's surface. The collapse of these bubbles generates intense local energy, effectively scrubbing away contaminants.
Ultrasonic cleaning is highly effective in removing a wide range of contaminants, including oils, grease, dirt, rust, scale, and other residues [43]. The cavitation action reaches into complex geometries and crevices that are difficult to access using other cleaning methods. This makes it particularly useful for cleaning intricate parts, such as machine components, automotive parts, electronics, jewelry, medical instruments, and precision equipment.
One typical aspect of dairy processing is the ultrafiltration of whey solutions. The economics of such a process are, however, greatly impacted by the regular fouling of ultrafiltration membranes and the following cleaning cycle. In this study performed by Muthukumaran et al. [44], it is monitored into how ultrasonics affect the cleansing of whey‐fouled membranes and what factors affect this result. A tiny single‐sheet membrane unit that was completely submerged in an ultrasonic bath was used for the experiments.
An earlier solution to the problems produced by the acidic ammonium salt crystallization of vanadium was the ultrasound crystallization (UC) technique [45]. This study looked closely at how several parameters affected the properties of vanadium crystallization [45]. The results demonstrated that using ultrasonic power of 600 W, a baseline pH value of 2.0, ambient temperature of 95 °C, ammonium salt addition coefficient of 0.5, period of five minutes, excessive vanadium precipitation ratio (99.67%), and vanadium level of 20 g/l, along with V2O5 purity (99.50%) of the outcomes of the reaction can be achieved.
1.3.3 Material Processing
Ultrasound is used in various material processing applications. It can be employed for emulsification, dispersion, and homogenization of liquids, as well as particle size reduction. Ultrasonic devices are also used for degassing, degreasing, and defoaming processes in industries like food and beverage, pharmaceuticals, and cosmetics.
Ji et al. have studied the crystalline structures of Sn–Ag–Cu alloy ingots formed through ultrasound‐assisted solidification, with an emphasis on the restrictions on ultrasonic processing depth and time imposed by the melt solidification's cooling rate [46]. Raising the ultrasonic power during cooling by air caused the –Sn phase to split from a dendritic structure into a circle‐like equiaxed shape by lowering the undercooling temperature and lengthening the process of the solidification period. The grain size was reduced from 300 to 20 mm.
Using Y2O3, CuCl2 as well as BaCl2 as the starting components for the co‐precipitation process, Jian‐feng et al. [47] have produced Y2BaCuO5 nanocrystallites with the aid of ultrasonic irradiation. Transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were used to characterize the crystallization and morphologies of nanoparticles as prepared. Results demonstrate that using a mixture of NaOH and Na2CO3 as a precipitator, Y2BaCuO5 monophase can be produced at calcining temperatures up to 900 °C. With a rise in sonicating power, Y2BaCuO5 crystallites' particle size reduces. When the sonicating power is increased to 300 W, it is possible to produce Y2BaCuO5 crystallites that are around 30 nm in size.
In order to establish an affordable method for producing bioethanol, the effort focuses on intensifying delignification and subsequent enzymatic‐hydrolysis of sustainable biomass such as coconut coir groundnut shells, and pistachio shells utilizing an ultrasound‐aided methodology [48]. The obtained results for delignification of biomass showed that the extent of delignification for groundnut shells, coconut coir, and pistachio shells under conventional alkaline treatment was 41.8%, 45.9%, and 38%, respectively, while it raised to 71.1%, 89.5%, and 78.9%, providing a nearly 80–100% boost under the ultrasound supported technique. The traditional technique produced reducing sugar yields of 10.2, 12.1, and 8.1 g/l for groundnut shells, coconut coir, and pistachio shells, respectively, under optimal conditions. In contrast, the yields from ultrasound‐assisted enzymatic hydrolysis were 21.3, 23.9, and 18.4 g/l in the identical amount of biomass.
1.3.4 Chemical and Biological Reactions
US is employed in chemical and biological reactions to enhance reaction rates, promote mixing, and improve mass transfer. It is used for various processes such as the synthesis of nanoparticles, extraction of bioactive compounds from plants, sonochemistry, and sono‐organic reactions.
Although the use of ultrasound in biotechnology is still relatively recent, it has been found to trigger a number of mechanisms that happen when cells or enzymes are present [49]
