Sonochemical Reactions

This book was written by authors in the field of ultrasound-assited synthesis and their applications. Among others, some of the topics covered are: ultrasound-assited synthesis of metal/metal oxide nanoparticles, graphene nanosheets, and ultrasound applications. In this book, authors focused on recent studies, applications, and new technological developments on fundamental properties of the ultrasound process.

Sonochemistry and cavitation are rapidly increasing in importance in modern chemistry as a result of many significant achievements made in recent years. In this current and comprehensive text, the author clearly details and illustrates these developments as well as the fundamental concepts. Much attention is given to the fundamental problems, such as the general kinetics of sonochemical reactions: energetic yields; the principles of the cavitation diffusion theory; the place of acoustic energy among other physical methods of action on matter; and the new electrical theory of cavitation phenomena, sonochemical reactions and sonoluminescence initiation (the theory developed by Professor Margulis). Results of low-frequency acoustic fields investigations are also observed. Special attention is given to the influence of acoustic fields on chemical reactions in nonaqueous systems, catalytic processes and the initiation of oscillating reactions. This publication is designed to broaden the application of ultrasound in chemical technology and improve the efficiency of existing production processes. Its comprehensiveness makes it a practical handbook which will prove invaluable to a broad readership amongst chemistry, engineering and physics undergraduates, graduates, researchers, and industrialists working in the fields of sonochemistry, ultrasonic and chemical technology, high energy chemistry, acoustics and biology.

Despite the fact that chemical applications of ultrasound are now widely acknowledged, a detailed presentation of inorganic systems covering nano-particles, catalysis, aqueous chemistry of metallic solutions and their redox characteristics, both from a theoretical and experimental perspective has eluded researchers of this field. Theoretical and Experimental Sonochemistry Involving Inorganic Systems fills this gap and presents a concise and thorough review of this fascinating area of Sonochemistry in a single volume.

TEAN-LOUIS LUCHE A French poet of this eentury, Pierre Mae Orlan, wrote "Adventure does not exist, it is only in the mind of he who is pursuing it, and, as soon as it is at one's finger tips, it vanishes to come back to life, far away, in a different shape, at the frontiers of imagination". This sentence could be used to define the adventure that many sonochemists experienced. Most of them did not even suspect that the "laboratory trick" they were using was the first contact with a considerable amount of science. If a personal note is allowed here, it ean be interesting to mention the part played by chance in my involvement in sonochemistry. Almost 20 years ago, we had to perform an apparently simple Grignard reaetion with n-butylmagnesium bromide and geranial, but the results were repeatedly unsatisfactory. The one-pot Barbier technique was attempted, also without success. From my studies at the University, I imagined that the failure of the latter reaction could be caused by a common phenomenon known by solid state chemists as passivation, which in some cases can be overcome by ultrasonication. By chance, an ultrasonie bath was sitting on the next beneh, borrowed to clean some equipment. We clamped our reluctant reaction mixture into the bath, the reaction proceeded vigorously, and ... the adventure started. Without knowing anything about cavitation, high energies, ete., we had an illustration of Goethe's word "Am Anfang war die Tat" (at the Beginning was the Act).

Traditionally heat and light are thought as energy sources to drive a particular chemical reaction, but now ultrasound is a promising energy source for this purpose. The collapse of a bubble generates a wide range of high temperatures and pressures, and therefore, use of ultrasound has a considerable potential in chemical and allied sciences. Ultrasound-assisted reactions are green and economically viable alternatives to conventional techniques. This new volume presents a complete picture of ultrasound-assisted reactions and technologies that can be used in organic synthesis, polymer synthesis and degradation, nanomaterials, wastewater treatment, food ingredients and products, pharmaceutical applications, bioenergy applications, and more. This volume aims to shed light on the diversified applications of ultrasound and its significant role as a green chemical pathway. Sonochemistry deals with the effect of ultrasonic waves on chemical systems. It has green value because of non-hazardous acoustic radiation and is therefore duly recognized as a green chemistry by synthetic chemists as well as environmentalists. There is no direct interaction of ultrasound with molecular species, but the observed chemical and physical effects of ultrasound are due to the cavitational collapse, which produces drastic conditions of temperature and pressure locally. It induces the formation of various chemical species, which cannot be easily attained under conventional conditions. Sometimes, these species are responsible for driving towards an unusual reactivity in molecular entities. This book, Sonochemistry: An Emerging Green Technology, provides the complete development of sonochemistry, starting with an introduction and basic concepts of sonochemistry and proceeding on to different types of sonochemical reactions, instrumentation, use of ultrasound in driving particular chemical reactions, and its applications in various fields, such as polymer synthesis, decontamination of water and wastewater, preparation of nanomaterials, food technology, pharmaceutical sciences, etc. The book also briefly discusses some areas that utilize ultrasounds of different frequencies. These include food products and their processing; anaerobic digestion of waste; and medical applications such as ultrasonography, sonodynamic therapy, drug delivery, etc. Sonochemistry will be successfully used on an industrial scale in pharmaceutical drugs, polymers, nanomaterials, food technology, material science, biogas production, etc. in years to come and will be an established green chemical technology of the future.

This book provides informative, useful, and stimulating reading on the topic of organic sonochemistry – the core of ultrasound-based applications. Given the increasing interest in new and improved technologies, allied to their green and sustainable character (not always a valid premise), there is a great attraction for organic chemists to apply these protocols in synthesis and process chemistry. Unfortunately, as with other enabling technologies, many researchers new to the field have received a simple and dishonest message: just switch on! Therefore a significant portion of sonochemical syntheses lack reproducibility (surprisingly cavitation control and/or ultrasonic parameters are omitted) and the actual role of sonication remains uncertain. While this book does not provide a detailed description of fundamentals, the introductory remarks highlight the importance of cavitational effects and their experimental control. It presents a number of concepts of sonochemical reactivity and empirical rules with pertinent examples, often from classical and recent literature. It then focuses on scenarios of current interest where organic chemistry, and synthesis in particular, may benefit from sonication in terms of both chemical and mechanical activation. The “sustainable corner” of this field is largely exemplified through concepts like atom economy, renewable sources, wasteless syntheses, and benign solvents as reaction media. This book is useful for both researchers and graduate students, especially those familiar with the field of sonochemistry and applications of ultrasound in general. However, it is also of interest to a broader audience as it discusses the fundamentals, techniques, and experimental skills necessary for scientists wishing to initiate the use of ultrasound in their domain of expertise.

Energy Aspects of Acoustic Cavitation and Sonochemistry: Fundamentals and Engineering covers topics ranging from fundamental modeling to up-scaled experiments. The book relates acoustic cavitation and its intrinsic energy balance to macroscopic physical and chemical events that are analyzed from an energetic perspective. Outcomes are directly projected into practical applications and technological assessments covering energy consumption, thermal dissipation, and energy efficiency of a diverse set of applications in mixed phase synthesis, environmental remediation and materials chemistry. Special interest is dedicated to the sonochemical production of hydrogen and its energetic dimensions. Due to the sensitive energy balance that governs this process, this is seen as a "green process" for the production of future energy carriers. Provides a concise and detailed description of energy conversion and exchange within the single acoustic cavitation bubble and bubble population, accompanying physical and chemical effects Features a comprehensive approach that is supported by experiments and the modeling of energy concentration within the sonochemical reactor, jointly with energy dissipation and damping phenomenon Gives a clear definition of energy efficiency metrics of industrial sono-processes and their application to the main emergent industrial fields harnessing acoustic cavitation and sonochemistry, notably for the production of hydrogen

Sonochemistry and the Acoustic Bubble provides an introduction to the way ultrasound acts on bubbles in a liquid to cause bubbles to collapse violently, leading to localized 'hot spots' in the liquid with temperatures of 5000° celcius and under pressures of several hundred atmospheres. These extreme conditions produce events such as the emission of light, sonoluminescence, with a lifetime of less than a nanosecond, and free radicals that can initiate a host of varied chemical reactions (sonochemistry) in the liquid, all at room temperature. The physics and chemistry behind the phenomena are simply, but comprehensively presented. In addition, potential industrial and medical applications of acoustic cavitation and its chemical effects are described and reviewed. The book is suitable for graduate students working with ultrasound, and for potential chemists and chemical engineers wanting to understand the basics of how ultrasound acts in a liquid to cause chemical and physical effects. Experimental methods on acoustic cavitation and sonochemistry Helps users understand how to readily begin experiments in the field Provides an understanding of the physics behind the phenomenon Contains examples of (possible) industrial applications in chemical engineering and environmental technologies Presents the possibilities for adopting the action of acoustic cavitation with respect to industrial applications