Ultrasound in Heterogeneous Systems and Applications in Food Processing

Grieser, Franz

doi:10.1016/b978-0-12-801530-8.00011-6

Cited by 7 publications

(4 citation statements)

References 59 publications

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“…This phenomenon is known as cavitation . The implosion of gas bubbles is accompanied by mechanical and chemical effects that will be transformed into energy. , Sonochemistry is based on the acoustic energy and the cavitation phenomenon produced by ultrasound . It should also be noted that upon ultrasonic activation radicals may be formed in the reaction mixture.…”

Section: Technologiesmentioning

confidence: 99%

Alternative Technologies That Facilitate Access to Discrete Metal Complexes

et al. 2019

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Organometallic complexes: these two words jump to the mind of the chemist and are directly associated with their utility in catalysis or as a pharmaceutical. Nevertheless, to be able to use them, it is necessary to synthesize them, and it is not always a small matter. Typically, synthesis is via solution chemistry, using a roundbottom flask and a magnetic or mechanical stirrer. This review takes stock of alternative technologies currently available in laboratories that facilitate the synthesis of such complexes. We highlight five such technologies: mechanochemistry, also known as solvent-free chemistry, uses a mortar and pestle or a ball mill; microwave activation can drastically reduce reaction times; ultrasonic activation promotes chemical reactions because of cavitation phenomena; photochemistry, which uses light radiation to initiate reactions; and continuous flow chemistry, which is increasingly used to simplify scaleup. While facilitating the synthesis of organometallic compounds, these enabling technologies also allow access to compounds that cannot be obtained in any other way. This shows how the paradigm is changing and evolving toward new technologies, without necessarily abandoning the round-bottom flask. A bright future is ahead of the organometallic chemist, thanks to these novel technologies. CONTENTS1. Introduction 7530 2. Technologies 7530 2.1. Grinding and Milling 7530 2.2. Microwave Irradiation 7531 2.3. Ultrasound Activation 7531 2.4. Photochemistry 7532 2.5. Continuous Flow 7532 3. Contribution of Each Technology Compared to Classical Syntheses 7533 4. Lithium and Magnesium 7534 4.1. Mechanochemical Access to Grignard Reagents 7534 4.2. Microwave Irradiation for the Synthesis of Magnesium Complexes 7534 4.3. Ultrasonic Procedures 7535 4.4. Continuous Flow Syntheses 7535 5. Groups 2, 3, 4, and 5 7537 5.1. Mechanochemical Procedures for Complexes of Groups 2, 3, and 4 7537 5.2. Microwave Irradiation for the Synthesis of Vanadium Complexes 7537 5.3. Synthesis of Vanadium Complexes Using Ultrasound 7538 6. Group 6 7538 6.1. Mechanosynthesis of Molybdenum and Chromium Complexes 7538 6.2. Microwave Irradiation for the Synthesis of Group 6 Metal Complexes 7539 6.3. Photochemistry for Synthesis of Group 6 Metal Complexes 7543 6.4. Continuous Flow Chemistry for Synthesis of Chromium Complexes 7545 7. Group 7 7545 7.1. Mechanosynthesis of Rhenium Complexes 7545 7.2. Microwave Irradiation for the Synthesis of Group 7 Metal Complexes 7546 7.3. Photochemical Synthesis of Manganese and Rhenium Complexes 7549 8. Group 8 7550 8.1. Synthesis of Iron and Ruthenium Complexes Using Ball Milling 7550 8.2. Microwave Procedures 7552 8.3. Ultrasonic Irradiation for Iron Complexes 7562 8.4. Syntheses of Iron and Ruthenium Complexes Using Photochemistry 7563 8.5. Continuous Flow Conditions to Prepare Iron and Ruthenium Complexes 7566 9. Group 9 7566 9.1. Synthesis of Cobalt and Rhodium Complexes by Mechanochemistry 7566 9.2. Procedures Using Microwave Irradiation 7569 9.3. Photochemical Synthesis of Iridium Complexes 7...

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Section: Technologiesmentioning

confidence: 99%

Alternative Technologies That Facilitate Access to Discrete Metal Complexes

et al. 2019

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“…Acoustic cavitation plays a key role in the field of sonochemistry, which includes ultrasonic cleaning, high-intensity ultrasound therapy, organic and inorganic syntheses, and food processing so on. 1,2) Intense ultrasound in liquids produces bubbles that undergo repeated expansion and contraction. These cavitating bubbles induce high-temperature and highpressure conditions on bubble collapse via quasi-adiabatic processes.…”

Section: Introductionmentioning

confidence: 99%

Multibubble sonoluminescence and bubble dynamics in glycerol/water mixture system

Munenori¹,

Choi²

2020

Jpn. J. Appl. Phys.

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We investigated viscosity dependence of sonoluminescence (SL) in aqueous solutions of glycerol at acoustic frequencies of 50 and 150 kHz. The concentration dependence of SL intensity showed opposite behaviors at the two frequencies. At 50 kHz, the SL intensity increased with increasing glycerol content taking a maximum at 80% glycerol. At 150 kHz, the SL intensity decreased monotonically with increasing glycerol content. Highspeed shadowgraphy of cavitating bubbles with a frame speed of 1 Mfps demonstrated the difference in bubble dynamics at the two frequencies, and clarified the observed results of SL intensity. The increase in SL intensity at 50 kHz resulted from the increase in the number of bubbles exhibiting spherical oscillation caused by the high viscosity. The decrease in SL intensity at 150 kHz resulted from the small expansioncompression ratio of bubble oscillation caused by viscous damping. A numerical simulation of bubble oscillation supported the results.

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“…Ademais, o surgimento de bolhas de nucleação também é dependente da presença e da concentração de impurezas, e da existência de fendas ou rachaduras no meio submetido à incidência de ondas acústicas (65), sendo dividida em dois tipos: homogênea e heterogênea. (61) As bolhas podem ocorrer mais facilmente em regiões do meio com menor resistência à tração.…”

Section: Nucleação Acústicaunclassified

“…( 102) A quantidade p B,min costuma ser referida como limiar de cavitação. (65,99) Tal pressão corresponde a pressão mínima necessária para a expansão da bolha de cavitação, ou seja, a pressão mínima que permite com que o gás preso no interior da bolha se expanda contra a tensão superficial. ( 103)…”

Section: Modelo De Blakeunclassified

Sobre as condições e probabilidades para a nucleação e cavitação acústicas no tecido biológico - uma análise teórica

Antunes¹

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Este trabalho é dedicado à todas as mulheres que fizerem e fazem ciência, e também àquelas que disseminam o conhecimento científico dentro e fora das universidades. AGRADECIMENTOSAos meus pais Edson e Marlene, por me darem todo o apoio necessário para que eu pudesse chegar até aqui. Sem vocês o caminho que tracei não seria possível.À minha irmã Daniele, pelo apoio emocional em todas as situações e por sempre acreditar que eu seria capaz de chegar até aqui mesmo quando eu não o fiz.

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Ultrasound in Heterogeneous Systems and Applications in Food Processing

Cited by 7 publications

References 59 publications

Alternative Technologies That Facilitate Access to Discrete Metal Complexes

Alternative Technologies That Facilitate Access to Discrete Metal Complexes

Multibubble sonoluminescence and bubble dynamics in glycerol/water mixture system

Sobre as condições e probabilidades para a nucleação e cavitação acústicas no tecido biológico - uma análise teórica

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