Practical Sonochemistry: Power Ultrasound Uses and Applications

166 Pages·2002·68.063 MB·English

by  Timothy J Mason, Dietmar Peters

PRACTICAL SONOCHEMISTRY:
Uses and Applications of Ultrasound, 2nd Edition
"Talking of education, people have now a-days" (said he) "got a strange
opinion that every thing should be taught by lectures. Now, I cannot see that
lectures can do so much good as reading the books from which the lectures
are taken. I know nothing that can be best taught by lectures, except where
experiments are to be shewn. You may teach chymestry by lectures. You
might teach making of shoes by lectures!"
James Boswell: Life ofS amuel Johnson 1766
ABOUT OUR AUTHORS
Tim Mason was born in 1946 and studied chemistry at Southampton
University where he received his B.Sc. in Chemistry in 1967 and his Ph.D.
for work in physical organic chemistry in 1970. After a period in the USA as
NATO Fellow at Amherst College, Massachusetts he returned to the UK
with short spells at York and Bradford Universities before finally moving to
Coventry in 1975. It was at Coventry University that he began his research
into sonochemistry, having been awarded a D.Sc. from Southampton in 1996
for work in this area.
He was the first president of the European Society of Sonochemistry and is
currently Senior Editor of the journal Ultrasonics Sonochemistry and of the
series of texts Advances in Sonochemistry.
He is now Director of the Sonochemistry Centre, University of Coventry
where his interests are in a range of applications of power ultrasound
technologies including environmental protection, materials processing, food
processing, electrochemistry and therapeutic ultrasound. He has published
over 200 papers and bas authored and edited 15 books on sonochemistry.
Dietmar Peten was born in Berlin in 1961 and obtained his first degree in
Chemistry at the University of Greifswald, and his Ph.D. in 1990 after
postgraduate study in organic chemistry at the University of Rostock. He
then went to the University of Lyon, France for post-doctorial study at the
Institute of Pharmaceutical and Biological Science (1993 - 1995).
He returned to East Germany as Scientific Assistant at the Department of
Chemistry, University of Rostock, where he is now Senior Assistant and
lecturer in organic chemistry, technical chemistry and sonochemistry,
becoming Reader in Organic Chemistry in 2000.
Since 2001 he has been Head of Carbohydrates and Wood/Cellulose
divisions of the Federal Ministry of Consumer Protection, Food and
Agriculture. He is a member of the Society of German Chemistry, European
Society of Sonocbemistry, and of the German University Lecturer
Association.
Practical Sonochemistry
Uses and Applications of Ultrasound, 2nd Edition

Timothy Mason
Director of Sonochemistry Centre
University of Coventry
and
Dietmar Peters
Reader in Organic Chemistry
University of Rostock

Oxford Cambridge Philadelphia New Delhi
Published by Woodhead Publishing Limited,
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First published by Horwood Publishing Limited, 2002, reprinted 2004
Reprinted by Woodhead Publishing Limited, 2011

© Timothy Mason and Dietmar Peters, 2002
The authors have asserted their moral rights

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British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library

ISBN 978-1-898563-83-7
v
Author's preface
The first edition of this book was published in 1991 when sonochemistry was relatively
young. At that time there was no text available that addressed the basic information
required for laboratory sonochemistry and it was conceived as a guide for those starting
out in the field. Since that time several books have been published which address the
subjects of acoustic cavitation, bubble dynamics, sonoluminescence and the theoretical
aspects of sonochemistry but when my original text went out of print I felt that there
was still a need for a general laboratory guide. When Ellis Horwood asked me to
prepare a second edition I was quite happy to do so but also conscious of the need for
the input of some other ideas. This is why I contacted Dietmar Peters, a colleague from
the executive of the European Society ofSonochemistry, and so the project began.
The main reasons for writing this text remain those that inspired the previous
edition. Firstly the desire to promote the use of sonochemistry more widely in the
laboratory and secondly to show that nowadays there exists a range of power ultrasonic
equipment which will enable laboratory preparations to be performed on an industrial
scale. This text is intended to serve as a laboratory guide in that it addresses the more
practical aspects of the subject and theory has been kept to a minimum. You will fmd
some sections of the text in boxes. These are designed as illustrative examples that can
be read separately while the main themes continue in regular print.
In Chapter 1 you will find a general introduction to the subjects of power
ultrasound and sonochemistry that includes an overview of acoustic cavitation which is
the underlying driving force for sonochemisty. This chapter also reviews the methods of
dosimetry available for the determination of the cavitation threshold for a medium and
the measurement of the ultrasonic power level entering a reaction. Chapters 2 and 3
contain practical details about the construction and method of use of ultrasonic baths
and probe systems respectively while Chapter 4 explores the type of equipment that is
currently available for large-scale sonochemistry. Chapter 5 consists of a collection of
sonochemical experiments designed as guides to correct laboratory practise.
My co-author and I hope that you will find our approach useful and that
sonochemistry will continue to be not only a routine laboratory procedure but also an
exciting research field.
Tim Mason, August 2002
VI
Table of contents
1. An introduction to the uses of power ultrasound in chemistry
1.1 The importance of sonochemistry 1
1.2 The power of sound 2
1.3 Cavitation -the origin of sonochemical effects 5
1.3.l The cavitation threshold 6
1.3.2 The cavitation event 7
1.4 Parameters that effect cavitation 8
1.4.l Acoustic factors 8
1.4.1. l Frequency 8
l.4.1.2/ntensity 8
1.4.1.3 Pulse IO
1.4.2 The influence of solvent 10
1.4.3 External factors 11
1.4.3. l Bubbled gas 11
1.4.3 .2 External temperature 11
1.4.3.3 External pressure 11
1.5 Physical, chemical, and biological effects of acoustic cavitation 12
1.5.1 Physical effects inside the bubble 12
1.5.2 Physical effects outside the bubble 13
1.5.3 Chemical effects 15
l.5.3.1 Radical formation 15
l.5.3.2Mechanical effects 17
1.5.3 .3 Effects on Single Electron Transfer (SET) processes 20
l.5.4 Biological effects 20
1.6 The generation of ultrasound - transducers 21
1.6.1 Gas-driven transducers 21
l.6.2 Liquid-driven transducers 23
1.6.3 Electromechanical transducers . 24
1.6.3.1 Magnetostrictive transducers 24
1.6.3.2Piezoelectric transducers 25
1.7 Coupling of ultrasound to liquids 26
Table of contents vii
1.8 Types of sonochemistry equipment 29
1.8.1 Batch systems 29
1.8.1.1 The ultrasonic bath 30
1.8.1.2 The probe system 31
1.8.2 Flow systems 31
1.8.3 The safety of sonochemical equipment 31
1.9 Dosimetry of ultrasonic systems 33
1.9.l Determination of the cavitation threshold 33
1.9.1.1 Through the detection ofb ubbles 33
1.9.1.2 Through the detection ofs onoluminesccence 33
1.9.1.3 Through the initiation ofc hemical reactions 34
I .9. l .4An exposure system 34
1.9.2 Determination of the acoustic power 36
1.9.2.1 Measurement ofv ibrational amplitude 36
1.9 .2.2 Measurement ofe lectrical power to the transducer 37
l.9.2.3Acoustical dosimetry 37
1.9.3. Determination of ultrasonic effects in the liquid 37
1.9.3.1 Calorimetry 37
1.9.3.2 Chemical dosimetry 38
1.10 Comparing systems with different frequencies 43
I.II The sonochemical yield 44
1.12 References 46
2. The ultrasonic bath
2.1 Bath design and construction 50
2.1.1 The ultrasonic bath - low frequency studies 50
2.1.2 The ultrasonic bath - high frequency studies 52
2.1.3 Bath having transducer in direct contact with liquid 53
2.1.4 Other apparatus related to bath-type ultrasonic equipment 55
2.2 Choosing the correct type of ultrasonic bath 57
2.3 Setting up an ultrasonic cleaning bath for sonochemistry 57
2.3.1 Positioning the reaction vessel 57
2.3.2 Power control 58
2.3.3 Temperature control 59
2.4 The design of the reaction vessel 59
2.5 Advantages and disadvantages of an ultrasonic bath 62
2.5.1 Advantages 62
2.5.2 Disadvantages 62
2.6 References 63
3. The ultrasonic probe
3.1 Ultrasonic probe construction 64
3.1.1 The generator 65
viii Table of contents
3.1.2 The transducer 66
3.1.3 The horn 66
3.1.3.1 The upper (fixed) horn 66
3.1.3.2 The detachable horn element 67
3.1.3.3 Length oft he horn 67
3.1.3.4Horn shape 68
3.2 Choosing a probe system for sonochemistry 69
3.2.1 Conventional probe systems 69
3.2.2 Additional desirable features 70
3.3 Laboratory reacton involving probe systems 70
3.3.1 The problems associated with using a probe system 70
3.3.2 Fitting a probe system into standard glassware 71
3.3.3 The design of the reaction vessels 72
3.3.3.1 Home-made glass cell 72
3.3.3.2 The use ofg lass beads 72
3.3.3.3 Dimple cell 73
3.3.3.4 Rosett cell 73
3.3.3.S Pressure cells 73
3.3.3.6 Cooled cell with reagent holder 74
3.4 The effect of external parameten on sonochemistry 75
3.4.l The system for study 75
3.4.1.1 The effect ofb ubbled gas 75
3.4.1.2 The effect ofr eaction temperature 76
3.4.1.3 The effect oft emperature on resonance frequency 77
3.4.1.4 The effect of.f requency on chemical reactivity 77
3.4.1.5 The effect ofr eaction volume 79
3.5 Advantages and disadvantages of a probe system 79
3.5.1 Advantages 79
3.5.2 Disadvantages 80
3.6 References 81
4. Large scale sonoehemistry
4.1 The challenge of scale-up 83
4.2 Large scale bath systems with mounted transducen 89
4.2.1 The ultrasonic cleaning bath 89
4.2.2 Reactors with external transducers 90
4.2.3 Reactors with submersible transducers 91
4.3 Large scale probe systems 91
4.3.1 General 91
4.3.1.1 Batch reactors 91
4.3.l.2Flow systems 92
4.3.2 The Harwell ultrasonic reactor 94
4.3.3 The Branson modulai: reactor 95
4.3.4 The Martin Walther push-pull system 95
Table of contents ix
4.4 Tubular systems with mounted transducers 96
4.4.1 The pentagonal reactor 96
4.4.2 The hexagonal reactor 97
4.4.3 Cylindrical pipe reactor 98
4.4.4 Cylindrical reactor with core cooling 99
4.4.5 The Sodeva sonotube reactor 99
4.4.6 The Bandelin reactor SR 1000 100
4.4.7 The Telsonic reactor 101
4.4.8 The STN Atlas reactor SORA 4000 102
4.4.9 The ELAC reactor PIA-300 103
4.5 Large systems using magnetostrictive transducers 104
4.5.1 The N.A.P. (R.U.M.) system 104
4.5.2 The vibrating tray 105
4.6 Reactors with multifrequency ultrasonic structural actuators 106
4.7 The Hquid whistle reactor 107
4.8 Low frequency vibrating bar transducer system 109
4.9 Future prospects 110
4.10 References 111
s.
Sonochemistry experiments
S.1 Demonstrations of the effects of ultrasound 114
5.1.1 The effect of added detergent 114
5.1.2 Ultrasonic degassing 114
5.1.3 Reactions involving metal surfaces 115
5.1.4 Reactions involving powders ll.5
5.1.5 Emulsion reactions 115
5.1.6 Particles in a standing acoustic field 116
5.1.7 Homogeneous generation of iodine 116
5.1.8 A comparison ofthennal excitation with sonochemistry 117
5.1.9 Sonochemically enhanced chemiluminescence 117
S.2 Laboratory experiments and procedures using ultrasonic baths
5.2.l Organometallic reactions
5. 2.1.1 The synthesis ofP -cuparenone 118
5.2.1.2Conjugate additions in aqueous media: The
preparation ofa key intermediate in the synthesis
ofs ide-chain hydroxylated metabolites ofv itamin D3 119
5.2.1.3 Carbon-sulphur bond cleavage ofs ulfolane 121
5.2.1.4 Preparation ofp etfluoroheptanal 122
5.2.1.S Synthesis of( Z)-1-methoxytetracos-15-en-7-one 123
5.2.2 Reactions involving solid reagents
5.2.2.lA Wittig-Homer reaction using an activated
barium hydroxide catalyst (C-200) 125
5.2.2.2 Preparation of 1,2,5,6-Diisopropylidene glucofuranose 126
5.2.2.3 Preparation offluorobenzene 128