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Encyclopaedia of emulsion technology, vol 2, applications
The Chemical Engineering
Journal, 34 (1987)
55 - 56
55
Book Reviews
Interfacial Phenomena: Equilibrium and Dynamic Effects by Clarence A. Miller and P. Neogi; published by Marcel Dekker, New York and Basel, 1985; 354 pp; price, U.S. $69.50 (U.S.A. and Canada), U.S. $83.25 (all other countries)
In their preface, the authors point out that, with the entry in the 1950s of greater numbers of chemical engineers into the field of interfacial phenomena, there developed particular interests in dynamic (non-equilibrium) interfacial phenomena. These interests arose because of the importance of flow and transport near interfaces in such operations as distillation and solvent extraction, and indeed in mass-transfer operations generally. In these, one is often concerned with the behaviour of drops and bubbles which continually move and deform. The stated purpose of the present book is to cover non-equilibrium interfacial phenomena such as wave motion and Marangoni flow, including particularly the advances made during the last 25 years. The authors believe that while their approach provides a useful means of introducing the study of dynamic; phenomena relatively early in a course on interfaces, those planning to specialize in the field will also wish to take a thorough course on conventional surface and colloid chemistry, or study carefully some of the existing textbooks on the subject. With this the reviewer agrees. The present book is strongly mathematical in its approach, and hence in this complicated field is necessarily concerned with idealized systems. There is a noticeable lack of experimental data, and there is (perhaps inevitably in a book of this length) considerable selectivity in topics and in the references to the literature. It would have been a much easier book to use had there been an author index, a table of symbols used, and a consistent use of either cgs or S.I. units. As it is, the reader is faced with a mixture of A and nm, ergs and joules, dynes cm-’ and N m-i. But more serious is the authors’ concentration (without enough cautions) on ideal systems. One example concerns the coagulation
of aqueous colloidal suspensions. First, it is not made clear whether, in the practical systems that chemical engineers encounter, longrange forces of attraction are important or not. The second point concerns the coagulation of colloids with polyvalent electrolytes: in practice the specific adsorption energies of the different ions is so important, and the surface potentials are so low at near-coagulation conditions, that any attempt to justify the Schulze-Hardy rule by valency alone cannot be regarded as confirming the DLVO theory, as the authors claim (pp. 115 - 117). As might be expected from the authors’ interests, the book includes useful and authoritative fundamental analyses of interfacial instability, wave motion, foam stability, Marangoni effects, diffusion-related spontaneous emulsification, micro-emulsions and contact angles. The carefully chosen problems are an excellent way of familiarizing the student with the use of the mathematical concepts in the text. Again, the systems considered here are “ideal” in many ways (e.g. low Reynolds numbers). In general, the book presents a good account of various mathematical treatments of interfacial phenomena published during the last 25 years, and it is to be hoped that a new edition will rectify the blemishes. As a readable summary of the mathematical theories, it will long be a useful reference book. It is reproduced photographically from typescript and for such production it is relatively expensive. J. T. DAVIES
Encyclopaedia of Emulsion Technology, Vol. 2, Applications edited by P. Becher; published by Marcel Decker, New York and Basel, 1985; 536 pp.; Price, U.S. $95 (U.S.A. and Canada), U.S. $114 (all other countries)
There comes a time when it is appropriate to produce a comprehensive state of the art 0 Elsevier Sequoia/Printed in The Netherlands
56
review of each developing area of process technology. The present volume is the second in a series of three which attempts this daunting task for the subject of emulsion technology, and employs the often-used sectional format with various authors under the overall responsibility of an editor. Volume 1, produced in 1983 by the same editor, thoroughly presented basic theory and has undoubtedly proved of general use to many workers in the field. Indeed a library copy shows sign of much use, although the poor state of the cover suggests some brittleness in the type of binding. At first glance, some significant areas seemed to be missing from this second volume, on “Applications”. However, a listing of the proposed contents of Volume 3 indicates an overspill of two areas (petroleum industry, explosives) into that future volume, together with six proposed chapters on measurements. Volume 2 itself starts with a useful chapter on demulsification, comprising a resume of mechanisms and then with the bulk of the chapter on demulsification techniques. Following the next rather specialist chapter on research techniques using emulsions, a further five chapters cover some more mainstream application areas. Concerning medical and pharmaceutical applications, the authors sound a cautionary note on dosage control constraints, but describe a number of areas where emulsion formulations can be advantageously used, concentrating largely on parenteral (injection) systems. The subsection on topical (skin, eye)
systems considers release of drugs from emulsions and gives a mathematical analysis which may have a more general applicability. The particular needs of agricultural applications are well covered in a chapter which also includes a useful review of the phenomenon of spontaneous emulsification, a subsection which again was perhaps of a more general nature. Two chapters then focus on the wide range of applications in the food industry, the first of these combining deeply theoretical considerations with practical aspects of food emulsions, and the second comprising a concise but informative description of emulsions stabilised by proteins. The consumer oriented emphasis of cosmetics is the final application area of the volume, although an additional chapter gives a comprehensive updated bibliography on the hydrophilelipophile balance (HLB). Retrospectively it would perhaps have been preferable to have incorporated all the major application areas, particularly petrochemicals, into Volume 2. This could have been achieved by a rather different split of contents between Volumes 2 and 3, perhaps transferring the chapters on research technique and HLB to Volume 3. However it is clear that taken together, the contents of the three volumes will combine to give a truly comprehensive and well referenced update of emulsion technology, with Volume 2 proving particularly useful to those working in the application areas covered.
R. B. WILCOCKSON
Journal, 34 (1987)
55 - 56
55
Book Reviews
Interfacial Phenomena: Equilibrium and Dynamic Effects by Clarence A. Miller and P. Neogi; published by Marcel Dekker, New York and Basel, 1985; 354 pp; price, U.S. $69.50 (U.S.A. and Canada), U.S. $83.25 (all other countries)
In their preface, the authors point out that, with the entry in the 1950s of greater numbers of chemical engineers into the field of interfacial phenomena, there developed particular interests in dynamic (non-equilibrium) interfacial phenomena. These interests arose because of the importance of flow and transport near interfaces in such operations as distillation and solvent extraction, and indeed in mass-transfer operations generally. In these, one is often concerned with the behaviour of drops and bubbles which continually move and deform. The stated purpose of the present book is to cover non-equilibrium interfacial phenomena such as wave motion and Marangoni flow, including particularly the advances made during the last 25 years. The authors believe that while their approach provides a useful means of introducing the study of dynamic; phenomena relatively early in a course on interfaces, those planning to specialize in the field will also wish to take a thorough course on conventional surface and colloid chemistry, or study carefully some of the existing textbooks on the subject. With this the reviewer agrees. The present book is strongly mathematical in its approach, and hence in this complicated field is necessarily concerned with idealized systems. There is a noticeable lack of experimental data, and there is (perhaps inevitably in a book of this length) considerable selectivity in topics and in the references to the literature. It would have been a much easier book to use had there been an author index, a table of symbols used, and a consistent use of either cgs or S.I. units. As it is, the reader is faced with a mixture of A and nm, ergs and joules, dynes cm-’ and N m-i. But more serious is the authors’ concentration (without enough cautions) on ideal systems. One example concerns the coagulation
of aqueous colloidal suspensions. First, it is not made clear whether, in the practical systems that chemical engineers encounter, longrange forces of attraction are important or not. The second point concerns the coagulation of colloids with polyvalent electrolytes: in practice the specific adsorption energies of the different ions is so important, and the surface potentials are so low at near-coagulation conditions, that any attempt to justify the Schulze-Hardy rule by valency alone cannot be regarded as confirming the DLVO theory, as the authors claim (pp. 115 - 117). As might be expected from the authors’ interests, the book includes useful and authoritative fundamental analyses of interfacial instability, wave motion, foam stability, Marangoni effects, diffusion-related spontaneous emulsification, micro-emulsions and contact angles. The carefully chosen problems are an excellent way of familiarizing the student with the use of the mathematical concepts in the text. Again, the systems considered here are “ideal” in many ways (e.g. low Reynolds numbers). In general, the book presents a good account of various mathematical treatments of interfacial phenomena published during the last 25 years, and it is to be hoped that a new edition will rectify the blemishes. As a readable summary of the mathematical theories, it will long be a useful reference book. It is reproduced photographically from typescript and for such production it is relatively expensive. J. T. DAVIES
Encyclopaedia of Emulsion Technology, Vol. 2, Applications edited by P. Becher; published by Marcel Decker, New York and Basel, 1985; 536 pp.; Price, U.S. $95 (U.S.A. and Canada), U.S. $114 (all other countries)
There comes a time when it is appropriate to produce a comprehensive state of the art 0 Elsevier Sequoia/Printed in The Netherlands
56
review of each developing area of process technology. The present volume is the second in a series of three which attempts this daunting task for the subject of emulsion technology, and employs the often-used sectional format with various authors under the overall responsibility of an editor. Volume 1, produced in 1983 by the same editor, thoroughly presented basic theory and has undoubtedly proved of general use to many workers in the field. Indeed a library copy shows sign of much use, although the poor state of the cover suggests some brittleness in the type of binding. At first glance, some significant areas seemed to be missing from this second volume, on “Applications”. However, a listing of the proposed contents of Volume 3 indicates an overspill of two areas (petroleum industry, explosives) into that future volume, together with six proposed chapters on measurements. Volume 2 itself starts with a useful chapter on demulsification, comprising a resume of mechanisms and then with the bulk of the chapter on demulsification techniques. Following the next rather specialist chapter on research techniques using emulsions, a further five chapters cover some more mainstream application areas. Concerning medical and pharmaceutical applications, the authors sound a cautionary note on dosage control constraints, but describe a number of areas where emulsion formulations can be advantageously used, concentrating largely on parenteral (injection) systems. The subsection on topical (skin, eye)
systems considers release of drugs from emulsions and gives a mathematical analysis which may have a more general applicability. The particular needs of agricultural applications are well covered in a chapter which also includes a useful review of the phenomenon of spontaneous emulsification, a subsection which again was perhaps of a more general nature. Two chapters then focus on the wide range of applications in the food industry, the first of these combining deeply theoretical considerations with practical aspects of food emulsions, and the second comprising a concise but informative description of emulsions stabilised by proteins. The consumer oriented emphasis of cosmetics is the final application area of the volume, although an additional chapter gives a comprehensive updated bibliography on the hydrophilelipophile balance (HLB). Retrospectively it would perhaps have been preferable to have incorporated all the major application areas, particularly petrochemicals, into Volume 2. This could have been achieved by a rather different split of contents between Volumes 2 and 3, perhaps transferring the chapters on research technique and HLB to Volume 3. However it is clear that taken together, the contents of the three volumes will combine to give a truly comprehensive and well referenced update of emulsion technology, with Volume 2 proving particularly useful to those working in the application areas covered.
R. B. WILCOCKSON