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Book Review Aspects of Chemical Evolution. XVIIth Solvay Conference on Chemistry. Edited by G. Nikolis

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Van’t
H o f f s studies were published at
a time when the
atomic theory had become common ground to (almost) all
chemists, and when thermodynamics was slowly beginning
to establish a foothold in chemistry. The measurements by
WiIhemy on the time-dependence of the inversion reaction
in cane sugar, which constitute the first ever study of reaction kinetics in the modern sense, had been made about
thirty years previously.
The book begins with a quantitative description of the
time-scale of chemical reactions, under the following headings:
Normal reactions: unimolecular, bimolecular, multimolecular-in each case with examples of suitably chosen reactions from the known chemistry of the day, whose kinetics
were carefully measured .by the author and his collaborators, presented to the reader in such a way that he could
follow the evaluation of the data.
Factors influencing reactions: a section which is still as relevant today as then, and from which uan’t Hoff s working
methods and experimental techniques come out especially
clearly.
Applications: this section is concerned with “multimolecular” reactions and the use of rate measurements to derive
reactant properties. In studying reactions of the type
4AsH3-As4+6H2, it occurred to van’t Hoffthat “the majority of these (chemical) equations give only a very distorted idea of the mechanism of the reaction ... and the
actual mechanism is nearly always uni- or bimolecular”.
Unfortunately this point does not appear to have become
more widely understood at the time.
The effect of temperature on chemical reactions, in
terms of the (correct) thermodynamic expressions for temperature dependence of rate constants, is given in this section, and the essential features of the theory of thermal explosions are presented through discussion and diagrams.
This too did not become a part of generally accepted
knowledge until much later.
The second half of the book is concerned with chemical
equilibria, vaporization equilibria, and other matters. Included here are the effects of external variables on such
equilibria, and chemical affinity, topics which are still associated today with the name of van? HofJ He introduced
the use of twin arrows for describing a chemical equilibrium, to indicate “that the chemical reaction proceeds in
two opposing directions simultaneously”.
Many of van’t Hoff s ideas which are recorded in his
“Etudes” were of a pioneering nature, and are now generally accepted knowledge, and some could have been written today. Just a few of these will be cited here, either literally or in summarized form. Time plays a special role in
the chemist’s thinking, it is usually not perceived. Van’t
Hqff thus concentrated on studying those reactions whose
progress could be directly followed. “Reactions which occur in immediate succession o r simultaneously make the
process complicated, and these must be avoided in order
to obtain a clearer understanding of reactions.” He thereby
defined a problem which still concerns reaction kineticists
today. For simple reactions he states the important principle that “The progress of a chemical reaction is characterized entirely by the number of molecules whose interaction
produces that reaction.”
The extent to which he contributed to ideas about detailed reaction mechanisms does not emerge from the text
of this book. In 1884 his papers on the size and shape of
molecules had already been published ten years before.
Anger,. Chem. In,. Ed. Engl. 26 119871 No. 9
Possibly he held back from discussing this topic because
conclusive experiments had only been carried out much
more recently.
Since 1884 chemists have been able to obtain much further insight into the progress of chemical reactions. Numerous proposed models have been investigated, and in
many cases have had to b e rejected. The desire which is
expressed in the Pimentel Report, perhaps almost impatiently, for more progress in “Understanding chemical
reactivity”, shows that uan’t Hoff s view that “the understanding of chemical reactions has not yet been put on to
such a firm basis as that of thermodynamics” is still relevant 100 years later. Nevertheless the prospects for attaining this objective have never been so good as they are today.
Herr L. Dunsch deserves praise for his translation, and
for his explanatory notes to the German edition.
Heinz-Georg Wagner [ N B 8 1 8 I El
Institut f u r Physikalische Chemie
der Universitat Gottingen (FRG)
Aspects of Chemical Evolution. XVIIth Solvay Conference
on Chemistry. Edited by G . Nikolis. Wiley, Chichester
1985. xvi, 286 pp., bound, L 52.25.--1SBN 0-471-88405-7
The international physics and chemistry institutes
founded in 1912 by the Belgian industrialist Ernest Soluay
can be viewed as unique catalysts in the development of
modern science. With a minimum of organization these famous institutes have succeeded again and again up to the
present day in bringing together prominent scientists from
every conceivable discipline to discuss their work, thereby
providing a significant impetus for the progress of
science.
The seventeenth Solvay Conference on Chemistry,
which was held jointly with the US National Academy of
Sciences on the occasion of the 150th anniversary of the
Belgian state, was concerned with the current research situation in chemical evolution, a fundamental problem area
of modern science, whose development has been greatly
influenced by the theoretical work of the Director of the
Solvay Institutes, Professor I . Prigogine.
This volume in the series “Advances in Chemical Physics” contains the lectures presented by the international
experts, together with a brief look back at the history of the
Solvay Institutes ( E . Amaldi and A. R . Llbbelokde) and an
introduction by I . Prigogine on the theme “Nonequilibrium Thermodynamics and Chemical Evolution”. We
find brilliant essays on “Atmospheric Chemistry” (M.Nicolet), “The Prebiotic Synthesis of Organic Molecules and
Polymers” ( S . L. Miller), “The Origin and Evolution of
Life at the Molecular Level” ( M . Eigen), “Optimization of
Mitochondria1 Energy Conversions” (J. W . Stucki). “Bifurcations and Symmetry Breaking in Far-from-Equilibrium
Systems: Towards a Dynamics of Complexity” (C. Nicoiisj.
“Bifurcation in Insect Morphogenesis” ( S . A . Kauffman),
’and “Logical Description, Analysis, and Synthesis of Biological and other Networks Comprising Feedback Loops”
( R . 7horna.s). The volume also includes brief commentaries
on problems of chirality, stochastic models, and oscillatory
chemical systems. Altogether, this volume truly reflects the
breadth of the interdisciplinary fields which are now involved in research on chemical evolution.
Benno Hess [NB 814 IE]
Max-Planck-Institut
fur Ernahrungsphysiologie, Dortmund (FRG)
937
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