Volume 77, Issue 8

The 18th IUPAC International Conference on Chemical Thermodynamics (ICCT-2004), concurrent with the 12th National Conference on Chemical Thermodynamics and Thermal Analysis, was held 17-21 August 2004 at the Fragrant Hill Hotel, Beijing, China. Professor Haike Yan was Conference Chair, Prof. Zhiwu Yu was Conference Co-chair, and Prof. Xibai Qiu was Secretary. The 395 participants came from 40 countries. During the official opening ceremony, there was a presentation of the first Doctorate Awards to be given by the International Association of Chemical Thermodynamics, with sponsorship from Elsevier. The three recipients were Dr. Lin Chen, Tsinghua University, Beijing; Mr. Dirk Wandschneider, University of Rostock, Germany; and Mr. Weiguo Xu, Liaoning University, China. They each received a certificate plus a cash prize of USD 500. The conference began with the Rossini lecture, presented by Prof. Jean-Pierre E. Grolier on "Advanced experimental techniques in polymer thermodynamics". The conference program consisted of eight symposia and three workshops. In Symposium 1, Electrolyte and Nonelectrolyte Solution Thermodynamics, Prof. Emmerich Wilhelm gave the plenary lecture "The fascinating world of pure and mixed nonelectrolytes". There were invited lectures by Profs. Eckhard Vogel, Fumio Hirata, and Takayoshi Kimura. In Symposium 2, New Materials, Prof. C. Richard Catlow presented the plenary lecture "Computational approaches to the catalytic activation of carbon-hydrogen bonds", and invited lectures were given by Profs. Mary Anne White and Vladimir Durov. The plenary lecture in Symposium 3, Phase Equilibrium, Supercritical Fluids, and Separation Technologies, was given by Prof. Pablo Debenedetti on "Thermodynamics of supercooled and glassy water", with invited lectures from Profs. Cornelis Peters and Ding-Yu Peng. Symposium 4, Biological, Medical, Pharmaceutical, Agricultural, and Food Thermodynamics, had as its plenary lecturer Prof. Stephan Grzesiek, who spoke on "Biomolecular interactions in solutions". Professors Lee Hansen and Ichiro Hatta were the invited lecturers. Symposium 5 was on Colloid and Interface Science. Professor Bernard Cabane presented the plenary lecture "Solid-liquid separation", and there were invited lectures from Dr. Gerd Olofsson and Profs. Watson Loh and Xueqin An. The title of Symposium 6 was Non-equilibrium Thermodynamics, Statistical Thermodynamics, and Molecular Simulation. The plenary lecture "Non-equilibrium pattern formation" was presented by Prof. Qi Ouyang, with an invited lecture by Prof. Zhen-Gang Wang. Symposium 7 considered Thermochemistry and Molecular Energetics, with Prof. Michio Sorai, the plenary lecturer, speaking on "Entropy diagnosis for phase transitions occurring in functional materials". Professor Juliana Boerio-Goates gave the invited lecture. Symposium 8 was on Industrial Thermodynamics and Data Bases. Dr. Michael Fenkel gave the plenary lecture on "Global communications and expert systems in thermodynamics: Connecting property measurement and chemical process design". Invited lectures were given by Profs. Pertti Koukkari and Zhoulan Yin. There were three workshops. Prof. Kazuya Saito was invited lecturer for the Workshop on Thermodynamic Frontiers and Education. Professors Joan Brennecke and Andreas Heintz were invited lecturers for the Ionic Liquids Workshop. Professors Joon Won Park and Junko Morikawa gave invited lectures at the Workshop on New Experimental Techniques, including Nanotechnology. In addition, there were over 180 oral presentations, spread over the symposia and workshops, and about 280 poster presentations. The Rossini lecture and plenary lectures, with the exception of the paper by Prof. P. Debenetti where the field was recently reviewed [1,2], are published in this issue, together with the invited paper by Prof. Lee Hansen entitled "A thermodynamic law of adaptation of plants to environmental temperatures". Selected papers from individual symposia will be published in the Journal of Molecular Liquids (Symposium 1), Fluid Phase Equilibria (Symposia 3 and 6), the Journal of Chemical Thermodynamics (Symposia 1, 2, and 7), Thermochimica Acta (Symposium 4), or in the Journal of Chemical and Engineering Data (Workshop on Ionic Liquids). After the previous weeks when it had been very hot and humid, the temperature dropped and the weather was most pleasant for the conference. This change in weather, together with the attractive setting of the hotel, the excellent hospitality, which included a welcome reception, an evening of acrobatics entertainment, a conference banquet in the Summer Palace, and the high standard of the presentations, made this conference memorable. In addition, there was a full program of tours for accompanying persons. Our thanks are extended to the Conference Chair and Co-chair, and to all members of the local Organizing Committee, the International Advisory Committee, and the International Scientific Committee. We are most grateful to IUPAC, the International Association of Chemical Thermodynamics, the China Association for Science and Technology, the National Natural Science Foundation of China, and the Chinese Academy of Sciences for sponsoring the conference. Thermodynamics will continue to be an important area of research for many years to come, with a wide range of applications from chemical engineering to the biosciences. We look forward to the presentation and discussion of the results of further advances in chemical thermodynamics at the next ICCT, which will take place in Boulder, Colorado in 2006. 1. P. G. Debenedetti. J. Phys.: Condens. Mater. 45, R1669-1726 (2003). 2. P. G. Debenedetti and H. E. Stanley. Phys. Today 56, 40-46 (2003). J. H. Dymond Conference Editor

Scanning transitiometry is at the center of several new developments to generate original unprecedented data over extended ranges of temperatures and pressures. Simultaneous in situ spectroscopic readings noticeably extend the performance of scanning transitiometry. The modulation of temperature superimposed to temperature scanning for thermal analysis is a major step forward to unambiguously identify glass transitions from other overlapping phenomena. The combination of a weighing technique (vibrating-wire technique) with a pressure decay technique ( pVT technique) allows us to estimate simultaneously, in situ on the same polymer sample, the gas solubility and the concomitant polymer swelling.

In the first part of this work, the focus is on the molar heat capacity C V at constant volume of fairly simple liquids. This quantity contains valuable information on the type of motion executed by the constituent molecules. Using the residual property formalism, the (hindered) rotational behavior of quasi-rigid molecules in the dense liquid phase will be discussed. To this end, the change of C V determined for states along the saturation curve has to be resolved into the separated changes with temperature and volume, respectively. In the second part, the focus is on binary liquid mixtures containing one strongly polar component. Polar interactions constitute an important example of orientational forces between molecules, and substantial deviations of the properties of polar fluids from those of comparable nonpolar fluids are to be expected and indeed observed. At sufficiently low temperatures, these directional forces lead to significantly increased local structure. Extension of these ideas to liquid mixtures allows a semi-quantitative discussion of W-shaped excess molar heat capacities C p E at constant pressure and M-shaped excess molar enthalpies H E .

Functionalities of materials manifest themselves as the result of a concerted effect among molecular structure, intermolecular interactions, and molecular motions. Since the entropy of substance directly reflects the degree of molecular motions, the entropy plays a crucial role when one discusses the stability of a given phase at finite temperatures. When a delicate balance of these three factors is broken, the condensed state faces a catastrophe and is transformed into another phase. Therefore, phase transition is a good probe for elucidation of the interplay between these three factors. As there is no selection rule in thermodynamics, the entropy gain at the phase transition is a good tool to diagnose the mechanism of phase transition. In this presentation, calorimetric investigations aimed at the elucidation of the mechanisms governing phase transitions occurring in molecule-based functional materials are reviewed.

This short article concerns the application of computer modeling techniques to the growing field of materials chemistry, where modeling techniques are widely used in an increasingly predictive manner. The article focuses on modeling at the atomic and molecular level.

Unprecedented growth in the number of custom-designed software tools for engineering applications has created an interoperability problem between the formats and structures of thermodynamic data files and required input/output structures designed for application software products. Various approaches for standardization of thermophysical and thermochemical property data storage and exchange are analyzed in this paper. Emphasis is made on the development of the XML-based IUPAC standard for thermodynamic data communications: ThermoML. A new process for global data submission and dissemination in the field of thermodynamics based on ThermoML and Guided Data Capture software is described. Establishment of the global submission and dissemination process for thermodynamic data lays the foundation for implementation of the new concept of dynamic data evaluation formulated at NIST/TRC, which requires the development of large electronic databases capable of storing essentially all “raw” experimental data known to date with detailed descriptions of relevant metadata and uncertainties. The combination of these databases with expert software designed primarily to generate recommended data based on available “raw” experimental data and their uncertainties leads to the possibility of producing data compilations automatically “to order”, forming a dynamic data infrastructure. Implementation of the dynamic data evaluation concept for pure compounds in the new NIST/TRC ThermoData Engine software is discussed.

Solid-liquid separation is an operation that starts with a dispersion of solid particles in a liquid and removes some of the liquid from the particles, producing a concentrated solid paste and a clean liquid phase. It is similar to thermodynamic processes where pressure is applied to a system in order to reduce its volume. In dispersions, the resistance to this osmotic compression depends on interactions between the dispersed particles. The first part of this work deals with dispersions of repelling particles, which are either silica nanoparticles or synthetic clay platelets, dispersed in aqueous solutions. In these conditions, each particle is surrounded by an ionic layer, which repels other ionic layers. This results in a structure with strong short-range order. At high particle volume fractions, the overlap of ionic layers generates large osmotic pressures; these pressures may be calculated, through the cell model, as the cost of reducing the volume of each cell. The variation of osmotic pressure with volume fraction is the equation of state of the dispersion. The second part of this work deals with dispersions of aggregated particles, which are silica nanoparticles, dispersed in water and flocculated by multivalent cations. This produces large bushy aggregates, with fractal structures that are maintained through interparticle surface-surface bonds. As the paste is submitted to osmotic pressures, small relative displacements of the aggregated particles lead to structural collapse. The final structure is made of a dense skeleton immersed in a nearly homogeneous matrix of aggregated particles. The variation of osmotic resistance with volume fraction is the compression law of the paste; it may be calculated through a numerical model that takes into account the noncentral interparticle forces. According to this model, the response of aggregated pastes to applied stress may be controlled through the manipulation of interparticle adhesion.

Spiral instabilities and their controls are investigated in a reaction-diffusion system using the Belousov-Zhabotinsky reaction. Two spiral instabilities, the long-wavelength instability and the Doppler instability, are reported, which can lead to spatiotemporal chaos. The long-wavelength instability occurs in an oscillatory regime, while the Doppler instability occurs in an excitable regime. To control these two instabilities, two different strategies are proposed according to their defect-generating mechanisms. For the long-wavelength instability in an oscillatory system, the control can be achieved by introducing a local pacemaker, which emits stable traveling waves to sweep off the unstable spiral defects. For the Doppler instability, the control can be achieved by trapping the spiral tip with a local area of higher diffusion coefficient than its surroundings.

High-resolution nuclear magnetic resonance (NMR) has emerged as one of the most versatile tools for the quantitative study of structure, kinetics, and thermodynamics of biomolecules and their interactions at atomic resolution. Traditionally, nuclear Overhauser enhancements (NOEs) and chemical shift perturbation methods are used to determine molecular geometries and to identify contact surfaces, but more recently, weak anisotropic orientation, anisotropic diffusion, and scalar couplings across hydrogen bonds provide additional information. Examples of such technologies are shown as applied to the quantitative characterization of function and thermodynamics of several biomacromolecules. In particular, (1) the structural and dynamical changes of the TipA multidrug resistance protein are followed upon antibiotic binding, (2) the trimer-monomer equilibrium and thermal unfolding of foldon, a small and very efficient trimerization domain of the T4 phagehead, is described in atomic detail, and (3) the changes of individual protein hydrogen bonds during thermal unfolding are quantitatively followed by scalar couplings across hydrogen bonds.

A thermodynamic law of adaptation of plants to temperature is developed. Plant growth rate is proportional to the product of the metabolic rate and the metabolic efficiency for production of anabolic products. Over much of the growth temperature range, metabolic rate is proportional to mean temperature and efficiency is proportional to the reciprocal of temperature variability. The mean temperature and short-term (hours to weeks) variability of temperature during the growth season at a particular location thus determine the optimum energy and growth strategy for plants. Because they can grow and reproduce most vigorously, plants with a growth rate vs. temperature curve that matches the time-at-temperature vs. temperature curve during the growth season are favored by natural selection. The law of temperature adaptation explains many recent and long-standing observations of plant growth and survival, including latitudinal gradients of plant diversity and species range.

Available experimental data on stability constants of proton (hydron) and metal complexes for seven complexones of particular biomedical and environmental interest: iminodiacetic acid [2,2'-azanediyldiacetic acid, IDA], (methylimino)diacetic acid [2,2'-(methylazanediyl)diacetic acid, MIDA]; 2,2',2'',2'''-{[(carboxymethyl)azanediyl]bis[(ethane-1,2-diyl)nitrilo]}tetraacetic acid (DTPA), 3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecanedioic acid (TTHA); 2,2',2''-(1,4,7-triazonane-1,4,7-triyl)triacetic acid (NOTA); 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA); 2,2',2'',2'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetraacetic acid (TETA), published in 1945-2000, have been critically evaluated. Some typical errors in stability constant measurements for particular complexones are summarized. Higher quality data are selected and presented as “Recommended” or “Provisional”.