Factual Data Banks Research Articles

Present status of the group contribution equation of state VTPR and typical applications for process development

For the development and design of industrial processes the reliable knowledge of thermophysical properties, in particular phase equilibria is most important. Assuming that 1000 components are of technical interest, vapor-liquid equilibrium data for approximately 500,000 binary systems are needed to fit all required binary interaction parameters. Due to the fact that the measurement of all needed properties is nearly impossible, the process engineer depends on factual data banks.Besides the different phase equilibria, the Dortmund Data Bank as worldwide largest factual data bank for thermophysical properties contains nearly all worldwide available pure component, excess and transport properties. Although more than 66,300 binary VLE data sets for non-electrolyte systems are currently stored in the DDB, in total up to now VLE data for only 13,540 different binary systems are available. The reason is that some systems are very popular and were measured very often, e.g. ammonia – water, ethanol-water and so on. When the 1000 most important components are considered, VLE data for only 8635 binary systems are available. This means for only 1.73% of the systems the required binary interaction parameters can be fitted. Since the assumption of ideal behavior for the missing binary systems can be very erroneous and measurements are very time consuming, predictive group contribution models can be successfully applied to estimate the missing thermophysical properties.To cover sub- and supercritical conditions, group contribution equations of state have to be applied. They automatically take into account both phases and can be used up to high pressures and supercritical conditions. This allows for example the calculation of phase envelopes. Furthermore, the introduction of Henry coefficients for gaseous compounds is not required. At the same time, enthalpies, heat capacities, densities and so on can be predicted. Today the most sophisticated group contribution equation of state is the volume translated Peng-Robinson group contribution equation of state VTPR. In this paper, typical applications of VTPR for process development are shown and new parameters for 24 additional group combinations are given.

Thermodynamic models and factual data banks - ideal tools for the development of chemical processes

The synthesis, design and simulation of chemical processes, in particular thermal separation processes is today carried out by solving the resulting balance equations of a mathematical model of the considered unit operation or the whole chemical plant using sophisticated commercial process simulation software. The reliability and correctness of the simulation results is mainly influenced by the reliability and correctness of the thermophysical property parameters used for the pure compounds and their mixtures. For the description of the required phase equilibria GE-models and equations of state were developed. These models allow the prediction of the phase equilibrium behavior of multicomponent systems using binary experimental data only. However, since the number of experimental binary data is limited, these methods often cannot be applied. Therefore in particular for process development reliable predictive models with a large range of applicability are most important. With the help of the worldwide largest factual data bank (Dortmund Data Bank (DDB)) for pure component properties, phase equilibria and excess properties, in the last 35 years powerful group contribution methods (UNIFAC, modified UNIFAC) have been developed in my research group. By combination of cubic equations of state with the group contribution concept, now even the phase equilibrium behavior with supercritical compounds can be predicted. At the same time other important properties (e.g. densities, enthalpies, heat capacities, etc.) can directly be predicted. With the development of an adequate electrolyte model (LIQUAC, LIFAC) the equation of state approach was even extended to systems with strong electrolytes. Today ideal predictive thermodynamic tools are available, which can be used in combination with factual data banks for the development of chemical processes. In the lecture the status of the factual data bank and the different predictive models will be shown. Furthermore important applications of industrial interest of the predictive thermodynamic models and the Dortmund Data Bank will be presented.

Factual data banks and their application to the synthesis and design of chemical processes and the development and testing of thermophysical property estimation methods

Abstract Factual data banks nowadays play an important role as a source for thermophysical property data for use in chemical process simulation, environmental models, and many other computer-based applications. In this work, the historical developments leading to modern factual data banks, the differences compared to other more bibliographically oriented data banks, and their most important applications and future potential will be discussed by using the example of the Dortmund Data Bank (DDB). As the development of the different predictive models for mixtures is covered in a separate publication, this paper focuses on pure-component property estimation, regression of model parameters, test and verification of model parameters prior to process simulation, and advanced topics in process synthesis such as selection of entrainers and data-mining applications.

Toxicological Information Resources at the National Library of Medicine

TOXicology Data NETwork (TOXNET) 〈www.toxnet. nlm.nih.gov〉, is a web-based information system that provides access to information regarding the medical, occupational, pharmacokinetic, toxicological, and environmental effects of biological and chemical substances. TOXNET is maintained by the National Library of Medicine’s Division of Specialized Information Services, a part of the National Institutes of Health within the U.S. Department of Health and Human Services. TOXNET includes bibliographic, factual, and dictionary data banks. One factual data bank is the Hazardous Substances Data Bank (HSDB) 〈www.toxnet.nlm.nih.gov/cgibin/sis/htmlgen?HSDB〉, which contains more than 5,000 comprehensive records for unique chemical compounds. The data covered in this resource include the following: chemical identification, chemical and physical properties, safety and handling, human and nonhuman toxicity data, pharmacology, metabolism, environmental fate, monitoring and analysis, and regulatory information. HSDB files are peer-reviewed by a group of nationally and internationally recognized scientists and physicians. Another factual data bank is Haz-Map 〈www.hazmap.nlm.nih.gov/〉, which provides information about occupational exposures to chemical substances. Haz-Map also contains acute human toxicity information. Another data bank, Household Products Database 〈www.hpd.nlm.nih.gov/〉, contains data derived from material safety data sheets and product labels for items commonly purchased in grocery stores and hardware shops. The Toxics Release Information (TRI) 〈www.toxnet. nlm.nih.gov/cgi-bin/sis/htmlgen?TRI〉 provides data reported to EPA on the amount of specified (regulated) chemicals that industrial and governmental organizations release into the environment (air, water, soil), as well as data on the amounts removed from a particular facility. ToxMap (Environmental Health e-Maps) 〈www.toxmap.nlm. nih.gov/toxmap/main/index.jsp〉 is a data bank that provides geographic representation of TRI data, showing chemical plants and facilities releasing selected hazardous substances to the environment Information can be retrieved by locality (name of state, county, zip code), as well as by chemical name or other identifier or facility name. Another TOXNET data bank, the Chemical Carcinogenesis Research Information System (CCRIS) 〈www.toxnet. nlm.nih.gov/cgi-bin/sis/htmlgen?CCRIS〉, provides data on carcinogenesis, mutagenesis, and tumor promotion studies. The content of the file is reviewed by experts at the National Cancer Institute. Meanwhile, the GENETOX data bank 〈www.toxnet.nlm.nih.gov/cgi-bin/sis/ htmlgen?GENETOX〉, reviewed by EPA scientific experts, contains citations and test results from mutagenicity studies. The Integrated Risk Information System (IRIS) 〈www. toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?IRIS〉 is a TOXNET data bank built by the EPA. IRIS contains data on animal and human risk calculations for selected chemicals. By contrast, the ITER data bank 〈www.toxnet.nlm.nih.gov/ cgi-bin/sis/htmlgen?iter〉 built by Toxicology Excellence for Risk Assessment (TERA), contains over 600 chemical records, including risk assessment information based on noncancer oral, cancer oral, non-cancer inhalation, and cancer inhalation endpoints. Central to TOXNET is ChemIDplus 〈www.chem.sis.nlm. nih.gov/chemidplus/〉, a dictionary-type data bank for nearly 400,000 compounds. ChemIDplus provides synonyms, pointers to other NLM files containing information on the chemical selected, and pointers to non-NLM sources, including links to the Agency for Toxic Substances Disease Registry, the American Council of Governmental and Industrial Hygienists (ACGIH), the International Agency for Research on Cancer (IARC), the EPA, the Food and Drug Administration (FDA), the National Institute of Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the World Health Organization (WHO). TOXLINE 〈www.toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen? TOXLINE〉 on TOXNET is a bibliographic toxicology information set, with citations and abstracts from various resources, including standard journal literature, technical reports, and other special collections. TOXLINE records can be searched using chemical name, CAS registry number, synonyms, and index terms or keywords. Developmental and Reproductive Toxicology (DART) 〈www.toxnet.nlm.nih.gov/ cgi-bin/sis/htmlgen?DARTETIC〉 is another bibliographic

Group contribution methods for estimating the properties of polymer systems

Polymer materials are nowadays used in a wide range of technological applications. Reliable knowledge of the thermo physical properties of pure polymers and their mixtures in the whole composition and a wide temperature and pressure range determines whether a given polymer is suitable for a specific application. On the other hand, accurate knowledge of the thermodynamic properties of the systems is a vital prerequisite for computer-aided syntheses, design, and the optimization of industrial polymer processes. However, the experimental data on polymer solubility are often scarce, and at this point, thermodynamics provide a powerful tool for modeling and extrapolating the experimental data. These models, together with factual data banks, are powerful software tools for the reliable development of chemical processes and other applications of industrial interest. The status of the different approaches and important applications of industrial interest using thermodynamic information derived from data banks or by using predictive thermodynamic models are presented in this review.

Potential of thermodynamic tools (group contribution methods, factual data banks) for the development of chemical processes

Reliable knowledge of the thermophysical properties of pure compounds and their mixtures in the whole composition and a wide temperature and pressure range is a vital prerequisite for the computer aided synthesis, design and optimization of chemical processes. At the beginning of the development of thermodynamic models, the main interest was directed to the development of predictive g E-models for vapor–liquid equilibria (VLE) of subcritical compounds. Today group contribution equations of state are available which can also handle supercritical compounds, very asymmetric systems and even systems with strong electrolytes. These sophisticated models together with factual data banks (e.g. the Dortmund Data Bank) are powerful software tools for the reliable development of chemical processes and other applications of industrial interest. In this paper, the status of the different approaches and important applications of industrial interest using thermodynamic information derived from factual data banks or by using sophisticated predictive thermodynamic models will be presented.

Synthesis of Distillation Processes Using Thermodynamic Models and the Dortmund Data Bank

A new and comprehensive procedure for process synthesis for binary and ternary distillation processes with an emphasis on entrainer selection is presented. This procedure consists of two complementary methods for entrainer selection and a variety of graphical tools for the representation of various mixture properties of the given system. The methods for entrainer selection are based on (a) the concept of thermodynamic models, such as group contribution methods (e.g., modified UNIFAC), and (b) the access to a large computerized factual data bank with experimental data on activity coefficients at infinite dilution and azeotropes. Explicit criteria for the selection of solvents for azeotropic and extractive distillation are reported. With the help of residue curves and contour lines it is shown how further information for a comparison and advanced selection of entrainers can be obtained.

Toxicological and environmental health information from the National Library of Medicine.

The National Library of Medicine's Toxicology and Environmental Health Information Program is the outgrowth of a 1966 document on "Handling of Toxicological Information," prepared by the Presidents Science Advisory Committee (National Library of Medicine, 1995). The Toxicology and Environmental Health Program is responsible for the creation and deployment of both bibliographic and factual files concerned with toxicology, carcinogenesis, developmental and reproductive effects of chemical substances, toxic chemical releases, and the medical and environmental behavior of chemical substances. The two main computer systems that provide bibliographic and factual data banks are Toxicology Data Network (TOXNET) and ELHILL. A number of the files found in the TOXNET system are built and maintained by other federal agencies such as the National Cancer Institute, the U.S. Environmental Protection Agency, the National Institute for Occupational Safety and Health.

Hazardous substances data bank (HSDB) as a source of environmental fate information on chemicals

The Hazardous Substances Data Bank (HSDB),a factual data bank on the National Library of Medicine's (NLM) TOXNET (Toxicology Data Network) online system, provides information in areas such as chemical substance identification, chemical and physical properties, safety and handling, toxicology, pharmacology, environmental fate and transformation, regulations, and analytical methodology. This article discusses how environmental fate data is handled in HSDB.

The Gmelin Factual Databank A modern information source in chemistry and physics

AbstractIn chemistry especially, it is becoming increasingly difficult to survey the large amount of material published if poorly defined search strategies are employed – in 1991 and 1992, Chemical Abstracts cited over 500 000 publications, including reports and patents. Traditional comprehensive literature searches require a suitable perspective, a great deal of time and patience, and access to all relevant information sources. The Gmelin Factual Databank can offer improved search strategies for the scientific literature in the area of inorganic and organometallic chemistry.

Registering and analysing data on detection of chemicals in the environment

As part of the research project “information system for environmental chemicals” a factual databank on a testset of 68 chemicals was developed. The set-up of the databank is described and the analysis of the results is shown for benzo(k)fluoranthene using a graphical boxplot illustration.

Early detection of environmental chemicals in food by means of specific substance criteria

In an approach to selecting potential food contaminants by means of specific substance criteria we came up with a list of 68 chemicals. Among them, we found chemicals which are already well known as food contaminants such as polycyclic aromatic hydrocarbons and chloroaromatic compounds. So far, other chemicals have not been mentioned as food contaminants. During a project called "Information System for Environmental Chemicals" we conducted, for these 68 chemicals, an intensive literature search in databases for their occurrence in food. The results are stored in our factual databank named "LEBKON" and are graphically described in profiles. For 44 of the chemicals, we found information for their detection in food or in drinking water. We plan to analyse the remaining substances for which no data have been found in the literature. We placed emphasis on the toxicological properties and the production volume of the substances in question. This approach should represent a contribution to the question of monitoring systems oriented by the consumer and monitoring systems oriented by cause.

Use of COALDATA to help retrieve and estimate the physical properties of coals, coal liquids and coal chemicals

COALDATA, a factual databank of the properties of coal samples, coal liquids (distillation cuts from coal liquefaction products) and coal chemicals (pure chemical compounds con tained in the coal liquids) was developed. It contains data on: (i) physical properties of coals, such as calonfic values, ash content, ash properties, maceral analyses, ultimate analyses. (ii) thermophysical properties of coal liquids and coal chem icals, e.g. vapour pressures, vapour-liquid-equilibrium data, heat capacities, transport properties, surface ten sions, densities. The databank is managed by DECHEMA's Data Retrieval System DEDARS, which stores numerical data as well as non-numerical data, such as bibliographic information. Data and substances are labelled by "tags" which characterize the kind of stored data and substances. All the information is organized in the form of documents. Each document refers, for example, to a scientific paper or book and is composed of a bibliographic part, a list of descriptors, an abstract, a compo nent description, numerical values and their units. Besides literature data COALDATA contains recom mended property values. These are stored as regression coeffi cients and with the help of implemented correlation methods it is possible to calculate the properties.

Use of information technology in UK agricultural information work: a review

A brief review of the UK agricultural industry and the organisations which support it is given. The increasing use of computers, large and small, to assist in all aspects of scientific and technical information (STI) and library work in organiza tions of all kinds and sizes is discussed, with examples. The move beyond on-line bibliographic literature searches to those involving specialist factual databanks and the link with word processing to provide indexes to in-house reports is included. The differing needs of small and large organizations, and those with several office locations are considered. The problem of software packages' (lack of) robustness and comprehensiveness together with their specificity which prevents easy data transfer between computers or over networks is highlighted. The possi bilities of videotex as a bridging device for end-users to bypass computing type problems' are discussed, along with the need to keep data secure from unauthorised users. It is argued that the opportunity for total integration of information services in an organization, beyond traditional STI and library areas, with the help of computers, should now be taken.

EMIS – the electronic publication of materials data*

The development of numeric and factual data banks presents an opportunity for producers to develop close links with the user community in order to facilitate the provision of evaluated and collated data. EMIS (Electronic Materials Information Service) was launched by INSPEC, the Information Divisio n of The Institution of Electrical Engineers, in 1981. Researchers active in the field of electronic materials have cooperated in the development of records for the electronic publication of materials data. These records and the contribution of researchers are discussed in this paper.

Some problems related to an environmental factual database: the case Aeolian project

Factual databanks can make an important contribution to environmental management. They help considerably with the difficult processes of integrating the various scientific languages used, and also with the development of valid methods for interdisciplinary research. In the planning the Aeolian project (a multidisciplinary study of an Archipelago north of Sicily), it was considered useful to include a group of workers on methodology and computer science. The hope is that they will help to facilitate the exchange of data and thus contribute to a better understanding of the various phenomena occurring on the islands. This paper discusses the conceptual working aspects of environmental information, together with those characteristics that render it suitable for inclusion in a modern computer‐based system.