DECHEMA database

Polymer-solvent VLE Vapor-hquid data, both at intermediate concentrations and at the infinite dilution of the solvent, are available in two extensive databases DECHEMA and DIPPR Polymer Project. - These databases are also available in electronic form. The data are restricted to single solvent systems and often cover various temperatures. A more recent compilation of VLE has been published by Wohlfarth. Basically low-pressure VLE data are available. Very few high-pressure VLE data exist for polymer-solvent systems (with nongasesous solvents), e.g., the work by Surana et al. ... 

This database provides thermophysical property data (phase equilibrium data, critical data, transport properties, surface tensions, electrolyte data) for about 21 000 pure compounds and 101 000 mixtures. DETHERM, with its 4.2 million data sets, is produced by Dechema, FIZ Chcmic (Berlin, Germany) and DDBST GmhH (Oldenburg. Germany). Definitions of the more than SOO properties available in the database can be found in NUMERIGUIDE (sec Section 5.18). 

The Aspen NRTL-SAC solvent database was identified from the list of solvents presented in the pharmaceutical based International Committee on Harmonization s guidelines for residual solvents in API [28], Hexane, Acetonitrile and Water were selected as the basis for the X, Y and Z segments respectively, the binary interaction parameters for the segments together with molecular descriptors in terms of X,Y and Z segments were then regressed from experimental vapour-liquid and liquid-liquid equilibrium data from the Dechema database. The list of solvent parameters that were used in the case study are given in Table 13. 

Dortmunder Datenbank DDE (DETHERM database) [online]. Available from STN International, DECHEMA e.V. server, 2001. 

Physical properties of pure supercritical fluids may be found in many of the standard reference textbooks and journals (10). There are also computerized databases (qv) available for physical properties, eg, DIPPERS, DECHEMA, NIST 14, and SUPERTRAP (11). 

The existing database of solvent infinite dilution activity coefficients is quite large, using the convenient gas chromatographic technique. These data are stored in two databases, which are also available in computerized form from DECHEMA and DIPPR. ... 

ELDAR Database available on-line at http //www.uni-regensburg.de/Fakulta-eten/nat Fak rV/Physikalische Chemie/Kunz/eldar/eldhp.html also available through DECHEMA s DETHERM database at http //www.dechema.de/detherm-design-l.html. 

At this point is worthy to mention DECHEMA database (Nagata, Gmehling and Onken, 1977), as a thesaurus of interaction parameters with various liquid activity models. This database has been updated several times, and may be accessed from some software systems, as Aspen Plus. 

Dortmund Data Bank — Maintains extensive databases on thermodynamic and transport properties of pure compounds and mixtures of industrial interest. The data are distributed through DECHEMA, ElZ CHEMIE, and other outlets. An abbreviated database system is also available for educational use. Address DDBST GmbH, Industriestr. 1, 26121 Oldenburg, Germany [www.ddbst.de]. 

DECHEMA Chemical Data Series — DECHEMA distributes the DETHERM database, which emphasizes data used in process design in the chemical industry, including thermodynamic and transport properties of about 20,000 pure compounds and 90,000 mixtures. Access is available... 

CRC Combined Chemical Dictionary Crystallography Open Database (COD) DECHEMA (DETHERM)... 

ChemWeb Databases Coblentz Infrared Spectra CODATA Home Page DECHEMA (DTHERM)... 

Vapor-Liquid Equilibrium Data Collection (Gmehling et al., 1980). In this DECHEMA data bank, which is available both in more than 20 volumes and electronically, the data from a large fraction of the articles can be found easily. In addition, each set of data has been regressed to determine interaction coefficients for the binary pairs to be used to estimate liquid-phase activity coefficients for the NRTL, UNIQUAC, Wilson, etc., equations. This database is also accessible by process simulators. For example, with an appropriate license agreement, data for use in ASPEN PLUS can be retrieved from the DECHEMA database over the Internet. For nonideal mixtures, the extensive compilation of Gmehling (1994) of azeotropic data is very useful. 

Solvent activities of polymer solutions have been measured for about 60 years now. However, the database for polymer solutions is still modest, in comparison with the enormous amount of data available for mixtures of low-molecular substances. Three explicit databases have been published in the literature up to now. The database prepared by Wen Hao et al. is summarized in two parts of the DECHEMA Chemistry Data Series. Danner and Higtf provided a database and some calculation methods on a floppy disk with their book. WoUfarth prepared the most complete data collection regarding vapor-liquid equilibrium data of polymer solutions. His annually updated electronic database is not commercially available however, personal requests can be made via his e-mail address given above. 

For inputting equilibrium data, select NRTL as the property method. Aspen Plus has its own database for parameters, but the Aspen Plus method of inputting the parameter values is different than the DECHEMA method. On the input page for NRTL, select one of the columns for a binary pair and click on the DECHEMA button. Then input the Aij and Aji and alpha values from DECHEMA in Aspen Plus. Be sure that the button for LLE is clicked, not the button for VLE. This column in the table should now list user for source and units should be K. Repeat this procedure for the other two binary pairs. 

Compilations of data can be found in the classical papers, e.g., by Pitzer and coworkers [2] or Barthel and coworkers [3-7], in books [8] as well as in printed data collections as the DECHEMA Chemistry Data Series [9, 10], which contains a sound collection of electrolyte data, mainly transport properties (conductivity, viscosity, dielectric properties, and phase equilibria). Part of DECHEMA s Chemistry Data is the Electrolyte Data Collection pubhshed by Prof. J. Barthel and his coworkers from the University of Regensburg. The printed collection and the database ELDAR (described later) have complementary functirms. The data books are giving a clear arrangement of selected recommended data for each property of an electrolyte solution. The electrolyte solutions are classified according to their solvents and solvent mixtures. All solution properties have been recalculated from the original measured data with the help of compatible property equations. A typical page of the books contains for the described system ... 

ELDAR is distributed as part of DECHEMA s numerical database for theimophysical property data DETHERM [16, 17], To access ELDAR, one can therefore use several options. 

DETHERM, DECHEMA Chemistry Data Series Database, Version 1.4 (December 2(XX))... 

This method for solvent selection is particularly useful, because it avoids the need for direct liquid-liquid measurements and it makes use of the existing databases of solvent infinite dilution activity coefficients, which is quite large (e.g., the DECHEMA and DIPPR databases ). 

---