Combination of commercial QSPR (quantitative structure−property relationship) software with an evaluated database creates a powerful tool for development of thermophysical property correlations. By using data quality codes in the DIPPR relational database, a training set of property values within a desired accuracy level can be obtained for use in QSPR regression software. Moreover, additional database queries can be used to restrict the training set to specified families or functional groups and further refine the molecular descriptors that are used to correlate the property. This provides a good basis for rapid development of QSPR correlations of known uncertainty and chemical domain. This procedure is illustrated by its application to the extension of the Macleod−Sugden (Trans. Faraday Soc. 1923, 19, 38. Chem. Soc. 1924, 125, 32.) correlation for surface tension based upon the parachor. Quayle (Chem. Rev. 1953, 53, 439−591.) correlated the parachor in terms of additive atomic and structural increments but used a training set limited in temperature and scope. In this work, new molecular descriptors were selected consistent with the accuracy of the training set extracted from the DIPPR database, and their additive increments to the parachor were regressed from 8697 surface tension values of uncertainty less than 5% for 649 different compounds. This produced a correlation with an average absolute deviation (AAD) of 3.2%. This can be compared with an AAD of 6.9% using the Quayle descriptors for the same set.

The flash point is an important indicator of the flammability of a chemical. For safety purposes, many data compilations report the lowest value and not the most likely. This practice, combined with improper documentation and poor data storage methods, has resulted in compilations filled with fire-hazard data that are inconsistent with related properties and between members of homologous chemical series. In this study, the flash points reported in the DIPPR 801 database and more than 1,400 other literature values were critically reviewed based on measurement method, inter-property relations, and trends in chemical series. New measurements for seven compounds illustrate the differences between experimental flash points and data commonly found in fire-hazard compilations. With a critically reviewed set of experimental data, published predictive methods for the flash point were evaluated for accuracy.

No abstract

A simple relationship between the solid density of organic compounds and the liquid density at the triple point is presented as an extension of a previous relationship used internally by the DIPPR 801 database project. The relationship allows estimation of solid density (of the solid phase most stable at the triple point) for organic compounds over a wide range of temperatures with an average uncertainty of approximately 6%.

No abstract