4 research outputs found
Comparison between multi-linear- and radial-basis-function-neural-network-based QSPR Models for the prediction of the critical temperature, critical pressure and acentric factor of organic compounds
Critical properties and acentric factor are widely used in phase equilibrium calculations
but are difficult to evaluate with high accuracy for many organic compounds. Quantitative
Structure-Property Relationship (QSPR) models are a powerful tool to establish accurate correlation
between molecular properties and chemical structure. QSPR multi-linear (MLR) and radial
basis-function-neural-network (RBFNN) models have been developed to predict the critical
temperature, critical pressure and acentric factor of a database of 306 organic compounds. RBFNN
models provided better data correlation and higher predictive capability (an AAD% of 0.92–2.0%
for training and 1.7–4.8% for validation sets) than MLR models (an AAD% of 3.2–8.7% for training
and 6.2–12.2% for validation sets). The RMSE of the RBFNN models was 20–30% of the MLR ones.
The correlation and predictive performances of the models for critical temperature were higher
than those for critical pressure and acentric factor, which was the most difficult property to predict.
However, the RBFNN model for the acentric factor resulted in the lowest RMSE with respect to
previous literature. The close relationship between the three properties resulted from the selected
molecular descriptors, which are mostly related to molecular electronic charge distribution or polar
interactions between molecules. QSPR correlations were compared with the most frequently used
group-contribution methods over the same database of compounds: although the MLR models
provided comparable results, the RBFNN ones resulted in significantly higher performance
Tartu Ülikooli keemiaosakond 1947-2002
http://www.ester.ee/record=b1720730*es
Relationships of Critical Temperatures to Calculated Molecular Properties
Quantitative structure-property relationships (QSPR) of critical temperatures with small numbers of physically significant molecular descriptors are developed using the CODESSA (comprehensive descriptors for structural and statistical analysis) technique. A highly significant one-parameter model correlates to the critical temperatures of 76 hydrocarbons at R 2) 0.953. A successful three-parameter model for 165 diverse compounds (R 2) 0.955) reveals fundamental structural influences on liquid-state properties