Thermodynamic studies in CO2 capture through gas hydrate formation technology.

Ph. D. University of KwaZulu-Natal, Durban 2015.Abstract available in PDF file

A Group Contribution Model for Determining the Vaporization Enthalpy of Organic Compounds at the Standard Reference Temperature of 298 K

Article on a group contribution model for determining the vaporization enthalpy of organic compounds at the standard reference temperature of 298 K

A group contribution model for determining the sublimation enthalpy of organic compounds at the standard reference temperature of 298 K

Article discussing a group contribution model for determining the sublimation enthalpy of organic compounds at the standard reference temperature of 298 K

A group contribution model for determining the vaporization enthalpy of organic compounds at the standard reference temperature of 298K

Article on a group contribution model for determining the vaporization enthalpy of organic compounds at the standard reference temperature of 298 K

Quantitative Structure–Property Relationship Study to Predict Speed of Sound in Diverse Organic Solvents from Solvent Structural Information

The interaction of solvents with ultrasonic waves is of drastic importance and has been the subject of many studies in recent years. In this study, the effect of solvent structural parameters on the speed of sound in chemical solvents was investigated through a quantitative structure–property relationship (QSPR). Genetic algorithm–multiple linear regression (GA-MLR) analysis was employed to select the most relevant subset of descriptors and, then, to develop the model. The validity of the obtained 10-parameter model was assessed by most widely used validation techniques. The predictive power of the model was evaluated by use of an external data set. The high level of accuracy of results approved the model. According to the model, those solvents that have stronger solvent–solvent interactions can create a more appropriate medium for passing and propagating sound waves and will result in higher speed of sounds

Estimation of lower flammability limit temperature of chemical compounds using a corresponding state method

Special Issue of The Second International Symposium on Gasification and its ApplicationInternational audienceThis work aims at presenting a corresponding state method to estimate the lower flammability limit temperature of 1480 organic compounds from 77 chemical families. The parameters of this model include the critical temperature, critical pressure, acentric factor, and normal boiling temperature of the compounds. The obtained average absolute relative deviation of the results (1.6, 1.6 and 1.8% for training, optimization and prediction sets, respectively) demonstrates improved accuracy of the presented model with respect to previously proposed methods

Computation of normal melting temperature of ionic liquids using a group contribution method

International audienceIn this communication, a comprehensive literature survey has been performed to provide a data set for the normal melting temperature (T m) of 799 ionic liquids (ILs) from various 143 references. Using this data set, an accurate group contribution method has been developed to estimate the T m of ILs. The model employs a total of 80 sub-structures to predict the T m of ILs. To better distinct the effects of anion and cation on the latter property, 31 sub-structures related to chemical structure of anion, and 49 substructures related to the chemical structure of cation have been implemented. The results of this method show a low average relative deviation (AARD%) of 5.82% for a data set including 799 ILs

Group contribution model for estimation of surface tension of ionic liquids

International audienceIn this communication, a reliable group contribution method is developed for estimation of surface tension of ionic liquids. A data set including 920 experimental data for 51 ionic liquids collected from various references is used to develop and assess the predictive capability of the model. The data set covers a temperature range of 268.3 through 743.7K and a surface tension range of 0.02499 through 0.0647Nm -1. It employs a total of 19 sub-structures plus temperature to predict the surface tension. To better distinct the effects of anion and cation on the surface tension of ionic liquids, 12 sub-structures related to chemical structure of anion, and 7 substructures related to the chemical structure of cation were implemented. The results of this method show an average absolute relative deviation (AARD) of 3.6% from experimental data

Corresponding states method for estimation of upper flammability limit temperature of chemical compounds

International audienceThe accuracy and predictability of predictive methods to determine the flammability characteristics of chemical compounds are of drastic significance in the chemical industry. This work aims at continuing application of the gene expression programming (GEP) mathematical strategy to modify the existing thermophysical properties correlations available in the literature to pursue the following objectives: optimization of the number of independent parameters, amplification of the generality, and improvement of the accuracy and predictability. This work deals with presenting a simple corresponding states model to predict the upper flammability limit temperature of 1462 organic compounds from 76 chemical families. The parameters of the correlation include the critical temperature and the acentric factor of the compounds. The obtained statistical parameters including average absolute relative deviation of the results from DIPPR 801 database values (1.7, 1.8, 1.7% for training, optimization, and prediction sets, respectively) demonstrate improved accuracy of the presented correlations

A group contribution method for estimation of glass transition temperature ionic liquids

International audienceIn this study, a new accurate model is presented for estimation of the glass transition temperature of ionic liquids. To develop this simple model, the contribution of ILs' anions and cations are separately considered through a number of occurrences of 50 substructures (17 anion-based and 33 cation-based). This simple model shows a low average relative deviation (AARD) of 3.65% for a data set including 496 (396 for training and 100 for validation) experimental glass transition temperature. Furthermore, the predictive power of the model is evaluated using the NIST Standard Reference Database #147 data. The model shows an AARD% of 4.3%