A reliable prediction of the phase behaviour and thermodynamic properties for acid gas
absorption in aqueous alkanolamines is highly desirable in the design and optimisation of carbon capture processes. This thesis contains the development of reliable models for the design and optimisation of alkanolamine solvents using the recently developed SAFT-g Mie group-contribution (GC) equation of state as a predictive framework to study the thermodynamic properties of these multi-functional compounds. The SAFT-g Mie
approach allows the determination of the thermo-physical properties of molecules and mixtures in terms their constituent functional groups. The parameters of each functional group are developed from fluid-phase equilibrium data for simple compounds and sometimes mixtures data. Once estimated, the models developed are applied to the study of more complex molecules in a predictive manner. Novel SAFT-g Mie models are developed for pure and up to quaternary systems; including alkylamines, alkanolamines, water, and
carbon dioxide. These GC models are able to describe accurately the phase behaviour and thermodynamic properties and are also transferable to the modelling of multi-functional compounds. The development of predictive methods for Henry's constants and surface tensions are also demonstrated using the SAFT-g Mie groups developed. The findings in this thesis validate the applicability of the SAFT-g Mie approach in modelling complex multi-functional molecules and demonstrate its broad relevance for a carbon capture processes.