A novel methodology for the identification of azeotropic binary mixtures by TG-FTIR techniques

A methodology based on simultaneous thermogravimetric and infrared spectrometric (TG-FTIR) analysis was developed, providing data on the evaporation temperatures of a liquid mixture and on the presence of azeotropic points. The technique also enables the estimation of the azeotropic composition and the attainment of preliminary data on the thermal stability of the components. The method may be applied to the investigation of any binary system where the separation of the contributions of each component to the recorded IR spectra is possible. Although the dynamic configuration of the TG-FTIR experiments causes the method to be less accurate than conventional techniques, its main advantage is the very limited amount of sample required for experimental runs (<30 mul per run). The methodology proved to be potentially useful for a preliminary investigation of the possibility of separation by distillation methods of binary homogeneous mixtures. The much lower quantities of samples required make the TG-FTIR technique attractive due to the significant reduction of time, costs and of safety and disposal problems associated to conventional methods.