SAFT-LC: Predicting mesophase formation from a statistical mechanics-based equation of state

The SAFT-liquid crystal (LC) equation of state was used to predict isotropic/discotic nematic phase behavior for carbonaceous, oligomeric pitches over a wide range of conditions, where either excess or orientational free energy effects dominate, both with and without solvents. In particular, supercritical toluene extraction conditions were identified for producing pitch fractions that, upon solvent removal, consist of 100% liquid crystalline mesophase (e.g., 330 °C, 100 bar, and a toluene-to-pitch ratio of 3:1). Temperature versus composition diagrams generated using SAFT-LC illustrate the effect of both temperature, pitch composition, and solvent addition on phase transitions from liquid crystalline to isotropic phase behavior. MALDI mass spectrometry was used to facilitate the selection of physically meaningful pseudocomponents for modeling the feed pitch.