Solubility Measurement Setup for Rapid Determination of Solid-Liquid Equilibrium Behavior and Process Synthesis

Abstract

The synthesis of crystallization-based separation processes requires experimental solid-liquid equilibrium (SLE) behavior of the system under consideration, effective representation of such SLE data, selection of crystallization solvent, and determination of crystal quality under different experimental conditions. Often, because of the considerable time and labor required for a thorough investigation of a given system, some of these steps are omitted, resulting in a suboptimal process, or worse, completely missing a feasible, superior process alternative. In order to tackle this problem, a solubility measurement system was developed. With the use of multiple turbidity probes, online monitoring of the turbidity in multiple crystallization experiments was achieved. The data extracted from the system was fed to SLEEK – a solid-liquid equilibrium engineering software code, which allows for the visualization and interpretation of solid-liquid phase behavior. Several solid-liquid equilibrium phase diagrams of organic systems including adipic acid in water (binary), paracetamol in various organic solvents (binary), phenol/o-cresol/tert-butanol (ternary), bisphenol A/acetone/water (LL forming), and others were measured. These demonstrate that, taken together, this rapid solubility measurement setup and SLEEK, is highly effective in solubility data measurement, for identifying liquid-liquid region, solvent selection, and synthesizing crystallization-based separation processes.