Fully Automated Workstation for Liquid−Liquid Equilibrium Measurements

Abstract

A fully automated workstation has been developed and applied to the measurement of liquid−liquid equilibrium. The measurements, starting from solution preparations through equilibrium establishment and chemical analysis of both phases and ending with the determined solute concentration in both phases, can be done on a 24 h per day basis with no human intervention at all. To evaluate the accuracy of the measurements, the equilibrium distribution ratios of acetone between toluene and water at 20 °C and of caprolactam between toluene and water at 40 °C and between benzene and water at 20 °C are measured and the results are compared with the values reported in the literature and, for the caprolactam systems, also with those obtained in a jacketed equilibrium cell. Furthermore, the distribution ratio of caprolactam between toluene and water has been measured several times for the same initial caprolactam mass fraction in order to evaluate the repeatability. The obtained results are in very good agreement with the literature values for the acetone system and with those measured in the glass cell for the caprolactam systems, while a coefficient of variation of 1.8% for a seven times repeated measurement was found.

Efficient Determination of Liquid–Liquid Equilibria Using Microfluidics and Raman Microspectroscopy

“…Conventional experiments for the characterization of LLEs are time-consuming and need large sample volumes . Recent methods overcome these disadvantages by using smaller sample volumes and automation. , However, these methods employ standard analytical methods like gas or high-performance liquid chromatography which take a long time per sample and are therefore often the bottleneck in these new automated approaches. Additionally, an internal standard is needed in many cases, which increases the overall consumption of chemicals .…”

Reactive extraction of carboxylic acids from apolar hydrocarbons using aqueous solutions of sodium hydrogen carbonate with back-recovery using carbon dioxide under pressure

“…The jacketed glass cells and applied procedure for the measurement of the distribution ratio of the components between the aqueous and organic phase are already described in our earlier papers [11,18,19]. Hence, only the specific details for this case are given here.…”

Visualization of High-Dimensional Liquid−Liquid Equilibrium Phase Diagrams

“…Common experimental methods and description of apparatuses used in determining the LLE data have been discussed in detail . A fully automated workstation, which allows more measurements to be performed per day, has been developed for LLE measurements …”