BSc-project description tutor: Thomas Brouwer

Supervisor: Boelo Schuur

Investigate the influence of salt on the extraction of toluene using sulfolane

Sometimes, distillation is impractical to separate mixtures due to high energy consumption, or even it might be impossible due to azeotropes. Alternatively, affinity separation processes such as extractive distillation (ED) and liquid-liquid extraction (LLX) can be applied. The separation of aromatic from aliphatic compounds is one example where ordinary distillation can be impractical.

This BSc-project is part of a larger project where we try to understand molecular interactions between solvents and mixtures that we want to separate. In order to do so, we study both common solvents such as sulfolane that have been industrially used for decennia already and innovative new solvents or additives.

During this BSc-project the potential of enhancing the toluene extraction by addition of a salt is evaluated. The π-system of the toluene normally interacts with the acidic protons on the sulfolane. The idea behind adding a salt is depicted in the figure below.

Figure 1: The proposed interaction of toluene, a cation (in this case Na+) and sulfolane

The cation- π-system interaction may be stronger than the sulfolane- π-system interaction. In this case the cation will form a complex with toluene. Potentially this complex is extracted to a greater extent than solely toluene. During this BSc-project the concentration of salts, the type of salts and the toluene concentration can for instance be varied.



Literature study on aromatic-aliphatic separation. In particular heptane-toluene separation


Literature study on salt enhanced liquid-liquid extraction


Liquid-liquid extraction experiments of heptane-toluene-sulfolane-salt system


Different salts


Different salt concentrations


Different toluene concentrations


Evaluation of the enhancing capabilities of salts on the toluene extraction.