Crystallization from solution is a promising unit operation to separate linear and branched isomers. To reduce the number of experiments, a thermodynamic modeling approach is proposed to calculate the required phase equilibria. Hereby, the thermodynamic data of pure substances are required to fit model parameters, but the branched isomers are often not available. Therefore, a methodology which allows for the prediction of phase equilibria of systems containing branched molecules was developed in this contribution. The basic idea is to fit the model parameters to experimental data of linear molecules and combine these parameters with information about the molecular architecture of the branched isomers to predict the phase equilibria of these isomers. For this purpose the lattice cluster theory which considers directly the molecular architecture was applied in combination with the chemical association lattice model. As model systems linear and branched alkanes dissolved in an alcohol were investigated. The developed methodology is able to predict the binary liquid–liquid equilibria of the branched alkanes dissolved in an alcohol in good agreement to experimental data. Furthermore, the thermodynamic model is able to simultaneously calculate the liquid–liquid equilibrium and the solid–liquid equilibrium with the same model parameters in good agreement with experimental data.

Oiling-out is an unwanted phenomenon during crystallization processes since it influences the product properties negatively and should, therefore, be avoided. To reduce the time of process development, thermodynamic modeling is usually applied. In the course of fitting model parameters, thermodynamic data of the present molecules are required. In case of branched molecules these thermodynamic data are often not available. To overcome this limitation, a methodology, which allows for the prediction of liquid–liquid equilibria (LLE) of binary systems containing branched molecules was developed recently. The developed methodology was applied in this contribution in order to predict the superposition of ternary LLE and solid–liquid equilibria (SLE) of the system n-hexadecane + 2,2,4,4,6,8,8-heptamethyl­nonane + ethanol. To consider the influence of the molecular architecture on phase equilibria, the lattice cluster theory in combination with the chemical association lattice model was applied. The prediction of the ternary phase equilibria was based on the binary subsystems. It could be shown that the ternary LLE and the ternary SLE can be predicted in very good agreement with experimental data using the same set of model parameters. All model parameters were fitted using only binary LLE data of linear alkanes dissolved in ethanol. Neither binary experimental data of the branched alkane nor ternary ones were used for parameter fitting.

This work analyzed the separation and purification of terpenyl amine by a reactive extraction in which an acid was used as complexing agent. Several different acids were investigated to form a water-soluble complex, but only carboxylic acids were found to be suitable for a reactive extraction of terpenyl amine. The best results according to yield and selectivity were found for acetic acid. Moreover, there was no formation of an emulsion using the acetic acid. The reaction mechanism and reaction location were determined to characterize this complexation reaction of acetic acid with terpenyl amine. The main mechanism was the Hbond formation at the interface between the organic and aqueous phases. Finally, the pseudomole-fraction-based equilibrium constant of 4.26 was estimated with a complex factor of 1 to 4.26 with selectivity above 98%.