Design of the Distillation-Extraction Tandem to Separate Ethyl Propanoate from Heptane Solutions Using Pyridinium-Derived Organic Salts as Entrainers. Its Use as a Potential Bioactive Compound

Ethyl propanoate is present in certain foods and participates actively in the digestion. Different ionic liquids are used as entrainer in the separation processes. This work analyzes the efficacy of four pyridine-derived hydrophilic ionic liquids to separate the azeotropic mixture ethyl propanoate+heptane. The study was carried out following a sequence of operations: experimentation↔modeling↔simulation. In our investigations the separation of ethyl propanoate is justified by its presence in some foods and its future employment as a bioactive pharmaceutical product mainly associated with digestive processes. The ILs were almost immiscible in hydrocarbon, but partially miscible in ester, in the order [b2mpy]­[BF₄]<[bpy]­[BF₄]<[b3mpy]­[BF₄]<[b4mpy]­[BF₄], producing LLE type II in the ternaries. The representation of all the systems was done with our own polynomial model and with NRTL, with good results. The predictions made with the COSMO-RS methodology were not suitable for the systems studied here and this was not employed in the simulation process. The result of the simulation of the extractive distillation process with the different ILs suggests using [b4mpy] [BF4] as entrainer if an ester of extreme purity is not required.