Protic ionic liquids as constituent of aqueous two-phase system based on acetonitrile: Synthesis, phase diagrams and genipin pre-purification

• Published in: Fluid phase equilibria 2020-03, Vol.507, p.112425, Article 112425
• Main Authors: Alves Camêlo, Lídia Cristina, de Souza Dias Santos, Gabriela, Lucena de Souza, Ranyere, Faria Soares, Cleide Mara, Brandão Pereira, Jorge Fernando, Lima, Álvaro Silva
• Format: Article
• Language: English
• Subjects: Extraction; Genipin; Integrated process; Phase equilibria; Protic ionic liquid
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2019.112425

The aim of this study was to evaluate the formation of aqueous two-phase systems (ATPS) based on different protic ionic liquids (PIL), synthesized using amines, and organic or inorganic acid, and acetonitrile (ACN). The ATPSs are used to pre-purify genipin from genipap (Genipa americana L.). All PILs (purity above 98%) were able to form ATPSs with ACN, the size of the biphasic region being directly dependent on salting-out aptitude of PIL anions and relative hydrophilicity of the corresponding cations. The highest solid–liquid extraction of genipin from genipap was achieved by using aqueous ACN solution at 75% (16.79 ± 0.06 mg g−1 dry raw material) as extractant. After the extraction stage, the ATPS was used as an integrated platform to pre-purify the genipin present in the extract. Three different overall mixture point compositions were tested, and those formed by [MEA][H2Cit] (25 wt%) + ACN (45 wt%) + water (30 wt%) at 298.15 ± 1.00 K and 0.10 ± 0.01 MPa showed the highest selectivity (S = 4.202 ± 0.009) and recovery of genipin in top phase (RTG = 56.74 ± 0.04%), and the purification factor in top phase was 5.9 fold. •Equilibrium data based on acetonitrile + protic ionic liquid + water are presented.•Top phase is rich in acetonitrile, while bottom phase is rich in protic ionic liquid.•Acetonitrile is the best extracting solvent for genipin (16.79 mg per dry extract).•Genipin was preferably partitioned to the top phase.•The best selectivity to genipin purification was 4.202.