Synthesis of Purine-Based Ionic Liquids and Their Applications
authors Carreira, ARF; Veloso, T; Schaeffer, N; Pereira, JL; Ventura, SPM; Rizzi, C; Plenet, JS; Passos, H; Coutinho, JAP
nationality International
journal MOLECULES
author keywords synthesis; ecotoxicity; solubility; liquid-liquid equilibrium; thermoresponsive systems
keywords AQUEOUS BIPHASIC SYSTEMS; VIBRIO-FISCHERI; 2-PHASE SYSTEMS; THEOBROMINE; SOLUBILITY; TOXICITY; WATER; ACID; BIODEGRADATION; PARTITION
abstract Bio-based ionic liquids (ILs) are being increasingly sought after, as they are more sustainable and eco-friendly. Purines are the most widely distributed, naturally occurring N-heterocycles, but their low water-solubility limits their application. In this work, four purines (theobromine, theophylline, xanthine, and uric acid) were combined with the cation tetrabutylammonium to synthesize bio-based ILs. The physico-chemical properties of the purine-based ILs were characterized, including their melting and decomposition temperatures and water-solubility. The ecotoxicity against the microalgae Raphidocelis subcapitata was also determined. The ILs show good thermal stability (> 457 K) and an aqueous solubility enhancement ranging from 53- to 870-fold, in comparison to their respective purine percursors, unlocking new prospects for their application where aqueous solutions are demanded. The ecotoxicity of these ILs seems to be dominated by the cation, and it is similar to chloride-based IL, emphasizing that the use of natural anions does not necessarily translate to more benign ILs. The application of the novel ILs in the formation of aqueous biphasic systems (ABS), and as solubility enhancers, was also evaluated. The ILs were able to form ABS with sodium sulfate and tripotassium citrate salts. The development of thermoresponsive ABS, using sodium sulfate as a salting-out agent, was accomplished, with the ILs having different thermosensitivities. In addition, the purine-based ILs acted as solubility enhancers of ferulic acid in aqueous solution.
publisher MDPI
isbn 1420-3049
year published 2021
volume 26
issue 22
digital object identifier (doi) 10.3390/molecules26226958
web of science category 18
subject category Biochemistry & Molecular Biology; Chemistry, Multidisciplinary
unique article identifier WOS:000727341700001
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journal analysis (jcr 2019):
journal impact factor 3.267
5 year journal impact factor 3.589
category normalized journal impact factor percentile 56.714
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