6 documents found, page 1 of 1
A critical assessment of the mechanisms governing the formation of aqueous biph...
Claudio, Ana Filipa M.; Pereira, Jorge F. B.; McCrary, Parker D.; Freire, Mara G.; Coutinho, Joao A. P.; Rogers, Robin D.An extensive study on the formation of aqueous biphasic systems (ABS) using aqueous solutions of protic ionic liquids (PILs) and polyethylene glycol (PEG) was performed in order to understand the mechanisms underlying the phase separation. Aqueous solutions of PEG polymers with different molecular weights (600, 1000, 2000, and 3400 g mol(-1)) and several N-alkyl-, dialkyl-, and trialkyl-ammonium salts of acetat...
Hydrogen-bond acidity of ionic liquids: an extended scale
Kurnia, Kiki A.; Lima, Filipa; Claudio, Ana Filipa M.; Coutinho, Joao A. P.; Freire, Mara G.One of the main drawbacks comprising an appropriate selection of ionic liquids (ILs) for a target application is related to the lack of an extended and well-established polarity scale for these neoteric fluids. Albeit considerable progress has been made on identifying chemical structures and factors that influence the polarity of ILs, there still exists a high inconsistency in the experimental values reported b...
The magic of aqueous solutions of ionic liquids: ionic liquids as a powerful cl...
Claudio, Ana Filipa M.; Neves, Marcia C.; Shimizu, Karina; Canongia Lopes, Jose N.; Freire, Mara G.; Coutinho, Joao A. P.Hydrotropes are compounds able to enhance the solubility of hydrophobic substances in aqueous media and therefore are widely used in the formulation of drugs, cleaning and personal care products. In this work, it is shown that ionic liquids are a new class of powerful catanionic hydrotropes where both the cation and the anion synergistically contribute to increase the solubility of biomolecules in water. The ef...
Development of back-extraction and recyclability routes for ionic-liquid-based ...
Claudio, Ana Filipa M.; Marques, Carlos F. C.; Boal-Palheiros, Isabel; Freire, Mara G.; Coutinho, Joao A. P.In the last decade, aqueous two-phase systems (ATPS) composed of ionic liquids (ILs) and inorganic salts have been largely explored as novel extractive platforms. The use of ILs as phase-forming components in ATPS has led to outstanding extraction performances compared to more traditional approaches. Nevertheless, despite those exceptional achievements, IL regeneration, recycling and reuse lagged behind and sti...
Extended scale for the hydrogen-bond basicity of ionic liquids
Claudio, Ana Filipa M.; Swift, Lorna; Hallett, Jason P.; Welton, Tom; Coutinho, Joao A. P.; Freire, Mara G.In the past decade, ionic liquids (ILs) have been the focus of intensive research regarding their use as potential and alternative solvents in many chemical applications. Targeting their effectiveness, recent investigations have attempted to establish polarity scales capable of ranking ILs according to their chemical behaviours. However, some major drawbacks have been found since polarity scales only report rel...
Enhanced extraction of caffeine from guarana seeds using aqueous solutions of i...
Claudio, Ana Filipa M.; Ferreira, Ana M.; Freire, Mara G.; Coutinho, Joao A. P.The extraction of caffeine from bioresources using more benign and cost-effective processes is of fundamental relevance towards the finding of alternative (bio) pesticides. Classically, the best attempts to extract caffeine from biomass have resulted in low efficiency and in a large consumption of hazardous organic solvents and/or energy requirements. Here, we report an enhanced and selective extraction of caff...