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Understanding the Role of Cholinium Carboxylate Ionic Liquids in PEG-Based Aqueous Biphasic Systems
journal contribution
posted on 2014-10-06, 00:00 authored by Teresa Mourão, Liliana
C. Tomé, Catarina Florindo, Luís Paulo
N. Rebelo, Isabel M. MarruchoThis work aims at exploring new sustainable
separation processes
based on ionic liquids. Aqueous biphasic systems (ABS) based on poly(ethylene
glycol) (PEG) with low molecular weight (600 and 4000 g mol–1) and cholinium-based ionic liquids and salts containing anions derived
from carboxylic acids (oxalate, malonate, succinate, l-malate,
fumarate, glutarate and citrate), available in natural compounds,
are here presented. Contrary to common ionic liquids, the cholinium-based
ionic liquids used in this work are biodegradable, nontoxic, cheap,
and simple to prepare, and PEG is also a cheap and nontoxic phase
promoter agent. The data reported in this work allows novel insights
into the phase splitting mechanism of these ABSs regarding the influence
of alkyl chain length of the anion and the presence of substituent
groups in the anion. The effect of PEG molecular weight in the ABS
was also addressed. Furthermore, the possible application of these
systems for the extraction/separation of antioxidants, namely, tert-butylhydroquinone (TBHQ), was evaluated.