Aqueous Biphasic Systems Containing Customizable Poly(Ionic Liquid)s for Highly Efficient Extractions

Abstract

Ionic liquid (IL)‐based aqueous biphasic systems (ABSs) provide a sustainable and efficient alternative to conventional liquid–liquid extraction techniques and can be used for the extraction, recovery, and purification of diverse solutes. However, the construction of a high‐performance ABS that has both excellent phase separation ability and extraction performance remains challenging. This study concerns the preparation of a family of novel ABSs based on poly(ionic liquid)s (PILs) with customized structure and controllable molecular weight for the extraction of bioactive compounds. Several tailor‐made PILs consisting of a hydrophobic backbone, hydrophilic imidazolium pendant groups and strong hydrogen bonding basic counteranions are prepared by reversible addition fragmentation chain‐transfer polymerization. The PILs have a perfect balance of hydrophobicity/hydrophilicity and functionality, affording outstanding phase separation, which was better than with either the IL monomer poly(1‐butyl‐3‐vinylimidazolium bromide ([BVIm]Br) or the normal free‐radical polymer P[BVIm]Br*. More importantly, PIL‐based ABSs exhibited unprecedented high partition coefficients for six bioactive compounds including tryptophan, phenylalanine, and caffeine, as well as high extraction yields. The performance of the PIL‐based ABSs could also be tuned by changing the molecular weight and anionic character of the PILs. This work shows that tailor‐made PIL‐based ABSs are a promising platform for bioactive compound extraction and provides significant clues for the design of new ABSs for various applications.

Recent advances in poly(ionic liquid)s for biomedical application

“…141 PIL-based aqueous biphasic systems can be used for the extraction, recovery and purification of proteins and is a high-efficiency alternative to traditional liquid-liquid extraction technology. 142 The stationary phase based on PILs with a positively charged backbone structure represents a rapid and simple method for the recovery of bacteriophage. 143 Comparing with the 60% loss of traditional purification, separation based on PILs can alleviate the recovery rate to 70%.…”

“…141 PIL-based aqueous biphasic systems can be used for the extraction, recovery and purification of proteins and is a high-efficiency alternative to traditional liquid–liquid extraction technology. 142…”

The research progress on CO<sub>2</sub> absorption and conversion by metal coordination-based (chelate-based) ionic liquids

“…[2~4] 、材料合成 [5] 、电化学 [6,7] 、 催化 [8,9] 等领域. 金属配位型ILs是一类由金属离子与有 机或无机配体通过配位作用形成的低温熔盐, 由Hurley 和WIer [10] 在1951年首次报道并应用于电化学.…”

Stimuli‐Responsive Ionic Liquids and the Regulation of Aggregation Structure and Phase Behavior†

“…Since the 21 st century, a large number of novel ILs with cations such as quaternary ammonium, quaternary phosphonium, pyrrole, diimidazole, pyridine, naphthenate, and sulfur salts have been reported. [ 3‐5 ] Due to the designability of ILs, the third‐generation ILs, namely functionalized ILs, are prepared carefully by combining different cations and anions of functional groups based on specific applications, such as gas absorption, [ 6‐11 ] extraction and separation, [ 12‐17 ] catalytic reaction, [ 18‐24 ] organic synthesis, [ 25‐27 ] biomass utilization, [ 28‐36 ] and electrochemistry. [ 36‐39 ] These third‐generation ILs have attracted increasing attention from academia to industrial communities with the rise of green chemistry.…”