Ionic Polyureas—A Novel Subclass of Poly(Ionic Liquid)s for CO2 Capture

Abstract

The growing concern for climate change and global warming has given rise to investigations in various research fields, including one particular area dedicated to the creation of solid sorbents for efficient CO2 capture. In this work, a new family of poly(ionic liquid)s (PILs) comprising cationic polyureas (PURs) with tetrafluoroborate (BF4) anions has been synthesized. Condensation of various diisocyanates with novel ionic diamines and subsequent ion metathesis reaction resulted in high molar mass ionic PURs (Mw = 12 ÷ 173 × 103 g/mol) with high thermal stability (up to 260 °C), glass transition temperatures in the range of 153–286 °C and remarkable CO2 capture (10.5–24.8 mg/g at 0 °C and 1 bar). The CO2 sorption was found to be dependent on the nature of the cation and structure of the diisocyanate. The highest sorption was demonstrated by tetrafluoroborate PUR based on 4,4′-methylene-bis(cyclohexyl isocyanate) diisocyanate and aromatic diamine bearing quinuclidinium cation (24.8 mg/g at 0 °C and 1 bar). It is hoped that the present study will inspire novel design strategies for improving the sorption properties of PILs and the creation of novel effective CO2 sorbents.

A Review on Ionic Liquid Gas Separation Membranes

“…PILs diversity is further enriched by the way of their monomer assembly, or more precisely, by their architecture ( Figure 4 ). The major architecture types of PILs are linear (a) [ 141 , 142 , 143 ], branched and/or hyperbranched (b) [ 132 ], and cross-linked (c) [ 140 ], where the branched are further subdivided into dendrimer (d) [ 144 ], star (e) [ 145 , 146 ], and cyclic (f) [ 147 ]. This variability in charge carrying group configurations and polymer architecture not only highlights the creativity of synthetic chemists, but also underscores the versatility of PILs with inexhaustible possibilities for their performance fine-tuning.…”

“…Recently, cationic polyureas with tetrafluoroborate anions have been synthesized. It was shown that CO 2 sorption depends on the type of the cation and the structure of the diisocyanate, with the highest sorption of 24.8 mg g −1 at 0 °C and 1 bar [ 141 ].…”

“…Usually, the presence of aromatic groups in the polymer backbone significantly improves the CO 2 uptake, but only at low gas pressures. Recently, a condensation of various diisocyanates with novel ionic diamines and subsequent ion metathesis reaction was studied by Morozova et al [ 141 ]. The resulting PILs exhibited remarkably high CO 2 capture (10.5–24.8 mg g −1 at 0 C and 1 bar).…”

Fixation of Carbon Dioxide with Functionalized Ionic Liquids

“…The catalyst was easily recoverable, usable more than five times, and its activity had no obvious loss and good stability (Scheme 6). Shaplov et al [56] synthesized a series of new poly (ionic liquid) containing cationic polyurea (PUR) and tetrafluoroborate (BF4) anions. Condensation of various diisocyanates with novel ionic diamines and subsequent ionic rede composition reactions yield the high mole mass ion PUR, which has high thermal stability (up to 260 °C) and glass transition temperatures in the temperature range of 153-286 °C.…”

“…Shaplov et al [56] . synthesized a series of new poly (ionic liquid) containing cationic polyurea (PUR) and tetrafluoroborate (BF4) anions.…”