Franciele L. Bernard

Rationalizing the role of the anion in CO2 capture and conversion using imidazolium-based ionic liquid modified mesoporous silica

Covalently supported ionic liquids in mesoporous materials were prepared by grafting 1-methyl-3-(3-trimethoxysylilpropyl)imidazolium chloride in MCM-41. Subsequently, the [Cl−] anion was changed to [BF4−], [PF6−] or [Tf2N−]. These materials that present an advantageous combination of the properties of mesoporous solid materials and ionic liquids were evaluated for CO2 sorption as well as catalysts for CO2 conversion into cyclic carbonate using propylene oxide. The material with the [Cl−] anion had the best performance for both CO2 sorption and conversion. A CO2 sorption of 11 w/w% on the adsorbent was achieved and the cycloaddition reaction exhibited a conversion of 67% with 82% selectivity with the catalyst remaining active after 5 cycles, proving that the same sorbent/catalyst setup can be used for both CO2 capture and conversion. Based on the experimental data and electronic-structure numerical simulations, we have hypothesized two major reasons why chloride out performs other anions when adsorbed on MCM-41 unlike unsupported ionic liquids.

Syntheses and characterization of new poly(ionic liquid)s designed for CO2 capture

A series of new poly(ionic liquid)s-p(IL)s based on polyurethane structures were synthesized and characterized and their behavior evaluated in CO2 sorption tests under different pressures. The synthesized materials were characterized according to structure, composition, and thermal stability, by techniques such as FTIR, 1H-NMR, TGA and DSC. The CO2 sorption measurements were carried out in a Magnetic Suspension Balance-PTGA and proved that the change of the components of the polymer chain directly indicates the sorption behavior. The best performance for CO2 sorption (75.7 mol% at 20 bar) was achieved with the p(IL) PUA-02a obtained from HDI and PTMG-2000 with [bmim]+ as a counter-ion. The synthesized p(IL)s presenting nitrogenated and polyether structures into the backbone allied to imidazolium counter-cations proved to be worthy of note in the CO2 sorption besides being based on poly(urethane) a versatile and low-cost material. The results also highlighted the good performance of PUA-02 when compared with traditional solvents used in pre-combustion process, as well as the p(IL)s described in the literature.

A New Approach to CO2 Capture and Conversion Using Imidazolium Based-Ionic Liquids as Sorbent and Catalyst

Although the carbon capture and storage (CCS) technologies are receiving great attention for mitigation of greenhouse gas effect, the increasing costs and energy penalties associated to its implementation are still major drawbacks. However, the use of CO2 as a C1 building block in organic synthesis can be very attractive for the design of environmentally friendly processes. In this work, we have studied both the CO2 sorption and catalytic activities of some imidazolium based ionic liquids (ILs) for cyclic carbonate synthesis. The work demonstrates that the presence of a nucleophilic group in the catalytic system can enhance its performance by the use of an IL with a halide anion or by mixing a halide co-catalyst with ILs. The latter approach allowed to obtain an effective system for CO2 capture constituted by a fluorinated IL plus ZnBr2 that performs cyclic carbonate synthesis with 90% yield and 82% of selectivity.

CHAPTER 17:Capturing CO2 with Poly(Ionic Liquid)s

The development of new and the improvement of existing materials for designing new solvents/sorbents for CO2 separation is an urgent priority and significant goal to deal with climate change. Polymerizable ionic liquids or poly(ionic liquid)s (PILs) appear to be promising materials for this use. The aim of this chapter is to present the latest developments in PILs providing a broad overview of the subject. Furthermore, it will explore the subject from an application point of view, giving a comprehensive introduction to the main aspects of PILs including their synthesis routes, as well as the influence of the PIL backbone, anion type and modification on the CO2 sorption capacity.