Insights into the Properties and Potential Applications of Renewable Carbohydrate-Based Ionic Liquids: A Review

Carbohydrate-derived ionic liquids have been explored as bio-alternatives to conventional ionic liquids for over a decade. Since their discovery, significant progress has been made regarding synthetic methods, understanding their environmental effect, and developing perspectives on their potential applications. This review discusses the relationships between the structural properties of carbohydrate ionic liquids and their thermal, toxicological, and biodegradability characteristics in terms of guiding future designs of sugar-rich systems for targeted applications. The synthetic strategies related to carbohydrate-based ionic liquids, the most recent relevant advances, and several perspectives for possible applications spanning catalysis, biomedicine, ecology, biomass, and energy conversion are presented herein.

Continuous Process for Carbon Dioxide Capture Using Lysine and Tetrabutyl Phosphonium Lysinate Aqueous Mixtures in a Packed Tower

The CO2 absorption process using aqueous solutions of lysine (Lys), the ionic liquid (IL) tetrabutyl phosphonium lysinate ([TBP][Lys]) and their mixtures was studied by means of a packed tower. The performance of these systems was evaluated through the volumetric overall mass transfer coefficient ( K G a V ) , conducting experiments under diverse conditions such as inlet CO2 concentration from 10 to 40 vol.%, gas and absorbent flow rates from 100 to 200 mL/min and from 3 to 5 mL/min, respectively, absorbent concentration from 5 to 15 wt.% and temperature from 15 to 40 °C. The obtained results for all the previous experimental conditions were better for the IL/Lys mixture than for the isolated components; the best performance was shown by the experiment varying the absorbent concentration, where the increasing K G a V was benefited by the IL/Lys synergistic effect.

Cooperative CO2 absorption by amino acid-based ionic liquids with balanced dual sites

In this study, a variety of functionalized ILs with dual sites including amino acid group (AA) and basic anion (R) were synthesized to investigate the suppression and cooperation between the sites in CO₂ absorption. The basic anions selected in this study with different basicity include sulfonate (Su), carboxylate (Ac), imidazolium (Im), and indolium (Ind). These ILs ([P₆₆₆₁₄]₂[AA-R]) were applied to CO₂ absorption. The results present that CO₂ capacity increases first and then decreases later with the continuous increase in the activity of the anion site. Combined with CO₂ absorption experiments, IR and NMR spectroscopic analyses and DFT calculation demonstrate that the ability of one site to capture CO₂ would be suppressed when the activity of another site is much stronger. Thus, the cooperation of dual site-functionalized ILs and high CO₂ capacity might be achieved through balancing the two sites to be equivalent. Based on this point, [P₆₆₆₁₄]₂[5Am-iPA] was further synthesized by taking the advantage of the conjugated benzene ring. As expected, [P₆₆₆₁₄]₂[5Am-iPA] showed capacity as high as 2.38 mol CO₂ per mol IL at 30 °C and 1 bar without capacity decrease even after 10 times recycling performance of CO₂ absorption and desorption.

Protein-Rich Biomass Waste as a Resource for Future Biorefineries: State of the Art, Challenges, and Opportunities

Protein-rich biomass provides a valuable feedstock for the chemical industry. This Review describes every process step in the value chain from protein waste to chemicals. The first part deals with the physicochemical extraction of proteins from biomass, hydrolytic degradation to peptides and amino acids, and separation of amino acid mixtures. The second part provides an overview of physical and (bio)chemical technologies for the production of polymers, commodity chemicals, pharmaceuticals, and other fine chemicals. This can be achieved by incorporation of oligopeptides into polymers, or by modification and defunctionalization of amino acids, for example, their reduction to amino alcohols, decarboxylation to amines, (cyclic) amides and nitriles, deamination to (di)carboxylic acids, and synthesis of fine chemicals and ionic liquids. Bio- and chemocatalytic approaches are compared in terms of scope, efficiency, and sustainability.