Protic Ionic Liquids: Properties and Applications

Ionic liquids (ILs) are organic salts with melting points near room temperature (or by convention below 100 degrees C). Recently, their unique materials and solvent properties and the growing interest in a sustainable, "green" chemistry has led to an amazing increase in interest in such salts. A huge number of potential cation and anion families and their many substitution patterns allows the desired properties for specific applications to be selected. Because it is impossible to experimentally investigate even a small fraction of the potential cation-anion combinations, a molecular-based understanding of their properties is crucial. However, the unusual complexity of their intermolecular interactions renders molecular-based interpretations difficult, and gives rise to many controversies, speculations, and even myths about the properties that ILs allegedly possess. Herein the current knowledge about the molecular foundations of IL behavior is discussed.

Understanding Ionic Liquids at the Molecular Level: Facts, Problems, and Controversies

Superoxide ion (O2•–) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of O2•– is rather scarce. In addition, numerous studies on O2•– were conducted within the latter half of the 20th century. Therefore, the current advancement in technology and instrumentation will certainly provide better insights into mechanisms and products of O2•– reactions and thus will result in new findings. This review emphasizes the state-of-the-art research on O2•– so as to enable researchers to venture into future research. It comprises the main characteristics of O2•– followed by generation methods. The reaction types of O2•– are reviewed, and its potential applications including the destruction of hazardous chemicals, synthesis of organic compounds, and many other applications are highlighted. The O2•– environmental chemistry is also discussed. The detection methods of O2•– are categorized and elaborated. Special attention is given to the f...

Superoxide Ion: Generation and Chemical Implications

Global warming resulting from the emission of greenhouse gases, especially CO2, has become a widespread concern in the recent years. Though various CO2 capture technologies have been proposed, chemical absorption and adsorption are currently believed to be the most suitable ones for post-combustion power plants. The operation of the chemical absorption process is reviewed in this work, together with the use of absorbents, such as the ionic liquid, alkanolamines and their blended aqueous solutions. The major concerns for this technology, including CO2 capture efficiency, absorption rate, energy required in regeneration, and volume of absorber, are addressed. For adsorption, in addition to physical adsorbents, various mesoporous solid adsorbents impregnated with polyamines and grafted with aminosilanes are reviewed in this work. The major concerns for selection of adsorbent, including cost, adsorption rate, CO2 adsorption capacity, and thermal stability, are compared and discussed. More effective and less energy-consuming regeneration techniques for CO2-loaded adsorbents are also proposed. Future works for both absorption and adsorption are suggested.

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A Review of CO2 Capture by Absorption and Adsorption

Room temperature ionic liquids and their mixtures—a review

New experimental results are presented for the solubility of carbon dioxide in the ionic liquid 1-N-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) for temperatures from (293 to 393) K and pressures up to about 9.7 MPa. Solubility pressures are correlated by means of the extended Henry's law.

Solubility of CO2 in the Ionic Liquid [bmim][PF6]

Solubility of CO2 in the ionic liquid [hmim][Tf2N]

A high-pressure view-cell technique based on the synthetic method was used to determine the solubility of carbon dioxide in the ionic liquid 1-n-butyl-3-methylimidazolium methyl sulfate ([bmim][CH3...

Solubility of CO2 in the Ionic Liquids [bmim][CH3SO4] and [bmim][PF6]

Solubility of CO in the ionic liquid [bmim][PF6]

A thermodynamic model for describing the phase equilibrium for the system CO 2 + methyldiethanolamine + water has been extended, allowing for the presence of piperazine. Model parameters are estimated from new experimental results for the solubility of carbon dioxide in aqueous solutions of piperazine (for piperazine molalities up to 4 mol per kilogram of water, temperatures between 313 and 393 K, and pressures up to about 9.6 MPa). The model is tested by comparing predicted and experimental carbon dioxide solubilities in aqueous mixtures of both amines (2 molal MDEA + 2 molal piperazine, at 353 K, and pressures up to about 6.4 MPa).

Álvaro Pérez-Salado Kamps

Papers

Solubility of CO2 in the Ionic Liquid [bmim][PF6]

Solubility of CO2 in the ionic liquid [hmim][Tf2N]

Solubility of CO2 in the Ionic Liquids [bmim][CH3SO4] and [bmim][PF6]

Solubility of CO in the ionic liquid [bmim][PF6]

Solubility of CO2 in (H2O+piperazine) and in (H2O+MDEA+piperazine)