2.5. Ionic Liquids Presented in This Review 2020 3. Cyclocondensation Reactions 2020 4. Synthesis of Three-Membered Heterocycles 2022 4.1. Aziridines 2022 5. Synthesis of Five-Membered Heterocycles 2022 5.1. Pyrroles 2022 5.2. Furans 2022 5.3. Thiophenes 2023 5.4. Pyrazoles 2024 5.5. Imidazoles 2025 5.6. Isoxazoles 2027 5.7. Oxazoles, Oxazolines, and Oxazolidinones 2027 5.8. Thiazoles and Thiazolidinones 2028 6. Synthesis of Six-Membered Heterocycles 2030 6.1. Pyridines 2030 6.2. Quinolines 2031 6.3. Acridines 2033 6.4. Pyrans 2033 6.5. Flavones 2035 6.6. Pyrimidines and Pyrimidinones 2035 6.7. Quinazolines 2037 6.8. -Carbolines 2038 6.9. Dioxanes 2039 6.10. Oxazines 2039 6.11. Benzothiazines 2040 6.12. Triazines 2040 7. Synthesis of Seven-Membered Heterocycles: Diazepines 2041

Ionic liquids in heterocyclic synthesis.

Ionic liquids (ILs) offer a wide range of promising applications because of their much enhanced properties. However, further development of such materials depends on the fundamental understanding of their hierarchical structures and behaviors, which requires multiscale strategies to provide coupling among various length scales. In this review, we first introduce the structures and properties of these typical ILs. Then, we introduce the multiscale modeling methods that have been applied to the ILs, covering from molecular scale (QM/MM), to mesoscale (CG, DPD), to macroscale (CFD for unit scale and thermodynamics COSMO-RS model and environmental assessment GD method for process scale). In the following section, we discuss in some detail their applications to the four scales of ILs, including molecular scale structures, mesoscale aggregates and dynamics, and unit scale reactor design and process design and optimization of typical IL applications. Finally, we address the concluding remarks of multiscale strat...

Multiscale Studies on Ionic Liquids

Some of the most active scientific research fronts of the past decade are centered on ionic liquids These fluids present characteristic surface behavior and distinctive trends of their surface tension versus temperature One way to explore and understand their unique nature is to study their surface properties This critical review analyses most of the surface tension data reported between 2001 and 2010 (187 references)

Surface tension of ionic liquids and ionic liquid solutions

Self-organization of imidazolium ionic liquids in aqueous solution

Micelle formation of imidazolium ionic liquids in aqueous solution

Aqueous solutions of three kinds of surface active ionic liquids composed of the 1-alkyl-3-methylimidazolium cation have been investigated by means of surface tension and electrical conductivity measurements at room temperature (298 K). The surface tension measurements provided a series of parameters, including critical micelle concentration (cmc), surface tension at the cmc (γcmc), adsorption efficiency (pC20), and effectiveness of surface tension reduction (Πcmc). In addition, with application of the Gibbs adsorption isotherm, maximum surface excess concentration (Γmax) and minimum surface area/molecule (Amin) at the air−water interface were estimated. The effect of sodium halides, NaCl, NaBr, and NaI, on the surface activity was also investigated. It was found that both the pC20 and the Πcmc were rather larger than those reported for traditional ionic surfactants and the cmc values were somewhat lower than those for typical cationic surfactants, alkyltrimethylammonium bromides, and comparable to typica...

Surface adsorption and micelle formation of surface active ionic liquids in aqueous solution.

Three amphiphilic imidazolium ionic liquids (ILs), 1-[n-(N-carbazole)alkyl]-3-methylimidazolium bromide [carbazoleC(n)mim]Br (n = 6, 10, and 12), that incorporate a fluorescent carbazole moiety at the terminal of the hydrocarbon chain, were designed and synthesized. Their surface activity, aggregation behavior, and thermodynamics of micelle formation in aqueous solutions were systematically investigated by surface tension, electrical conductivity, and (1)H NMR spectroscopy. The incorporation of bulky carbazole groups led to the loose arrangement of [carbazoleC(n)mim]Br molecules at the air-water interface. Both the enhanced hydrophobicity and the pi-pi interaction due to the incorporation of carbazole groups contributed to the lower critical micelle concentration (cmc) and higher micellar aggregation number, reflecting a strong capability of the designed carbazole-tailed imidazolium ILs for the formation of micelle. The analysis of (1)H NMR spectra revealed that the carbazole moieties may overlap with the middle methylenes of the alkyl chains. The amphiphilic carbazole-tailed imidazolium ILs demonstrated strong and stable fluorescence properties, indicating their potential application in the combined field of surface chemistry and photochemistry.

Self-aggregation behavior of fluorescent carbazole-tailed imidazolium ionic liquids in aqueous solutions.

Surface tension measurements were carried out for the solutions of polyoxyethylene (20) sorbitan monolaurate (Tween 20) in 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and hexafluorophosphate (bmimPF6) at various temperatures. Two transition points were found in the surface tension−concentration curves at each temperature. The freeze-fracture transmission electron microscopy revealed that two kinds of particles with different sizes are formed at the concentrations of each transition point. Thus, the surfactant concentrations of the two transition points are regarded as critical aggregation concentrations, CAC1 and CAC2. From the CAC values and their temperature dependence, we estimated the thermodynamic parameters of the aggregate formation, ΔGagg0, ΔHagg0, and ΔSagg0. The thermodynamic parameters related to CAC1 are almost independent of temperature. On the other hand, as for the aggregate formation at CAC2, a positiveΔSagg0 contributes to a negative ΔGagg0 at low temperature, while a negative...

Aggregation Behavior of Polyoxyethylene (20) Sorbitan Monolaurate (Tween 20) in Imidazolium Based Ionic Liquids

The phase behavior of an aqueous mixture of octaethylene glycol dodecyl ether (C12E8) was investigated by means of differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy, and 13C nuclear magnetic resonance (13C NMR) spectroscopy. The phase diagram in the temperature range from −10 to 70 °C was constructed on the basis of DSC experiments, according to which four mesophases, that is, Lα, V1, H1, and I1, appear in this mixture system depending on the composition and temperature. The FT-IR measurements as a function of composition and temperature revealed the events occurring in the mixture associated with the phase transformation. When the mixture transforms from solid to mesophases, the hydrogen bonds between terminal OH groups of the surfactant molecules are broken. Accompanied by this phase transformation, the ordered conformational structure of both the polyoxyethylene (POE) and alkyl chains is mostly broken, and the residual order in the chain is lost gradually by the i...

Phase Behavior of an Aqueous Mixture of Octaethylene Glycol Dodecyl Ether Revealed by DSC, FT-IR, and 13C NMR Measurements

13C NMR was applied to investigate the various phases formed in aqueous mixtures of heptaethylene glycol dodecyl ether (C12E7). On the basis of the analysis of NMR line width, a qualitative picture was drawn concerning the molecular motion of C12E7 in some mesophases as follows. In the H1 and Lα phases, the motion of the alkyl chain of the surfactant molecule is rather restricted, whereas the polyoxyethylene (POE) chain can undergo segmental motion to some extent. The molecular motion of the surfactants in the V1 phase, which appears between the H1 and Lα phases, is quite rapid and is close to that in the liquid phase. The V1 phase is known to show the highest bulk viscosity in the mesophases due to the network structure constituted by the surfactant bilayer. The rapid motion of C12E7 in the V1 phase suggests that the surfactant molecules are packed rather loosely in the surfactant bilayer. The signal of carbon atoms in the POE chain was shifted upfield by the addition of water in a manner that the extent...

Tohru Inoue

Papers

Surface adsorption and micelle formation of surface active ionic liquids in aqueous solution.

Self-aggregation behavior of fluorescent carbazole-tailed imidazolium ionic liquids in aqueous solutions.

Aggregation Behavior of Polyoxyethylene (20) Sorbitan Monolaurate (Tween 20) in Imidazolium Based Ionic Liquids

Phase Behavior of an Aqueous Mixture of Octaethylene Glycol Dodecyl Ether Revealed by DSC, FT-IR, and 13C NMR Measurements

13C NMR Study of Mesomorphic Phases Formed in Aqueous Mixtures of Heptaethylene Glycol Dodecyl Ether