RECENT ADVANCES IN SURFACTANT-ENHANCED ORGANIC SYNTHESIS IN AQUEOUS MICELLES

Soluting effect of amino acids on 1‑decyl‑3‑methylimidazolium bromide and 1‑dodecyl‑3‑methylimidazolium bromide as cationic surfactants and sodium dodecyl sulfate as anionic surfactant in aqueous solutions

Multi-Component Reactions (MCRs) have emerged as an excellent tool in organic chemistry for the synthesis of various bioactive molecules. Among these, one-pot MCRs are included, in which organic reactants react with domino in a single-step process. This has become an alternative platform for the organic chemists, because of their simple operation, less purification methods, no side product and faster reaction time. One of the important applications of the MCRs can be drawn in carbon- carbon (C-C) and carbon-heteroatom (C-X; X = N, O, S) bond formation, which is extensively used by the organic chemists to generate bioactive or useful material synthesis. Some of the key carbon- carbon bond forming reactions are Grignard, Wittig, Enolate alkylation, Aldol, Claisen condensation, Michael and more organic reactions. Alternatively, carbon-heteroatoms containing C-N, C-O, and C-S bond are also found more important and present in various heterocyclic compounds, which are of biological, pharmaceutical, and material interest. Thus, there is a clear scope for the discovery and development of cleaner reaction, faster reaction rate, atom economy and efficient one-pot synthesis for sustainable production of diverse and structurally complex organic molecules. Reactions that required hours to run completely in a conventional method can now be carried out within minutes. Thus, the application of microwave (MW) radiation in organic synthesis has become more promising considerable amount in resource-friendly and eco-friendly processes. The technique of microwaveassisted organic synthesis (MAOS) has successfully been employed in various material syntheses, such as transition metal-catalyzed cross-coupling, dipolar cycloaddition reaction, biomolecule synthesis, polymer formation, and the nanoparticle synthesis. The application of the microwave-technique in carbon-carbon and carbon-heteroatom bond formations via MCRs with major reported literature examples are discussed in this review.

The in vivo model on rabbit eyes and the in vitro cytotoxicity on fibroblasts were used to compare irritation effect of aqueous and oily (Miglyol 812) solutions of surfactants. Tween 20, Tween 80 and Cremophor EL were tested in different concentrations (0.1, 1 or 5%) and the in vitro test demonstrated that surfactants in oil are less cytotoxic than in aqueous solutions. In the in vivo study, the aqueous solutions of surfactants were characterized as non-irritant while small changes in conjunctiva were observed after application the oily solutions of surfactants and the preparations were classified as slightly irritant, however this effect was similar when Miglyol was applied alone. In conclusion, it is reported that the MTT assay does not correlate well with the Draize scores.

Aggregates of sodium hyaluronate with cationic and aminoxide surfactants in aqueous solution — light scattering study

Interaction between Triton X100 and Brij 58 in their binary mixed micelles: Micellization in aqueous solution and aqueous solution of Poloxamer 188 at the range of temperature T = (273.15–323.15) K

The polymeric graphitic carbon nitride (g-C3N4) has been one of the interesting earth abundant elements. Though g-C3N4 finds application as a photocatalyst, its photocatalytic behaviour is limited because of low efficiency, mainly due to rapid charge recombination. To overcome this problem, several strategies have been developed including doping of metal/non-metal in the cavity of g-C3N4. Moreover, the CoFe2O4 NPs have been used in many organic transformations because of its high surface area and easy separation due to its magnetic nature. This review describes the role of cobalt ferrite as magnetic nanoparticles and metal-doped carbon nitride as efficient heterogeneous catalysts for new carbon-carbon and carbon-hetero atom bond formation followed by heterocyclization. Reactions which involved new catalysts for selective activation of readily available substrates has been reported herein. Since nanoparticles enhance the reactivity of catalyst due to higher catalytic area, they have been employed in various reactions such as addition reaction, C-H activation reaction, coupling reaction, cyclo-addition reaction, multi-component reaction, ring-opening reaction, oxidation reaction and reduction reactions etc. The driving force for choosing this topic is based-on huge number of good publications including different types of spinels/metal doped-/graphitic carbon nitride reported in the literature and due to interest of synthetic community in recent years. This review certainly will represent the present status in organic transformation and for exploring further their catalytic efficiency to new organic transformations involving C-H activation reaction through coupling, cyclo-addition, multi-component, ring-opening, oxidation and reduction reactions.

Correlation between surface free energy of quartz and its wettability by aqueous solutions of nonionic, anionic and cationic surfactants

The Introduction of the Radical Cascade Reaction into Polymer Chemistry: A One-Step Strategy for Synchronized Polymerization and Modification.

Micellar and thermodynamic properties of anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl sulfonate (SDSn) in aqueous solutions of 5 wt% short-chain alcohols methanol, ethanol, and 1-butanol were investigated by experimental electrical conductivities, densities and sound velocities at 298.15 K. It was found that methanol behaves like a cosolvent and increases the critical micelle concentration (CMC) of both surfactants in aqueous solutions. However, the other investigated alkanols act as a cosurfactant and decrease the CMC by their presence. The values of the degree of counterion association on the micelles of both surfactants in aqueous methanol solution are same as those in pure water, and they decrease with increasing the alkyl chain length of alcohol. Furthermore, the values of the apparent molar volume and isentropic compressibility of the monomeric and micellar forms of the investigated surfactants were obtained from the experimental density and sound velocity data. It was found that the values of the apparent molar properties of both micellar and monomeric forms of the studied surfactants increase by increasing the alkyl chain of the alcohols.

Surface tension of polytetrafluoroethylene and its wetting by aqueous solution of some surfactants and their mixtures

Foreward. Preface. List of Contributors. Symbols and Abbreviations. 1 Important Natural Products (Hirokazu Arimoto and Daisuke Uemura). 1.1 Introduction. 1.2 Alkylation of Tertiary Carbon Centers. 1.3 Cycloaddition to Alkenes. 1.4 Rearrangement Reactions. 1.5 Carbometallation Reactions. 1.6 C-H Functionalization Reactions. 1.7 Asymmetric Modification of Enantiotopic/Diastereotopic Substituents of Quaternary Carbon Centers. 1.8 Summary. 2 Important Pharmaceuticals and Intermediates (Johannes G. de Vries). 2.1 The Chirality of Drugs and Agrochemicals. 2.2 Steroids. 2.3 Pharmaceuticals and Agrochemicals Based on a-Dialkylated Amino Acids. 2.4 Azole Antimycotics. 2.5 Alkaloids. 2.6 HIV Inhibitors. 2.7 &beta -Lactam Antibiotics. 2.8 The Tetracyclines. 2.9 Summary and Outlook. 3 Aldol Reactions (Bernd Schetter and Rainer Mahrwald). 3.1 Introduction. 3.2 Metal Enolates. 3.3 Catalytic Aldol Additions. 3.4 Conclusions. 3.5 Note Added in Proof 79 4 Michael Reactions and Conjugate Additions (Angelika Baro and Jens Christoffers). 4.1 Introduction. 4.2 Chiral Bronstedt Bases. 4.3 Chiral Metal Complexes. 4.4 Chiral Auxiliaries. 5 Rearrangement Reactions (Annett Pollex and Martin Hiersemann). 5.1 Introduction. 5.2 Applications. 5.3 Summary. 6 Cycloaddition Reactions (Giovanni Desimoni and Givseppe Faita). 6.1 Introduction. 6.2 [2+1] Cycloaddition Reactions. 6.3 [2+2] Cycloaddition Reactions. 6.4 1,3-Dipolar Cycloaddition Reactions. 6.5 Diels-Alder Reactions. 6.6 Hetero-Diels-Alder Reactions. 6.7 Consecutive Cycloaddition Reactions. 7 Asymmetric Cross-coupling and Mizoroki-Heck Reactions (Louis Barriault and Effiette L. O. Sauer). 7.1 The Asymmetric Heck Reaction. 7.2 Metal-catalyzed Cross-coupling Reactions. 7.3 Summary. 8 Alkylation of Ketones and Imines (Diego J. Ramon and Miguel Yus). 8.1 Introduction. 8.2 Diastereoselective Additions. 8.3 Enantioselective Additions by Modulated Processes. 8.4 Enantioselective Additions by Promoted Processes. 9 Asymmetric Allylic Alkylation (Manfred Braun). 9.1 Introduction. 9.2 Electrophilic Allylic Alkylation. 9.3 Nucleophilic Allylic Alkylation. 9.4 Miscellaneous Methods. 9.5 Outlook. 10 Phase-Transfer Catalysis (Takashi Ooi and Keiji Maruoka). 10.1 Introduction. 10.2 Carbon-Carbon Bond Formation Through PTC. 10.3 Carbon-Heteroatom Bond Formation Through PTC. 10.4 Conclusion. 11 Radical Reactions (Kalyani Patil and Mukund P. Sibi). 11.1 Introduction. 11.2 Radical Cyclization. 11.3 Atom- and Group-transfer Cyclizations. 11.4 Intermolecular Radical Allylations. 11.5 Other Metallic Reagents. 11.6 Radical Reactions in the Solid State. 11.7 Conclusion. 11.8 Experimental. 12 Enzymatic Methods (Uwe T. Bornscheuer, Erik Henke, and Jurgen Pleiss). 12.1 Introduction. 12.2 Strategies for the Kinetic Resolution of Sterically Demanding Substrates. 12.3 Conclusion. Index.

In this study, the effect of surfactants and liquid temperature on boiling regime transitions of high-temperature rod during quenching was examined using inverse heat transfer analysis. Liquid pools of the aqueous sodium dodecyl sulfate (SDS) and Triton X-100 solutions were used with pure water. In the present experimental range, the critical heat flux (CHF) and minimum film boiling (MFB) point for all test fluids increased as the liquid temperature decreased. On the other hand, the SDS and Triton X-100 surfactants suppressed the CHF and MFB point, which might be due to the enhancement of vapor film stability caused by reduced surface tension. Some previous experimental studies have reported that the surfactants enhance the boiling regime transitions, but their results seem to be contradictory to the present ones. Considering the present study with the previous works, the surfactants seem to have different effect on boiling phenomena depending on the boiling regime. In other words, in the aqueous surfactant solution, the boiling regime transition points seem to be markedly influenced by a path of boiling regime. In addition, boiling mode diagrams were presented for pure water and aqueous surfactant solutions.

Porphyrin-surfactant interactions in aqueous solutions are known to result in the selfassembly of various supramolecular structures, including pigment-surfactant complexes, J- and H-aggregates, and solubilized dye species. Detailed studies on the mechanisms of the intermolecular interactions governing the above self-assembly processes allow to predict the aggregation state and hence, the photophysical properties of the dye-surfactant assemblies in order to perform a direct synthesis of the desired porphyrin-based nanostructures at the appropriate experimental conditions. This paper describes a novel example of the surfactant-induced J-aggregate formation from the diprotonated hydrophobic tetraphenylporphyrin species in submicellar aqueous anionic surfactant solutions. The above assemblies are characterized by a rod-like morphology and possess supramolecular chirality according to the CD measurements.

Association properties of two silicone surfactants based on poly(dimethylsiloxane)-graft-polyethers in aqueous solutions of 2-butoxyethanol, poly(ethylene glycol), and glucose were determined using various techniques such as surface tension, small-angle neutron scattering, and viscosity. Dilute solution phase diagrams were also constructed, and cloud points were measured for different concentrations of both the surfactants in additive aqueous solutions. The thermodynamic parameters for the micellization were obtained from the temperature-dependent data on critical micelle concentration. The influence of given additive on the micellization of silicone surfactants was monitored from the changes in the free energy of micellization values for the surfactant solutions in water and water + additives. The cloud points and the critical micelle concentration values for the surfactant solutions were found to be decreased in the presence of the selected three additives. The analysis of the changes in the relative permittivities and partial molar volumes for the surfactant solutions in the presence of water and water + additives suggests that the solvent environment around the surfactant solute molecules is different in mixed solvent systems vis-a-vis water and the micellization and surface activity of silicone surfactants were dictated predominantly by the preferential hydration of cosolute additives. The analysis of small angle neutron scattering curves for the surfactant aqueous solutions in the presence of additives showed that the micelles formed have oblate ellipsoidal shape at 30 °C with, however, increased characteristic axial ratios than those in pure water. The increase in the concentration of additives has also increased the size of the micelles. The increase in temperatures corresponding to the values close to the turbid boundaries in the phase diagrams caused a transition from the oblate to the disklike micellar shape. The changes in the hydration values of the micellar associates were monitored from the dilute solution viscosity measurements. The dehydration of the micelles in the presence of additives at 30 °C and also at elevated temperatures occur from the interior to the fringe of the core−outer shell parts and to the outer shell successively.

In aqueous solution at a pH of about 6.5, the micellization of binary mixtures constituted by sodium n-dodecyl diamine sulfonate (C12AS) and three octylphenol polyoxyethylene ether (OP-n) with different numbers of oxyethylene glycol ether (n), including OP-4, OP-7, and OP-10, was examined by the UV–vis spectroscopy method. The critical micelle concentration (cmc) values were determined by the UV–vis spectroscopy method and the tensiometric method. The experimental data were analyzed according to various mixing thermodynamic models within the framework of the pseudophase separation model. For all mixed systems, the negative deviation of experimental cmc values from the ideal values calculated from the Clint equation was found, and negative values for the interaction parameter were obtained, suggesting nonideal mixing of two surfactants in aqueous solution and a synergistic effect between surfactants. Among the C12AS/OP-n mixed systems, the stronger hydrophilicity of nonionic surfactant results in an increa...