1,721,082 research outputs found
Surfactant for better tomorrow: applied aspect of surfactant aggregates from laboratory to industry
Full text linkSurfactant is a special kind of amphiphilic compound composed of water-loving and hating parts. The remarkable physical properties like interfacial tension, wettability, emulsifying and dispersing ability make the surfactant accessible for numerous applications from laboratory to commercial products. In recent years, the commercial applications of surfactant have led to greater relevance on account of the environmental concerns and market pressures of this compound. The utility of surfactants in global market increases steadily since its formulation with several beneficial aspects in pharmaceutical, detergent, cosmetic, paint, food science, gas hydrate, nanotechnology, petroleum recovery, bioremediation, chemical transformation and drug delivery. This review briefly discusses the applied aspect of surfactants in diverse area as well as catalytic effect of micelle in organic reactions from the recent literature survey. The trend of increasing use of bioderived surfactants in the modern field of research is also considered in this report. The recent advancement of surfactant-based organic transformations has been emphasized with the role of surfactant aggregates in course of different organic reactions
Transition Metal Catalysis in Micellar Media: Much More Than a Simple Green Chemistry Promise
Full text linkThe micellar approach, whose major feature is the possibility to operate in water as the reaction medium, is already a major tool in the hands of synthetic organic chemists and is on the way to become an important green technology with ubiquitous fields of application. Surfactants are self-assembling auxiliaries, widely available on the market, that need no special technique to be used but are simply added to water. They allow the use of transition metal complexes developed for work in organic solvents, already optimized by ordinary synthetic elaboration without any special modification to make them compatible with water. Their use does not require any significant plant design or operational changes in the industrial practice while simplifying the separation processes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Pt(II) Pentafluorophenyl Complexes as Highly Active and Selective Catalysts in the Isomerization of Alkenes
No full textMinimalistic β-sitosterol based designer surfactants for efficient cross-coupling in water
Full text linkIn this contribution, we report about the synthesis, the aggregation properties and their application in cross-coupling catalysis of two new designer surfactants comprising a rigid hydrophobic portion based on β-sitosterol directly linked by an etheric bond to methyl polyoxoethylene chains. The proposed amphiphilic compounds represent a minimalistic approach with respect to the Lipshutz's third generation designer surfactant Nok. The amphiphiles displayed improved chemical stability, shorter synthesis, and good properties in Pd-catalyzed cross-coupling reactions in water under mild conditions, as compared with other neutral commercially available surfactants
Epoxidation of Terminal Olefins with Hydrogen Peroxide Catalyzed by Cationic pentafluorophenyl Platinum(II) Complexes
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Recent designer surfactants for catalysis in water
Full text linkThe use of water as a solvent for chemical transformations and catalysis is not only a counter-intuitive original approach with respect to catalysis in traditional media, but thanks to micellar catalysis and the recent development of new designer surfactants, it is becoming an important real benchtop alternative to the employment of organic solvents. Micellar catalysis has received new focus thanks to the recent introduction of the so-called designer surfactants by the group of Lipshutz as surfactants specifically designed and tested for catalysis in water. In particular, the advent of the benchmark TPGS-750-M has really revolutionized chemical synthesis and catalysis in aqueous media, leading also to important positive outcomes suitable for industrial scale applications. The present contribution covers the preparation and the applications in chemical transformations and catalysis of very recent new designer surfactants. These are readily available and economic amphiphiles, mostly prepared from renewable resources, that are specifically designed and tested for catalytic reactions in water. In particular, different neutral designer surfactants are covered and critically classified and discussed
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