Lack Of Vapor Pressure Research Articles

Sessile Liquid Features as Molds for Silicone Elastomers.

Liquid applied to a chemically patterned (wetting/nonwetting, lyophilic/lyophobic) substrate forms a 3-dimensional contoured surface, the shape of which depends on the volume of liquid applied and the shape of the three-phase contact lines of air (or other phase in contact), liquid, and the wetted pattern. The resulting binary contoured interface with air, which consists of flat unwetted regions of the substrate and the mean curvature liquid-vapor interfaces of the sessile structures, can be used as a mold for imprinting solid polymers by curing liquid resins in contact. The success, flexibility with regard to shape, and reproducibility of this molding process depend on numerous issues. These include the substrate surface chemistry, the liquid application method, properties of the liquid (vapor pressure, surface tension, viscosity, and permeability in the resin), the contact angles of the liquid on the patterned substrate, and the resin curing chemistry and conditions. We investigate the room temperature platinum(0)-catalyzed curing of the most commonly studied commercial silicone elastomer, Sylgard 184, using molds composed of sessile drops of liquids on circular wetting features (bare silicon wafer) patterned on covalently attached fluoroalkylsilyl monolayers. Liquids reported are water, glycerol, an ethylene glycol oligomer, and an ionic liquid. The vapor pressure of water and its permeability in dimethyl silicone were important (and problematic) issues that could be controlled by adjusting humidity. The ionic liquid N-ethyl-N'-methylimidazolium methanesulfonate poisoned/inhibited the curing chemistry and affected silicone cross-link density and the resulting feature shape, but its lack of vapor pressure was useful in studying flow coating as a scalable liquid application method. The ethylene glycol oligomer exhibited compatibility with (and diffusion into) the silicone. Glycerol proved to be the most well-behaved and controllable liquid studied and was used to demonstrate that condensation/evaporation can be used to adjust feature shape.

Ionic Liquids as Extractor Agents and Reaction Media in Ester Synthesis

AbstractDuring the last decade, ionic liquids technology has received growing attention due to the advantages they offer with respect to organic solvents. Although, in many cases, ionic liquids have simply been used to replace organic solvents, mainly due to their lack of vapor pressure, they have often led to improve process. In this work, the focus is on the application of ionic liquid technology as reaction media in the enzymatic synthesis of esters and also as extractor agents in the separation of reaction mixtures in the synthesis of esters. As reaction media, ionic liquids are opening up new fields in nonaqueous enzymology. The advantages of using ionic liquids over the use of organic solvents as reaction medium for biocatalysis include enhancement of enzyme activity, stability and selectivity. In this work, the effect of the nature of the ionic liquid on activity, selectivity, and stability of enzymes which catalyze esters synthesis has been carefully analyzed. The use of ionic liquids as extraction agent is also overviewed. Specifically, liquid‐liquid extraction using ionic liquids and supported liquid membranes based on ionic liquids have been studied.

Potential of Nanoparticle-Enhanced Ionic Liquids (NEILs) as Advanced Heat-Transfer Fluids

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPotential of Nanoparticle-Enhanced Ionic Liquids (NEILs) as Advanced Heat-Transfer FluidsNicholas J. Bridges, Ann E. Visser, and Elise B. Fox*View Author Information Savannah River National Laboratory, Aiken, South Carolina 29808, United StatesTelephone: 803-507-8560. E-mail: [email protected]Cite this: Energy Fuels 2011, 25, 10, 4862–4864Publication Date (Web):September 26, 2011Publication History Received8 August 2011Revised26 September 2011Published online4 October 2011Published inissue 20 October 2011https://doi.org/10.1021/ef2012084Copyright © 2011 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1212Altmetric-Citations98LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (680 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Fluids,Heat capacity,Salts,Solvents,Thermal stability Get e-Alerts

Ionic Liquids: Perspectives for Organic and Catalytic Reactions

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Ionic liquids: perspectives for organic and catalytic reactions

Ionic liquids are attracting a great deal of attention as possible replacement for conventional molecular solvents for catalytic and organic reactions. They complete the use of environmentally friendly water, supercritical fluids or perfluorinated solvents. Features that make ionic liquids attractive include their lack of vapor pressure and the great versatility of their chemical and physical properties. By a judicious combination of cations and anions, it is possible to adjust the solvent properties to the requirement of the reactions, thus creating an almost indefinitely set of “designer solvents”. Besides the possibility of recycling the catalytic system, one main potential interest in using ionic liquids results in the unique interactions of these media with the active species and in the possibility to modify the reaction activity and selectivity. Their successful use as solvents has been demonstrated for a wide range of organic reactions including acid catalyzed reactions and transition metal catalyzed transformations.