00934nas a2200157 4500008004100000022001400041245013800055210006900193260007100262300001400333490000700347520025200354100001600606700002200622856013200644 2007 eng d a0022-326300aIonic liquids as powerful solvent media for improving catalytic performance of silyl borate catalyst to promote Diels-Alder reactions0 aIonic liquids as powerful solvent media for improving catalytic  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a8111-81140 v723 a

[GRAPHICS] Use of the acidic chloroaluminate ionic liquid, including the recycled ones, can improve the catalytic activity of the toluene-coordinated silyl borate in enhancing rates, stereoselectivities, and yields of Diels-Alder reactions.

1 aKumar, Anil1 aPawar, Sanjay, S. uhttps://library.ncl.res.in/content/ionic-liquids-powerful-solvent-media-improving-catalytic-performance-silyl-borate-catalyst-001408nas a2200205 4500008004100000022001400041245010600055210006900161260007500230300001400305490000700319520059300326653002200919653002200941653002500963653003700988653003001025100001601055856013101071 2007 eng d a0095-978200aIsopiestic osmotic coefficients of tetra-n-methylammonium chloride with guanidinium salts at 298.15 k0 aIsopiestic osmotic coefficients of tetranmethylammonium chloride a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScDEC a1569-15840 v363 a

Isopiestic osmotic coefficients are presented for aqueous mixtures of tetra-n-methylammonium chloride, (CH3)(4)NCl, with guanidinium salts such as GnCl, CH(3)COOGn, GnNO(3), GnClO(4) and Gn(2)SO(4) at 298.15 K up to an ionic strength of 2 mol center dot kg(-1). The osmotic coefficients are analyzed in terms of the Scatchard-Rush-Johnson equations. The activity coefficients of each electrolyte in the mixtures were calculated and fitted by the Harned-type equations. The molar excess Gibbs energy of mixing, Delta(m) G(E), of the mixtures were analyzed with Friedman's equations.

10aaqueous solutions10aisopiestic method10aOsmotic coefficients10aScatchard-Rush-Johnson equations10atetramethylammonium salts1 aKumar, Anil uhttps://library.ncl.res.in/content/isopiestic-osmotic-coefficients-tetra-n-methylammonium-chloride-guanidinium-salts-29815-k-001973nas a2200289 4500008004100000022001400041245012800055210006900183260009500252300001200347490000800359520098400367653002301351653000801374653001701382653002901399653000901428653000901437653001701446653001501463653001401478100001801492700001101510700001901521700001601540856012701556 2008 eng d a0021-979700aInsight into the micellization of dodecyldimethylethylammonium bromide (DDAB) in the presence of bovine serum albumin (BSA)0 aInsight into the micellization of dodecyldimethylethylammonium b a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcJUL a426-4340 v3233 a

in this work, we report the effect of concentration of bovine serum albumin (BSA) on the micellization of a cationic surfactant, doclecyldimethylethylammonium bromide (DDAB). Several samples covering a wide range of concentrations of protein and surfactant have been investigated. The interactions between the moieties are investigated by measuring fluorescence quenching of BSA molecules. The aggregation number of DDAB micelles is found to be small in the presence of BSA. The formation of DDAB-BSA complex is confirmed by FTIR. Absorbance spectroscopy indicates that at higher concentration, the conformational stability of BSA in DDAB is higher. The viscosity data for protein-surfactant systems confirm conformational changes in protein chains induced by the surfactant. The cmc values for DDAB increase with increasing concentration of BSA. At higher temperatures the micellization-complexation becomes enthalpy-dominated. (c) 2008 Elsevier Inc. All rights reserved.

10aAggregation number10aBSA10aconductivity10aconformational stability10aDDAB10aFFIR10afluorescence10aUV-visible10aviscosity1 aMehta, S., K.1 aBhawna1 aBhasin, K., K.1 aKumar, Anil uhttps://library.ncl.res.in/content/insight-micellization-dodecyldimethylethylammonium-bromide-ddab-presence-bovine-serum-001747nas a2200169 4500008004100000022001400041245009800055210006900153260007100222300001400293490000700307520107100314100002201385700002601407700001601433856012801449 2008 eng d a0022-326300aIntramolecular Diels-Alder reaction in ionic liquids: effect of ion-specific solvent friction0 aIntramolecular DielsAlder reaction in ionic liquids effect of io a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV a9075-90830 v733 a

The present work aims at understanding the role of viscosity or solvent friction in ionic liquids for an intramolecular Diels-Alder (IMDA) reaction of (E)-1-phenyl-4-[2-(3-methyl-2-butenyloxy)benzylidene]-5-pyrazolone (1). The results have been analyzed on the basis of the current theoretical models, and their failure to account for the observed trends is discussed in terms of ``effective'' viscosity or microviscosity. The rates of the reaction decrease with the increasing viscosity of the ionic liquids. As evident from the anionic effect, the solute-solvent specific interactions play a role in governing the kinetics of the reaction. The lower viscosities of the bistrifluoromethanesulfonimide [NTf(2)](-) based ionic liquids as compared to those based on tetrafluoroborate [BF(4)](-) anion fail to result in a corresponding acceleration in the rates of the reaction. These contradictory results indicate that solvent microviscosity, rather than the bulk macroscopic viscosity, should be the criteria for selecting the ionic liquids as reaction media.

1 aTiwari, Shraeddha1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/intramolecular-diels-alder-reaction-ionic-liquids-effect-ion-specific-solvent-friction-001523nas a2200205 4500008004100000022001400041245007500055210006900130260011300199300001400312490000700326520075800333653002201091653002301113653002101136653002001157653001901177100001601196856010501212 2008 eng d a0033-454500aIonic interactions in aqueous mixtures of hydrophilic and -phobic ions0 aIonic interactions in aqueous mixtures of hydrophilic and phobic a104 TW ALEXANDER DR, PO BOX 13757, RES TRIANGLE PK, NC 27709-3757 USAbINT UNION PURE APPLIED CHEMISTRYcJUN a1267-12790 v803 a

Ions of both hydrophilic and -phobic nature play a pivotal role in biological systems and during synthesis of many organic molecules. However, the interaction of a hydrophilic ion with a hydrophobic one is not a simple physical process and is useful in understanding the rate enhancement in organic transformations and thermal stability of DNA and RNA. During the talk, an attempt was made to present some of the experimental work on aqueous mixtures of these ions carried out at National Chemical Laboratory, Pune, and give a theoretical interpretation of the binary, ternary, and quaternary interactions operating in these systems. The contribution of these interaction terms to the excess free energy of mixing, Delta(m)G(E), will be analyzed.

10aaqueous solutions10aexcess free energy10ahydrophobic ions10aionic solutions10amixing effects1 aKumar, Anil uhttps://library.ncl.res.in/content/ionic-interactions-aqueous-mixtures-hydrophilic-and-phobic-ions-001188nas a2200157 4500008004100000022001400041245010100055210006900156260008900225300001200314490000700326520053600333100002200869700001600891856012300907 2008 eng d a0376-471000aIonic liquids: physico-chemical, solvent properties and their applications in chemical processes0 aIonic liquids physicochemical solvent properties and their appli aDR K S KRISHNAN MARG, NEW DELHI 110 012, INDIAbNATL INST SCIENCE COMMUNICATIONcAPR a495-5030 v473 a

A new class of compounds, called as ionic liquids, has recently emerged as potential substitute for volatile organic solvents. Ionic liquids possess certain special physico-chemical characteristics that render them very useful in different areas of research and development. In this review, the physico-chemical properties and the applications of ionic liquids in chemical processes are critically discussed and recommendations made for probing further the poorly understood aspect of this newly emerging class of compounds.

1 aSingh, Geetanjali1 aKumar, Anil uhttps://library.ncl.res.in/content/ionic-liquids-physico-chemical-solvent-properties-and-their-applications-chemical-001433nas a2200157 4500008004100000022001400041245009300055210006900148260007100217300001600288490000800304520081500312100002201127700001601149856011001165 2009 eng d a1089-563900aInterfacial reactivity of ``on water'' reactions in the presence of alcoholic cosolvents0 aInterfacial reactivity of on water reactions in the presence of  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC a13685-136930 v1133 a

A detailed study of the variation in the interfacial reactivity and selectivity of ``on water'' reactions in the presence of increasing amounts of alcoholic cosolvents is discussed in the present work. The initial increase in the rates of ``on water'' reactions on the addition of alcoholic cosolvents is contrary to the sharp decrease in rates observed for homogeneous aqueous reactions. The existing theoretical framework is presented in terms of a typical ``on water'' process to enable a discussion of the experimental observations with reference to changing composition of the reaction medium. On the basis of the interesting observations of reactivity and selectivity variations with composition of the reaction medium, a simple ``signature'' characteristic for ``on water'' reactions is proposed.

1 aTiwari, Shraeddha1 aKumar, Anil uhttps://library.ncl.res.in/content/interfacial-reactivity-water-reactions-presence-alcoholic-cosolvents-001162nas a2200229 4500008004100000022001400041245005600055210005500111260011000166300001200276490000700288520037100295653002300666653002800689653001800717653003100735653002300766653001400789100002600803700001600829856008700845 2010 eng d a0376-471000aIonic liquids: new materials with wide applications0 aIonic liquids new materials with wide applications aDR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIAbNATL INST SCIENCE COMMUNICATION-NISCAIRcMAY a635-6480 v493 a

Ionic liquids have emerged as possible substitutes for volatile organic solvents and have found many applications in a variety of research areas. In this review, an effort has been made to discuss the special properties of ionic liquids that render these unique solvent media useful in chemical transformations, electrochemical applications, extractions, etc.

10aChemical processes10aElectrochemical devices10aionic liquids10aPhysicochemical properties10aSolvent properties10aviscosity1 aKhupse, Nageshwar, D.1 aKumar, Anil uhttps://library.ncl.res.in/content/ionic-liquids-new-materials-wide-applications-001145nas a2200157 4500008004100000022001400041245010200055210006900157260011000226300001400336490000700350520047000357100001900827700001600846856012500862 2013 eng d a1463-907600aInteresting thermal variations owing to cationic ring structural features in protic ionic liquids0 aInteresting thermal variations owing to cationic ring structural aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAPR a8050-80530 v153 a

The present communication divulges interesting thermal behavior of different protic ionic liquids arising due to the hydrophobicity modifications in their parent cationic ring structures. This work assists us in differentiating between protic ionic liquids, their aprotic counterparts and common electrolytes in water. The thermal signatures produced by protic ionic liquids, aprotic ionic liquids and electrolytes emerge as individual fingerprints for them.

1 aRai, Gitanjali1 aKumar, Anil uhttps://library.ncl.res.in/content/interesting-thermal-variations-owing-cationic-ring-structural-features-protic-ionic-001584nas a2200157 4500008004100000022001400041245011200055210006900167260007700236300001400313490000700327520093000334100001701264700001601281856012901297 2014 eng d a1439-423500aInvoking pairwise interactions in water-promoted diels-alder reactions by using ionic liquids as cosolvents0 aInvoking pairwise interactions in waterpromoted dielsalder react aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcOCT a3067-30770 v153 a

Rate constants and derived activation parameters of organic reactions in aqueous media, in particular Diels-Alder reactions, are sensitive to the presence of cosolvents in water. To enhance the solubility window of water, we introduced ionic liquids as cosolvents in the aqueous Diels-Alder reaction between anthracene-9-carbinol and N-ethylmaleimide. The reactive potentials of the organic compounds are parameterized by using semi-empirical quantum chemical methods. The principle of Savage-Wood additivity of group interactions is used to quantify the pairwise group interactions among chemically inert ionic liquids and organic reactants, both at initial and transition states of the reaction. The present approach shows promise, as the use of simple calculations from easily available kinetic data can help researchers to understand the versatility of green ionic-liquid alternatives to volatile organic solvents.

1 aManna, Arpan1 aKumar, Anil uhttps://library.ncl.res.in/content/invoking-pairwise-interactions-water-promoted-diels-alder-reactions-using-ionic-liquids-001602nas a2200241 4500008004100000022001400041245015300055210006900208260007500277300001200352490000700364520070200371653002301073653001801096653002201114653002001136653000901156653001401165100001601179700001901195700001601214856013001230 2015 eng d a0095-978200aInteresting viscosity changes in the aqueous urea-ionic liquid system: effect of alkyl chain length attached to the cationic ring of an ionic liquid0 aInteresting viscosity changes in the aqueous ureaionic liquid sy a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGER/PLENUM PUBLISHERScAPR a742-7530 v443 a

In the present article, we demonstrate the effect of urea on the structure of the ionic liquids in their aqueous solutions through viscometric methods. We unravel the structure altering effect of urea in its aqueous solutions of ionic liquids possessing higher alkyl chains. The finding is an attempt to discern the anomalous behavior of urea as shown in the past with the help of many techniques. Interestingly, in the aqueous solutions of the imidazolium based ionic liquids having substitution of -C4H9 and -C6H13 groups on the imidazolium ring, urea exhibits kosmotropic behavior. Further increase in the substituted alkyl group such as -C8H17 alters the urea behavior to be chaotropic.

10aAlkyl chain length10aionic liquids10aStructure-breaker10aStructure-maker10aUrea10aviscosity1 aNanda, Raju1 aRai, Gitanjali1 aKumar, Anil uhttps://library.ncl.res.in/content/interesting-viscosity-changes-aqueous-urea-ionic-liquid-system-effect-alkyl-chain-length-001655nas a2200169 4500008004100000245015300041210006900194260000800263300001600271490000700287520093700294653007301231100001901304700001701323700001601340856012901356 2016 eng d00aIsothermal titration calorimetric study of the ionic liquid solutions in alcohols in extreme dilutions: an investigation of ion-solvent interactions0 aIsothermal titration calorimetric study of the ionic liquid solu cAUG a1313–13310 v453 a

In this work an effort has been made to show the effect of an alcohol-rich environment on imidazolium-based ionic liquids at 298.15 K using an isothermal titration calorimeter. It is divulged from this study that the thermal behavior expressed in terms of excess partial molar enthalpy, \( H_{\text{IL}}^{\text{E}} \), of ionic liquids in various linear alcohols is governed by the increasing hydrophobicity of the residual alkyl group attached to the cation of an ionic liquid and to the alcohol molecules. An interesting observation about the systems consisting of ethylated residuals on both the cations of the ionic liquid and the alcohol molecules is that these systems do not follow the trend exhibited by other ionic liquid–alcohol systems. Interesting information on ionic interactions is obtained by using a simple methodology that gives the enthalpic interaction parameter \( H_{{I{\text{L - IL}}}}^{\text{E}} \).

10aIonic liquidsAlcoholsExcess enthalpyIsothermal titration calorimeter1 aRai, Gitanjali1 aJain, Preeti1 aKumar, Anil uhttps://library.ncl.res.in/content/isothermal-titration-calorimetric-study-ionic-liquid-solutions-alcohols-extreme-dilutions02583nas a2200145 4500008004100000245010900041210006900150260000800219300001600227490000800243520202600251100001902277700001602296856012502312 2017 eng d00aIntroducing the bipolar solvent media using the aqueous mixtures of amino acid anion-based ionic liquids0 aIntroducing the bipolar solvent media using the aqueous mixtures cDEC a11367-113750 v1213 aTo carry out a chemical reaction between the reactants with largely different polarities, it becomes important to have a reaction medium that possesses both the polar and nonpolar solvation environments. In an attempt to explore the reaction media with such unique polarity properties, the present study provides a thorough understanding of the bipolar solvent media using the aqueous mixtures of amino acid anion-based ionic liquids. The highly polar behavior of the binary mixtures used in the study has been ascribed to the pure ionic liquid state. However, the less polar solvation shells have been attributed to the presence of a neutral form of the anions. Addition of water in the amino acid anion-based ionic liquids causes the protonation of a certain fraction of the anions of the ionic liquids, resulting into the formation of a less polar nonionic protonated form along with the highly polar natural anionic form. This results into the formation of two solvation spheres with different polarities, which can be seen very clearly from the presence of two absorption bands (lower wavelength absorption band and higher wavelength absorption band) in the UV-vis absorption spectrum of Reichardt's E-T(30) dye and two emission bands (lower wavelength emission band and higher wavelength emission band) in the fluorescence emission spectrum of C481 dye. The values of the E-T(N) polarity parameter corresponding to the two solvation shells having different polarities have been calculated from the deconvoluted absorption spectra of the Reichardt's E-T(30) and were analyzed in three amino acid anion-based ionic liquids. Generation of the neutral form of anions in the aqueous mixtures formed via a protonation transfer reaction has been confirmed by the H-1 NMR spectroscopy and UV-vis absorption spectrum of 18DHAQ dye. The study also establishes that the Reichardt's E-T(30) dye can be used as a valid polarity probe to study the solvatochromic behavior of the binary mixtures of amino acid-based ionic liquids.1 aBeniwal, Vijay1 aKumar, Anil uhttps://library.ncl.res.in/content/introducing-bipolar-solvent-media-using-aqueous-mixtures-amino-acid-anion-based-ionic