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Aggregation and reactivity in aqueous solutions of cationic surfactants and aromatic anions across concentration scales. Curr Opin Colloid Interface Sci 2017. [DOI: 10.1016/j.cocis.2017.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Chemical kinetic and chemical trapping methods: Unique approaches for determining respectively the antioxidant distributions and interfacial molarities of water, counter-anions, and other weakly basic nucleophiles in association colloids. Curr Opin Colloid Interface Sci 2017. [DOI: 10.1016/j.cocis.2017.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Forconi M. Medium Effects in Biologically Related Catalysis. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2015. [DOI: 10.1016/bs.apoc.2015.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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4
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Bairagi B, Bhoite SA, Singh AK. Micellar effect on hydrolysis of 4-methyl-2-nitroaniline phosphate. COLLOID JOURNAL 2014. [DOI: 10.1134/s1061933x14060027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Katre Y, Singh M, Singh AK. An Efficient and Mild Procedure for the Preparation of Aldonic Acids via Oxidation of D-Sucrose by Employing N-Bromophthalimide Oxidant and Micellar System. TENSIDE SURFACT DET 2013. [DOI: 10.3139/113.110107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
The oxidation reactions of D-sucrose have been carried out with N-bromophthalimide in the presence of micellar aggregates at 45°C. The kinetics revealed first order dependence on N-bromophthalimide (NBP) and fractional order dependence on D-sucrose. Variation of mercuric acetate concentration has an insignificant effect on reaction rate. The stoichiometric ratio of NBP:D-sucrose was 1:2 and the oxidation product was aldonic acid confirmed by FeCl3–HCl test. The influence of salts on the reaction rate has also been studied. Phthalimide (NHP) and sulfuric acid (H2SO4) inhibit the rate. Thermodynamic and activation parameters have been evaluated and a mechanism consistent with the kinetic data has been proposed. Cetyltrimethylammonium bromide (CTAB) and TritonX-100 (TX-100) catalyze the reaction, while sodium dodecyl sulfate (SDS) inhibits the rate of reaction. The applicability of Berezin's model was tested to explain the observed micellar effects. The rate constants (kM) and binding constants (KS + KO) have been evaluated.
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Affiliation(s)
- Y. Katre
- Department of Chemistry, Kalyan Post Graduate College, Bhilai Nagar, Durg, (C.G.) – 490006, India
| | - M. Singh
- Department of Chemistry, Kalyan Post Graduate College, Bhilai Nagar, Durg, (C.G.) – 490006, India
| | - A. K. Singh
- Department of Chemistry, Vishwanath Yadav Tamaskar Post Graduate College, Durg, (C.G.), India
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Onel L, Buurma NJ. The Nature of the Sodium Dodecylsulfate Micellar Pseudophase as Studied by Reaction Kinetics. J Phys Chem B 2011; 115:13199-211. [DOI: 10.1021/jp208171w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lavinia Onel
- Physical Organic Chemistry Centre, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Niklaas J. Buurma
- Physical Organic Chemistry Centre, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
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Campos-Rey P, Cabaleiro-Lago C, Hervés P. Solvolysis of Substituted Benzoyl Chlorides in Nonionic and Mixed Micellar Solutions. J Phys Chem B 2010; 114:14004-11. [DOI: 10.1021/jp107538v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- P. Campos-Rey
- Department of Physical Chemistry, Faculty of Chemistry, University of Vigo, 36310 Vigo, Spain, and Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, 22100 Lund University, Lund, Sweden
| | - C. Cabaleiro-Lago
- Department of Physical Chemistry, Faculty of Chemistry, University of Vigo, 36310 Vigo, Spain, and Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, 22100 Lund University, Lund, Sweden
| | - P. Hervés
- Department of Physical Chemistry, Faculty of Chemistry, University of Vigo, 36310 Vigo, Spain, and Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, 22100 Lund University, Lund, Sweden
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8
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Kinetic medium effects on organic reactions in aqueous colloidal solutions. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2009. [DOI: 10.1016/s0065-3160(08)00001-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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9
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Farrukh MA, Beber RC, Priebe JP, Lal Satnami M, Micke GA, Costa ACO, Fiedler HD, Bunton CA, Nome F. Reactivity and models for anion distribution: specific iodide binding to sulfobetaine micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:12995-13000. [PMID: 18950202 DOI: 10.1021/la802179m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The reaction of I (-) with methyl naphthalene-2-sulfonate (MeONs) is accelerated by the micellized sulfobetaine surfactants N-decyl, N-dodecyl, N-tetradecyl, and N-hexadecyl- N, N-dimethylammonio-1-propanesulfonate. Concentrations of micellar-bound I (-) were determined by using ion-selective electrodes (ISE), and capillary electrophoresis. At low concentrations, I (-) incorporation fits Langmuir isotherms and is related to changes in micellar surface potentials. Rate effects of dilute KI are fitted quantitatively by a pseudophase model that describes I (-) binding in terms of a sorption isotherm, but at higher [KI], where the simple model predicts saturation, rates increase due to electrolyte invasion. This model considers transfer equilibria of both reactants between water and micelles and second-order rate constants in each pseudophase. Estimated second-order rate constants for reaction of MeONs with I (-) in the micellar pseudophase are 3.2- to 3.5-fold higher than the second-order rate constant, k 2w, in water, depending on surfactant structure and assumptions in the treatment.
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Affiliation(s)
- M Akhyar Farrukh
- Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina 88040-900, Brazil.
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Katre Y, Singh M, Patil S, Singh AK. Effect of Cationic Micellar Aggregates on the Kinetics of Dextrose Oxidation by N-Bromophthalimide. J DISPER SCI TECHNOL 2008. [DOI: 10.1080/01932690802313410] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Singh J, Miller J, Ranganathan R. Physicochemical characterization of phospholipid solubilized mixed micelles and a hydrodynamic model of interfacial fluorescence quenching. J Phys Chem B 2007; 111:9317-24. [PMID: 17629323 DOI: 10.1021/jp0720340] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Mixed micelles of solubilized dimyristoyl phosphatidylcholine (DMPC) and the zwitterionic detergent dodecyldimethylammoniopropane sulfonate are characterized employing time-resolved fluorescence quenching (TRFQ), electron spin resonance (ESR), and surface tensiometry toward the goal of investigating interfacial reactions using these micelles as host reaction media. The properties measured are the micelle aggregation numbers, interfacial hydration index, microviscosity, and the critical micelle concentrations for various molar fractions, XDMPC, of DMPC, 0<or=XDMPC<0.35. A complementary interpretation of the experimental results from TRFQ and ESR within the framework of a polar shell model for the mixed micelle yields some microstructural features, including the micelle core radius, polar shell thickness, and the fraction of the total hydrocarbon that overlaps with the micelle-water interface. The results of the characterization are applied in investigating an interfacial reaction; namely, micellar fluorescence quenching. A bulk hydrodynamic model when modified appropriately so as to be applicable to reaction within the interface is shown to describe micellar fluorescence quenching kinetics and also provides some insight into the location of guest molecules in micelles.
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Affiliation(s)
- Jasmeet Singh
- Department of Physics and Center for Supramolecular Studies, California State University, Northridge, California 91330-8268, USA
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Romsted LS. Do amphiphile aggregate morphologies and interfacial compositions depend primarily on interfacial hydration and ion-specific interactions? The evidence from chemical trapping. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:414-24. [PMID: 17209589 DOI: 10.1021/la062411k] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Surface-active amphiphiles aggregate spontaneously in water to form association colloids such as micelles, microemulsions, and vesicles. The hydrophobic effect drives aggregation, but the opposing forces that provide balance and determine equilibrium morphologies are not understood, in particular, how specific ion effects, which often follow a Hofmeister series, affect the properties of association colloids. We have harnessed the competitive trapping of arenediazonium ions by weakly basic nucleophiles such as halide counterions, anionic headgroups, alcohols, urea, and water, to estimate their concentrations in the interfacial regions of association colloids from reaction product yields. In the chemical trapping method, product yields are proportional to the concentrations of water and other nucleophiles within the interfacial region, not their stoichiometric concentrations in solution. Changes in the balance of forces controlling aggregate structure are reflected in changes in interfacial concentrations of water and other components in association colloids as reported by the chemical trapping method. Significant changes in interfacial water and counterion concentrations are observed during structural transitions. Specific ion effects on sphere-to-rod transitions of cationic amphiphiles are interpreted in terms of the strengths of headgroup and counterion pairing and ion hydration interactions. Trapping results also provide important information on interfacial compositions of microemulsions, vesicles, nonionic micelles and macroemulsions, reverse micelles, micelles in aqueous urea, and anionic polyelectrolytes. Identifying relationships between aggregate morphology and interfacial composition by chemical trapping has just begun.
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Affiliation(s)
- Laurence S Romsted
- Department of Chemistry and Chemical Biology, Wright-Rieman Laboratories, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA.
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Oliveira CS, Bastos EL, Duarte EL, Itri R, Baptista MS. Ion pairs of crystal violet in sodium bis(2-ethylhexyl)sulfosuccinate reverse micelles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:8718-26. [PMID: 17014109 DOI: 10.1021/la061117p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The interfacial localization and the ion pair formation of the positively charged dye crystal violet (CV) in sodium bis(2-ethylhexyl)sulfosuccinate reverse micelles (AOT RMs) were studied by several structural and spectroscopic techniques and by quantum chemical calculations. The size and shape of the AOT RMs in the presence of CV were investigated by small-angle X-ray scattering, showing that CV does not significantly change the RM structure. CV localization as a function of the water to surfactant molar ratio (w(0)) was characterized by H(1) and (13)C NMR, indicating the close proximity of CV to the sulfosuccinate group of AOT at small and large w(0) values. These results were confirmed by calculation of magnetic shielding constants using the gauge-independent atomic orbital method with the HF/6-31G(d) basis set. Two different types of ion pairs between AOT and CV, i.e., contact ion pair (CIPs) and solvent-separated ion pair (SSIPs), were characterized by UV-vis spectroscopy and quantum chemical calculations using the semiempirical ZINDO-CI method. In nonpolar isotropic solvents CIPs are formed with an association constant (K(ASSOC)) of 2 x 10(4) mol(-1) L in isooctane and 750 mol(-1) L in chloroform. In AOT RMs at low w(0), CV-AOT CIPs are also formed. By increasing w(0), there is a sharp decrease in the CIP association free energy, and SSIPs are formed. (CV(+))(H(2)O)(AOT(-)) SSIPs are stable in the AOT RM up to the largest w(0) tested (w(0) = 33).
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Affiliation(s)
- Carla S Oliveira
- Departamento de Bioquímica, IQ-USP, São Paulo-SP, C.P. 26077, 05599-970, Brazil
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Klijn JE, Engberts JBFN. Vesicular catalysis of an S(N)2 reaction: toward understanding the influence of glycolipids on reactions proceeding at the interface of biological membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:9809-17. [PMID: 16229496 DOI: 10.1021/la0504715] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The kinetics of the S(N)2 reaction of a series of aromatic alkylsulfonates with water and bromide ions in membrane mimetic media have been investigated. These media include vesicles formed from only synthetic amphiphiles, vesicles composed only of phospholipids and mixtures of these components. Special focus is placed on the influence of the addition of n-dodecyl-beta-glucoside as a mimic for glycolipids. The kinetic data have been analyzed by using the pseudophase model for bimolecular reactions. Contrary to previous results on a base-catalyzed E2 reaction (Org. Biomol. Chem. 2004, 2, 1789-1799), the presence of n-dodecyl-beta-glucoside at the vesicular surface does not lead to large rate accelerations for the S(N)2 reaction. In fact, when present at 50 mol % (i.e., the additive covers 34% of the vesicular surface) these glycolipid mimics appear not to affect the bimolecular rate constants, but they only decrease the local water concentration by about 40%. The reactivity of water at the surface of vesicles that are formed from cationic amphiphiles appears to be increased about 10-fold relative to the reactivity of water in the bulk liquid, whereas in zwitterionic vesicles the reactivity is comparable to that in bulk water. The obtained rate constants are also compared to micellar rate constants.
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Affiliation(s)
- Jaap E Klijn
- Physical Organic Chemistry Unit, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Blagoeva IB, Ouarti N, El Seoud OA, Ruasse MF. Interfacial ion exchange between monovalent and divalent anions in cationic micelles, revised in the light of correlation analysis. J PHYS ORG CHEM 2005. [DOI: 10.1002/poc.953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Geng Y, Romsted LS, Froehner S, Zanette D, Magid LJ, Cuccovia IM, Chaimovich H. Origin of the sphere-to-rod transition in cationic micelles with aromatic counterions: specific ion hydration in the interfacial region matters. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:562-568. [PMID: 15641824 DOI: 10.1021/la0478954] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Sphere-to-rod transitions of cetyltrimethylammonium (CTA+) micelles with dichlorobenzoate counterions are remarkably substituent dependent. Simultaneous estimates of the interfacial molarities of H2O, MeOH, and Cl- and 2,6- and 3,5-dichlorobenzoate (2,6OBz and 3,5OBz) counterions were obtained by the chemical trapping method in mixed micelles of CTACl/CTA3,5OBz and CTACl/CTA2,6OBz without added salt. Increasing the CTA3,5OBz mole fraction produces a marked concurrent increase in interfacial 3,5OBz- and a decrease in interfacial H2O concentrations through the sphere-to-rod transition. No abrupt concentration changes are observed with increasing CTA2,6OBz mole fraction. Counterion-specific changes in the interfacial water concentration may be a major contributor to the delicate balance of forces governing micellar morphology.
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Affiliation(s)
- Yan Geng
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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