Activity coefficients, aggregation, and thermodynamics of tridodecylammonium salts in nonpolar solvents

Kertes, A.S.; Markovits, G.

doi:10.1021/j100858a045

Cited by 47 publications

(11 citation statements)

References 5 publications

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“…Despite earlier studies on phase-transfer catalysts indicating the presence of ion–ion aggregates, − it has been suggested that the structure of these aggregates consists of water-in-oil reverse micelles. ,− Reverse micelle nanoparticle syntheses allow for water to swell the reverse micelle to control the size of the produced nanoparticles. − However, a recent study suggested the formation of small ion–ion aggregates without an aqueous core . Ion–ion aggregation is controlled by the size and electronegativity of the anion ,− but has not been demonstrably linked to the formation of nanoparticles and may provide new opportunities to control nanoparticle size.…”

Section: Introductionmentioning

confidence: 99%

Precursor Ion–Ion Aggregation in the Brust–Schiffrin Synthesis of Alkanethiol Nanoparticles

et al. 2016

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Tetraoctylammonium bromide is used in the Brust–Schiffrin nanoparticle synthesis to phase-transfer chloroaurate ions from the aqueous phase to the organic phase. While it is established that the quaternary ammonium complex self-associates in the organic phase, the actual self-assembled structure is poorly understood. We have confirmed the presence of ion–ion aggregates through quantitative 1H nuclear magnetic resonance spectroscopy (NMR), pulsed field gradient, diffusion-ordered NMR (DOSY-NMR), and density functional theory (DFT) based NMR chemical shift calculations. Tetraoctylammonium complexes (TOA-X, where X = Br, Cl, AuCl4–x Br x , AuBr4/Br, and AuBr4/Cl/Br) were investigated to measure the extraction of water into deuterated chloroform. 1H NMR- and DFT-based NMR shielding calculations indicated that deshielding of water is due to hydration of the anion and not the formation of the aqueous core of a reverse micelle. DOSY-NMR results were consistent with the formation of small aggregates at typical Brust–Schiffrin synthesis concentrations. The extent of aggregation correlated with the electronegativity of the anion and was analyzed with a modified, isodesmic, indefinite aggregation model. The substitution of bromoauric acid for chlororoauric acid at conditions emulating the Brust–Schiffrin synthesis in chloroform increased the aggregation of the quaternary ammonium complex. The increase in aggregation corresponded with an increase in the size of the produced nanoparticles from 4.3 to 4.6 nm. Understanding the self-assembly and supramolecular structure of precursors in the Brust–Schiffrin synthesis will enable further refinement of models describing the growth of noble metal nanoparticles.

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Section: Introductionmentioning

confidence: 99%

Precursor Ion–Ion Aggregation in the Brust–Schiffrin Synthesis of Alkanethiol Nanoparticles

et al. 2016

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“…[2], it is apparent that this equation predicts that practical molal osmotic coefficients will vary linearly with molality for very dilute solutions, i.e., d+/dm + A , -A, as m + 0. Thus, this rational function predicts the same limiting behavior as the more conventional polynomial fit (8,9).…”

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confidence: 62%

“…In this apparatus, the steady-state temperature difference is measured between a drop of pure solvent (n-octane) and a I are for the reprocessing of drop of solution, both drops being maintained in a chamber irradiated fuel (1). We have begun a pro-saturated with pure solvent vapor (8,9). Thermistors areused as gram to study interfacial properties rekvant to temperature sensors, and the difference in the voltage develthese solvent extraction systems (2, 3), and thus, oped across the two thermistors, AV, is measured at aconstant we need to know activity coefficients for organic bridge current.…”

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Osmotic and activity coefficients of triorganophosphates in n-octane

Sagert¹,

Lau²

1982

Can. J. Chem.

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. Can. J. Chem. 60,2755Chem. 60, (1982. Vapor pressure osmometry was used to measure osmotic coefficients for tributylphosphate (TBP), tricresylphosphate (TCP), and triethylhexylphosphate (TEHP) in 11-octane at 30,40,50, and 60°C andat molalities up to0.3 mollkg. Activity coefficients andexcess thermodynamic properties (unsymmetrical definition) were calculated from these osmotic coefficients. At 30"C, the excess Gibbs free energies for 0.1 mol of solute in 1.0 kg 11-octane were -42 J, -66 J, and -20 J for TBP, TCP, and TEHP, respectively. Themore ideal behavior of the TEHP-octane system is attributed to the increasing importance of hydrocarbon-hydrocarbon interactions as the chain length is increased. The excess enthalpies for 0.1 mol of solute in 1.0 kg of solvent were -100 J, -300 J , and -150 J for TBP, TCP, and TEHP, respectively. Thus, association of these solutes arises primarily from entropic effects.Our data could generally be accommodated adequately by postulating association of monomers into dimers. The exception was TCP at lower temperatures, where more complex models were required. Nos donnkes peuvent gentralement s'accomoder de f a~o n adequate en postulant une association de monomeres dans les dimkres. Le TCP fait exception 2 de basses temperatures oh des modkles plus complexes sont necessaires.[Traduit par le journal] 1 Introduction Experimental IThe neutral organic phosphates, particularlyOsmotic coefficients were measured at 30, 40, 50, and 60°Ci tributylphosphate (TBP), are used in many solvent using a CoronaIWescan Model 232A vapor pressure osmom-I extraction processes. In the nuclear industry, such eter. In this apparatus, the steady-state temperature difference is measured between a drop of pure solvent (n-octane) and a I are for the reprocessing of drop of solution, both drops being maintained in a chamber irradiated fuel (1). We have begun a pro-saturated with pure solvent vapor (8,9). Thermistors areused as gram to study interfacial properties rekvant to temperature sensors, and the difference in the voltage develthese solvent extraction systems (2, 3), and thus, oped across the two thermistors, AV, is measured at aconstant we need to know activity coefficients for organic bridge current. The operation of this particular instrument is described in detail by Burge (10). To extend the range of the phosphates in various hydrocarbon and aqueous technique to higher solute molalities, solutions whose osmotic media. The purpose of this work is to measure coefficients were known were used as both reference solution activity coefficients of three triorganophosphates, and vapor-saturating solution. The AV's were obtained relative TBP, tricresylphosphate (TCP), and triethylhexyl-to these reference solutions (11).At each of the four temperatures employed, the instrument phosphate (TEHP)y in '-Octane' Osmotic coef-was calibrated using solutions of n-hexadecane in n-octane as ficients of triorgan0phosphates have been mea-standards (1 I). The voltage difference, AV, was divided by the sured previous...

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Anion‐Dependent Tendency of Di‐Long‐Chain Quaternary Ammonium Salts to Form Ion Quadruples and Higher Aggregates in Benzene

Rocchigiani¹,

Bellachioma²,

Ciancaleoni³

et al. 2010

ChemPhysChem

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The self-aggregation tendency of [N(CH(3))(2)(C(18)H(37))(2)]X [1X; X(-)=BF(4) (-), PF(6) (-), OTf(-), NTf(2) (-), BPh(4) (-), BTol(4) (-), BAr(F-), and B(C(6)F(5))(4) (-)] salts to form ion quadruples (IQs) and higher aggregates (HAggs) in [D(6)]benzene is investigated by means of diffusion NMR spectroscopy. The experimental results indicate that salts containing small anions (1BF(4), 1PF(6), and 1OTf) are present in solution as IQs even at the lowest investigated concentration of C=5×10(-5) M and show a limited tendency to further self-aggregate, reaching a maximum average aggregation number (N=V(H)/V(H)(0IP), where V(H)=measured hydrodynamic volume and V{H}{0IP}=hydrodynamic volume of the ion pair) of about 6-8 (C=0.050-0.100 M). Salts with larger counterions [1BPh(4), 1BTol(4), 1BAr(F), and 1B(C(6)F(5))(4)] form instead ion pairs at low concentration but steadily self-aggregate (especially the non-fluorinated ones) on increasing their concentration up to N values exceeding 50 (C=0.030-0.050 M). 1NTf(2) behaves in an intermediate fashion. The self-aggregation tendency of salts is quantified by formulating the dependence of V(H) on C by means of the equations of indefinitive aggregation models. The following rankings for the formation of IQs and HAggs are obtained: IQs: 1BF(4)≈1PF(6)≈1OTf> 1NTf(2)>1B(C(6)F(5))(4)≥1BPh(4)≥1BTol(4)≥1BAr(F); HAggs: 1BTol(4)>1BPh(4)> 1NTf(2)>1B(C(6)F(5))(4)> 1BAr(F)>1BF(4)≈1PF(6)≈1OTf. Interionic NOE NMR studies and DFT calculations were conducted in order to determine the relative anion-cation orientation in the self-aggregating units.

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Activity coefficients, aggregation, and thermodynamics of tridodecylammonium salts in nonpolar solvents

Cited by 47 publications

References 5 publications

Precursor Ion–Ion Aggregation in the Brust–Schiffrin Synthesis of Alkanethiol Nanoparticles

Precursor Ion–Ion Aggregation in the Brust–Schiffrin Synthesis of Alkanethiol Nanoparticles

Osmotic and activity coefficients of triorganophosphates in n-octane

Anion‐Dependent Tendency of Di‐Long‐Chain Quaternary Ammonium Salts to Form Ion Quadruples and Higher Aggregates in Benzene

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