ORCID Profile
0000-0001-9388-2783
Current Organisation
Murdoch University
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Publisher: Elsevier BV
Date: 07-1971
Publisher: Springer Berlin Heidelberg
Date: 2010
Publisher: American Chemical Society (ACS)
Date: 20-06-2002
DOI: 10.1021/JP0143589
Publisher: American Chemical Society (ACS)
Date: 07-10-2006
DOI: 10.1021/CR040087X
Publisher: CSIRO Publishing
Date: 1991
DOI: 10.1071/CH9910791
Abstract: Leaving group effects on the electrochemical dehalogenation of organic vicinal dihalides have been examined in acetonitrile for the 1,2-dihalo-1,2-diphenylethanes and trans-1,2-dihalo-cyclohexanes. Reduction potentials and product distributions support a stepwise addition of two electrons, as previously proposed for the isomers of 1,2-dibromo-1,2-diphenylethane. A general reduction mechanism for the vicinal dihalides is proposed. Literature data for the electrochemical reduction of the 5,6-dihalodecanes, previously thought to favour a concerted two-electron mechanism, may be explained in terms of a stepwise process.
Publisher: Elsevier BV
Date: 04-1978
Publisher: American Chemical Society (ACS)
Date: 05-11-2010
DOI: 10.1021/JE900676B
Publisher: Springer Science and Business Media LLC
Date: 05-1997
DOI: 10.1007/BF02767599
Publisher: Elsevier BV
Date: 08-2014
Publisher: Wiley
Date: 06-11-2006
Abstract: A detailed investigation of aqueous solutions of magnesium sulfate has been made by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2<or=nu/GHz<or=89), concentrations (0.02<or=m/mol kg(-1)<or=2.3) and temperatures (5<or=theta/ degrees C<or=65). Consistent with literature data from other techniques, the spectra show clear evidence at all temperatures for the simultaneous existence of double solvent-separated (2SIP), solvent-shared (SIP) and contact (CIP) ion pairs and a triple ion (TI), Mg(2)SO(4) (2+)(aq). Increased formation of CIPs and especially TIs occurs with increasing temperature. The overall standard ion-association constant, K(A) degrees , corresponding to the equilibrium: Mg(2+)(aq)+SO(4) (2) (-)(aq) MgSO(4) (0)(aq) is in good agreement with literature data at lower temperatures but is overestimated at higher temperatures due to processing difficulties. Despite the limited precision of the spectra, analysis of the in idual steps in the ion-association process is possible for the first time. The 2SIPs are formed with little disturbance to their hydration shells, the (partial) destruction of which appears to occur mostly during the formation of SIPs. Effective hydration numbers derived from the DRS spectra indicate that both Mg(2+) and SO(4) (2-) influence solvent water molecules beyond their first hydration spheres but that MgSO(4)(aq) is less strongly hydrated than the previously studied CuSO(4)(aq).
Publisher: American Chemical Society (ACS)
Date: 26-06-2004
DOI: 10.1021/CR030047D
Publisher: Wiley
Date: 11-08-2021
DOI: 10.5694/MJA2.51218
Publisher: Springer Science and Business Media LLC
Date: 1999
Publisher: Elsevier BV
Date: 11-1977
Publisher: Elsevier BV
Date: 05-2001
Publisher: American Chemical Society (ACS)
Date: 29-09-2007
DOI: 10.1021/JE700265D
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5DT02129D
Abstract: Speciation modelling incorporating redox equilibria provides a plausible explanation for copper deposition in the human eye associated with Wilson's disease.
Publisher: American Chemical Society (ACS)
Date: 05-05-2005
DOI: 10.1021/JE0500126
Publisher: Wiley
Date: 02-1996
DOI: 10.1002/(SICI)1096-987X(199602)17:3<306::AID-JCC5>3.0.CO;2-Z
Publisher: Elsevier BV
Date: 02-2000
DOI: 10.1016/S0162-0134(99)00222-6
Abstract: Estimates of the concentrations and identity of the predominant complexes of iron with the low-molecular-mass ligands in vivo are important to improve current understanding of the metabolism of this trace element. These estimates require a knowledge of the stability of the iron-citrate complexes. Previous studies on the equilibrium properties of the Fe(III)-citrate and Fe(II)-citrate are in disagreement. Accordingly, in this work, glass electrode potentiometric titrations have been used to re-determine the formation constants of both the Fe(III)- and Fe(II)-citrate systems at 25 degrees C in 1.00 M (Na)Cl and the reliability of these constants has been evaluated by comparing the measured and predicted redox potentials of the ternary Fe(III)-Fe(II)-citrate system. The formation constants obtained in this way were used in computer simulation models of the low-molecular-mass iron fraction in blood plasma. Redox equilibria of iron are thus included in large models of blood plasma for the first time. The results of these calculations show the predominance of Fe(II)-carbonate complexes and a significant amount of aquated Fe(II) in human blood plasma.
Publisher: Royal Society of Chemistry (RSC)
Date: 1995
DOI: 10.1039/FT9959102789
Publisher: AIP Publishing
Date: 26-06-2006
DOI: 10.1063/1.2205861
Abstract: The “dynamic exchange” model of ion association proposed by Watanabe and Hamaguchi, [J. Chem. Phys.123, 034508 (2005)] for aqueous solutions of MgSO4 is shown to be inconsistent with the extensive information available from Raman, relaxation, and thermodynamic studies, all of which can be explained by the Eigen equilibrium model.
Publisher: Springer Science and Business Media LLC
Date: 18-09-2019
Publisher: Wiley
Date: 15-05-2019
DOI: 10.1111/CRJ.13031
Publisher: Elsevier BV
Date: 12-1996
Publisher: Royal Society of Chemistry (RSC)
Date: 1998
DOI: 10.1039/A805271I
Publisher: American Chemical Society (ACS)
Date: 29-08-2008
DOI: 10.1021/IC702396R
Abstract: Ion association in aqueous solutions of scandium sulfate has been investigated at 25 degrees C and at concentrations from 0.01 to 0.8 M by broadband dielectric spectroscopy over the frequency range 0.2 <or= nu/GHz <or= 89. Detailed analysis of the spectra reveals the presence of both inner- and outer-sphere 1:1 [ScSO 4] (+)(aq) complexes, similar to solutions of other high-valent metal sulfates. Outer-outer-sphere 1:1 complexes are probably also formed, but their contribution is sw ed by the presence of higher-order inner-sphere complexes. The latter predominate in the more concentrated solutions, causing major changes to the low-frequency end of the spectrum. The data, while not definitive, are consistent with fac-[Sc(SO 4) 3(OH 2) 3] (3-) as the major species present. The speciation is strikingly different from that recently reported for aluminum sulfate solutions and indicates that the often-postulated similarity between the aqueous chemistry of Al(III) and Sc(III) has to be treated with caution.
Publisher: American Chemical Society (ACS)
Date: 09-04-2015
Abstract: Ionic hydration and ion association in aqueous solutions of KH2PO4, K2HPO4, and K3PO4 at 25 °C up to high concentrations have been investigated using dielectric relaxation spectroscopy (DRS). The three phosphate anions were found to be extensively hydrated, with total hydration numbers at infinite dilution of ~11 (for H2PO4(-)), ~20 (HPO4(2-)), and ~39 (PO4(3-)). These values are indicative of the existence of a second hydration shell around HPO4(2-) and especially PO4(3-). Two types of hydrating water molecules could be quantified: irrotationally bound (ib, H2O molecules essentially "frozen" on the DRS time scale) and "slow" (loosely bound water molecules with identifiably slower dynamics than bulk water). For H2PO4(-) over the entire concentration range and for HPO4(2-) and PO4(3-) at concentrations c ≲ 1 mol L(-1), only "slow" H2O was detected however, at higher concentrations of the latter two anions, an increasing fraction of ib water appears, making up ~50% of the total hydration number close to the saturation limit of K2HPO4. Contrary to common belief, all three salts showed significant ion pair formation, with standard association constants of the 1:1 species increasing in the order: KH2PO4(0)(aq) < KHPO4(-)(aq) < KPO4(2-)(aq). The main type of ion pair in solution shifted from solvent-shared ion pairs (SIPs) to double-solvent-separated ion pairs (2SIPs) in the same sequence.
Publisher: American Chemical Society (ACS)
Date: 11-11-2013
DOI: 10.1021/JP4089436
Abstract: A detailed study has been made of the solvation and ion association of the trifluoromethanesulfonate (Tf(-)) salts of aluminum(III), scandium(III), and lanthanum(III) in N,N-dimethylformamide (DMF) at 25 °C using dielectric relaxation spectroscopy over the frequency range of 0.1 ≲ ν/GHz ≤ 89. The spectra of all solutions exhibited either two (for ScTf3 and LaTf3) or three (for AlTf3) relaxation processes, a dominant mode centered at ∼15 GHz due to the solvent and one or (for AlTf3 solutions) two solute-related processes at lower frequencies (νmax ≲ 2 GHz). Effective solvation numbers, Zib, calculated from the solvent relaxation process indicated that all three cations were strongly solvated by DMF with Zib(0) values at infinite dilution in the order (Al(3+) ≈ Sc(3+) ≈ 10) < (La(3+) ≈ 13), consistent with at least partial formation of a second solvation shell around each cation. One solute-related mode for each set of salt solutions was assigned to the rotational diffusion of solvent-shared ion pairs (SIPs) of 1:1 stoicheometry the additional slower process for AlTf3 solutions in DMF was attributed to the presence of double-solvent-separated IPs. The overall association constants at infinite dilution for the 1:1 IPs, KA°(MTf(2+)), were significant, but as expected from Debye-Hückel considerations, the KA values decreased rapidly with increasing solute concentration.
Publisher: Elsevier BV
Date: 1991
Publisher: AIP Publishing
Date: 24-04-2008
DOI: 10.1063/1.2906132
Abstract: When salts are added to water, generally the viscosity increases, suggesting that the ions increase the strength of the water’s hydrogen-bond network. However, infrared pump-probe measurements on electrolyte solutions have found that ions have no influence on the rotational dynamics of water molecules, implying no enhancement or breakdown of the hydrogen-bond network. Here, we report optical Kerr effect and dielectric relaxation spectroscopic measurements, which have enabled us to separate the effects of rotational and transitional motions of the water molecules. These data show that electrolyte solutions behave like a supercooled liquid approaching a glass transition in which rotational and translational molecular motions are decoupled. It is now possible to understand previously conflicting viscosity data, nuclear magnetic resonance relaxation, and ultrafast infrared spectroscopy in a single unified picture.
Publisher: American Chemical Society (ACS)
Date: 05-2002
DOI: 10.1021/JE020003M
Publisher: Springer Science and Business Media LLC
Date: 06-1996
DOI: 10.1007/BF00973084
Publisher: American Chemical Society (ACS)
Date: 27-03-2019
Abstract: The composition and structures of the two protonated species formed from uncharged molybdic acid, MoO
Publisher: American Chemical Society (ACS)
Date: 23-12-2015
Publisher: MDPI AG
Date: 08-03-2018
DOI: 10.3390/MIN8030110
Publisher: Elsevier BV
Date: 02-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 1994
DOI: 10.1039/FT9949001899
Publisher: Springer Science and Business Media LLC
Date: 1997
Publisher: Springer Science and Business Media LLC
Date: 23-10-2007
Publisher: Wiley
Date: 12-11-2019
DOI: 10.1111/RESP.13439
Publisher: Springer Science and Business Media LLC
Date: 09-2005
Publisher: American Chemical Society (ACS)
Date: 10-09-2008
DOI: 10.1021/JP800083V
Abstract: Densities and heat capacities of various 1:1 and higher-charged electrolytes have been measured in N,N-dimethylformamide (DMF) at 25 degrees C using a series-connected flow densimeter and Picker calorimeter. Standard molar volumes V (o) and isobaric heat capacities C p (o) derived from these data were split into their ionic contributions using the tetraphenylphosphonium tetraphenylborate (TPTB) reference electrolyte assumption. The values so obtained have enabled a meaningful separation of the effects of cationic size and charge for the first time in a nonaqueous solvent. As in water, V (o)(M (n+) ) values in DMF are markedly more negative for higher-charged cations due to increasing electrostriction of the solvent. In contrast, ionic charge has a much smaller effect on C p (o)(M (n+) ) in DMF than in water. Ionic volumes in DMF show the expected dependence on size but those of small monatomic monovalent cations and anions imply a significant difference in accessibility of the electron donor and acceptor sites on the DMF molecule. Ionic heat capacities in DMF show a relatively weak dependence on ionic size that, when corrected for charge, is opposite to that in water. Both V (o)(R 4N (+)) and C p (o)(R 4N (+)) in DMF show the usual linear dependence on carbon number but differ from their values in aqueous solution due to the absence of hydrophobic interactions in DMF.
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B508838K
Abstract: Raman spectra of concentrated alkaline aluminate solutions in various M'OH media (M'(+) = Na(+), K(+), Cs(+) and (CH(3))(4)N(+)) have been investigated systematically as a function of concentration and water activity, a(w). All spectra at [Al(III)](T) < or = 1 M and at 0.1 < or = [M'OH](T)/M 10 M, probably due to ion-pairing. Spectra at [M'OH](T) < 10 M have been interpreted quantitatively by assuming that the integrated peak area of the 620 cm(-1) mode is linearly proportional to [Al(OH)(4)(-)] at constant a(w) and that the only significant equilibrium in these systems is the formation of a dimer that can be represented as (Al(OH)(4))(2)(2-)(aq), although it may exist in an oxo-bridged form such as [(HO)(3)Al-O-Al(OH)(3)](2). The (aquated) species Na(+), OH(-), Al(OH)(4)(-), the dimer, and their ion-pairs, were sufficient to interpret all the Raman observations. No evidence was found for various other species that have been claimed to exist in concentrated alkaline aluminate solutions.
Publisher: American Chemical Society (ACS)
Date: 19-07-2002
DOI: 10.1021/CR010031S
Publisher: Springer Science and Business Media LLC
Date: 03-1984
DOI: 10.1007/BF00645876
Publisher: Walter de Gruyter GmbH
Date: 10-08-2009
Abstract: Thermodynamically consistent models based on accurately measured data are required for reliable predictions of equilibria and thermodynamic properties for a wide variety of multicomponent, multiphase systems and reactions relevant to hydrometallurgy. Recent developments in our laboratory concerning the measurement and modeling of physicochemical properties of electrolyte solutions over wide ranges of conditions are reviewed. Particular emphasis is on applications to the refining of alumina via the Bayer process, in which various solubility phenomena involving solid, aqueous, and gaseous phases are of critical importance to product yield and purity as well as to economical and environmental sustainability. Appropriately designed models and software allow these aspects to be tackled by thermodynamic process simulations of alumina refinery circuits.
Publisher: Elsevier BV
Date: 06-1999
DOI: 10.1016/S0039-9140(98)00346-4
Abstract: Values of the association constant, beta(NaSO(4)(-)), for the weak ion-pair formed by sodium and sulfate ions in aqueous solution have been determined at 25 degrees C by high precision sodium ion-selective electrode potentiometry in solutions of ionic strength ranging from 0.50 to 7.00 M in CsCl media and in 1.00 M Me(4)NCl. The data in CsCl media were fitted to an extended form of the Debye-Hückel equation which yielded log beta(NaSO(4)(-))(0)=0.834+/-0.005 at infinite dilution. Evidence is also presented for the formation of very weak ion-pairs between Cs(+) and SO(4)(2-).
Publisher: Association for Materials Protection and Performance (AMPP)
Date: 08-1997
DOI: 10.5006/1.3290298
Publisher: American Chemical Society (ACS)
Date: 23-06-2001
DOI: 10.1021/IC001415O
Abstract: A detailed investigation of the Pb(II)/OH(-) system has been made in NaClO(4) media at 25 degrees C. Combined UV-vis spectrophotometric-potentiometric titrations at [Pb(II)](T) < or = 10 microM using a long path length cell detected only four mononuclear hydroxide complexes. The values of log beta(1)(q)(), for the equilibria Pb(2+)(aq) + qH(2)O Pb(OH)(q)()((2)(-)(q)()()+)(aq) + qH(+)(aq), were -7.2, -16.1, -26.5, and -38.0 for q = 1-4, respectively, at ionic strength I = 1 M (NaClO(4)). Similar results were obtained at I = 5 M (NaClO(4)). No evidence was found for higher order complexes (q > 4) even at very high [OH(-)]/[Pb(II)] ratios, nor for polynuclear species at [Pb(II)](T) < or = 10 microM. Measurements using (207)Pb-NMR and Raman spectroscopies and differential pulse polarography (DPP) provided only semiquantitative confirmation. The mononuclear Pb(OH)(q)()((2)(-)(q)()()+)(aq) complexes are the only hydrolyzed species likely to be significant under typical environmental and biological conditions.
Publisher: Elsevier BV
Date: 11-1996
Publisher: Springer Science and Business Media LLC
Date: 2001
Publisher: American Chemical Society (ACS)
Date: 19-04-2002
DOI: 10.1021/JE010314H
Publisher: Elsevier BV
Date: 11-2007
Publisher: Springer Science and Business Media LLC
Date: 1998
Publisher: Wiley
Date: 21-07-2022
DOI: 10.1111/IMJ.15833
Abstract: Computed tomography‐guided transthoracic biopsy (CT‐TTB) is the ‘gold standard’ biopsy for lung nodules. Radial‐endobronchial ultrasound (R‐EBUS) bronchoscopy is another recommended biopsy but carries a lower diagnostic yield. Addition of cryobiopsy with R‐EBUS (Cryo‐Radial) has shown promising results. There are no studies comparing CT‐TTB with Cryo‐Radial biopsy. The co‐primary aims were the diagnostic yeild and safety. The secondary aim: ability to test epidermal growth factor receptor (EGFR). A randomised controlled, multicentre exploratory study was conducted at three tertiary hospitals. Patients with nodules cm on CT of the chest were randomised to CT‐TTB or Cryo‐Radial. With Cryo‐Radial, patients had 1–3 cryo‐biopsies in addition to at least one R‐EBUS biopsy through the 2.6 mm guide sheath. Forty‐eight patients were randomised: 22 to CT‐TTB and 26 to Cryo‐Radial. Sixteen in the CT‐TTB and 20 in the Cryo‐Radial received the allocated biopsy. The diagnostic yield was CT‐TTB 93.8% (15/16) versus Cryo‐Radial 85% (17/20) P = 0.61 and the odds ratio was 0.37. For 5/13 (38%), a diagnosis was solely made on cryobiopsy. Eleven (78%) of 14 in CT‐TTB versus 7/10 (70%) Cryo‐Radial were suitable for EGFR testing P = 0.66, with odds ratio 0.63. Pneumothorax occurrence was 44% (7/16) in CT‐TTB versus 4.2% (1/24) in Cryo‐Radial. Two (12.5%) of 16 CT‐TTB required chest drain insertion. Cryo‐Radial is comparable in diagnostic yield and ability to perform EGFR testing with a significantly lower risk of pneumothorax, compared with CT‐TTB. Cryo‐Radial has the additional advantage of mediastinal staging during the same procedure with Linear‐EBUS and is a promising first‐line tool in the diagnostic method of lung cancer.
Publisher: Walter de Gruyter GmbH
Date: 1989
Publisher: Elsevier BV
Date: 1990
Publisher: American Chemical Society (ACS)
Date: 09-12-2012
DOI: 10.1021/JP207504D
Abstract: Dielectric relaxation (DR) spectra have been measured for aqueous solutions of sodium formate (NaOFm) and sodium acetate (NaOAc) over a wide range of frequencies (0.2 ≤ ν/GHz ≤ 89) up to solute concentrations c is less or approximately equal to 3.2 M and is less or approximately equal to 3.7 M, respectively, at 25 °C. Measurements were also made on NaOAc(aq) at 15 ≤ T/°C ≤ 35. In addition to the usual dominant bulk-water relaxation process at ~20 GHz, one or two further relaxation modes were detected. One process, centered at ~8 GHz and observed for both NaOFm(aq) and NaOAc(aq), was attributed to the presence of slow water in the hydration shells of the anions. A lower-frequency process at ~0.6 GHz, observed only for NaOAc(aq) at c is less or approximately equal to 1 M, was thought to be due to the presence of very small concentrations of ion pairs. Detailed analysis of the spectra indicated that very few (<2 per anion) water molecules were irrotationally bound (frozen) on the DR time scale. Nevertheless, both anions are strongly hydrated, as evidenced by the significant amounts of slow water detected. Such H(2)O molecules with reduced dynamics result from two distinct effects. The first is the relatively strong hydrophilic interaction of water with the -COO(-) moiety, which is similar for the two anions and little affected by increasing solute concentration. The second (for OAc(-) only) is the hydrophobic hydration of the -CH(3) group, which is fragile, decreasing markedly with increasing solute concentration and temperature. The activation parameters for bulk-water relaxation in NaOAc(aq) indicated a breakdown of the bulk water structure at high solute concentrations.
Publisher: Elsevier BV
Date: 04-1990
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B9AY00064J
Publisher: Elsevier BV
Date: 10-1991
Publisher: Walter de Gruyter GmbH
Date: 07-04-2011
Abstract: Impurities in hydrometallurgical process liquors frequently impact on product quality and yield, change physicochemical properties of the liquor, and form hard scale on heat exchangers and condensers. Organic compounds are of particular concern especially in the Bayer process, where impurities build up in the recycled liquor if not controlled. Depending on the redox state of the liquor, such compounds can undergo a variety of complex chemical reactions, including the formation of volatiles that can potentially cause environmental, health, and safety concerns. To aid in the development of appropriate control strategies, robust thermodynamic models for multicomponent aqueous systems containing large numbers of electrolytes and nonelectrolytes are required. Applications of thermodynamic models are discussed that range from the partitioning of volatile compounds in flash trains to the prediction of mixing properties of organic impurities with major Bayer liquor components.
Publisher: American Chemical Society (ACS)
Date: 19-06-2009
DOI: 10.1021/JP9024574
Abstract: Dielectric spectra over the frequency range of 0.2 less, similar nu/GHz < or = 89 have been measured for the room-temperature ionic liquid 1-N-ethyl-3-N-methylimidazolium ethylsulfate ([emim][EtSO(4)], IL) and its mixtures with dichloromethane (DCM) at temperatures of 5 < or = vartheta/ degrees C or = 0.2) in DCM.
Publisher: Elsevier BV
Date: 2004
Publisher: American Chemical Society (ACS)
Date: 14-09-2016
Publisher: Elsevier BV
Date: 10-1979
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B602209J
Abstract: Dielectric relaxation measurements as a function of temperature, and of concentration in a non-coordinating solvent, the first reported for an ionic liquid, indicate a crossover in the relaxation mechanism due to varying levels of ion aggregation and the interplay of formation kinetics and relaxation dynamics of associates.
Publisher: American Chemical Society (ACS)
Date: 06-2005
DOI: 10.1021/IE050024K
Publisher: American Chemical Society (ACS)
Date: 27-02-2013
DOI: 10.1021/IE3024824
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CP21371G
Abstract: Ion association of the ionic liquid [bmim][Cl] in acetonitrile and in water was studied by dielectric spectroscopy for salt concentrations c ≤ 1.3 M at 298.15 K and by measurement of molar electrical conductivities, Λ, of dilute solutions (c ≤ 0.006 M) in the temperature range 273.15 ≲ T/K ≤ 313.15. Whilst acetonitrile solutions of [bmim][Cl] exhibit moderate ion pairing, with an association constant of K°(A) ≈ 60 M(-1) and increasing with temperature, [bmim][Cl] is only weakly associated in water (K°(A) ≈ 6 M(-1)) and ion pairing decreases with rising temperature. Only contact ion pairs were detected in both solvents. Standard-state enthalpy, entropy and heat capacity changes of ion association were derived, as well as the activation enthalpy of charge transport and the limiting conductivity of the cation, λ(∞) ([bmim](+)). These data, in conjunction with effective solvation numbers obtained from the dielectric spectra, suggest that the solvation of [bmim](+) is much weaker in water than in acetonitrile.
Publisher: Wiley
Date: 12-1993
Publisher: Elsevier BV
Date: 05-1997
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.TALANTA.2006.02.008
Abstract: (27)Al NMR and Raman spectra of alkaline aluminate solutions with 0.005M</=[Al(III)](T)</=3M in various M'OH solutions (M'(+)=Na(+), K(+) and Li(+)) were recorded and analysed. Caustic concentrations up to 20M were used to explore whether higher aluminium hydroxo complexes are formed at extremely high concentrations of hydroxide. A single peak was observed on the (27)Al NMR spectrum of each solution. The chemical shift of this peak shifts significantly upfield with increasing [M'OH](T) in solutions with [Al(III)](T) /=0.8M. For Raman spectra of solutions with [Al(III)](T)=0.8M and [NaOH](T)>/=10M, the peak maximum of the symmetric nu(1)-AlO(4) stretching of Al(OH)(4)(-) shifted progressively from approximately 620 to approximately 625cm(-1) and decreased in intensity with increasing [NaOH](T). In parallel, modes centred at approximately 720 and approximately 555cm(-1) (cf. approximately 705 and approximately 535cm(-1) at lower [NaOH](T), ascribed to a dimeric aluminate species appeared, and their intensities increased with increasing [NaOH](T). These variations in the (27)Al NMR and Raman spectra can be interpreted in terms of contact ion-pairs formed between the cation of the medium and the well-established Al(OH)(4)(-) or the dimeric aluminate species. Assumption of higher aluminium hydroxo complex species (e.g., Al(OH)(6)(3-)) is not necessary to explain the spectroscopic effects observed.
Publisher: American Chemical Society (ACS)
Date: 19-05-2000
DOI: 10.1021/IC991248W
Abstract: A careful reinvestigation by high-field 19F NMR (470 MHz) spectroscopy has been made of the Al3+/F- system in aqueous solution under carefully controlled conditions of pH, concentration, ionic strength (I), and temperature. The 19F NMR spectra show five distinct signals at 278 K and I = 0.6 M (TMACl) which have been attributed to the complexes AlFi(3-i)+(aq) with i < or = 5. There was no need to invoke AlFi(OH)j(3-i-j)+ mixed complexes in the model under our experimental conditions (pH < or = 6.5), nor was any evidence obtained for the formation of AlF6(3-)(aq) at very high ratios of F-/Al3+. The stepwise equilibrium constants obtained for the complexes by integration of the 19F signals are in good agreement with literature data given the differences in medium and temperature. In I = 0.6 M TMACl at 278 K and in I = 3 M KCl at 298 K the log Ki values are 6.42, 5.41, 3.99, 2.50, and 0.84 (for species i = 1-5) and 6.35, 5.25, and 4.11 (for species i = 1-3), respectively. Disappearance of the 19F NMR signals under certain conditions was shown to be due to precipitation. Certain 19F NMR signals exhibit temperature- and concentration-dependent exchange broadening. Detailed line shape analysis of the spectra and magnetization transfer measurements indicate that the kinetics are dominated by F- exchange rather than complex formation. The detected reactions and their rate constants are AlF2(2+) + *F- reversible AlF*F2+ + F- (k02 = (1.8 +/- 0.3) x 10(6) M-1 s-1), AlF3(0) + *F- reversible AlF2*F0 + F- (k03 = (3.9 +/- 0.9) x 10(6) M-1 s-1), and AlF3(0) + H*F reversible AlF2*F0 + HF (kH03 = (6.6 +/- 0.5) x 10(4) M-1 s-1). The rates of these exchange reactions increase markedly with increasing F- substitution. Thus, the reactions of AlF2+(aq) were too inert to be detected even on the T1 NMR time scale, while some of the reactions of AlF3(0)(aq) were fast, causing large line broadening. The ligand exchange appears to follow an associative interchange mechanism. The cis-trans isomerization of AlF2+(aq), consistent with octahedral geometry for that complex, is slowed sufficiently to be observed at temperatures around 270 K. Difference between the Al3+/F- system and the much studied Al3+/OH- system are briefly commented on.
Publisher: Elsevier BV
Date: 03-1978
Publisher: Springer Science and Business Media LLC
Date: 05-2014
Publisher: Walter de Gruyter GmbH
Date: 29-03-2011
Abstract: The numerical modeling of Cd II speciation amongst the environmental inorganic ligands Cl – , OH – , CO 3 2– , SO 4 2– , and PO 4 3– requires reliable values for the relevant stability (formation) constants. This paper compiles and provides a critical review of these constants and related thermodynamic data. It recommends values of log 10 β p,q,r ° valid at I m = 0 mol kg –1 and 25 °C (298.15 K), along with the equations and empirical reaction ion interaction coefficients, ∆ & epsilon , required to calculate log 10 β p,q,r values at higher ionic strengths using the Brønsted–Guggenheim–Scatchard specific ion interaction theory (SIT). Values for the corresponding reaction enthalpies, ∆ r H , are reported where available. Unfortunately, with the exception of the Cd II -chlorido system and (at low ionic strengths) the Cd II -sulfato system, the equilibrium reactions for the title systems are relatively poorly characterized. In weakly acidic fresh water systems (–log 10 {[H + ]/ c °} & 6), in the absence of organic ligands (e.g., humic substances), Cd II speciation is dominated by Cd 2+ (aq), with CdSO 4 (aq) as a minor species. In this respect, Cd II is similar to Cu II [2007PBa] and Pb II [2009PBa]. However, in weakly alkaline fresh water solutions, 7.5 & –log 10 {[H + ]/ c °} & 8.6, the speciation of Cd II is still dominated by Cd 2+ (aq), whereas for Cu II [2007PBa] and Pb II [2009PBa] the carbonato- species MCO 3 (aq) dominates. In weakly acidic saline systems (–log 10 {[H + ]/ c ϒ} & 6 –log 10 {[Cl – ]/ c °} & 2.0) the speciation is dominated by CdCl n (2– n )+ complexes, ( n = 1–3), with Cd 2+ (aq) as a minor species. This is qualitatively similar to the situation for Cu II and Pb II . However, in weakly alkaline saline solutions, including seawater, the chlorido- complexes still dominate the speciation of Cd II because of the relatively low stability of CdCO 3 (aq). In contrast, the speciation of Cu II [2007PBa] and Pb II [2009PBa] in seawater is dominated by the respective species MCO 3 (aq). There is scope for additional high-quality measurements in the Cd 2+ + H + + CO 3 2– system as the large uncertainties in the stability constants for the Cd 2+ -carbonato complexes significantly affect the speciation calculations.
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/CH00126
Abstract: Raman spectra of carbonate and sulfate ions were recorded in aqueous solutions in the presence of large excesses of M′X (M′+ = Na+, K+ or Cs+ X– = OH– or Cl–) at 25°C. The positions of the v1(A1′) symmetric stretching vibrations for both CO32– (at ~1060 cm–1) and SO42– (at ~980 cm–1) shift, by up to 10 cm–1, to lower frequencies and broaden (by up to 25%) with increasing concentrations of M′X. The shifts are slightly smaller for SO42– than for CO32– and also differ somewhat between M′OH and M′Cl solutions. The changes in the peak positions, which are indicative of contact ion pairing, show a clear dependence on the nature of the cation. However, the observed order, Na+ K+ Cs+, is directly opposite to the magnitudes of the (overall) ion-pairing constants. This anomaly is thought to be due to decreased hydration of Cs+ cf. Na+ in these highly concentrated, water-deficient solutions. Some implications of this for understanding ionic interactions in concentrated electrolyte solutions are suggested.
Publisher: Springer Science and Business Media LLC
Date: 1998
Publisher: American Chemical Society (ACS)
Date: 18-03-2016
Publisher: American Chemical Society (ACS)
Date: 02-12-2019
Abstract: Aqueous solutions of three alkali metal fluorides-NaF, KF, and CsF-have been studied by dielectric relaxation spectroscopy (DRS) over the frequency range 0.2 ≲ ν/GHz ≤ 89 at 25 °C and at concentrations 0.05 ≲
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH04063
Abstract: Abstract Complex formation between Hg(ii) and the common environmental ligands Cl−, OH−, CO32−, SO42−, and PO43− can have profound effects on Hg(ii) speciation in natural waters with low concentrations of organic matter. Hg(ii) is labile, so its distribution among these inorganic ligands can be estimated by numerical modelling if reliable values for the relevant stability constants are available. A summary of critically reviewed constants and related thermodynamic data is presented. Recommended values of log10βp,q,r° and the associated reaction enthalpies, ΔrHm°, valid at Im = 0 mol kg−1 and 25°C, along with the equations and specific ion interaction coefficients required to calculate log10βp,q,r values at higher ionic strengths and other temperatures are also presented. Under typical environmental conditions Hg(ii) speciation is dominated by the reactions Hg2+ + 2Cl− ↔ HgCl2(aq) (log10β2° = 14.00 ± 0.07), Hg2+ + Cl− + H2O ↔ Hg(OH)Cl(aq) + H+ (log10β° = 4.27 ± 0.35), and Hg2+ + 2H2O ↔ Hg(OH)2(aq) + 2H+ (log10*β2° = −5.98 ± 0.06).
Publisher: Elsevier BV
Date: 1972
Publisher: Elsevier BV
Date: 03-2003
Publisher: Elsevier BV
Date: 04-2015
Publisher: Elsevier BV
Date: 15-04-2010
DOI: 10.1016/J.TALANTA.2009.11.049
Abstract: The JESS software package, which is a widely-used tool for modelling chemical speciation in complex aqueous environments, has been extended to allow comprehensive predictions of physicochemical properties for strong electrolytes in aqueous solution. Another large database, this time of physicochemical property data, has been added to the JESS suite, along with the computational methods which automatically turn these erse literature data into a thermodynamically-consistent calculation for water activities, densities, heat capacities, etc. Given the recent emphasis on the role of water activity in predicting electrolyte mixing behaviour, we expect that this capability will lead to major changes in the way aquatic chemistry is modelled in future.
Publisher: American Chemical Society (ACS)
Date: 11-02-2010
DOI: 10.1021/JE9010773
Publisher: Springer Science and Business Media LLC
Date: 2000
Publisher: American Chemical Society (ACS)
Date: 30-12-2021
Publisher: Elsevier BV
Date: 04-1998
Publisher: AIP Publishing
Date: 06-2005
DOI: 10.1063/1.1796631
Abstract: The mutual solubilities and related liquid–liquid equilibria of C6H8–C6H12 hydrocarbons with water and heavy water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 11 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For seven systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated or unsaturated aliphatic hydrocarbons was used.
Publisher: Informa UK Limited
Date: 03-1984
Publisher: Elsevier BV
Date: 04-1993
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B906555P
Abstract: Despite its immense abilities to quantify many aspects of ion-ion and ion-solvent interactions, dielectric relaxation spectroscopy (DRS) has long been neglected as a tool for the investigation of the structure and dynamics of electrolyte solutions. The reasons for this are briefly discussed and it is shown that many of the difficulties associated with this technique have been overcome in recent years by technological developments. Representative applications of DRS to the investigation of ion solvation and ion association in electrolyte solutions of chemical, industrial, geochemical and biological interest, including room temperature ionic liquids and polyelectrolyte systems, are discussed. The advantages of linking DRS measurements to information obtained from other experimental techniques and from computer simulations are highlighted.
Publisher: Royal Society of Chemistry (RSC)
Date: 1993
DOI: 10.1039/C39930001704
Publisher: Elsevier BV
Date: 08-1998
Publisher: Walter de Gruyter GmbH
Date: 2006
Abstract: Spectroscopic techniques such as UV/vis, NMR, and Raman are powerful tools for the investigation of chemical speciation in solution. However, it is not widely recognized that such techniques do not always provide reliable information about ion association equilibria. Specifically, spectroscopic measurements do not in general produce thermodynamically meaningful association constants for non-contact ion pairs, where the ions are separated by one or more solvent molecules. Such systems can only be properly quantified by techniques such as dielectric or ultrasonic relaxation, which can detect all ion-pair types (or equilibria), or by traditional thermodynamic methods, which detect the overall level of association. Various types of quantitative data are presented for metal ion/sulfate systems in aqueous solution that demonstrate the inadequacy of the major spectroscopic techniques for the investigation of systems that involve solvent-separated ion pairs. The implications for ion association equilibria in general are briefly discussed.
Publisher: Elsevier BV
Date: 1991
Publisher: American Chemical Society (ACS)
Date: 18-06-2020
Publisher: American Chemical Society (ACS)
Date: 16-05-2017
Publisher: American Chemical Society (ACS)
Date: 16-02-2006
DOI: 10.1021/JP057189R
Abstract: A systematic study of the dielectric relaxation spectra of aqueous solutions of NaBPh4 and Ph4PCl has been made at solute concentrations of 0.02 < or = c/M < or = 0.82 and 0.20, respectively, and over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) at 25 degrees C. The spectra were best described by a superposition of four Debye processes, consisting of a very small ion-pair contribution with an average relaxation time of about 300 ps, a "slow"-water relaxation at 17 ps, and two bulk-water relaxations at 8 ps and 0.25 ps, respectively. The slow-water process has been assigned to the presence of a sheath of water molecules surrounding BPh4- and Ph4P+, whose structure has been enhanced by its proximity to the bulky hydrophobic phenyl rings. A structure-making effect on the remaining solvent water can also be observed at low concentrations. More importantly, BPh4- and Ph4P+ show almost identical hydration characteristics, which provides indirect support for the use of the tetraphenylphosphonium tetraphenylborate reference electrolyte assumption in deriving single-ion thermodynamic properties.
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/CH06251
Abstract: A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.
Publisher: AIP Publishing
Date: 06-2002
DOI: 10.1063/1.1484155
Publisher: Elsevier BV
Date: 1993
Publisher: American Chemical Society (ACS)
Date: 15-09-1998
DOI: 10.1021/JP981244X
Publisher: Springer Science and Business Media LLC
Date: 05-1994
DOI: 10.1007/BF00972746
Publisher: Royal Society of Chemistry (RSC)
Date: 2000
DOI: 10.1039/A910335J
Publisher: Springer Science and Business Media LLC
Date: 03-1990
DOI: 10.1007/BF00650455
Publisher: American Chemical Society (ACS)
Date: 16-04-2003
DOI: 10.1021/JP026429P
Publisher: Springer Science and Business Media LLC
Date: 09-1997
DOI: 10.1007/BF02768262
Publisher: Wiley
Date: 09-04-2003
Abstract: Dielectric spectra have been measured for aqueous sodium oxalate solutions up to the saturation concentration (0.04 < or = c[mmol L-1] < or = 0.25) at 25 degrees C over the approximate frequency range 0.2 < or = v [GHz] < or = 20. The spectra exhibit a process at about 1 GHz associated with the presence of ion pairs, in addition to the dominant solvent relaxation process at about 18 GHz. Detailed analysis of the solvent dispersion litude indicates that the oxalate ion is highly hydrated but that its solvation sheath is "fragile", decreasing quickly with increasing solute concentration. The NaOx(aq)- ion pair is shown to be of the double-solvent-separated (2SIP) type, with an infinite dilution association constant KA = 1.04 +/- 0.02. Analysis of the ion-pair relaxation time as a function of solute concentration gave rate constants for the formation (k12 = (7.3 +/- 0.4) 10(9) L mol-1 s-1) and dissociation (k21 = (6.7 +/- 0.5) 10(8) s-1) of the ion pair. These values are reasonably close to the diffusion-controlled values predicted by the Eigen theory, consistent with a 2SIP structure for the ion pair.
Publisher: American Chemical Society (ACS)
Date: 22-12-2006
DOI: 10.1021/LA0519711
Abstract: A dielectric relaxation study of binary mixtures of nonionic surfactant C12E5 + water has been made as a function of temperature in the isotropic micellar, lamellar, and hexagonal regions of the phase diagram. Two dielectric dispersion steps were found and could be assigned to the intermolecular cooperative dynamics of water at the micellar interface and in the bulk water domains. A quantitative analysis is given. The relaxation litudes were used to determine effective hydration numbers. The activation energies of water relaxation were calculated from the relaxation times. The data indicate weaker surfactant-water and water-water interactions near the micellar interface compared to those of bulk liquid water. Further analysis revealed the presence of water clusters large enough to show a cooperative relaxation mode even at high surfactant concentrations. However, the relaxation time of this mode is larger compared to that of pure water. This points out the importance of confinement effects on water dynamics.
Publisher: Springer Science and Business Media LLC
Date: 07-1984
DOI: 10.1007/BF00647171
Publisher: Walter de Gruyter GmbH
Date: 2007
Abstract: Complex formation between Cu II and the common environmental ligands Cl - , OH - , CO 3 2- , SO 4 2- , and PO 4 3- can have a significant effect on Cu II speciation in natural waters with low concentrations of organic matter. Copper(II) complexes are labile, so the Cu II distribution amongst these inorganic ligands can be estimated by numerical modeling if reliable values for the relevant stability (formation) constants are available. This paper provides a critical review of such constants and related thermodynamic data. It recommends values of log 10 β p,q,r ° valid at I m = 0 mol kg -1 and 25 °C (298.15 K), along with the equations and specific ion interaction coefficients required to calculate log 10 β p,q,r values at higher ionic strengths. Some values for reaction enthalpies, Δr H m, are also reported where available. In weakly acidic fresh water systems, in the absence of organic ligands, Cu II speciation is dominated by the species Cu 2+ (aq), with CuSO 4 (aq) as a minor species. In seawater, it is dominated by CuCO 3 (aq), with Cu(OH) + , Cu 2+ (aq), CuCl + , Cu(CO 3 )OH - , Cu(OH) 2 (aq), and Cu(CO 3 ) 2 2- as minor species. In weakly acidic saline systems, it is dominated by Cu 2+ (aq) and CuCl + , with CuSO 4 (aq) and CuCl 2 (aq) as minor species.
Publisher: Elsevier BV
Date: 09-2008
Publisher: Elsevier BV
Date: 02-2020
Publisher: Springer Science and Business Media LLC
Date: 2001
Publisher: Elsevier BV
Date: 04-2015
Publisher: AIP Publishing
Date: 06-2005
DOI: 10.1063/1.1796651
Abstract: The mutual solubility and related liquid–liquid equilibria of C6H14 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in five chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For all five systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated or unsaturated aliphatic hydrocarbons was used.
Publisher: American Chemical Society (ACS)
Date: 02-09-2005
DOI: 10.1021/JP053299M
Abstract: A systematic study of the dielectric relaxation spectra of aqueous solutions of NaBr, NaI, NaNO(3), NaClO(4), and NaSCN has been made over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) and solute concentrations (0.05 < or = c/M < or = 1.5) at 25 degrees C. The spectra could be adequately described by a single Cole-Cole (CC) process, symmetrically broadened relative to that of pure water. However, similar quality fits were also obtained with a three-Debye-process (3D) model consisting of a small ion-pair contribution at lower frequencies and two solvent relaxations at higher frequencies. Assuming the ions to be solvent separated, the 3D model provided estimates of their association constants and their rate constants for formation and dissociation. The bulk water relaxation times obtained from both models showed almost no dependence on the nature of the anion. Nevertheless, there were subtle differences in the concentration dependences of the relaxation times which correlated with some, but not all, of the anion properties that are believed to be relevant for explaining the anionic Hofmeister series.
Publisher: Elsevier BV
Date: 04-2010
Publisher: AIP Publishing
Date: 16-08-2005
DOI: 10.1063/1.1839880
Abstract: The mutual solubility and related liquid-liquid equilibria of C8H8–C8H10 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 5 chemically distinct binary systems that appeared in the primary literature prior to the end of 2002 are compiled. For all the systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
Publisher: Springer Science and Business Media LLC
Date: 29-11-2018
Publisher: American Chemical Society (ACS)
Date: 24-04-2018
Publisher: Springer Science and Business Media LLC
Date: 03-1989
DOI: 10.1007/BF00652986
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CC00187A
Abstract: S 2− (aq) is a widespread but deleterious artefact which needs to be eliminated by the chemical community.
Publisher: SAGE Publications
Date: 04-1999
Abstract: A series of solid sodium (hydroxy)aluminates has been prepared from highly caustic aqueous sodium aluminate solutions. The coordination geometry of the aluminum in these compounds was established by 27 Al magic angle spinning nuclear magnetic resonance ( 27 Al-MAS-NMR) spectroscopy and was used to identify the Raman and IR vibration frequencies characteristic of tetrahedral (Raman: 440 cm −1 IR: 823 cm −1 and 540 cm −1 ) and octahedral (Raman: 490–500 cm −1 IR: 728 cm −1 ) aluminum sites. The vibrational spectra of these solids differ markedly from those observed for concentrated aqueous solutions, and it appears that solid-state vibrational spectra cannot be used to predict the structure of aluminate species existing in solutions.
Publisher: American Chemical Society (ACS)
Date: 05-2007
DOI: 10.1021/JP0713413
Abstract: Mixtures of water or D2O + 1,4-dioxane (DX) have been studied at 25 degrees C by dielectric relaxation spectroscopy over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) for DX mole fractions 0 < or = x2 < or = 0.67. The spectra were best fitted by the sum of two Debye terms. The slower process was assigned to the cooperative relaxation of the hydrogen-bond network of water, whereas the faster mode reflects the dynamics of H2O molecules in a DX-rich environment. Analysis of the relaxation parameters revealed a largely microheterogeneous structure of the mixtures. The marked slowing-down of the cooperative mode on addition of DX is ascribed to the reduction of available H-bond acceptor sites and geometrical constraints on the H2O molecules in the water-rich regions.
Publisher: American Chemical Society (ACS)
Date: 21-09-2018
Publisher: American Chemical Society (ACS)
Date: 19-09-2008
DOI: 10.1021/JP8045627
Abstract: Dielectric spectra have been measured at 25 degrees C for mixtures of the room temperature ionic liquid 1- N-butyl-3- N-methylimidazolium tetrafluoroborate (IL) with dichloromethane (DCM) over the entire composition range at frequencies 0.2 less than or approximately nu/GHz < or = 89. The spectra could be satisfactorily fitted by assuming only two relaxation modes: a Cole-Cole process at lower frequencies and a Debye process at higher frequencies. However, detailed analysis indicated that both spectral features contain additional modes, which could not be resolved due to overlaps. The spectra indicate that the IL appears to retain its chemical character to extraordinarily high levels of dilution ( x IL greater than or approximately 0.5) in DCM. At even higher dilutions ( x IL less than or approximately 0.3), the IL behaves as a conventional but strongly associated electrolyte.
Publisher: American Chemical Society (ACS)
Date: 07-07-2006
DOI: 10.1021/JP0620769
Abstract: Aqueous solutions of copper(II) sulfate have been studied by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2 less, similar nu/GHz < or = 89), concentrations (0.02 < or = m/mol kg(-1) less, similar 1.4), and temperatures (5 < or = t/ degrees C < or = 65). The spectra show clear evidence for the simultaneous existence of double-solvent-separated, solvent-shared, and contact ion pairs at all temperatures, with increasing formation especially of contact ion pairs with increasing temperature. The overall ion association constant corresponding to the equilibrium: Cu2+(aq) + SO4(2-)(aq) right harpoon over left harpoon CuSO4(0)(aq) was found to be in excellent agreement with literature data over the investigated temperature range. However, the precision of the spectra and other difficulties did not allow a thermodynamic analysis of the formation of the in idual ion-pair types. Effective hydration numbers derived from the DRS spectra were high but consistent with simulation and diffraction data from the literature. They indicate that both ions influence solvent water molecules beyond the first hydration sphere. The implications of the present findings for previous observations on copper sulfate solutions are briefly discussed.
Publisher: Elsevier BV
Date: 06-2011
DOI: 10.1016/J.CHEMOSPHERE.2011.02.048
Abstract: Eight hydroxylammonium-based room temperature ionic liquids (ILs) have been synthesized by acid-base neutralization of ethanolamines with organic acids. The ILs were characterized by infrared and nuclear magnetic resonance spectroscopies and elemental analysis. Their anti-microbial activities were determined using the well-diffusion method. All eight ILs were toxic to Staphylococcus aureus, while 2-hydroxyethylammonium lactate and 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium acetate showed high anti-microbial activity against a wide range of human pathogens.
Publisher: Wiley
Date: 31-07-2018
DOI: 10.1111/RESP.13375
Publisher: Royal Society of Chemistry (RSC)
Date: 1996
DOI: 10.1039/FT9969204445
Publisher: Springer Science and Business Media LLC
Date: 10-1996
DOI: 10.1007/BF00140604
Abstract: Learning and memory disorders and decreased neuroplasticity are the main clinical manifestations of age-induced cognitive dysfunction. Orexin A (OxA) has been reported to show abnormally elevated expression in the cerebrospinal fluid (CSF) of patients with Alzheimer's disease (AD) and to be associated with cognitive impairment. Here, we further assessed whether the excitatory neurotransmitter OxA is involved in neuroplasticity and cognitive function in senescence-accelerated mouse prone 8 (SAMP8) mice. In this study, we investigated the mechanism of OxA by using behavioral tests, CSF microdialysis, immunofluorescence, toluidine blue staining, gene silencing, transmission electron microscopy, and Western blotting. The results showed that 10 Hz electroacupuncture (EA) effectively alleviated learning and memory impairment in 7-month-old SAMP8 mice, reduced OxA levels in the CSF, increased the level of the neurotransmitter glutamate, alleviated pathological damage to hippoc al tissue, improved the synaptic structure, enhanced synaptic transmission, and regulated the expression of cAMP/PKA/CREB signaling pathway-related proteins. These results suggest that EA enhances neuroplasticity in SAMP8 mice by regulating the OxA-mediated cAMP/PKA/CREB signaling pathway, thus improving cognitive function. These findings suggest that EA may be beneficial for the prevention and treatment of age-induced cognitive impairment.
Publisher: Elsevier BV
Date: 04-2010
Publisher: Walter de Gruyter GmbH
Date: 2005
Abstract: The importance of ion solvation in determining the properties of electrolyte solutions in aqueous–organic solvent mixtures is discussed. Solubility measurements are shown to be particularly useful for determining the Gibbs energies of transfer of ions between solvents, which reflect differences in the overall solvation of the ions in different solvent mixtures. Solubility measurements can also be used to determine the other thermodynamic parameters of transfer, but such quantities are usually better obtained by more direct methods. The inadequacy of current theories of ion solvation to quantitatively account for the thermodynamics of ion transfer is discussed by reference to measurements on some simple model systems. Although donor/acceptor interactions can explain many of the observed effects between pure solvents, the situation is more complex in aqueous–organic mixtures because selective solvation and even solvent–solvent interactions may become significant. This is illustrated by consideration of ion transfer from water to water + t -butanol solutions, where spectacular effects are observed in the enthalpies and entropies and especially in the heat capacities and volumes.
Publisher: Springer Science and Business Media LLC
Date: 1989
DOI: 10.1007/BF01142555
Publisher: Wiley
Date: 14-03-2005
DOI: 10.1002/0470867833
Publisher: Elsevier BV
Date: 04-2004
Publisher: Springer Science and Business Media LLC
Date: 03-1997
DOI: 10.1007/BF02767997
Publisher: Springer Science and Business Media LLC
Date: 1982
DOI: 10.1007/BF00664333
Publisher: Elsevier BV
Date: 10-2009
Publisher: Elsevier BV
Date: 1984
Publisher: CSIRO Publishing
Date: 1990
DOI: 10.1071/CH9901791
Abstract: A study of the electrochemical characteristics of the copper(II)/copper(I) redox couple has been made in chloride and bromide media in dimethyl sulfoxide (Me2SO) and their aqueous analogues. The formal potentials of the CuII/CuI couple in the Me2SO media are approximately 0.15 V less positive than in their aqueous counterparts probably due to a combination of solvation and complexation effects. Diffusion coefficients for both CuI and CuII are 5-10 times lower in Me2SO than in H2O as a result of the higher viscosity of Me2SO solutions. Heterogeneous electron-transfer rate constants for the CuII/CuI system on platinum are also an order of magnitude smaller than in aqueous solution. In general the electrochemical characteristics of the CuII/CuI system parallel those reported elsewhere for the FeIII/FeII couple. However, a detailed investigation of the CuII/CuI system by cyclic voltammetry indicates that the overall electrode process is complex, probably involving a quasi-reversible electron-transfer step coupled to a rate-determining loss of Cl - from CuII.
Publisher: AIP Publishing
Date: 16-08-2005
DOI: 10.1063/1.1840737
Abstract: The mutual solubility and related liquid-liquid equilibria of C7 hydrocarbons with water and heavy water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 23 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 9 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
Publisher: Wiley
Date: 02-08-2022
DOI: 10.1111/RESP.14338
Abstract: We have previously described reversal of collateral ventilation (CV) in a severe chronic obstructive pulmonary disease (COPD) patient with endoscopic polymer foam (EPF), prior to endoscopic lung volume reduction (ELVR) with valves. The aim of this study was to investigate the efficacy of this in a larger cohort and compare outcomes with a similar cohort with no CV. Patients with severe COPD, with the left upper lobe (LUL) targeted for ELVR, were assessed for CV with high resolution computed tomography (HRCT). If fissure completeness was % they were enrolled as controls for valves alone (endobronchial valve control group [EBV‐CTRL]). If fissure completeness was 80%–95%, defects were mapped to the corresponding segment, where EPF was instilled following confirmation of CV with CHARTIS. EBVs were inserted 1 month afterwards. Fourteen patients were enrolled into both arms. After 6 months, there were significant improvements in both groups in forced expiratory volume in 1 s (FEV1 +19.7% EPF vs. +27.7% EBV‐CTRL, p 0.05) residual volume (RV −16.2% EPF vs. −20.1% EBV‐CTRL, p = NS) SGRQ (−15.1 EPF vs. −16.6 EBV‐CTRL p = NS) and 6 min walk (+25.8% EPF [77.2 m] vs. +28.4% [82.3 m] EBV‐CTRL p = NS). Patients with fissural defects mapped to the lingula had better outcomes than those mapped to other segments (FEV1 +22.9% vs. +16.3% p 0.05). There were no serious adverse reactions to EPF. EPF successfully reverses CV in severe COPD patients with a left oblique fissure that is 80%–95% complete. Following EBV, outcomes are similar to patients with complete fissures undergoing ELVR with EBV alone. EPF therapy to reverse CV potentially increases the number of COPD patients suitable for ELVR with minimal adverse reactions.
Publisher: American Chemical Society (ACS)
Date: 04-01-2022
Publisher: Walter de Gruyter GmbH
Date: 21-08-2023
Abstract: The International Union of Pure and Applied Chemistry has a long tradition of supporting the compilation of chemical data and their evaluation through direct projects, nomenclature and terminology work, and partnerships with international scientific bodies, government agencies, and other organizations. The IUPAC Inter isional Subcommittee on Critical Evaluation of Data has been established to provide guidance on issues related to the evaluation of chemical data. In this first report, we define the general principles of the evaluation of scientific data and describe best practices and approaches to data evaluation in chemistry.
Publisher: American Chemical Society
Date: 18-12-2009
Publisher: American Chemical Society (ACS)
Date: 05-02-2013
DOI: 10.1021/JP310029C
Abstract: Aqueous solutions of sodium propanoate (NaOPr) and n-butanoate (NaOBu) have been studied at concentrations of c ~/< 3 M by broadband dielectric relaxation spectroscopy over the frequency range 0.2 ≤ ν/GHz ≤ 89 at 25 °C. Three relaxation modes were resolved, centered at (approximately) 1, 8, and 18 GHz, for both sets of solutions. The two faster modes were assigned to the cooperative relaxation of "slow" and bulk water molecules. Detailed analysis of the spectra indicated that both OPr(-) and OBu(-) were strongly hydrated, with ~23 and ~33 slow water molecules per anion, respectively, at infinite dilution. These effective hydration numbers include ~6 water molecules hydrophilically bound to the carboxylate moiety, with the remainder arising from the hydrophobic hydration of the nonpolar alkyl chains. The latter shows a characteristic rapid decrease with increasing solute concentration, which facilitated the separation of the hydrophobic and hydrophilic contributions. The lowest frequency mode was a composite with contributions from ion-cloud, ion-pair, and anion relaxations. Although this low intensity mode provided specific evidence of weak ion pairing between Na(+)(aq) and the carboxylate anions, reliable estimates of the association constant could not be made because of its composite nature.
Publisher: SPIE
Date: 11-02-2010
DOI: 10.1117/12.840185
Publisher: Informa UK Limited
Date: 05-1996
Publisher: American Chemical Society (ACS)
Date: 09-11-2011
DOI: 10.1021/JE2009329
Publisher: Elsevier BV
Date: 02-1971
Publisher: Royal Society of Chemistry (RSC)
Date: 1994
DOI: 10.1039/FT9949002475
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1007/BF00811002
Publisher: American Thoracic Society
Date: 09-2020
Publisher: CSIRO Publishing
Date: 1988
DOI: 10.1071/CH9881971
Abstract: Enthalpies of transfer of potassium fluoride from water to water-methanol mixtures over the whole composition range have been determined by calorimetry. Combination of these values with literature data has enabled calculation of the enthalpies and entropies of transfer for the in idual ions through the tetraphenylarsonium tetrapbenylborate ( tatb ) assumption. The values of ΔtH°(F-) and ΔtS°(F-) show a complex dependence on solvent composition which closely parallels the dependence of the other halide ions. These effects are discussed in terms of ion-solvent and solvent-solvent interactions. The halide ions appear to be (weakly) preferentially solvated by H2O, and the alkali metal ions by MeOH.
Publisher: Springer Science and Business Media LLC
Date: 1998
Publisher: Royal Society of Chemistry (RSC)
Date: 1996
DOI: 10.1039/FT9969200757
Publisher: Springer Science and Business Media LLC
Date: 10-1997
DOI: 10.1007/BF02768053
Publisher: Elsevier BV
Date: 06-1983
Publisher: CSIRO Publishing
Date: 1990
DOI: 10.1071/CH9901421
Abstract: The mechanism of the electrochemical dehalogenation of organic vicinal dihalides has been examined in acetonitrile by using meso- and (�)-1,2-dibromo-1,2-diphenylethane. Reduction potentials and product distributions obtained from the isomeric dibromides could not be accommodated within a mechanism involving a concerted addition of two electrons. However, these results can be explained by a stepwise addition of electrons, allowing the possibility of bond rotation at an intermediate stage. The product distributions obtained from the reduction of the (�)- dibromide were found to be potential-dependent, a result not previously observed for this compound, but consistent with a stepwise mechanism.
Publisher: Elsevier BV
Date: 02-1972
Publisher: American Chemical Society (ACS)
Date: 16-03-2021
Publisher: Elsevier BV
Date: 02-1992
Publisher: Walter de Gruyter GmbH
Date: 23-11-2013
Abstract: The numerical modeling of Zn II speciation amongst the environmental inorganic ligands Cl & ndash , OH & ndash , CO 3 2& ndash , SO 4 2& ndash , and PO 4 3& ndash requires reliable values for the relevant stability (formation) constants. This paper compiles and provides a critical review of these constants and related thermodynamic data. It recommends values of log 10 & beta p,q,r & deg valid at I m = 0 mol& middot kg & ndash and 25 & deg C (298.15 K), and reports the empirical reaction ion interaction coefficients, ∆ & epsilon , required to calculate log 10 & beta p,q,r values at higher ionic strengths using the Br& oslash nsted& ndash Guggenheim& ndash Scatchard specific ion interaction theory (SIT). Values for the corresponding reaction enthalpies, ∆ r H , are reported where available. There is scope for additional high-quality measurements for the Zn 2+ + H + + CO 3 2& ndash system and for the Zn 2+ + OH & ndash and Zn 2+ + SO 4 2& ndash systems at I & 0. In acidic and weakly alkaline fresh water systems (pH & 8), in the absence of organic ligands (e.g., humic substances), Zn II speciation is dominated by Zn 2+ (aq). In this respect, Zn II contrasts with Cu II and Pb II (the subjects of earlier reviews in this series) for which carbonato- and hydroxido- complex formation become important at pH & 7. The speciation of Zn II is dominated by ZnCO 3 (aq) only at pH & 8.4. In seawater systems, the speciation at pH = 8.2 is dominated by Zn 2+ (aq) with ZnCl + , Zn(Cl) 2 (aq), ZnCO 3 (aq), and ZnSO 4 (aq) as minor species. This behaviour contrasts with that for Cu II and Pb II for which at the pH of seawater in equilibrium with the atmosphere at 25 & deg C (log 10 {[H + ]/ c & deg } & asymp 8.2) the MCO 3 (aq) complex dominates over the MCl n (2& ndash n )+ species. The lower stability of the different complexes of Zn II compared with those of Cu II , Pb II , and Cd II is also illustrated by the percentage of uncomplexed M 2+ in seawater, which is ca. 55, 3, 2, and 3.3 % of [M II ] T , respectively.
Publisher: American Chemical Society (ACS)
Date: 13-07-2009
DOI: 10.1021/JA903315V
Abstract: We have measured the intermolecular dynamics of the 1,3-dialkylimidazolium-based room-temperature ionic liquids (RTILs) [emim][BF(4)], [emim][DCA], and [bmim][DCA] at 25 degrees C from below 1 GHz to 10 THz by ultrafast optical Kerr effect (OKE) spectroscopy and dielectric relaxation spectroscopy (DRS) augmented by time-domain terahertz and far-infrared FTIR spectroscopy. This concerted approach allows a more detailed analysis to be made of the relatively featureless terahertz region, where the higher frequency diffusional modes are strongly overlapped with librations and intermolecular vibrations. Of greatest interest though, is an intense low frequency (sub-alpha) relaxation that we show is in accordance with recent simulations that have reported mesoscopic structure arising from aggregates or clusters--structure that explains the anomalous and inconveniently high viscosities of these liquids.
Publisher: American Chemical Society (ACS)
Date: 05-11-2021
Publisher: American Chemical Society (ACS)
Date: 19-04-2019
Abstract: Enthalpies of solution, Δ
Publisher: AIP Publishing
Date: 06-1997
DOI: 10.1063/1.1148161
Abstract: A significantly improved apparatus for the isopiestic measurement of thermodynamic activities at elevated temperatures is described. Details of the new design and of an analysis of the propagation of the experimental errors are presented. The apparatus was tested by measurements of calcium chloride against sodium chloride at 353.15 K. Accuracies of better than 0.1% in the osmotic coefficient are routinely achieved. Data are also given for the osmotic coefficient of aqueous sodium hydroxide solutions at 353.15 K as a function of molality (up to 13 mol/kg), measured with respect to both sodium chloride and calcium chloride solutions as reference electrolytes.
Publisher: American Chemical Society (ACS)
Date: 15-11-2011
DOI: 10.1021/JE200964M
Publisher: Elsevier BV
Date: 05-1978
Publisher: Springer Science and Business Media LLC
Date: 04-2003
Publisher: Elsevier BV
Date: 03-1976
Publisher: Walter de Gruyter GmbH
Date: 29-10-2009
Abstract: Complex formation between Pb II and the common environmental inorganic ligands, Cl – , OH – , CO 3 2– , SO 4 2– , and PO 4 3– , can be significant in natural waters with low concentrations of organic matter. Numerical modeling of the speciation of Pb II amongst these inorganic ligands requires reliable values for the relevant stability (formation) constants. This paper provides a critical review of such constants and related thermodynamic data. It recommends values of log 10 β p,q,r ° valid at I m = 0 mol kg –1 and 25 °C (298.15 K), along with the equations and empirical coefficients required to calculate log 10 β p,q,r values at higher ionic strengths using the Brønsted–Guggenheim–Scatchard specific ion interaction theory (SIT). Some values for reaction enthalpies, Δ r H , are also reported. In weakly acidic fresh water systems (–log 10 {[H + ]/ c° } & 6), the speciation of Pb II is similar to that of Cu II . In the absence of organic ligands, Pb II speciation is dominated by Pb 2+ (aq), with PbSO 4 (aq) as a minor species. In weakly alkaline solutions, 8.0 & –log 10 {[H + ]/ c° } & 9.0, the speciation is dominated by the carbonato species PbCO 3 (aq) and Pb(CO 3 ) 2 2– . In weakly acidic saline systems (–log 10 {[H + ]/ c° } & 6), the speciation is dominated by PbCl n (2– n )+ complexes, ( n = 0–3), with Pb 2+ (aq) as a minor species. In this medium (and in seawater), the speciation contrasts with that of Cu II because of the higher stability of the Pb 2+ -chlorido- complexes. In seawater at –log 10 {[H + ]/ c° } = 8.2, the calculated speciation is less well defined, although it is clearly dominated by the uncharged species PbCO 3 (aq) (41 % of [Pb] T ) with a significant contribution (16 %) from Pb(CO 3 )Cl – and minor contributions (5–10 %) from PbCl n (2– n )+ , ( n = 0–3) and Pb(CO 3 ) 2 2– . The uncertainty in calculations of Pb II speciation in seawater arises from (a) the large uncertainty in the stability constant for the apparently dominant species PbCO 3 (aq), (b) the reliance on statistical predictions for stability constants of the ternary species Pb(CO 3 )Cl – and Pb(CO 3 )OH – , and (c) the uncertainty in the stability constant for PbCl 4 2– , the available value being considered "indicative" only. There is scope for additional detailed high-quality measurements in the Pb 2+ + CO 3 2– + Cl – system.
Publisher: Royal Society of Chemistry (RSC)
Date: 1983
DOI: 10.1039/C39830001123
Publisher: Springer Science and Business Media LLC
Date: 1997
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B513357B
Abstract: A detailed electrochemical investigation using H2/Pt electrode potentiometry as well as Raman and NMR spectroscopy was carried out to develop a comprehensive chemical explanation for the unusual patterns of hydroxide concentrations observed in strongly alkaline, highly concentrated aluminate solutions (Bayer-liquors). For this, aluminate solutions with various alkaline metal background cations were investigated. The effect of the temperature on the observed patterns was also studied, and for comparison with solutions of similar concentrations, the chemical speciation of borate solutions was also studied. The formation of the NaOH 0 ion-pair has been proven with the formation constant (defined in terms of activities) beta 0 = 0.78 +/- 0.08. The formation of analogous KOH 0 or CsOH 0 ion-pairs under the experimental conditions applied is negligible. Assuming the formation of the NaAl(OH)4 (0) ion-pair is not necessary for modeling the experimental findings, as its formation causes only secondary effects on the potentiometric patterns. It has also been shown that all experimental data can be interpreted quantitatively if the formation of the doubly charged dimeric aluminate species is included in the calculation of the changes in the mean activity coefficients. The formation constant of the aluminate dimer could not be estimated purely from the H2/Pt potentiometric data but a lower limit for its formation constant (defined in terms of activities) has been derived. These conclusions are in full congruency with those derived from the Raman spectra of solutions with similar concentrations, so the two independent experimental methods lead to the same set of chemical species in highly concentrated alkaline aluminate solutions.
Publisher: Walter de Gruyter GmbH
Date: 1993
Publisher: Springer Science and Business Media LLC
Date: 06-1988
DOI: 10.1007/BF00651461
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CP00248G
Abstract: Lanthanide ions affect water out to the third shell and form double solvent-separated and solvent-shared ion pairs.
Publisher: AIP Publishing
Date: 27-04-2006
DOI: 10.1063/1.2132316
Abstract: The mutual solubility of C5–C26 hydrocarbons with seawater is exhaustively and critically reviewed. Reports of experimental determination of solubility in 46 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 15 of these systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units.
Publisher: Springer Science and Business Media LLC
Date: 02-2002
Publisher: Elsevier BV
Date: 05-2011
Publisher: AIP Publishing
Date: 27-04-2006
DOI: 10.1063/1.2132315
Abstract: The mutual solubilities and related liquid–liquid equilibria of C13–C36 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 56 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 17 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all the experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
Publisher: American Chemical Society (ACS)
Date: 22-02-2011
DOI: 10.1021/JP1116307
Abstract: Solutions of sodium trifluoromethanesulfonate, magnesium trifluoromethanesulfonate, and barium perchlorate in N,N-dimethylformamide (DMF) have been investigated using broadband dielectric relaxation spectroscopy at 25 °C. All spectra were dominated by a solvent relaxation process centered at ∼15 GHz but also exhibited one (for NaCF(3)SO(3)) or two (for the 2:1 salts) low- litude processes, centered at frequencies below 2 GHz, that could be attributed to the presence of ion pairs. Effective solvation numbers calculated from the solvent relaxation litudes indicated strong solvation of all three cations, with evidence for the formation of a second solvation sheath for Mg(2+) and possibly Ba(2+). Detailed analysis of the solute-related processes showed that solvent-shared ion pairs (SIPs) were formed in NaCF(3)SO(3) solutions in DMF. The data for Mg(CF(3)SO(3))(2) and Ba(ClO(4))(2) solutions were not definitive but, consistent with the solvation evidence, favored the presence of double solvent-separated ion pairs and SIPs. Overall association constants, K(A), were small for all three salts in DMF and increased in the order: NaCF(3)SO(3)<Ba(ClO(4))(2)<Mg(CF(3)SO(3))(2).
Publisher: American Chemical Society (ACS)
Date: 05-1970
DOI: 10.1021/IC50087A004
Publisher: American Chemical Society (ACS)
Date: 26-05-2016
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2020
Publisher: AIP Publishing
Date: 25-01-2006
DOI: 10.1063/1.2131103
Abstract: The mutual solubilities and related liquid–liquid equilibria of C10 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 20 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For ten systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
Publisher: Springer Science and Business Media LLC
Date: 2002
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 13-11-2019
Publisher: AIP Publishing
Date: 25-01-2006
DOI: 10.1063/1.2134730
Abstract: The mutual solubilities and related liquid–liquid equilibria of C11 and C12 hydrocarbons with water and heavy water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 24 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 12 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all the experimental data for a given series of aliphatic and aromatic hydrocarbons was used.
Publisher: American Chemical Society (ACS)
Date: 14-08-2004
DOI: 10.1021/JP048575W
Publisher: American Chemical Society (ACS)
Date: 12-11-2009
DOI: 10.1021/JE900584K
Publisher: Elsevier BV
Date: 1984
Publisher: American Chemical Society (ACS)
Date: 25-08-2021
Publisher: AIP Publishing
Date: 1992
DOI: 10.1063/1.350723
Abstract: Infrared spectroscopy and thermal effusion have been used to study the nature of the silicon-hydrogen bond in sputtered a-Si:H alloys. The s les were prepared by reactive sputtering under different deposition conditions to produce varying hydrogen contents. The Fourier transform infrared spectra have been analyzed using the simplex algorithm to deconvolute the component peaks. This technique has been applied separately to both the stretching- and bending-mode regions of the infrared absorption spectra. Studies have been made of the effects of annealing on both the infrared and the thermal evolution spectra of hydrogen. The results indicate a redistribution and transformation of different bonding configurations due to annealing. A comparative study is presented of the thermal-effusion spectra for partial and total degassing with the infrared spectra taken before and after each phase of degassing.
Publisher: American Chemical Society (ACS)
Date: 04-1984
DOI: 10.1021/AC00268A035
Publisher: Elsevier BV
Date: 05-2005
Publisher: American Chemical Society (ACS)
Date: 14-12-2012
DOI: 10.1021/IE302096E
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1FD00054C
Abstract: The structure and dynamics of ionic liquids (ILs) are unusual due to the strong interactions between the ions and counter ions. These microscopic properties determine the bulk transport properties critical to applications of ILs such as advanced fuel cells. The terahertz dynamics and slower relaxations of simple alkylammonium nitrate protic ionic liquids (PILs) are here studied using femtosecond optical Kerr-effect spectroscopy, dielectric relaxation spectroscopy, and terahertz time-domain spectroscopy. The observed dynamics give insight into more general liquid behaviour while comparison with glass-forming liquids reveals an underlying power-law decay and relaxation rates suggest supramolecular structure and nanoscale segregation.
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A900812H
Publisher: American Chemical Society (ACS)
Date: 16-07-2012
DOI: 10.1021/JE300086W
Publisher: American Chemical Society (ACS)
Date: 08-06-2000
DOI: 10.1021/JE000019H
Publisher: Springer Science and Business Media LLC
Date: 13-07-2016
Publisher: American Chemical Society (ACS)
Date: 08-02-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B308951G
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2018
Publisher: Elsevier BV
Date: 12-1997
Publisher: American Chemical Society (ACS)
Date: 29-08-2017
Publisher: AIP Publishing
Date: 19-05-2005
DOI: 10.1063/1.1790006
Abstract: The mutual solubilities and related liquid-liquid equilibria of benzene with water and heavy water are exhaustively and critically reviewed. Reports of experimental determination of solubility in these two chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For the system benzene-water sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of all experimental data for a homologous series of aromatic hydrocarbons was used.
Publisher: Elsevier BV
Date: 05-2000
Publisher: Elsevier BV
Date: 04-1997
DOI: 10.1016/S0039-9140(96)02074-7
Abstract: The ionic product of water, pK(w) = - log[H(+)][OH(-)] has been determined in aqueous solutions of tetramethylammonium chloride over the concentration range of 0.1-5.5 M at 25 degrees C using high-precision glass electrode potentiometric titrations. pK(w) data relating to aqueous potassium and sodium chlorides at ionic strengths up to 5 M are markedly lower than the tetramethylammonium chloride results. These differences are almost certainly due to weak associations between potassium and (especially) sodium and hydroxide ions.
Publisher: Elsevier BV
Date: 11-1997
Publisher: Elsevier BV
Date: 10-2001
Publisher: Elsevier BV
Date: 11-2017
Publisher: Springer Science and Business Media LLC
Date: 11-1991
DOI: 10.1007/BF00649097
Publisher: AIP Publishing
Date: 19-05-2005
DOI: 10.1063/1.1790005
Abstract: The mutual solubility and related liquid–liquid equilibria of C5 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 13 chemically distinct binary systems for which data appeared in the primary literature prior to end of 2002 are compiled. For seven systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated or unsaturated aliphatic hydrocarbons was used.
Publisher: American Chemical Society (ACS)
Date: 02-07-2015
DOI: 10.1021/JP502935T
Abstract: Dielectric relaxation (DR) and optical Kerr-effect (OKE) spectra of the archetypal protic ionic liquids ethyl- and propylammonium nitrate (EAN and PAN) have been measured over an unusually large frequency range from 200 MHz to 10 THz at temperatures (mostly) between 5 and 65 °C. Analysis of the low-frequency α-relaxation, associated with the cooperative relaxations of the cations (DR) and anions (OKE) and any clusters present, indicated that ion reorientation in EAN is decoupled from viscosity and occurs via cooperative relaxation involving large-angle jumps rather than rotational diffusion. Detailed consideration of the high-frequency parts of the DR and OKE spectra showed that the observed intensities were a complex combination of overlapping and possibly coupled modes. In addition to previously identified intermolecular H-bond vibrations, there are significant contributions from the librations of the cations and anions. The present assignments were shown to be consistent with the isotopic shifts observed for deuterated EAN.
Publisher: Elsevier BV
Date: 02-1996
Publisher: American Chemical Society (ACS)
Date: 18-11-2021
Publisher: Elsevier BV
Date: 06-2017
Publisher: American Chemical Society (ACS)
Date: 19-11-2021
Publisher: Elsevier BV
Date: 10-2014
Publisher: American Chemical Society (ACS)
Date: 30-03-2001
DOI: 10.1021/JE000347H
Publisher: Wiley
Date: 06-1994
Publisher: Springer Science and Business Media LLC
Date: 1999
Publisher: CSIRO Publishing
Date: 1990
DOI: 10.1071/CH9900257
Abstract: Equilibrium constants for the formation of ZnCln2-n complexes have been measured in some acetonitrile ( MeCN )-water mixtures ranging from 0 to 100% MeCN at 25°C and I = 0.1 M (Et4NClO4), by potentiometric titration. The equilibria shift strongly in favour of the formation of the higher-order complexes (n = 3, 4) at high MeCN concentrations. This is shown to be due to differences in the magnitude of unfavourable solvation of the Zn2+, Cl - and ZnCln2-n ions in MeCN-H2O solutions. The Gibbs free energies of transfer of all of these ions from water to MeCN-H2O mixtures are strongly positive, but the net change in the transfer function for the formation of the higher-order complexes is favourable. Thus the formation of these complexes is predominant in MeCN -rich aqueous solutions. Approximate measurements in propiononitrile indicate that the ZnCln2-n complexes are even stronger than in acetonitrile.
Publisher: Springer Science and Business Media LLC
Date: 09-2006
Publisher: American Chemical Society (ACS)
Date: 09-1995
DOI: 10.1021/JE00021A003
Publisher: Elsevier BV
Date: 1990
Publisher: American Chemical Society (ACS)
Date: 28-03-2008
DOI: 10.1021/JP800852Z
Abstract: Precise dielectric spectra have been determined at 25 degrees C over the exceptionally broad frequency range of 0.1 <or= nu/GHz <or= 3000 for the imidazolium-based room-temperature ionic liquids (RTILs) [bmim][BF4], [bmim][PF6], [bmim][DCA], and [hmim][BF4]. The spectra are dominated by a low-frequency process at approximately 1 GHz with a broad relaxation time distribution of the Cole-Davidson or Cole-Cole type, which is thought to correspond to the rotational diffusion of the dipolar cations. In addition, these RTILs possess two Debye relaxations at approximately 5 GHz and approximately 0.6 THz and a d ed harmonic oscillation at approximately 2.5 THz. The two higher-frequency modes are almost certainly due to cation librations, but the origin of the approximately 5 GHz mode remains obscure.
Publisher: American Chemical Society (ACS)
Date: 10-08-2020
Publisher: Springer Science and Business Media LLC
Date: 2000
Publisher: Walter de Gruyter GmbH
Date: 2005
Abstract: This document presents a critical evaluation of the equilibrium constants and reaction enthalpies for the complex formation reactions between aqueous Hg(II) and the common environmental inorganic ligands Cl – , OH – , CO 3 2– , SO 4 2– , and PO 4 3– . The analysis used data from the IUPAC Stability Constants database, SC-Database , focusing particularly on values for 25 °C and perchlorate media. Specific ion interaction theory (SIT) was applied to reliable data available for the ionic strength range I c 3.0 mol dm –3 . Recommended values of log 10 β p,q,r ° and the associated reaction enthalpies, ∆ r H m °, valid at I m = 0 mol kg –1 and 25 °C, were obtained by weighted linear regression using the SIT equations. Also reported are the equations and specific ion interaction coefficients required to calculate log 10 β p,q,r ° values at higher ionic strengths and other temperatures. A similar analysis is reported for the reactions of H + with CO 3 2– and PO 4 3– . Diagrams are presented to show the calculated distribution of Hg(II) amongst these inorganic ligands in model natural waters. Under typical environmental conditions, Hg(II) speciation is dominated by the formation of HgCl 2 (aq), Hg(OH)Cl(aq), and Hg(OH) 2 (aq).
Publisher: Wiley
Date: 07-08-2023
DOI: 10.1111/RESP.14568
Abstract: Outside clinical trials, there is limited long‐term data following bronchial thermoplasty (BT). In a cohort of real‐world severe asthmatics in an era of biological therapy, we sought to evaluate the safety and efficacy of BT 5 years post‐treatment. Every patient treated with BT at two Australian tertiary centres were recalled at 5 years, and evaluated by interview and record review, Asthma Control Questionnaire (ACQ), spirometry and high‐resolution CT Chest. CT scans were interpreted using the modified Reiff and BRICS CT scoring systems for bronchiectasis. Fifty‐one patients were evaluated. At baseline, this cohort had a mean age of 59.0 ± 11.8 years, mean ACQ of 3.0 ± 1.0, mean FEV1 of 55.5 ± 18.8% predicted, and 53% were receiving maintenance oral steroids in addition to triple inhaler therapy. At 5 years, there was a sustained improvement in ACQ scores to 1.8 ± 1.0 ( p 0.001). Steroid requiring exacerbation frequency was reduced from 3.8 ± 3.6 to 1.0 ± 1.6 exacerbations per annum ( p 0.001). 44% of patients had been weaned off oral steroids. No change in spirometry was observed. CT scanning identified minor degrees of localized radiological bronchiectasis in 23/47 patients with the modified Reiff score increasing from 0.6 ± 2.6 at baseline to 1.3 ± 2.5 ( p 0.001). However, no patients exhibited clinical features of bronchiectasis, such as recurrent bacterial infection. Sustained clinical benefit from BT at 5 years was demonstrated in this cohort of very severe asthmatics. Mild, localized radiological bronchiectasis was identified in a portion of patients without clinical features of bronchiectasis.
Publisher: Elsevier BV
Date: 10-2018
Publisher: AIP Publishing
Date: 02-1999
DOI: 10.1063/1.1149610
Abstract: An improved apparatus for measuring solubilities of solid–liquid systems at temperatures to 90 °C is described. The apparatus has a high capacity (up to 56 s les) and a long term temperature stability of ±3 mK. The design allows the saturated solution to be multiply s led and microfiltered at the equilibration temperature, making it particularly suited to rapidly equilibrating systems. The reliability of the apparatus and s ling procedures were tested by measuring the solubilities of NaCl, Na2SO4, and Na2CO3 in water. The data obtained showed a routine precision of ±0.05% relative and agreed to within ±0.1% of recommended International Union of Pure and Applied Chemistry values.
Publisher: American Chemical Society (ACS)
Date: 18-06-2012
DOI: 10.1021/JP3020673
Abstract: A detailed investigation of the binary mixtures of the ionic liquids (ILs) 1-N-R-3-N-methylimidazolium tetrafluoroborate (R = ethyl, n-butyl, n-hexyl) with the important molecular solvent acetonitrile (AN) over the entire composition range has been made at 25 °C using broadband dielectric spectroscopy. All spectra showed two modes: a Cole-Cole (CC) mode centered at ~2 GHz and a Debye mode centered at ~50 GHz. However, detailed analysis indicated both relaxations were composites. The Debye mode arises from the rotational diffusion of free AN molecules with contributions from ultrafast vibrations and librations of the ILs. The CC mode corresponds to the jump rotation of the imidazolium cations and the hindered rotational diffusion of "slow" AN molecules solvating them. At very low IL concentrations 1:1 contact ion pairs are dominant. Overall, these IL + AN mixtures can be ided into two broad regions: at IL mole fraction (x(IL)) ≲ 0.2 the IL behaves as a rather weakly associated conventional electrolyte while at x(IL) ≳ 0.2 it takes on its IL characteristics, "lubricated" by the AN.
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.CHEMOSPHERE.2011.06.088
Abstract: A new mathematical model has been developed that expresses the toxicities (EC₅₀ values) of a wide variety of ionic liquids (ILs) towards the freshwater flea Daphnia magna by means of a quantitative structure-activity relationship (QSAR). The data were analyzed using summed contributions from the cations, their alkyl substituents and anions. The model employed multiple linear regression analysis with polynomial model using the MATLAB software. The model predicted IL toxicities with R²=0.974 and standard error of estimate of 0.028. This model affords a practical, cost-effective and convenient alternative to experimental ecotoxicological assessment of many ILs.
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/CH04230
Abstract: The formation constant β(NaOx−) of the extremely weak ion pair formed between sodium (Na+) and oxalate (Ox2−) ions in aqueous solutions has been determined at 25°C as a function of ionic strength in tetramethylammonium chloride by Na+ ion-selective electrode potentiometry. The effects of trace Na+ impurities from all reagents were accounted for. An extrapolated value for β o of 6.6 ± 0.5 M−1 was obtained at infinite dilution, which is in good agreement with literature values. Attempts to measure this constant in 1 M CsCl media gave a β(NaOx−) value of 0.00 ± 0.06 M−1, probably because of competition between Cs+ and Na+ for Ox2−.
Publisher: Elsevier BV
Date: 02-2011
Publisher: Walter de Gruyter GmbH
Date: 20-05-2013
Abstract: Recent solubility measurements of a variety of solid electrolytes in water and aqueous solutions in the author& rsquo s laboratories are reviewed. The experimental challenge of performing such measurements with high accuracy is demonstrated using the solubility of solid sodium chloride in water at near-ambient temperatures as a paradigm. The special difficulties of measuring low solubilities are demonstrated using Pb(II) sulfate in various aqueous solutions and Pb(II) oxide in sodium hydroxide solutions, and the usefulness of such measurements for obtaining reliable information on homogeneous reactions in solution is briefly discussed. It is also shown, using the alkali metal triflate salts as ex les, that determination of the solubilities of even highly soluble salts can be problematic. Lastly, data for the solubilities of a series of sodium carboxylate salts of industrial relevance are discussed and are used to illustrate why the theoretical prediction of solid electrolyte solubilities remains such a challenge.
Publisher: Springer Science and Business Media LLC
Date: 24-09-2018
Publisher: Elsevier BV
Date: 07-1997
Publisher: Walter de Gruyter GmbH
Date: 1991
Publisher: Elsevier BV
Date: 03-1998
DOI: 10.1016/S0039-9140(97)00199-9
Abstract: The ionic product of water, pK(w)=-log[H(+)][OH(-)], has been determined in aqueous solutions of sodium perchlorate over the concentration range of 1.0-8.0 M at 25 degrees C from high-precision potentiometric titrations carried out in cells with liquid junction using both glass and hydrogen electrodes. The glass electrode results are systematically lower probably as a result of interference by Na(+) ions.
Publisher: American Chemical Society (ACS)
Date: 26-12-2014
DOI: 10.1021/JE4008475
Publisher: Informa UK Limited
Date: 10-1990
Publisher: Elsevier BV
Date: 02-1973
Publisher: Elsevier BV
Date: 07-2008
Publisher: American Chemical Society (ACS)
Date: 12-1982
DOI: 10.1021/AC00251A025
Publisher: American Chemical Society (ACS)
Date: 04-10-2005
DOI: 10.1021/JE0502400
Publisher: Wiley
Date: 14-03-2005
Publisher: American Chemical Society (ACS)
Date: 23-11-2005
DOI: 10.1021/JP053344Q
Abstract: The ultrasonic velocities, densities, viscosities, and electrical conductivities of aqueous solutions of magnesium nitrate and magnesium acetate have been measured from dilute to saturation concentrations at 0 < or = t/degrees C < or = 50. The temperature derivative of the isentropic compressibility, kappa(s), became zero at 2.28 and 2.90 mol kg(-1) for Mg(OAc)2 and Mg(NO3)2 solutions, respectively, at 25 degrees C. The total hydration numbers of the dissolved ions were estimated to be, respectively, 24.3 and 19.2 at these concentrations. Differences in kappa(s) for various M2+ salts, using the present and literature data, correlated with reported M2+-OH2 bond lengths and to a lesser extent with cationic charge densities (ionic radii). The influence of anions on kappa(s) appears to follow the Hofmeister series and also correlates approximately with the anionic charge density. Substantial differences between Mg(OAc)2(aq) and Mg(NO3)2(aq) occur with respect to their structural relaxation times (derived from compressibility and viscosity data) and their electrical conductivities. These differences were attributed to a much greater ion association in Mg(OAc)2 solutions. Raman spectra recorded at 28 degrees C confirmed the presence of various types of contact ion pairs including mono- and bidentate complexes in Mg(OAc)2(aq). In Mg(NO3)2(aq), only noncontact ion pairs appear to be formed even at high concentrations. The experimental results are supported by molecular dynamics simulations, which also reveal the much stronger tendency of OAc- compared to NO3- to associate with Mg2+ in aqueous solutions. The simulations also allow an evaluation of the ion-ion and ion-water radial distribution functions and cumulative sums and provide a molecular picture of ion hydration in Mg(OAc)2(aq) and Mg(NO3)2(aq) at varying concentrations.
Publisher: CSIRO Publishing
Date: 1998
DOI: 10.1071/C97220
Abstract: A detailed study of highly concentrated aqueous alkaline aluminate solutions has been made by hydrogen electrode potentiometry in cells with liquid junction at 25°C in 8 M Na(ClO4) media. Measurements were performed over the total concentration ranges 0·1 M [NaOH]T 4·0 M and 0·02 M [AlIII]T 3·2 M, and at total concentration ratios of 6·92 ≥ [OH-]T/[AlIII]T ≥ 4·3. Nernstian electrode behaviour was observed at [NaOH]T ≤ c. 2 M in pure NaOH/NaClO4 mixtures. At low [AlIII]T the data were consistent with the formation of only the well known Al(OH)4-(aq) species but there is clear evidence of a systematic release of hydroxide as [AlIII]T and [NaOH]T increase. The data are consistent with the formation of polymeric aluminate complexes having a stoichiometry of Alq(OH)3q - rr+ (q = 4–7, q + r = 1 or 2). However, unequivocal identification of these species is difficult on account of strong correlations in the data and the possible effects of ion-pairing.
Publisher: Elsevier BV
Date: 11-1997
DOI: 10.1016/S0162-0134(97)00097-4
Abstract: There is mounting evidence that Cu(I) is the most important oxidation state of copper in many physiological systems. Research into Cu(I)-thioamino acid complex formation serves not only to improve the chelation therapy for treating copper intoxication but may also provide a better understanding of many facets of normal copper metabolism. Formation constants for the ternary mixed ligand complexes of Cu(I) with cysteine (Cys), glutathione (GSH) and penicillamine (Pen) are reported here for the first time. Potentiometric titrations, using techniques specially developed for the stabilization of aqueous Cu(I), were performed at 25 degrees C in 1.00 M (Na)Cl. It was found that precipitation severely limits the experimentally accessible pH range and, consequently, the computer analysis of the binary metal-ligand systems however, it is also found that this is less of a problem when two different ligands are present. This latter fact permitted better models of the binary systems to be developed. The formation constants of Cu(I)-thioamino acids determined in this work were used in an improved computer simulation of copper speciation in blood plasma which, for the first time, incorporates redox equilibria.
Publisher: Elsevier BV
Date: 10-1972
Publisher: American Chemical Society (ACS)
Date: 11-07-2006
DOI: 10.1021/JE060107N
Publisher: American Chemical Society (ACS)
Date: 07-07-2021
Publisher: American Chemical Society (ACS)
Date: 11-10-2010
DOI: 10.1021/JP101520H
Abstract: A detailed investigation using broadband dielectric relaxation spectroscopy (DRS) has been made of the aqueous solutions of guanidinium chloride and carbonate, GdmCl(aq) and Gdm₂CO₃(aq), at 25 °C. The spectra indicate that Gdm(+) ions, C(NH₂)₃(+), do not bind strongly to water nor are they hydrophobically hydrated rather they appear to have a most unusual ability to dissolve in water without altering its dynamics. Although DRS is particularly sensitive to the presence of ion pairs, only weak ion pairing was detected in Gdm₂CO₃(aq) solutions and none at all in GdmCl(aq). Surprisingly, no evidence was found for the existence of the higher order homo- and heteroionic nanoscale aggregates that have been identified in recent years by Mason and co-workers using molecular dynamics simulations and neutron diffraction. Possible reasons for this discrepancy are discussed. The present DR spectra and other solution properties of GdmCl(aq) and Gdm₂CO₃(aq), such as apparent molar volumes and electrical conductivities, are shown to have strong similarities to those of the corresponding Na+ salts. However, such solutions also differ remarkably from their Na(+) analogues (and all other simple electrolytes in aqueous solution) in that their average water relaxation times correlate strongly with their bulk viscosities. The biological implications of the present results are briefly discussed.
Publisher: American Chemical Society (ACS)
Date: 21-08-2003
DOI: 10.1021/IC034087B
Abstract: A detailed investigation of the iron(III)-cyanide and iron(III)-hydroxide systems has been made in NaClO(4) media at 25 degrees C, using combined UV-vis spectrophotometric and pH-potentiometric titrations. For the Fe(III)/OH- system, use of low total Fe(III) concentrations (< or =10 microM) and a wide pH range (0 < or = pH < or = 12.7) enabled detection of six mononuclear complexes, corresponding to the following equilibria: Fe3+(aq)+rH2O Fe(OH)r(3-r)+(aq) + rH(+)(aq), where r = 1-6 with stability constants (log *beta 1r) of -2.66, -7.0, -12.5, -20.7, -30.8, and -43.4, respectively, at I = 1 M (NaClO(4)). It was also found to be possible to measure, for the first time, stability constants for most of the following equilibria: Fe3+(aq)+qCN-(aq) Fe(CN)q(3-q)+(aq), despite a plethora of complicating factors. Values of log beta(1q) = 8.5, 15.8, 23.1, and 38.8 were obtained at I = 1.0 M (NaClO(4)) for q = 1-3 and 6, respectively. No reliable evidence could be obtained for the intermediate (q = 4 or 5) complexes. Similar results were obtained for both systems at I = 0.5 M(NaClO(4)). Spectra for the in idual mononuclear complexes detected for Fe(III) with OH- and CN- are reported. Attempted measurements on the Fe(II)/CN- system were unsuccessful, but values of log beta(16)(Fe(CN)(6)(4-)) = 31.8 and log beta(15)(Fe(CN)(5)(3-) approximately 24 were estimated from well established electrode potential and other data.
Publisher: Elsevier BV
Date: 05-1974
Publisher: Springer Science and Business Media LLC
Date: 12-1996
DOI: 10.1007/BF00249926
Publisher: American Chemical Society (ACS)
Date: 30-06-2007
DOI: 10.1021/JP072425E
Abstract: A systematic study of the dielectric relaxation spectra of aqueous solutions of LiCl and Li2SO4 has been made at solute concentrations of 0.05 < or = c/M < or = 1.0 and 2.0, respectively, and over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) at 25 degrees C. The spectra were best described by a superposition of four Debye processes, consisting of the two well-known water relaxations at ca. 8 and 0.5 ps and two ion-pair contributions at ca. 200 and 20 ps, corresponding to the presence of double-solvent-separated (2SIP) and solvent-shared (SIP) ion pairs, respectively. Consistent with spectroscopic studies, no contact ion pairs were detected over the studied concentration range. The overall ion association constants K(o)(A) obtained were in good agreement with literature data for both salts. Detailed analysis of the solvent relaxations indicated that Li+ has a significant second solvation sheath although there were differences between the effective hydration numbers obtained from LiCl and Li2SO4, which might arise from competition for the solvent from the anions.
Publisher: Wiley
Date: 02-03-2009
Abstract: Dielectric spectra were measured for eight, mostly imidazolium-based, room temperature ionic liquids (RTILs) over a wide range of frequencies (0.2 < or = nu/GHz < or = 89) and temperatures (5 < or = theta/degrees C < or = 65). Detailed analysis of the spectra shows that the dominant low frequency process centred at ca. 0.06 to 10 GHz (depending on the salt and the temperature) is better described using a symmetrically broadened Cole-Cole model rather than the asymmetric Cole-Davidson models used previously. Evaluation of the temperature dependence of the static permittivities, effective dipole moments, volumes of rotation, activation energies, and relaxation times derived from the dielectric data indicates that the low frequency process cannot be solely due to rotational diffusion of the dipolar imidazolium cations, as has been thought, but must also include other contributions, probably from cooperative motions. Analysis of the Debye process observed at higher frequencies for these RTILs is not undertaken because it overlaps with even faster processes that lie outside the range of the present instrumentation.
Publisher: American Chemical Society (ACS)
Date: 21-10-2011
DOI: 10.1021/JE200589F
Publisher: Elsevier BV
Date: 02-1994
Publisher: Informa UK Limited
Date: 10-2000
Publisher: AIP Publishing
Date: 07-10-2005
DOI: 10.1063/1.1842098
Abstract: The mutual solubility and related liquid-liquid equilibria of C9 hydrocarbons with water are exhaustively and critically reviewed. Reports of the experimental determination of solubility in 18 chemically distinct binary systems that appeared in the primary literature prior to the end of 2002 are compiled. For 8 systems, sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction, as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Date Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
Publisher: AIP Publishing
Date: 07-10-2005
DOI: 10.1063/1.1842097
Abstract: The mutual solubility and related liquid-liquid equilibria of C8H12–C8H18 hydrocarbons with water are exhaustively and critically reviewed. Reports of experimental determinations of solubility in 20 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 5 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used.
No related grants have been discovered for Glenn Hefter.