Thermodynamics of Protonation and Sodium Binding of Sulfate in Concentrated NaCl and CsCl Solutions Studied by Raman Spectroscopy

2000 ◽  
Vol 53 (5) ◽  
pp. 363 ◽  
Author(s):  
Steven Kratsis ◽  
Glenn Hefter ◽  
Peter M. May ◽  
Pal Sipos
Keyword(s):  
Raman Spectroscopy ◽  
Excellent Agreement ◽  
Thermodynamic Data ◽  
Association Constant ◽  
Protonation Constant ◽  
Ion Pairing ◽  
Ion Pair ◽  
Enthalpy And Entropy Changes ◽  
Enthalpy And Entropy ◽  
Sodium Binding

The protonation constant (pKa) of SO42–(aq) has been determined at ionic strengths 0.5 M ≤I ≤4.0 M in NaCl and CsCl media at 25˚C by using Raman spectroscopy. These data were used to calculate the association constant of the NaSO4–(aq) ion pair in CsCl media. The results are in excellent agreement with previous values obtained by other techniques. The (pKa) was also measured at I = 4 M in both media at temperatures up to 85˚C and the associated enthalpy and entropy changes were calculated. However, reliable thermodynamic data for the ion-pairing reaction could not be obtained at higher temperatures probably because of competition from CsSO4–(aq).

Hydration of ferric chloride and nitrate in aqueous solutions: water-mediated ion pairing revealed by Raman spectroscopy

2019 ◽  
Vol 21 (35) ◽  
pp. 19172-19180
Author(s):  
Stephen M. Baumler ◽  
William H. Hartt V. ◽  
Heather C. Allen
Keyword(s):  
Raman Spectroscopy ◽  
Aqueous Solutions ◽  
Ferric Chloride ◽  
Ion Pairing ◽  
Ion Pair ◽  
Pair Formation ◽  
Ferric Ion ◽  
Ion Hydration ◽  
Ion Pair Formation

Ferric ion hydration differences are governed by ion pair formation uniquely affected by anion identity.

scholarly journals Direct measurement of enthalpy and entropy changes in NH3 promoted O2 activation over Cu‐CHA at low temperature

ChemCatChem ◽  
2021 ◽  
Author(s):  
Xueting Wang ◽  
Lin Chen ◽  
Peter N. R. Vennestrøm ◽  
Ton V. W. Janssens ◽  
Jonas Jansson ◽  
...  
Keyword(s):  
Low Temperature ◽  
Direct Measurement ◽  
O2 Activation ◽  
Entropy Changes ◽  
Enthalpy And Entropy Changes ◽  
Enthalpy And Entropy

Kinetics of Ion-Pair Effect of Aquation of Bromopentaammine Cobalt(III) Complex in Different Dicarboxylate Media

2011 ◽  
Vol 324 ◽  
pp. 166-169 ◽  
Author(s):  
Farah Zeitouni ◽  
Gehan El-Subruiti ◽  
Ghassan Younes ◽  
Mohammad Amira
Keyword(s):  
Free Energy ◽  
Solvent Effect ◽  
Compensation Effect ◽  
Ion Pairing ◽  
Reaction Rates ◽  
Ion Pair ◽  
Free Energy Of Activation ◽  
Different Types ◽  
Different Temperatures ◽  
Kinetics Of

The rate of aquation of bromopentaammine cobalt(III) ion in the presence of different types of dicarboxylate solutions containing tert-butanol (40% V/V) have been measured spectrophotometrically at different temperatures (30-600°C) in the light of the effects of ion-pairing on reaction rates and mechanism. The thermodynamic and extrathermodynamic parameters of activation have been calculated and discussed in terms of solvent effect on the ion-pair aquation reaction. The free energy of activation ∆Gip* is more or less linearly varied among the studied dicarboxylate ion-pairing ligands indicating the presence of compensation effect between ∆Hip* and ∆Sip*. Comparing the kip values with respect of different buffers at 40% of ter-butanol is introduced.

scholarly journals Conductometric studies of 1, 3, 5 –triazinothiocarbamide at different concentration and temperature

2021 ◽  
Vol 16 (2) ◽  
pp. 151-157
Author(s):  
DD Sonone ◽  
ME Shelke ◽  
DT Tayade
Keyword(s):  
Thermodynamic Parameters ◽  
Association Constant ◽  
Ion Association ◽  
Vital Role ◽  
Ion Pair ◽  
Pair Formation ◽  
Drug Diffusion ◽  
Ion Pair Formation

Conductivity plays vital role in drug diffusion. Thermodynamic parameters affected by substituents of drug. Thermodynamic parameters of 1, 3, 5 –triazinothiocarbamide (1a) have been investigated by using conductometrically carried out at different molar concentrations. This work highlights investigation of G, K and µ values. The thermodynamic parameters viz. ΔH, ΔS and ∆G for ion pair formation determine from the value of ion association constant. This technique is suitable and accurate to study of pharmokinetics and pharmodynamics parameters.

Raman Spectroscopy of Epitaxial Si/Si1-xGe, xHeterostructures

1998 ◽  
Vol 533 ◽  
Author(s):  
Ran Liu ◽  
Stefan Zollner ◽  
Ming Liaw ◽  
David O'meara ◽  
Nigel Cave
Keyword(s):  
Raman Spectroscopy ◽  
Thermal Treatment ◽  
Raman Scattering ◽  
Buffer Layer ◽  
Excellent Agreement ◽  
Lattice Mismatch ◽  
Theoretical Curve ◽  
Sum Rule ◽  
Si Substrates ◽  
Strain Coefficient

AbstractRaman scattering studies were carried out on epi Si/Si1-xGex (x = 0.1 to 0.3) heterostructures consisting of a thin Si cap layer (100 - 400 A˚), a grade-down Si1-xGex layer, a constant Si1-xGex, buffer layer and a grade-up graded Si1-xGex layer on (100) oriented Si substrates. Different Ge composition, Si1-xGex layer thicknesses and thermal treatment were used to achieve different relaxation in the Si1-xGex layers. It has been revealed that, to a very good approximation, the absolute strains in the cap Si and constant Si1-xGex layers follow a simple sum-rule that is imposed by the lattice mismatch between unstrained Si and completely relaxed Si1-x Gex. This sum rule can be used to determine the Ge composition and stresses in both cap Si and constant Si1-xGex layers. Excellent agreement was found between the theoretical curve obtained with LO phonon strain coefficient b=−930cm−1 and the experimental total strain for all samples, regardless of the degree of the relaxation of the grade-up Si1-xGex layer.

scholarly journals Reversed-Phase Ion-Pair Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Steam- Rolled Oat Baits and Steam-Rolled Oat/Wax Baits

1998 ◽  
Vol 81 (2) ◽  
pp. 349-358 ◽  
Author(s):  
Thomas M Primus ◽  
Doreen L Griffin ◽  
Stephanite A Volz ◽  
John J Johnston
Keyword(s):  
Petroleum Ether ◽  
Ion Pairing ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Extraction ◽  
Ion Pair ◽  
Limits Of Detection ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

abstract A reversed-phase ion-pair liquid chromatographic (LC) method was developed for analysis of steam-rolled oat (SRO) baits fortified with either chlorophacinone or diphacinone. Baits were prepared with and without paraffin wax. Chlorophacinone or diphacinone was extracted from wax-free SRO baits with 5 mM tetrabutylammonium phosphate methanolic ion-pairing solution. Wax baits were initially extracted with petroleum ether and then cleaned up by liquid extraction into methanolic ion-pairing solution containing 20% water. SRO extracts were analyzed with reversed-phase ion-pair LC. Chlorophacinone and diphacinone were quantified by UV absorption at 325 nm. Recoveries from SRO fortified with chlorophacinone at 25 and 150 μg/g were 90.7 and 90.8%, respectively, whereas for diphacinone at the same levels, recoveries were 93.5 and 92.3%, respectively. Recoveries from wax baits fortified at 25 and 75 μg/g chlorophacinone were 98.5 and 100%, respectively, whereas for diphacinone at the same levels, recoveries were 93.6 and 98.0%, respectively. Method limits of detection for chlorophacinone and diphacinone in SRO baits were estimated to be 1.0 and 0.76 μg/g, respectively. Method limits of detection for chlorophacinone and diphacinone in wax baits were estimated to be 4.2 and 2.8 μg/g, respectively.

scholarly journals Enhancement of Ion Pairing of Sr(II) and Ba(II) Salts by a Tritopic Ion‐Pair Receptor in Solution

ChemPhysChem ◽  
2020 ◽  
Vol 21 (17) ◽  
pp. 1957-1965
Author(s):  
Bence Kutus ◽  
Jun Zhu ◽  
Jian Luo ◽  
Qi‐Qiang Wang ◽  
Alexandru Lupan ◽  
...  
Keyword(s):  
Ion Pairing ◽  
Ion Pair

scholarly journals A THERMODYNAMIC ANALYSIS OF MITOTIC SPINDLE EQUILIBRIUM AT ACTIVE METAPHASE

1973 ◽  
Vol 57 (1) ◽  
pp. 133-147 ◽  
Author(s):  
R. E. Stephens
Keyword(s):  
Growth Conditions ◽  
Pool Size ◽  
Polarization Microscopy ◽  
Dissociation Kinetics ◽  
Mitotic Apparatus ◽  
Enthalpy And Entropy Changes ◽  
Enthalpy And Entropy ◽  
Best Fit ◽  
Two Temperature ◽  
Direct Immersion

The mitotic apparatus of first-division metaphase eggs of the sea urchin Strongylocentrotus drobachiensis was observed by means of polarization microscopy under controlled temperature conditions. Eggs were fertilized and grown at two temperature extremes in order to produce two different sizes of available spindle pool. Slow division time allowed successive samples of such cells to be observed at the same point in metaphase but at different equilibrium temperatures, yielding curves of metaphase equilibrium birefringence vs. observational temperature. Using the plateau value of birefringence at higher temperatures as a measure of total available spindle pool and the observed birefringence at lower temperatures as a measure of polymerized material at equilibrium, the spindle protein association was evaluated according to the method of Inoué. Both pool conditions produced linear van't Hoff functions. Analysis of these functions yielded enthalpy and entropy changes of +55–65 kcal/mol and +197–233 entropy units (eu), respectively. These values for active mitotic metaphase are quite comparable to those obtained by Inoué and co-workers for arrested meiotic metaphase cells. When other equilibrium treatments were considered, the best fit to the experimental data was still that of Inoué, a treatment which theoretically involves first-order polymerization and dissociation kinetics. Treatment of metaphase cells with D2O by direct immersion drove the equilibrium to completion regardless of temperature, attaining or exceeding a birefringence value equal to the cell's characteristic pool size; perfusion with D2O appeared to erase the original temperature-determined pool size differences for the two growth conditions, attaining a maximum value characteristic of the larger pool condition. These data confirm Inoué's earlier contention that D2O treatment can modify the available spindle pool.

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