Effect of halo-substituted aromatic salts on counterion binding constants obtained from cationic nanoparticle catalyzed reactions of piperidine and phenyl salicylate

2017 ◽  
Author(s):  
Ibrahim I. Fagge ◽  
Nor Saadah M. Yusof ◽  
Sharifuddin Md Zain ◽  
M. Niyaz Khan
Keyword(s):  
Binding Constants ◽  
Counterion Binding ◽  
Phenyl Salicylate ◽  
Catalyzed Reactions

Groundwater remediation by anionic surfactant micelles - an innovative double layer model applied to Na+ and Mg2+ association with dodecylsulfate micelles

1998 ◽  
Vol 38 (7) ◽  
pp. 99-106 ◽  
Author(s):  
Ching Yuan ◽  
Chung-Hsuang Hung ◽  
Chad T. Jafvert
Keyword(s):  
Anionic Surfactant ◽  
Groundwater Remediation ◽  
Electrical Potential ◽  
Binding Constants ◽  
High Concentration ◽  
Experimental Conditions ◽  
Counterion Binding ◽  
Double Layer Model ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation

The association reactions involving counterions, Na+ and Mg2+, and micelles composed of the anionic surfactant, dodecylsulfate (DS−), were investigated in ultrafiltration experiments. To access the data, an innovative model was developed that considered specific counterion binding within a Stern layer, with binding constant dependent upon the electrical potential as derived by the Poisson-Boltzmann equation and with calculation of the cmc as a function of counterion binding (or association). The experimental and model results both show that magnitude of counterion binding is greater for divalent species, Mg2+, than that for the monovalent species, Na2+. However, high concentration of Na+ compete for surface area diminishing the ability of the DS− to bind either divalent species. At experimental conditions from 0 to 100 mM NaCl addition, the binding ratio (BR) varied only from 0.58 to 0.63. The optimum binding constants, KMg and KNa, were determined to be 0.4 and 1.0 L mol−1, respectively, for the model. The experimental data and model calculated results were generally in good agreement.

Influence of mixed CTABr–C16E20 nanoparticles on relative counterion binding constants in aqueous solutions of inert salts (2-NaOC6H4CO2Na and NaBr): kinetic and rheometric study

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95504-95511 ◽  
Author(s):  
Ibrahim I. Fagge ◽  
Khalisanni Khalid ◽  
M. Azri M. Noh ◽  
Nor Saadah M. Yusof ◽  
Sharifuddin Md Zain ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Binding Constants ◽  
Counterion Binding ◽  
Semi Empirical ◽  
Salicylate Ion

A semi-empirical kinetic technique has been used to obtain the ratios of pure CTABr (cationic nanoparticle) and mixed CTABr–C16E20 (cationic–nonionic nanoparticle) micellar binding constants of counterions X and Br, KX/KBr (=KBrX or RBrX) for X = salicylate ion.

scholarly journals Kinetics and Mechanism of Nanoparticles-Catalyzed Piperidinolysis of Anionic Phenyl Salicylate

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Norazizah Abd. Razak ◽  
M. Niyaz Khan
Keyword(s):  
Rate Constants ◽  
Binding Constant ◽  
Cetyltrimethylammonium Bromide ◽  
Catalytic Effect ◽  
Binding Constants ◽  
Bulk Water ◽  
Kinetics And Mechanism ◽  
Water Phase ◽  
Phenyl Salicylate ◽  
Spherical Micelles

The values of the relative counterion (X) binding constantRXBr(=KX/KBr, whereKXandKBrrepresent cetyltrimethylammonium bromide, CTABr, micellar binding constants ofXv-(in non-spherical micelles),v=1,2, and Br−(in spherical micelles)) are 58, 68, 127, and 125 forXv−=1−, 12−, 2−, and22-, respectively. The values of 15 mM CTABr/[NavX] nanoparticles-catalyzed apparent second-order rate constants for piperidinolysis of ionized phenyl salicylate at 35°C are 0.417, 0.488, 0.926, and 0.891 M−1 s−1forNavX= Na1, Na21, Na2, and Na22, respectively. Almost entire catalytic effect of nanoparticles catalyst is due to the ability of nonreactive counterions,Xv-, to expel reactive counterions,3−, from nanoparticles to the bulk water phase.

Calculating Melting Temperature of Native and Modified Oligonucleotide Complexes at Various Cation Concentrations with the Use of Enhanced Counterion Condensation Model

2010 ◽  
Vol 3 (2) ◽  
pp. 61-75
Author(s):  
Aleksandr A. Lomzov ◽  
Dmitriy V. Pyshnyi
Keyword(s):  
Thermal Stability ◽  
Ionic Strength ◽  
Melting Temperature ◽  
Binding Constants ◽  
Data Sets ◽  
Dna Duplexes ◽  
Counterion Binding ◽  
Cation Concentration ◽  
Wide Range ◽  
Thermal Stability Of

A new model describing the influence of ionic strength on thermal stability of DNA comlexes of oligonucleotides is proposed. This model assumes that binding of cations with DNA polyanions influences solely the entropy of hybridization and has a saturating mode. The efficacy of counterion binding with single- and double-stranded DNA is different, and the number of cations which bind additionally with the oligonucleotide at duplex formation depends on bulk cation concentration. Analytical equations describing the influence of cation concentration on melting temperature of DNA-duplexes as function of the length of oligonucleotide, its GC-composition and presence of the modification (non-nucleotide insert) were obtained. The values of melting temperature (Tm ) and thermodynamic parameters ( o ∆H , o ∆S ) characterizing the hybridization of both native and «bridged» oligonucleotides (bearing non-nucleotide insert on the basis of diethylene glycol phosphodiester) with DNA in various concentrations of NaCl (0,01÷1 М) were obtained using the UV-melting technique. Based on both the data obtained and presented in literature the database (695 data sets) characterizing the influence of ionic strength on the thermal stability of oligonucleotide complexes of various structure is developed. The database analysis allows us to obtain the values of the equilibrium binding constants for condensation of caions on DNA and the number of ions required for saturation of a discrete binding site. The proposed enhanced model of cation condensation utilizing unified thermodynamic increments of dsDNA formation allows us to calculate melting temperatures of DNAduplexes in the wide range of ionic strength ([Na+] = 0,01÷1 М) with high accuracy.

Titration Simulations for Understanding of the Binding Equilibrium

2020 ◽  
Author(s):  
Dae Hyup Sohn
Keyword(s):  
Equilibrium Model ◽  
Binding Sites ◽  
Binding Constants ◽  
Reliability Evaluation ◽  
Binding Isotherm ◽  
Guest Chemistry

<p>The reliability evaluation of the predicted binding constants in numerous models is also a challenge for supramolecular host-guest chemistry. Here, I briefly formulate binding isotherm with the derivation of the multivalent equilibrium model for the chemist who wants to determine the binding constants of their compounds. This article gives an in-depth understanding of the stoichiometry of binding equilibrium to take divalent binding equilibria bearing two structurally identical binding sites as an example. The stoichiometry of binding equilibrium is affected by (1) the cooperativity of complex, (2) the concentration of titration media, and (3) the equivalents of guests. The simulations were conducted with simple Python codes.</p>

A Boronic Acid-Based Fluorescence Hydrogel for Monosaccharide Detection

2018 ◽  
Author(s):  
Suying Xu ◽  
Adam Sedgwick ◽  
Souad Elfecky ◽  
Wenbo Chen ◽  
Ashley Jones ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Boronic Acid ◽  
Binding Constants ◽  
Strong Fluorescence ◽  
Fluorescence Response ◽  
Turn On ◽  
Fluorescence Turn On ◽  
Hydrogel System

<p>A boronic acid-based anthracene fluorescent probe was functionalised with an acrylamide unit to incorporate into a hydrogel system for monosaccharide detection<i>. </i>In solution, the fluorescent probe<b> </b>displayed a strong fluorescence turn-on response upon exposure to fructose, and an expected trend in apparent binding constants, as judged by a fluorescence response where D-fructose > D-galactose > D-mannose > D-glucose. The hydrogel incorporating the boronic acid monomer demonstrated the ability to detect monosaccharides by fluorescence with the same overall trend as the monomer in solution with the addition of fructose resulting in a 10-fold enhancement (≤ 0.25 M). <b><u></u></b></p>

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