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.

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.

Energetics of the encapsulation of o-, m-, and p-hydroxybenzoic acids by β-cyclodextrin and its methylated and hydroxypropylated derivatives in aqueous solution

1999 ◽  
Vol 77 (3) ◽  
pp. 348-355 ◽  
Author(s):  
Elena Junquera ◽  
Valentin G Baonza ◽  
Emilio Aicart
Keyword(s):  
Aqueous Solution ◽  
Inclusion Complex ◽  
Aqueous Solutions ◽  
Inclusion Complexes ◽  
Binding Constant ◽  
Substituent Effect ◽  
Binding Constants ◽  
Hydroxybenzoic Acid ◽  
Guest Molecules ◽  
Hydroxybenzoic Acids

A fully computerized potentiometric technique has been used to analyze the energetics of the encapsulation of o-, m-, and p-hydroxybenzoic acids by β-cyclodextrin (β-CD) and (or) two of its most used derivatives: 2,6-di-O-methyl-β-cyclodextrin (DIMEB) and hydroxypropyl-β-cyclodextrin (HPBCD). The study has been carried out by measuring the pH of aqueous solutions of the three hydroxyacids in the absence of cyclodextrin at 25°C, and in the presence of cyclodextrin at several temperatures ranging from 15 to 40°C, keeping constant the concentration of the guest. The dissociation constant of the acids and the binding constants of the inclusion complexes formed have been simultaneously determined at all the temperatures by using a model previously derived by us. The carboxylic forms have been found to bind the CD with higher affinities than the carboxylate partners do, irrespective of the temperature, the cyclodextrin used, and the position of the substituents on the guest molecules. The formation of the inclusion complexes studied in this work has been found to be enthalpy driven, with a favorable enthalpic term dominant over an unfavorable entropic one. The effect of the substituents of both guest and host molecules on the thermodynamics of the inclusion processes has been analyzed. Key words: binding constant, β-cyclodextrin, hydroxybenzoic acid, inclusion complex, substituent effect.

scholarly journals Kinetics and Mechanism of Counterionic Salt-Catalysed Piperidinolysis of Anionic Phenyl Salicylate in the Presence of Cationic–Nonionic Mixed Micelles

2018 ◽  
Vol 43 (1) ◽  
pp. 41-52
Author(s):  
Ibrahim I. Fagge ◽  
W. Hamdah W. Ahmad ◽  
Sharifuddin Md Zain ◽  
M. Niyaz Khan
Keyword(s):  
Nonionic Surfactant ◽  
Binding Constants ◽  
Mean Value ◽  
Hexadecyltrimethylammonium Bromide ◽  
Quantitative Correlation ◽  
Cationic Micelles ◽  
Micellar Growth ◽  
Spherical Micelles ◽  
Poly Ethylene ◽  
Semi Empirical

The quantitative correlation of counterion-affinity to aqueous hexadecyltrimethylammonium bromide (HDAB, cationic micelles/nanoparticles) and the counterion-induced HDAB micellar growth, in the presence of different amounts of poly(ethylene glycol hexadecyl ether) (C16E20, nonionic surfactant), was achieved by the use of a semi-empirical kinetic (SEK) method. The values of the ratio of cationic HDAB, as well as mixed HDAB–C16E20, micellar binding constants of X and Br, KX/ KBr (= KXBr or RXBr) for X = 4-ClC6H4CO2-, were obtained by the SEK method. The concentration range (0.006–0.015 M) of pure HDAB was found to have no influence on the values of KXBr or RXBr. These observations were also recorded upon addition of a nonionic surfactant, C16E20, in an aqueous solution of HDAB. The mean value of KXBr or RXBr obtained in the presence of pure HDAB ( KXBr or RXBr = 50.3) is 2.3 times larger than that in the presence of mixed HDAB–C16E20 (m KXBr or m RXBr = 21.7). From rheometric measurements of aqueous HDA+/4-ClC6H4CO2- with 0.015 M HDAB, single symmetric maxima (at both 25 and 35 °C) were obtained at [4-ClC6H4CO2Na] = 0.03 M. This is evidence for the existence of wormlike micelles/nanoparticles. However, the absence of a maximum in rheometric data for aqueous HDA+/C16E20/4-ClC6H4CO2- with 0.015 M HDAB and 0.006 M C16E20 at various [4-ClC6H4CO2Na] revealed the existence of spherical micelles.

An Influence of the Spatial Arrangement, Length of the Alkyl Chain and Temperature on Micellar Properties of N-Alkyl-N-{[2-(benzyloxy)cyclohexylmethyl]}-N,N-dimethylammonium Bromides in Aqueous Solutions

1997 ◽  
Vol 62 (12) ◽  
pp. 1853-1862 ◽  
Author(s):  
Jarmila Oremusová ◽  
Veronika Mislovičová
Keyword(s):  
Aqueous Solutions ◽  
Alkyl Chain ◽  
Spatial Arrangement ◽  
Critical Micellar Concentration ◽  
Small Decrease ◽  
Counterion Binding ◽  
Micellar Properties ◽  
Fold Reduction ◽  
Increasing Temperature ◽  
Methylene Group

In this work we study influence of the length of the alkyl chain and temperature on critical micellar concentration (CMC) for cis and trans diastereoisomers of the N-alkyl-N-{[2-(benzyloxy)cyclohexylmethyl]}-N,N-dimethylammonium bromides in aqueous solutions using conductometric and spectrophotometric techniques. From the measured dependences, the degree of the counterion binding (β) and thermodynamic parameters of micellization (∆Gm0, ∆Hm0, ∆Sm0) were calculated and compared with the literature data on similar compounds. The results show that lengthening of the alkyl chain by one methylene group causes approximately a two-fold reduction in CMC. The β values decrease with temperature and with increasing length of the alkyl chain. While only a small decrease in the ∆Gm0 values (ca 1 kJ mol-1) due to increasing temperature was found, the decrease in ∆Hm0 is much more pronounced.

Semi-empirical proton binding constants for natural organic matter

2010 ◽  
Vol 74 (6) ◽  
pp. 1836-1851 ◽  
Author(s):  
Anthony Matynia ◽  
Thomas Lenoir ◽  
Benjamin Causse ◽  
Lorenzo Spadini ◽  
Thierry Jacquet ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Binding Constants ◽  
Proton Binding ◽  
Semi Empirical

scholarly journals Counterion Binding in Aqueous Solutions of Poly(vinylpyridines) as Assessed by Potentiometric Titration

2016 ◽  
Vol 06 (09) ◽  
pp. 249-261 ◽  
Author(s):  
Jim D. Roach ◽  
Mandy M. Bondaruk ◽  
Abdulaziz Al-Abdulghani ◽  
Zaid Shahrori
Keyword(s):  
Aqueous Solutions ◽  
Potentiometric Titration ◽  
Counterion Binding
Sign in / Sign up

Export Citation Format

Share Document