NMR studies on hydrophobic interactions in solution Part 4. Temperature and concentration dependence of the hydrophobic self-association of tert-butanol in water

1999 ◽  
Vol 1 (19) ◽  
pp. 4615-4618 ◽  
Author(s):  
Manghaiko Mayele ◽  
Manfred Holz ◽  
Antonio Sacco
Keyword(s):  
Concentration Dependence ◽  
Hydrophobic Interactions ◽  
Nmr Studies ◽  
Tert Butanol ◽  
Self Association

Micellization Behaviour of Cationic Surfactants in the Presence of Food Additives: Conductance and Spectroscopic Investigations

2020 ◽  
Vol 10 ◽  
Author(s):  
Sonika Arti ◽  
Neha Aggarwal
Keyword(s):  
Glutamic Acid ◽  
Cationic Surfactants ◽  
Hydrophobic Interactions ◽  
Food Additives ◽  
Specific Conductance ◽  
Food Additive ◽  
Nmr Studies ◽  
Degree Of Ionization ◽  
Increase With Increase ◽  
Micellization Process

Aim: The micellization behavior of cationic surfactants have been studied in the presence of food additives. Objectives: Micellization behaviour of cationic surfactants, cetyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB) has been studied in water and in various concentrations of salts (food additives) L-glutamic acid, sodium propionate, sodium citrate tribasic dihydrate and disodium tartrate dihydrate at (298.15, 308.15 and 318.15) K. Methods: Two methods used in the present study are specific conductance measurements and spectroscopy (NMR) studies. Results: From the specific conductance(κ), various parameters such as critical micelle concentration (CMC), degree of ionization of micelle (α), standard Gibbs free energy (ΔGom), enthalpy (ΔHom), and entropy (ΔSom) of micellization have also been calculated. Thermodynamic parameters related to the micellization process were also analyzed through NMR studies. Conclusion: The CMC values are influenced by the presence of food additive. The magnitude of CMC values increase with increase in concentration of food additive. In all the cases, enthalpy of micellization, ∆Hom values are found to be negative whereas entropy of micellization, ∆S om values are positive which indicate that hydrophobic interactions play a major role in the micellization process. Also, NMR studies reveal that tartrate and citrate are more hydrated than glutamic acid and propionate, resulting in more downfield shift.

Self-Association of Cholesterol in Carbon Tetrachloride

1979 ◽  
Vol 34 (3) ◽  
pp. 369-374 ◽  
Author(s):  
M. Kunst ◽  
D. van Duijn ◽  
P. Bordewijk
Keyword(s):  
Dipole Moment ◽  
Carbon Tetrachloride ◽  
Concentration Dependence ◽  
Equilibrium Constants ◽  
Molar Fraction ◽  
Dilute Solutions ◽  
Dielectric Parameters ◽  
Moment Equilibrium ◽  
Self Association

Abstract Analysis of infrared hydroxyl multimer absorbances of dilute solutions of cholesterol in carbon tetrachloride as a function of the monomer absorbance strongly favours the interpretation of the association of this alcohol with a monomer-dimer-tetramer model up to a molar fraction of 0.012. This model also explains very well the concentration dependence of the apparent dipole moment. Equilibrium constants and dielectric parameters have been determined. Suggestions about the structure of the various associates are made.

1H- and13C-NMR studies ofN-acetyl-L-alanine methylester andN-acetyl-L-alanine methylamide. I. Self-association

Biopolymers ◽  
1979 ◽  
Vol 18 (2) ◽  
pp. 467-477 ◽  
Author(s):  
Tetsuo Asakura ◽  
Masaru Kamio ◽  
Atsuo Nishioka
Keyword(s):  
Nmr Studies ◽  
1H And13c Nmr ◽  
Self Association

Solvation Effects on Self-Association and Segregation Processes in tert-Butanol–Aprotic Solvent Binary Mixtures

2013 ◽  
Vol 117 (35) ◽  
pp. 10221-10230 ◽  
Author(s):  
A. R. Abdel Hamid ◽  
R. Lefort ◽  
Y. Lechaux ◽  
A. Moréac ◽  
A. Ghoufi ◽  
...  
Keyword(s):  
Binary Mixtures ◽  
Aprotic Solvent ◽  
Solvation Effects ◽  
Tert Butanol ◽  
Self Association

Assessment of Surface Tension and Viscosity of In-Zn melt

2017 ◽  
pp. 15-19 ◽  
Author(s):  
R. P. Koirala ◽  
S. K. Yadav ◽  
B. P. Singh ◽  
I. S. Jha ◽  
D Adhikari
Keyword(s):  
Surface Tension ◽  
Thermodynamic Properties ◽  
Comparative Study ◽  
Concentration Dependence ◽  
Layered Structure ◽  
Association Model ◽  
Structure Approach ◽  
Self Association ◽  
Zn Alloy ◽  
Zn Alloys

A comparative study of the concentration dependence of surface tension and viscosity of molten In-Zn alloys at 700 K has been performed using energetics, obtained from thermodynamic analysis in the framework of self-association model. The surface tension of the alloys has been calculated from the two methods, layered structure approach and self associating mixture method, and viscosity from Moelwyn-Hughes equation and Kaptay equation. The theoretically computed results for the thermodynamic properties of the alloys are found in excellent agreement with the corresponding experimental results showing that the alloy is segregating in nature. Both surface tension and viscosity of the In-Zn alloy are found to increase with the addition of Zn atoms.The Himalayan Physics Vol. 6 & 7, April 2017 (15-19)

The self-association of the cyclotide kalata B2 in solution is guided by hydrophobic interactions

Biopolymers ◽  
2013 ◽  
Vol 100 (5) ◽  
pp. 453-460 ◽  
Author(s):  
K. Johan Rosengren ◽  
Norelle L. Daly ◽  
Peta J. Harvey ◽  
David J. Craik
Keyword(s):  
Hydrophobic Interactions ◽  
The Self ◽  
Self Association
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