NMR studies on hydrophobic interactions in solution Part 5. Effect of urea on the hydrophobic self-association of tert-butanol in water at different temperatures

2000 ◽  
Vol 2 (10) ◽  
pp. 2429-2434 ◽  
Author(s):  
Manghaiko Mayele ◽  
Manfred Holz
Keyword(s):  
Hydrophobic Interactions ◽  
Nmr Studies ◽  
Tert Butanol ◽  
Different Temperatures ◽  
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.

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

Pressure- and temperature-induced unfolding studies: thermodynamics of core hydrophobicity and packing of ribonuclease A

2006 ◽  
Vol 387 (3) ◽  
pp. 285-296 ◽  
Author(s):  
Josep Font ◽  
Antoni Benito ◽  
Joan Torrent ◽  
Reinhard Lange ◽  
Marc Ribó ◽  
...  
Keyword(s):  
Hydrophobic Interactions ◽  
Rnase A ◽  
Van Der Waals Interactions ◽  
Hydrophobic Core ◽  
Experimental Conditions ◽  
Unfolded State ◽  
Different Temperatures ◽  
Methylene Groups ◽  
The Stability ◽  
Core Packing

Abstract In this work we demonstrate that heat and pressure induce only slightly different energetic changes in the unfolded state of RNase A. Using pressure and temperature as denaturants on a significant number of variants, and by determining the free energy of unfolding at different temperatures, we estimated the stability of variants unable to complete the unfolding transition owing to the experimental conditions required for pressure experiments. The overall set of results allowed us to map the contributions to stability of the hydrophobic core residues of RNase A, with the positions most critical for stability being V54, V57, I106 and V108. We also show that the stability differences can be attributed to both hydrophobic interactions and packing density with an equivalent energetic magnitude. The main hydrophobic core of RNase A is tightly packed, as shown by the small-to-large and isosteric substitutions. In addition, we found that large changes in the number of methylene groups have non-additive positive stability interaction energies that are consistent with exquisite tight core packing and rearrangements of van der Waals' interactions in the protein interior, even after drastic deleterious substitutions.

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

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

NMR Studies on the Self-Association of Uridine and Uridine Analogues

1998 ◽  
Vol 4 (4) ◽  
pp. 621-628 ◽  
Author(s):  
Anita Dunger ◽  
Hans-Heinrich Limbach ◽  
Klaus Weisz
Keyword(s):  
The Self ◽  
Nmr Studies ◽  
Self Association

scholarly journals Synthesis of Novel Corrosion Inhibitor N-(1,3-Benzothiazol-2-yl)-4-aminobenzamide in 1 N Hydrochloric Acid Medium

2021 ◽  
Vol 33 (3) ◽  
pp. 622-626
Author(s):  
Senthilkumar Gopal ◽  
Umarani Chinnasamy ◽  
Ramachandran Arumugam
Keyword(s):  
Hydrochloric Acid ◽  
Corrosion Inhibitor ◽  
Acid Medium ◽  
Inhibition Efficiency ◽  
Nmr Studies ◽  
Steel Material ◽  
Hydrochloric Acid Medium ◽  
Different Temperatures ◽  
Corrosion Inhibition Efficiency ◽  
Loss Method

A novel corrosion inhibitor i.e. N-(1,3-benzothiazol-2-yl)-4-aminobenzamide was synthesized and its corrosion inhibitor on controlling the rate of mild steel material in hydrochloric acid medium (1 N) at different temperatures was investigated. Rate of corrosion and inhibition efficiency were analyzed and calculated using mass loss method and electrochemical studies. As the concentration of the inhibitor increase the inhibitor efficiency also increases gradually with decrease in the rate of corrosion. Therefore from this study the efficiency of the inhibitor was good at different temperature in 1 N HCl. The relative corrosion inhibition efficiency of synthesized organic compound has been explained on the basis of its structure dependent-electron donating properties of the inhibitor. Further the structure and compound present in the synthesized organic inhibitor compound was confirmed by FTIR and NMR studies.

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