Effect of temperature and solvents on ultrasonic velocity and thermodynamic parameters of 1,3,4-oxadiazole derivative solutions

2012 ◽  
Vol 168 ◽  
pp. 28-35 ◽  
Author(s):  
D.R. Godhani ◽  
P.B. Dobariya ◽  
A.M. Sanghani
2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ayssar Nahlé ◽  
Ideisan I. Abu-Abdoun ◽  
Ibrahim Abdel-Rahman

The inhibition and the effect of temperature and concentration of trans-4-hydroxy-4′-stilbazole on the corrosion of mild steel in 1 M HCl solution was investigated by weight loss experiments at temperatures ranging from 303 to 343 K. The studied inhibitor concentrations were between  M and  M. The percentage inhibition increased with the increase of the concentration of the inhibitor. The percentage inhibition reached about 94% at the concentration of  M and 303 K. On the other hand, the percentage inhibition decreased with the increase of temperature. Using the Temkin adsorption isotherm, the thermodynamic parameters for the adsorption of this inhibitor on the metal surface were calculated. Trans-4-hydroxy-4′-stilbazole was found to be a potential corrosion inhibitor since it contained not only nitrogen and oxygen, but also phenyl and pyridine rings that are joined together with a double bond (–C=C–) in conjugation with these rings.


2021 ◽  
Vol 18 (39) ◽  
pp. 14-32
Author(s):  
Hind Sadiq Al-WARD ◽  
Mouayed Qassssim AL-ABACHI ◽  
Mohammed Rifaat AHMED

Background: Tetracycline is one of the most important antibiotics. It is used to treat many different bacterial infections. It is often used in treating severe acne, or sexually transmitted diseases such as syphilis, gonorrhea, or chlamydia. In some cases, tetracycline is used when penicillin or another antibiotic cannot be used to treat serious infections such as the ones caused by Bacillus anthracis, Listeria, Clostridium, Actinomyces. Aim: synthesized a new novel reagent used to determine TCH spectrophotometrically by using diazonium and coupling reaction. Methods: Four new substituted procaine derivatives were prepared by simple organic methods using aniline derivatives. A spectrophotometric approach was established for the micro-determination of TCH. The stoichiometry was investigated using mole ratio and continuous variation methods, and the stability constant was also estimated. The ΔG, ΔH, and ΔS were determined as thermodynamic parameters for evaluating the effect of temperature on the reaction. Results: Substituted procaine derivatives were prepared, and o-hydroxy procaine seems to be the best reagent used to determine TCH by diazotization and coupling reaction. The result was a yellow water-soluble dye with a maximum absorbance of 380 nm. The reaction conditions were studied and optimized. Beers law was obeyed over a concentration range (2.5–50) μg.mL-1 for TCH. The molar absorptivity was (14.4669.103) L.mol-1.cm-1, and the detection limit was (0.5052) μg.mL-1. The stoichiometry of the formed product was found 1:1 (o-hydroxyprocaine: TCH). The stability constant indicated that the product formed was stable, and the thermodynamic parameters showed that the diazonium salt reaction was preferred to occur at a low temperature. Conclusions: a simple, accurate, and fast method was developed to determine TCH in pure form and pharmaceuticals by coupling the TCH with a newly synthesized procaine derivative reagent (o-hydroxy procaine) in a basic medium.


Author(s):  
A.B. Naik

Density, ultrasonic velocity of pure solvent, dimethylformamide (DMF) and ligand solutions of substituted thiazoles in DMF-water mixture were measured at different temperatures (303.15, 308.15, 313.15 and 318.15) K. Acoustical parameters such as adiabatic compressibility, intermolecular free length, acoustical impedance and relative association were determined from experimental data of density and ultrasonic velocity. The effect of temperature variations on the strength of molecular interaction has also been studied. An excellent correlation represents in terms of solute-solvent and solvent-solvent interaction at all temperatures.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Huai-Shuai Shang ◽  
Ting-Hua Yi

For use in fire resistance calculations, the relevant thermal properties of high-performance concrete (HPC) with fly ash were determined through an experimental study. These properties included compressive strength, cubic compressive strength, cleavage strength, flexural strength, and the ultrasonic velocity at various temperatures (20, 100, 200, 300, 400 and 500∘C) for high-performance concrete. The effect of temperature on compressive strength, cubic compressive strength, cleavage strength, flexural strength, and the ultrasonic velocity of the high-performance concrete with fly ash was discussed according to the experimental results. The change of surface characteristics with the temperature was observed. It can serve as a reference for the maintenance, design, and the life prediction of high-performance concrete engineering, such as high-rise building, subjected to elevated temperatures.


2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Ayssar Nahlé ◽  
Ideisan I. Abu-Abdoun ◽  
Ibrahim Abdel-Rahman

The corrosion inhibition of mild steel in 1 M HCl solution by a synthesized compound (3-benzoylmethyl benzimidazolium hexafluoroantimonate) was investigated electrochemically and by weight loss experiments. The concentration of this inhibitor ranged from5 ×10-7 M to5×10-4 M. The effect of temperature (from 303 to 343 K) and concentrations (from5×10-7 M to5×10-4 M) were investigated. The percentage inhibition increased with the increase of the concentration of the inhibitor and reached about 98% at the concentration of5×10-4 M at 303 K. The percentage inhibition decreased with the increase of temperature. The thermodynamic parameters for the adsorption of this inhibitor on the metal surface were calculated. This compound was found to be a very good corrosion inhibitor due to the presence of nitrogen in benzimidazole and phenyl ring.


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