Determining Thermodynamics of the Second Dissociation Constants of Protonated Piperazine-N, N′-bis-2-Hydroxypropane-Sulfonic Acid POPSO at Different Temperatures from 278.15 to 328.15 K | Chapter 1 | Chemistry and Biochemistry: Research Progress Vol. 1

The second acidic dissociation constants of protonated piperazine-N, N′-bis-2-hydroxypropane-sulfonic acid (POPSO sesquisodium salt) have been determined at 12 different temperatures (from 278.15 to 328.15) K including 310.15 K. Electromotive-force measurement technique was used employing hydrogen-silver chloride cells without liquid junction. The results of pK₂ are given by the equation: pK2 = -1041.77/T + 51.0459 - 6.97646lnT. The uncertainty of the fit is ±0.0008. At 289.15 K, pK₂ = 7.8029; whereas, at 310.15 K (body temperature), pK2 = 7.6862. Thus, the buffer solutions of POPSO and its sodium salt are useful for pH control in the physiological pH region of (7.0 to 8.5). The changes of Gibbs free energy (∆G°), enthalpy (∆H°), entropy (∆S°) and heat capacity ∆Cp° were computed from the temperature derivative of the pK2 for the dissociation of the zwitterionic acid POPSO±^-3 = POPSO^-4 + H⁺ in the standard state. At 298.15 K, these results are compared with those of similar components, which are the derivatives of the parent compounds TAURINE, PIPERAZINE and MORPHOLINE.

These results (slight increase in ∆Cp° of POPSO) suggest that the substitution and the presence of an extra monosodium POPSO molecule in POPSO disodium salt apparently have two effects: 1) progressive increase of hydrophobic characters (tending to increase ∆Cp°), and 2) some changes in the solvation pattern, that is, progressively greater steric hindrance (tending to increase ∆Cp° value by exclusion of solvent).

 

Author (s) Details

 

Rabindra N. Roy
Hoffman Department of Chemistry, Drury University, Springfield, MO, USA.

 

Lakshmi N. Roy
Hoffman Department of Chemistry, Drury University, Springfield, MO, USA.

 

Katherine E. Hundley
Hoffman Department of Chemistry, Drury University, Springfield, MO, USA.

 

Taylor R. Wehmeyer
Hoffman Department of Chemistry, Drury University, Springfield, MO, USA.

 

Lucas S. Tebbe
Hoffman Department of Chemistry, Drury University, Springfield, MO, USA.

 

Please see the book here:- https://doi.org/10.9734/bpi/cbrp/v1/3470

Using New Azo Derivative and Its Analytical Applications for Liquid-Liquid Extraction of Cobalt (II) Ion | Chapter 4 | Current Innovations in Chemical and Materials Sciences Vol. 8

The study of solvent extraction of Cobalt (II) ion by a new azo derivative of 8-Hydroxyquinolin (DPDQ), had been synthesized. Many effected parameters on the extraction process were studied. Solvent extraction is a mature technique in that extensive experience has led to a good understanding of the fundamental chemical reactions. At the same time, when compared with many other chemical separation processes like precipitation, distillation, or pyro metallurgical treatment, the large-scale application is solvent extraction. Parameters such as: acidity of the medium was found to be equal to pH of 10, the equilibrium time for the extraction was ten minutes, polarity of solvents showed the effectiveness of dielectric constant of solvents on extraction process, interference of some anion(s) and cation(s) effected on extraction,; optimum metal concentration that used in extraction method; effect of different salts such as: Sodium chloride, Sodium nitrate, etc. and effect of temperature which showed the stability of extracted complex at different temperatures were considered. The thermodynamic functions (∆H,∆G,∆S) were calculated and they showed that the reaction between the ligand and the metal ion was exothermic and spontaneous. The extraction stoichiometry was studied using two methods: Job's and Molar ratio. It was found to be (M: L) (1:2) the shape of complex was octahedral. The constant of stability of complex using the mole ration method was calculated. The spectroscopy of UV-visible, F.T.I. R, HNMR, CNMR, and mass were studied for both the reagent and complex in organic phase that identified the ligand and complex. Other physical constants such as melting point and conductivity were studied. Some biological species and drugs were used to extract Cobalt ion from its applications. From this research it was found the new ligand can be used to extract the Co2+ from biological and drug samples with good results.

Author(s) Details:

Hussein Mubarak Mohsin,
Department of Chemistry, Faculty of Science, University of Kerbala, Karbala, Iraq.

Alaa Frak Hussain,
Department of Chemistry, Faculty of Science, University of Kerbala, Karbala, Iraq.

Please see the link here: https://stm.bookpi.org/CICMS-V8/article/view/14091