The acidity constants of some amino acids (Am) were determined by potentiometric pH titration. The stability constants of the 1:1 complexes formed between M2+: Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+ or Zn2+ and Am2-, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that the stability of the bi...

Very strong organic acids (acid groups ionized at pH 3.0) represent a significant portion of the total acidity (4--25%) in samples of organic matter isolated from two lakes, a landfill leachate, and a Krafft mill effluent. On the basis of model compound behavior and established complexation constants, these very strongly acidic groups are predicted to be the key to the formation of strong surfa...

The acidity constants of some amino acids (Am) were determined by potentiometric pH titration. The stability constants of the 1:1 complexes formed between M2+: Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+ or Zn2+ and Am2-, were determined by potentiometric pH titration in aqueous solution (I = 0.1 M, NaNO3, 25°C). The order of the stability constants was reported. It is shown that the stability of the bi...

This work aimed to the study effect of ethanol ratios on acidity constants bromocresol purple. The BCP were determined in binary mixtures water with containing 0, 30, 40, 50, 60, and 70% (v/v) using spectrophotometric methods. results indicate dependence ratio ethanol. values log10Ka1 log10Ka2 correlated macroscopic (relative permittivity, ε) microscopic Kamlet–Taft parameters (α, β, π*) mixtur...

Ab initio molecular dynamics delivers the two thermodynamic pathways opened for reduction of CO 2 to HCOOH in aqueous media after first electron transfer and acidity constants intermediates (COOH HCOO) each pathways.

Vapor adsorption is an important process influencing the migration and the fate of many organic pollutants in the environment. In this study, vibrational sum frequency generation (SFG) spectroscopy was used to study the adsorption of two surface acidity probe molecules, 4-picoline (pKa = 5.94) and piperidine (pKa = 11.24), onto the amorphous SiO2 surface. The adsorption of 4-picoline onto the s...

Sulfate esters have recently been identified in the secondary organic aerosol (SOA) formed in the photooxidation of biogenic hydrocarbons both in laboratory and under ambient atmospheric conditions. In the present study, the kinetics feasibility of direct reactions between alcohols and sulfuric acid to form sulfate esters in aerosol particles is explored. Nuclear magnetic resonance methods were...

The acidity constants of some synthesized protonated pyrazolo quinazoline compounds were determined potentiometrically at ionic strength of 0.1 M in DMF: water (60:40 v/v) system at different temperatures (298.15 K to 318.15 K). The pKa values have been found to increase with increasing electron-donating nature of substitutions. Some thermodynamics parameters such as enthalpy (ΔH°), Gibb’s free...