the acid-base equilibrium of lorazepam was studied by means of potentiometry andmultiwavelengths spectrophotometry. the stoichiometric equilibrium constants were determinedat 25 °c and constant ionic strength 0.1 mol l-1 (nacl). the acidity constants pk1=1.58±0.05and pk2=11.67±0.07 were found by potentiometry, and pk1=1.54±0.02 and pk2=11.61±0.03 bymulti-wavelengths spectrophotometry. potentiom...

a spectrophotometric method is used to determine the acidity constants of some derivatives of 9,10-anthraquinone in binary methanol-water mixtures at 25 °c. there is a linear inverse relationship between pka of all acids and the mole fraction of methanol in the mixed solvent. the influence of substituents in the molecular structure on the ionization constants is discussed.

The acid-base equilibrium of lorazepam was studied by means of potentiometry andmultiwavelengths spectrophotometry. The stoichiometric equilibrium constants were determinedat 25 °C and constant ionic strength 0.1 mol L-1 (NaCl). The acidity constants pK1=1.58±0.05and pK2=11.67±0.07 were found by potentiometry, and pK1=1.54±0.02 and pK2=11.61±0.03 bymulti-wavelengths spectrophotometry. Potentiom...

In this work the acidity constants of Thiamine in water and water-Triton X-100 micelle media solutions, at 25 °C, have been determined spectrophotometrically. To evaluate the pH- absorbance data, a resolution based on the combination of soft-and hard-modeling is applied. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to a...

The acidity constants of 4-(2-pyridylazo)resorcinol (PAR, Scheme 1) in binary mixtures of methanol–water at 25 ◦C and an ionic strength of 0.1 M have been determined spectrophotometrically. DATa ANalysis (DATAN) program applied for determination of acidity constants. As percent of methanol increases in solvent mixtures the pKa constants also increased. There is linear relationship between acidi...

in this work the acidity constants of thiamine in water and water-triton x-100 micelle media solutions, at 25 °c, have been determined spectrophotometrically. to evaluate the ph- absorbance data, a resolution based on the combination of soft-and hard-modeling is applied. the acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an es...

: In this work, different levels of theory containing HF, B3LYP, and MP2 with different basis sets such as 6-31G, 6-31G*, 6-311G, 6-311+G, 6-31+G*, 6-31+G are used to predict relative acidity constants of some aniline derivatives. Three different kinds of radii containing UAHF, Bondi, and Pauling are used to study how cavity forms change acidity constants. In all cases, DPCM model is used to si...

A spectrophotometric method is used to determine the acidity constants of some derivatives of 9,10-anthraquinone in binary methanol-water mixtures at 25 °C. There is a linear inverse relationship between pKa of all acids and the mole fraction of methanol in the mixed solvent. The influence of substituents in the molecular structure on the ionization constants is discussed.  

: in this work, different levels of theory containing hf, b3lyp, and mp2 with different basis sets such as 6-31g, 6-31g*, 6-311g, 6-311+g, 6-31+g*, 6-31+g are used to predict relative acidity constants of some aniline derivatives. three different kinds of radii containing uahf, bondi, and pauling are used to study how cavity forms change acidity constants. in all cases, dpcm model is used to si...