14 research outputs found
Spectrophotometric Study of Acid-Base Equilibria in Non-Aqueous Solvents
The equilibrium constants for the reaction of 2,6-dichloro-4-
-nitrophenol, 2,6-dinitrophenol, 2,5-dinitrophenol and 2,4-dinitrophenol
with some aliphatic amines of different structures have been
determined spectrophotometrically in chlorobenzene, ethyl acetate
and carbon tetrachloride as solvents. The data show that such
reactions in inert solvents lead essentially to ion-pairs of the type
BH+ ... A- where, HA and B represent the phenol and ·amine
molecule, respectively. This conclusions was found to be in agreement
with that obtained by other workers. In chlorobenzene as a
solvent, the basic strengths fall in the order mono < di- < tri-n-
. -butyl amine, while in ethyl acetate the order of basic strengths
becomes: mono-> di-> tri-n-butyl amine. These results are discussed
from the point of view of solvation as an important role in
the determination of the relative strengths of butylamines, as well
as the extent to which dinitrophenols are affected by chelation
between the phenolic OH and ortho-nitro group. However, in chlorobenzene
and ethyl acetate as solvents, the relative basic strengths
of pyridine and aniline derivatives remain independent of the
solvent when bromophenol blue is used as a reference acid. The
of KBH+A- values for aniline derivatives proved to be more suitable
for judging the effect of the substituent than the basic strength in
aqueous solution
Solubility of Tris(hydroxymethyl)aminomethane in Water + Methanol +1-Propanol Mixtures at Various Temperatures
Article on the solubility of tris(hydroxymethyl)aminomethane in water + methanol + 1-propanol mixtures at various temperatures
Potentiometric Study of Acid-Base Interactions in Acetonitrile
The potentiometric titration curves of acids of different types
were studied using piperidine and tetra-n-butylammonium hydroxide,
(Bu4NOH), as titrants in acetonitrile (AN) as solvent. The
effect of methanol addition on the shape of the potentiometric
curves was discussed.
The dissociation constants, KHA, and homoconjugation constants,
KHA2- , of some acids were potentiometrically determined in
AN. No exact correlation was found between KHA of the studied
acids in AN and the corresponding values-in water. It was concluded
that the acid characteristics, its anion properties, and the solvent
. type are the most important factors determining KHA2-.
The heteroconjugation constants, KAHA,- of some anions with
different acids were also determined. K AHAc values for some substituted
benzoic acids with reference to acetate ion were found to
follow a linear free energy relationship with Hammett substituent
constants
Thermodynamics ofp-nitroanilinium ion and the acidity function in ethylene carbonate-water mixtures at 25�C
Solubility Determination of Tris(hydroxymethyl)aminomethane in Water + Methanol Mixtures at Various Temperatures Using a Laser Monitoring Technique
Article on solubility determination of tris(hydroxymethyl)aminomethane in water + methanol mixtures at various temperatures using a laser monitoring technique