Related Experiment Video
Updated: Jun 28, 2026

Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
Reliability of protonation constants of SNAZOXS oligomers
1Department of Analytical Chemistry, University of Chemical Technology, 532 10 Pardubice, Czech Republic.
Abstract:
Concentration protonation constants of variously protonated of oligomers of sulphoazoxine SNAZOXS were determined by regression analysis of potentiometric titration curves. The group and common parameters were estimated using different computational strategies of three regression programs, MINIQUAD, MIQUV and PSEQUAD. ANOVA proved that six various computational strategies of three regression programs have no significant influence on reliability of protonation constants estimated in comparison with the reproducibility of the titration. Chemical model of protonation equilibria L(2)H(5-), L(2)H(4-)(2), L(2)H(3-)(3), and L(2)H(2-)(4) and reaction scheme of oligomers protonation for SNAZOXS was found.
Related Concept Videos
SN1 Reaction: Mechanism
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a polar...
Polyprotic Acids
Titration of Polyprotic Acids with a Strong Base
Predicting Products: SN1 vs. SN2
With increased substitution on the alkyl halide,...
Titration of a Polyprotic Acid
SN1 Reaction: Stereochemistry
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...

