Title of article :
Determination of the acid dissociation constants of the p-sulphonato-calix[4]arene
Author/Authors :
Hajmalek, Monireh Department of Chemistry - Islamic Azad University - Science and Research Branch, Tehran , Khalili, Mohammad Sajjad Department of Chemistry - Faculty of Science and Engineering - Islamic Azad University - Saveh Branch, Saveh , Zare, Karim Department of Chemistry - Islamic Azad University - Science and Research Branch, Tehran , Zabihi, Omid Department of Chemistry - Islamic Azad University - Science and Research Branch, Tehran
Abstract :
The acid dissociation constants of the hydroxyl groups in 25, 26, 27, 28-tetrahydroxy-5, 11, 17, 23-tetrasulphoniccalix[
4]arene (SC4) were determined at 25οC by a combination of potentiometric and spectrophotometric titration
method. The first and second acid dissociation constants (pKa1, pKa2) were found to be 3.19 and 12.1, which
demonstrated pKa shift due to intramolecular hydrogen bonding interactions among hydroxyl groups in SC4.
Keywords :
p-sulfonatocalix[4]arene , acid–base properties , acid dissociation constant
Journal title :
Astroparticle Physics
