Physical Chemistry of Aqueous Systems: Meeting the Needs of Industry

ISBN Print: 978-1-56700-034-4

ISBN Online: 978-1-56700-445-8

A POTENTIOMETRIC STUDY OF THE HYDROLYSIS OF ETHYLENEDIAMINETETRAACETIC ACID TO 150°C

DOI: 10.1615/ICPWS-1994.1020
pages 809-815

要約

Ethylenediaminetetraacetate anions, EDTA4-, were titrated in a hydrogen-electrode concentration cell with an acidic titrant from 0 to 150°C at 25°C intervals. These titrations were carried out in the presence of the supporting electrolytes, sodium chloride (NaCl, 0.1, 0.2, and 1.0 mol∙kg-1) and tetramethylarnmonium trifluoromethylsulfonate, {(CH3)4N(F3CSO3) or TMATFMS, 1.0 mol∙kg-1} in order to assess the effect of both cation complexation by EDTA4- and anion activity coefficient variations. The resulting hydrolysis quotients are discussed with reference to applications in boiler and heat exchanger chemical cleaning, as well as chemical and nuclear waste containment. Some recent diverse uses of this emf technique that also pertain to these applications will be mentioned briefly, e.g., surface absorption -zero-point-of-charge - measurements to high temperatures and in situ pH measurements in solubility and kinetic experiments.