Modeling a Heterogeneous Cu(II)–H2O–OH––NH3 System with Data from Measuring pH

• Published in: Russian Journal of Physical Chemistry A Vol. 94; no. 12; pp. 2459 - 2466
• Main Authors: Markov, V. F., Yusupov, R. A., Bakhteev, S. A., Sitnikova, E. A., Suleimanov, A. T., Karpov, K. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2020
• Subjects: Chemistry; Chemistry and Materials Science; ON THE 100th ANNIVERSARY OF URAL FEDERAL UNIVERSITY; Physical Chemistry; aqueous solutions; mathematical model; copper(II) compounds; heterogeneous equilibria; equilibrium constant; potentiometric titration
• ISSN: 0036-0244; 1531-863X
• DOI: 10.1134/S0036024420120171

A mathematical model of the Cu(II)–H 2 O–OH – –NH 3 system is developed using experimental data obtained by analyzing data on the residual concentration and pH, allowing determination of the conditions for the formation of copper compounds in a solution and in precipitated form. The solubility with respect to the intermediate and the rule for choosing the preferred precipitate are used in the model along with the rules of the product of solubility and molecular solubility to calculate regions of the formation of a solid phase. The values of the effective equilibrium constants of homogeneous and heterogeneous processes are calculated, using the proposed model for forty compounds formed in the system. In a number of cases, the compositions of the compounds are confirmed via X-ray fluorescence, X-ray diffraction, and differential thermographic analysis. It is established that in light of new theoretical concepts, the model allows the conditions for the hydrochemical synthesis of different target compounds to be optimized and provides a more efficient way of creating a database using the final experimental results.