ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Inhibition of aluminium reaction in aqueous sodium hydroxide solution

M. Miadoková and J. Petrtýlová

Department of Physical Chemistry, Faculty of Natural Sciences, Komenský University, CS-842 15 Bratislava

Abstract: Phenol and its derivatives inhibit the dissolution of aluminium in aqueous NaOH solution with increased efficiency in the sequence: phenol, p-nitrophenol, p-aminophenol. The postulated mechanism of inhibition is based on the donor-acceptor properties of the system metal—organic substance, on the arrangement of the electrons in the molecule under the action of prevailing mesomeric effects of function groups on the aromatic rings. The expressive increase of inhibition efficiency of p-aminophenol in the presence of added Ca²⁺ ions is explained by preferred adsorption of these ions on the metal surface, consecutive shielding of its negative charge and thereby the facilitation of binding the organic molecule on the surface. Another explanation takes into consideration the possibility of creation of Ca²⁺ complexes with protective properties.

Full paper in Portable Document Format: 392a237.pdf

Chemical Papers 39 (2) 237–244 (1985)