Anticorrosion Properties of 8-Oxyquinoline Derivatives

Abstract

For the development of new complex inhibitors of acid corrosion in steels within the framework of the QSPR approach, we study the anticorrosion properties of the samples of arylsulfonyl esters of 8-oxyquinoline in sulfuric acid and compare their electronic characteristics with the data of quantumchemical analysis in the РМ7 semiempirical approximation. The following series of esters were investigated: naphthalene-1-yl-benzosulfonate (1), 4-methylbenzosulfonate (2), 4-nitrobenzosulfonate (3), 2-methylbenzosulfonate (4), naphthalene-1-sulfonate (5) and, for the sake of comparison, the original compound, i.e., 8-oxyquinoline (0). Samples of 20 steel were tested in a model corrosive medium by the gravimetric method under the following conditions: 0.1 М solution of sulfuric acid, a temperature of the medium equal to 55°С, the duration of experiment equal to 2.5 h (in the vibration mode), and a concentration of sulfonyl esters of 0.01 mole/liter. We obtain the following sequence of increase in the anticorrosion activity of these compounds: (0) << (1) < (4) < (2) < (3) < (5), which completely agrees with the changes in the molecular volume and the Van-der-Waals surface area of the molecules computed in the РМ7 approximation. This effect demonstrates the predominance of these descriptors in analyzing the influence of the structure of esters on their anticorrosion properties. It is also established that all these compounds are potential fungicides and, hence, can be used in complex inhibiting compositions as admixtures to protective lacquer anticorrosion coatings.