Open AccessAdsorption and corrosion inhibition behaviour of new theophylline–triazole-based derivatives for steel in acidic medium
Author(s) -
Araceli Espinoza-Vázquez,
Francisco Javier Rodríguez-Gómez,
Ivonne Karina Martínez-Cruz,
Deyanira Ángeles-Beltrán,
Guillermo E. NegrónSilva,
Manuel PalomarPardavé,
Leticia Lomas Romero,
Diego Luis Valera Martínez,
Alejandra M. NavarreteLópez
Publication year - 2019
Publication title -
royal society open science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 51
ISSN - 2054-5703
DOI - 10.1098/rsos.181738
Subject(s) - physisorption , chemisorption , corrosion , adsorption , theophylline , dielectric spectroscopy , langmuir adsorption model , chemistry , electrochemistry , inorganic chemistry , nuclear chemistry , materials science , organic chemistry , electrode , medicine , endocrinology
The design and synthesis of a series of theophylline derivatives containing 1,2,3-triazole moieties are presented. The corrosion inhibition activities of these new triazole–theophylline compounds were evaluated by studying the corrosion of API 5 L X52 steel in 1 M HCl medium. The results showed that an increase in the concentration of the theophylline–triazole derivatives also increases the charge transference resistance ( R ct ) value, enhancing inhibition efficiency and decreasing the corrosion process. The electrochemical impedance spectroscopy under static conditions studies revealed that the best inhibition efficiencies (approx. 90%) at 50 ppm are presented by the all-substituted compounds. According to the Langmuir isotherm, the compounds 4 and 5 analysed exhibit physisorption–chemisorption process, with exception of the hydrogen 3 , bromo 6 and iodo 7 substituted compounds, which exhibit chemisorption process. The corrosion when submerging a steel bar in 1 M HCl was studied using SEM-EDS. This experiment showed that the corrosion process decreases considerably in the presence of 50 ppm of the organic inhibitors. Finally, the theoretical study showed a correlation between E HOMO , hardness ( η ), electrophilicity (W), atomic charge and the inhibition efficiency in which the iodo 7 substituted compound presents the best inhibitor behaviour.