Halogen-substituted pyrazolo-pyrimidine derivatives as corrosion inhibitors for copper in sulfuric acid solution

• Y. Xu¹, S. Zhang¹, L. Guo², B. Tan¹, C. Liao¹, Y. Zhou¹ and L.H. Madkour³

¹ School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
² School of Material and Chemical Engineering, Tongren University, Tongren 554300, China
³ Chemistry Department, Faculty of Science and Arts, Al Baha University, Baljarashi 65635, Saudi Arabia

Abstract: Sulfuric acid is widely used in several industrial fields, such as acid pickling, acid cleaning and acid descaling, which cause serious corrosion issues. Especially, copper being widely applied in industrial is vulnerable to be corroded by the acid. The usage of corrosion inhibitor is one of the most important techniques for controlling the corrosion. Several organic inhibitors containing hetero-atom, π-electrons and double bond have been applied for the corrosion inhibition of copper, which are found to exhibit high inhibiting properties by providing electrons to interact with metal surface. However, the use of several heterocyclic inhibitors has caused negative impact on the environment due to their toxicity and non-biodegradability. In this paper, pyrazolo-pyrimidine derivatives are found to attract great attention owing to their eco-friendly properties. Corrosion inhibited properties of three pyrazolo-pyrimidine derivatives namely 4-amino pyrazolo-pyrimidine (APP), 3-bromine 4-amino pyrazolo-pyrimidine (Br-APP) and 3-iodine 4-amino pyrazolo-pyrimidine (I-APP) on copper in 0.5 M H2SO4 solution were studied using electrochemical method and surface analysis techniques. Corrosion of copper has been largely inhibited by the inhibitors and the inhibited efficiency increase with the augment of concentration. The adsorption isotherms were simulated to explore the adsorption mode of inhibitors. Furthermore, theoretical calculations were applied to research the mechanism of inhibitors on copper.

Keywords: corrosion inhibitor, copper, electrochemical, molecular simulation, pyrazolo-pyrimidine

Int. J. Corros. Scale Inhib., 2018, 7, no. 2, 236-249 PDF (1 186 K)
doi: 10.17675/2305-6894-2018-7-2-9

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