Synthesis and anti-corrosion performance of C₂₁H₂₅NO on corrosion of N80 steel in hydrochloric acid solution

Abstract

Purpose In this work, a kind of Mannich base (C21H25NO) was synthesized with cinnamal aldehyde, acetophenone and diethylamine in a condensing reflux device based on the conventional method. Optimization of the inhibitor concentration was explored. Design/methodology/approach Spectral properties of this compound was investigated by FTIR, and its inhibition efficiency and mechanism on N80 steel in 20% hydrochloric acid solution were studied by weight loss measurement, electrochemical measurement (potentiodynamic polarization and electrochemical impedance spectroscopy) and surface analytical measurement (scanning electron microscope with energy dispersive spectrometer). Findings The results showed that the new inhibitor reduced the double-layer capacitance and increased the charge transfer resistance. The inhibition efficiency is 99.7% when the concentration of C21H25NO is 3%. The adsorption of C21H25NO on N80 steel surface in 20% HCl solution was found to be spontaneous and steady. Observed from the steel surface, an inhibition film was confirmed to be presented after adding inhibitor and successfully hindered the corrosive ions from reaching the bulk steel. Originality/value A new Mannich base (C21H25NO) was synthesized by cinnamal aldehyde, acetophenone and diethylamine for the corrosion prevention of N80 steel in 20% hydrochloric acid solution.

Newly Synthesized Morpholinyl Mannich Bases as Corrosion Inhibitors for N80 Steel in Acid Environment

“…The EIS data show that the MPO and MPPO show good performance in corrosion inhibition, with an inhibition efficiency of up to 91.31% and 91.48% at 300 ppm, respectively, and the MPPO has a higher inhibition efficiency than the MPO. Compared with other Mannich base corrosion inhibitors in the literature, such as the bis-Mannich base studied by Zhang et al [32] and the imidazoline-based Mannich base synthesized and studied by Zhu et al [37] for corrosion inhibition of N80 steel in HCl solution, the morpholine-based Mannich base corrosion inhibitor synthesized in this paper still has a high inhibition efficiency in a high concentration of acid.…”