Inhibitive performance of 4-Methoxyphenethylamine on low-carbon steel in 1 M hydrochloric acid: Kinetics, theoretical, and mathematical views

•4-Methoxyphenethylamine (MPTA) was used as a powerful corrosion inhibitor.•Maximum inhibition efficiency was 91% at 30 °C and 200 ppm.•Kinetics studies revealed a first order corrosion mechanism.•Quantum chemical results showed that MPTA predominantly interacts with the metal surface.•A significant mathematical models were obtained between corrosion rate and independent variables. The current study looked at the inhibition performance of 4-Methoxyphenethylamine (MPTA) in 1 M HCl. Besides the experimental investigation, a theoretical and mathematical attempt to correlate some chemical characteristics and inhibitor efficacy was also made. The inhibiting effect was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy, and weight loss techniques. Corrosion rate was evaluated as function of time, MPTA concentration, and temperature. The results show that MPTA suppressed both cathodic and anodic processes of low-carbon steel corrosion in acidic solutionby adsorption on the surface, which followed a Langmuir adsorption isotherm. Maximum corrosion inhibition efficiency was 91% at 30 °C and 200 ppm. Kinetics studies revealed that the corrosion reaction was behaved according to the first order mechanism. Mathematical studies showed a high correlation coefficient was obtained between predicated and experimental corrosion rate. The 6-311G (d, p) base set and Density Functional Theory (DFT) were employed. MPTA's inhibitory capabilities were discovered to be connected to the charge on the nitrogen atom as well as the total of the net charges of the six atoms in the cyclic ring. MPTA was studied in a three states, ground state (1), oxygen protonated state (2), nitrogen protonated state (3). Physical characteristics such as dipole moment, hardness, ionization energy, and softness of MPTA and its protonated states were computed. Theoretical order of inhibitor efficiency was 2 > 3 > 1. It is concerned with an experimental, theoretical, and mathematical explanations between electronic and structural characteristics of MPTA and its inhibitor efficiency.