Azo Schiff base derived from 2-hydroxy-1-naphthaldehyde as corrosion inhibitors for carbon steel in HCl medium: Experimental and theoretical studies Hadi Thamer Obaid, Mouayed Yousif Kadhum, Adnan Sultan Abdulnabi ⇑ Department of Chemistry, College of Education for Pure Sciences, Basrah University, Basrah, Iraq article info Article history: Available online xxxx Keywords: Corrosion inhibitors Azo Schiff base Carbon steel Hydrogen evolved Potentiodynamic polarization DFT abstract 3-((E)-(2-hydroxy-4-methylphenyl)diazenyl] has an inhibiting action. The effects of -1-((E)-(2-hydroxy- ethylphenylimino)methyl)naphthalen-2-ol (S1H) on the corrosion process of carbon steel in 1 M HCl were studied using two techniques: effective potentiodynamic polarization methods and hydrogen evo- lution. Furthermore, scanning electron microscopy (SEM) was used to assess surface morphology as cor- rosion progressed. The results showed that as the concentration of the synthesized chemical is increased, the efficiency of inhibition increases. The studied S1H had a greatest inhibition efficiency of (90.00% using hydrogen evolution method and 91.33% using the hydrodynamic method) at a concentration of 5.0 mM and a temperature of 298 K, the polarization results showed that the examined S1H compound can be used as a mixed type inhibitor. It showed adsorption behavior. For the S1H inhibitor the system obeys Langmuir isotherms. Results of the methods for effective dynamic polarization and hydrogen gas evolu- tion were supported by SEM analyze. Computational chemistry calculations were accomplished using density functional (DFT) method. Theoretical and experimental methods were discussed and the findings displayed that the inhibition efficiency values by closely agreed. Copyright Ó 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Confer- ence on Latest Developments in Materials & Manufacturing 1. Introduction Corrosion is defined as a subversive attack of metals by interac- tion with surrounding environment [1] and is a prevalent potential danger related with gas and oil factor production and many other industries [2]. Metals in contact with harsh conditions corrode, reducing the life span of metallic structures. Using of corrosion inhibitors is the most cost-effective approach of metallic protec- tion in such conditions [3].The inhibitor is a compound applied to reduction corrosion by changing the chemistry of an aggressive media. Inhibitors are the best one of compounds to conserve min- erals specifically in a system containing acid [4,5] Because it is widely used in pickling, descaling, acid cleaning, and oil well acidizing, HCl is considered a very corrosive acid to most common metals and alloys. As a result of the aggressive attack on metallic materials, the metal is readily dissolved, resulting in numerous costs. [6,7] Many organic substances containing (O,N and S) have been evaluated as corrosion inhibitors for metals. Corrosion inhibi- tors are extremely practical, as they are widely used to reduce metallic corrosion [8].Compounds with G-bonds in general have good inhibitory characteristics due to their interaction with the d-orbital on the metal surface [9] The azomethine and azo-schiff compounds containing C@NA and AN@NA linking respectively [10,11] have each of the above characteristics paired with a struc- ture that makes them possible corrosion inhibitors [12]. The con- nection between molecular structure, chemical reactivity, and corrosion inhibition process selectivity is crucial to be determined using computational chemistry simulations. The effectiveness of a chemical reaction is linked to the spatial and electronic molecular structures of a molecule [13]. A theoretical study also enables for the pre-selection of organic molecules with the necessary struc- tural characteristics for chemical reactions. The current study aims to create a corrosion inhibitor based on azo dye and Schiff base and test their inhibitory efficacy as corrosion inhibitors of steel in 1.0 M HCl using hydrogen evolution and potentiodynamic polarization. Two criteria were used to choose these compounds: (i) the exis- tence of an azo–azomethine group’s G-bond or the G-electrons of https://doi.org/10.1016/j.matpr.2021.10.380 2214-7853/Copyright Ó 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Latest Developments in Materials & Manufacturing ⇑ Corresponding author. E-mail address: adnan.abdulnabi@uobasrah.edu.iq (A.S. Abdulnabi). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: Hadi Thamer Obaid, Mouayed Yousif Kadhum and Adnan Sultan Abdulnabi, Azo Schiff base derived from 2-hydroxy-1-naphthaldehyde as corrosion inhi- bitors for carbon steel in HCl medium: Experimental and theoretical studies, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2021.10.380