Comparative analysis and design of novel organic inhibitors based on anhydride derivatives for corrosion protection: A theoretical study

Theoretical chemistry is a modern and essential method and study tool for developing organic corrosion inhibitors. All theoretical calculations were conducted using Gaussian 09, Gauss view 6.0, and density function theory (DFT). This method saved money, effort, and time and expanded the path toward theoretical chemistry development, using the (B3LYP/6–311 G) as a basis set to find optimization and the frequency of compounds; thermodynamic calculations were carried out for all the resulting inhibitors. This study comprehensively evaluates critical electronic parameters to assess various organic compounds' stability and inhibition efficiency, specifically anhydrides derived from carboxylic acids. Compounds I-D, II-C, III-D, IV-A, and V-D were analyzed for energy gap (ΔE), ionization potential (I), electron affinity (A), hardness (η), softness (σ), electronegativity (χ), chemical potential (μ), and electrophilicity index (ω). The results reveal that compound IV-A demonstrates the most stable electronic structure and superior inhibition efficiency. Novel organic inhibitors were designed and synthesized by incorporating anhydride groups, leading to improved electronic properties for corrosion protection. Inhibition efficiency was evaluated theoretically and experimentally, showing varied outcomes influenced by molecular interactions and structural features. Thermodynamic analyses, including enthalpy, entropy, and Gibbs free energy, confirm the spontaneity and feasibility of the reactions. These findings establish a foundation for developing advanced corrosion inhibitors based on anhydride derivatives.