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Successful preparation of Schiff base 4‐(4‐aminophenoxy)‐N‐(1‐(pyridin‐2‐yl)ethylidene)aniline derived from refluxing of 4,4‐oxydianniline with 2‐acetylpyridine within 2 h in 1:1 molar ratio was performed. Different transition metal complexes were synthesized by reacting metal chlorides with the formed ligand in 1:1 molar ratio. Structural features of the complexes were obtained from different tools such as infrared (IR), 1H‐nuclear magnetic resonance (1H‐NMR), ultraviolet–visible (UV‐vis), molar conductivity, thermogravimetric (TG)/differential thermogravimetric (DTG), microanalysis, and mass spectrometry. All complexes had an octahedral structure and Schiff base acted as a neutral bidentate ligand that linked to metal centers via N‐azomethine and N‐pyridine atoms. Cr(III), Fe(III), and Ni(II) complexes were electrolytes while other complexes were nonelectrolytes. The molecular structure of Schiff base was optimized theoretically and its HOMO and LUMO energies were dictated by B3LYP/DFT calculations. The in vitro antibacterial activity versus some selected bacteria species showed that all prepared compounds were biologically active except Fe(III) complex against certain species and Co(II) complex had the highest biological activity values. Molecular docking was used to determine effective binding modes between ligand and its [Co(L)(H2O)2Cl2]·4H2O complex with active sites of 4WJ3, 4ME7, 4K3V, and 3T88 receptors. The strongest binding of Co(II) complex was with the 4ME7 receptor with lowest binding energy value −25.4 kcal mol−1. Schiff base as corrosion inhibitors for mild steel in 1.0‐M HCl had been investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), and electrochemical frequency modulation (EFM). The results showed that the inhibitor acts as a mixed‐type inhibitor. The inhibition efficiency increases with increasing inhibitor concentration to its maximum of 97.5% at 1 × 10−3 M solution. The adsorption model obeys the Langmuir isotherm, and Gibbs free energy was around −40 kJ/mol, indicating that it is spontaneously and chemically adsorbed on the surface. SEM/EDX results proved the sticking of a barrier film on the mild steel sample.

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The research on the flowability of waxy oil has spanned more than a century and is still attracting much attention. How to improve the flowability of waxy oil to ensure safe and efficient pipeline transportation and storage is of great practical importance for the industry. In this work, we have systematically reviewed the research advances in improving the flowability of waxy oil. First, the crystallization properties and phase behavior of waxes are described based on their chemical structure, thermodynamic properties, and solution phase properties, with emphasis on the solventized layer properties of wax crystals. Then, the mechanisms, process, and research progress in flow improvement of waxy oil are discussed from three major aspects: process improvement, equipment improvement, and chemical treatment, with emphasis on the summary of waxy oil pour point depressants in recent years. The remaining challenges and perspectives for future research on flow improvement of waxy oil are presented.