Characterization of a supramolecular complex based on octadecylamine and β-cyclodextrin and its corrosion inhibition properties in condensate water

Highlights: • A supramolecular complex was prepared by β-cyclodextrin and octadecylamine. • Octadecylamine could dissolve in the water with the help of β-cyclodextrin. • Octadecylamine could be released from β-cyclodextrin in the condensate water. • A monomolecular hydrophobic film could be formed by adsorption on the carbon steel. • The corrosion rate of carbon steel was 0.0098 mm/a after adding the complex. - Abstract: A supramolecular complex was synthesized based on β-cyclodextrin (β-CD) and octadecylamine (ODA) in n-hexane through speeding hybrid method. From the phase solubility diagram, the increased solubility of ODA in aqueous solution was observed. The data of proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and differential scanning calorimeter (DSC) demonstrated the formation of supramolecular structure between β-CD and ODA. The complex could release ODA molecules in the condensate water, which could form a monomolecular hydrophobic layer on the mild carbon steel to protect the metal by isolating the corrosive ions and dissolved oxygen