Synthesis, spectroscopic characterization, and prevention of carbon steel corrosion in hydrochloric acid of a new bis-isoxazoline-carvone

Abstract

A series of C(3)-mono-substituted isoxazoline of type mono- and bis-isoxazoline, have been prepared from (R)-carvone 1 in a two-step procedure. First, (R)-carvone was treated with O-methoxy-benzaldoxime via a 1,3-dipolar cycloaddition reaction. The resulting mono-isoxazoline 2 was then converted into bis-isoxazoline(3), followed by an optimization study on the yield by varying the number of the equivalent of O-methoxy-benzaldoxime. The structures of mono- and bis-isoxazoline(3) newly synthesized were fully identified based on their HRMS and NMR spectral data. The bis-isoxazoline compound was used to evaluate the anticorrosion effect. The inhibitory properties of bis-isoxazoline-carvone(3) were evaluated using a variety of methods including weight loss(wl), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), surface morphology analysis (SEM), quantum chemical calculations (DFT), and Monte Carlo simulation (MC). The results of (PDP) show that compound(3), which is a mixed type inhibitor, significantly reduces the corrosion rate of carbon steel (CS) through the creation of a protective film on the metal surface. According to EIS, SEM and theoretical studies, a bis-isoxazoline-carvone(3) is a better corrosion inhibitor with higher corrosion rates of about 92% at 298 K. The Langmuir isothermal model is the most appropriate to describe the adsorption of bis-isoxazoline-carvone(3) on the surface was mixed (chemisorption and physisorption).