Heterocycles as Corrosion Inhibitors in Harsh Conditions

To improve the flow of oil and gas, 15–28 wt% of HCl is pumped into steel tubings (mainly N80) in the oil and gas industries. However, HCl solutions at such a high concentration corrode the metal tubings severely, increasing the production cost. Heterocyclic corrosion inhibitors are less toxic and are widely known for mitigating corrosion in highly aggressive electrolytes. This chapter comprehensively discusses different azole-, azine-, quinoline-, and indolizine-based heterocyclic acidizing corrosion inhibitors. The experimental conditions, toxicity issues, structural features, and inhibition efficiencies associated with various heterocycles have also been highlighted in the discussion. Toward the end, some suggestions have been proposed as part of future directions in heterocyclic acidizing corrosion inhibitor research. This chapter may infuse interest in more exciting works regarding heterocyclic acidizing corrosion inhibitors, overcoming the issues holding some inhibitors back from having full-fledged practical applications.