Experimental and Theoretical Studies of (2R)-5-hydroxy-7-methoxy-2-phenyl-2,3-dihydrochromen-4-one as corrosion inhibitor for Iron in Hydrochloric Acid

Abstract

The corrosion inhibition on the iron surfaces by (2R)-5-hydroxy-7-methoxy-2-phenyl-2,3-dihydrochromen-4-one (PN), isolated from Kaempferia pandurata Roxb, has been conducted both experimentally and theoretically. The corrosion inhibition effectiveness of PN was studied by gravimetric and electrochemical experiments and density function calculation at B3LYP level of theory. The PN successful isolation was confirmed by spectroscopic techniques. The presence of an inhibitor can effectively inhibit iron corrosion in 1M HCl. The adsorption of PN on the iron surface obeyed the Temkin adsorption and physisorption mechanism. The effect of electron donating and withdrawing groups on the inhibition efficiency was studied by density functional theory method. The inhibition efficiency of PN increased with the addition of the N-NH2 function group whereas the NO2 group gave the opposite result.