Computational evaluation of the effect of structural parameters of 3-flouro thiophene and 3-thiophene malonic acid on corrosion inhibition efficiency of mild steel in acidic media

Abstract

The effect of the substituent's, halide and carboxylic group on thiophene compounds, namely 3-flourothiophene (3FT) and 3-thiophene malonic acid (3TMA) on the corrosion inhibition efficiency of mild steel in acidic media has been predicted using quantitative structure activity relationship (QSAR) model and quantum chemical calculation. The results from QSAR model show that 3TMA exhibit higher corrosion inhibition efficiency of 85.3 and 91.7%, which may be due to the increase in length of the malonic acid then 3FT which tends to exhibit higher electron withdrawing ability as a result of the fluorine substitution and hence lower corrosion inhibition efficiency of 40.6 and 42.1% respectively. Similarly the molecular structure of the compounds was investigated using density functional theory (DFT) calculation with 6-311G++(d,p) basis set. Quantum chemical parameters were calculated, the results show that QSAR model can be used to predict the corrosion inhibition performance of a compound prior to experimental.