Session: Green Chemistry & Engineering Poster Session

Corrosion is a worldwide problem that seriously affect the economy by damaging materials used in the industrial sector. To hinder this phenomenon, the usage of corrosion inhibitors is the most chosen technique. It consists of a substance, usually organic, which is applied directly to the aggressive medium, interacting with the metal alloy and forming a protective film. The interaction happens because these organic molecules have structural elements, such as heteroatoms and n and/or π-electrons, that allows a physical or chemical interaction between the components. Unfortunately, the synthesis of the compounds generally has steps that are hazardous for the environment and maybe even human life. So, with that in mind, we made modifications to the synthetic procedure of O-propargyl-N-phenylcarbamate (PPC) to respect the 12 Principles of Green Chemistry and evaluate it as a corrosion inhibitor for ASTM A36 mild steel in acid medium (HCl 1 mol L^-1). The new synthesis was made with 100% atom economy and recovery of the solvent, meaning that it was synthesized with a very low E factor, being environmental acceptable. Gravimetric and electrochemical measurements showed excellent concordance and great average anticorrosive efficiency at low concentrations of the organic compound (51.1% at 0.031 mmol L^-1) and a maximum of 97.1% at 6.211 mmol L^-1, diminishing the corrosion rate from 2.264 to 0.094 mm year^-1. The polarization curves characterized PPC as a mixed-type corrosion inhibitor and physical-chemical parameters helped understand better the system. Atomic Force Microscopy and Scanning Electron Microscopy with Energy Dispersive X-Ray pointed to the formation of a protective film on the metal surface, confirming the inhibitory action of O-propargyl-N-phenylcarbamate.

Eduardo Ponzio

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