Novel synthesis of vegetable oil derived corrosion inhibitors

Abstract

This thesis has been able to examine a novel one-pot synthesis of fatty acid amides which is derived from natural vegetable oil. The sodium methoxide was used to esterify a series of natural products of vegetable oil, which include: linseed oil, sunflower oil, peanut oil, cress oil, almond oil and canola oil. The mixture was refluxed for 1 hour at 90 °C under N 2 gas atmosphere in order to produce methylester. Then, a concentrated aqueous ammonia solution was added to the product of the first step reaction and refluxed for 3 hours at 150 °C with no N2 gas to form a fatty acid amide. The progress of the reaction was qualitatively followed using a Thin Layer Chromatography (TLC) technique with ethyl acetate as eluent. TLC plates at which spots of each of the vegetable oil, methylester and amide were placed and then investigated using UV lamp. Fourier Transform Infrared Spectroscopy (FTIR) was used to investigate the different samples of the reaction mixture in order to determine the functional group transformation between the starting material and the final product. Both TLC and FTIR techniques were successful and showed respectively, different migration rates and functional group transformation. Corrosion studies of carbon steel were performed in vigorously stirred aerated seawater, one of the most corrosive natural environments. Samples of carbon steel were cut and prepared. Two methods of corrosion rate measurement were used, namely; mass loss of carbon steel coupons and Linear Polarization Resistance (LPR) over time. Mass loss is a technique used to identify the corrosion rate by decrease of the mass of the coupon due to a corrosive layer on its surface. While LPR is a technique used to determine the corrosion rate at electrode or solution interface of carbon steel immersed in sea-water using a Gamry potentiostat. Our results showed correlation between the corrosion inhibition efficiencies obtained using both techniques and corrosion rates were up to 98% for some of the oil, equivalent to a corrosion rate reduction of 44. The one pot synthetic route chosen avoids complexity and is consequently a low cost approach to the formation of fatty acid amides. In addition, the use of solvents to clean up intermediaries is eliminated.

Date of Award	2016
Original language	American English
Supervisor	Paul Rostron (Supervisor)