THE EFFECT OF FUNCTIONAL GROUPS TRANSFORMATION ON SALICYLIC ACID INTO ASPIRIN TOWARDS THE EFFICIENCY INHIBITION ON CARBON STEEL IN BUFFER ACETATE SOLUTION

• Main Author: Saktiana Putri S., Therecia
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/35359
• Institution: Institut Teknologi Bandung

Corrosion is decline the quality of metal because of the interaction that occurs between the metal or alloy with its environment. One of the prevention corrosion on the inner surface of carbon steel, used to flow the crude oil and natural gas is by injecting corrosion inhibitor into the fluid. In this research, the inhibitor used is salicylic acid (1) and aspirin (2). The use of both inhibitors is to study the effect of changes in phenolic group from 1 into 2 on their ability to inhibit the performance of corrosion. Aspirin is an organic compound which are potential to become corrosion inhibitor because it has phi electrons in conjugated double bonds and the character as electron donating group. The second compound was synthesized using Microwave Assisted Organic Synthesis (MAOS) method. The resulting compound 2 was then characterized through qualitative test using FeCl3 solution shows a negative test to produce brownish solution and the color is brown. The melting point of 2 is 133oC. Mass Spectroscopy analysis of 2 utilizing HRMS TOF ES [M-H+] showed the best molecular formula of 2 is C9H7O4 with the molecular mass of 179.0375 and the measuring of compound 2 using 1H- NMR spectrum and 13C-NMR ensured that the compound obtained was aspirin. Corrosion inhibition test on 1 and 2 was done using Electrochemical Impedance Spectroscopy and Tafel methods. The maximum inhibition efficiency of compounds 1 at 45oC with the concentration of 40 ppm is 83.58%, and the compound 2 at 25oC with the concentration of 40 ppm is 85.77%. The calculated activation energy of uninhibited system is 24.34 kJ/mol. The presence of compounds 1 and 2 increase the activation energy up to 29.13 kJ/mol and 30.82 kJ/mol. The replacement of hydroxyl functional groups within compound 1 into compound 2 shows the improvment in efficiency inhibition corrosion of compounds 2 towards carbon steel in buffer acetate solution pH 4.2 at room temperature.