THE EFFECT OF MODIFICATIONS BENZOTHIAZOLE-2-THIOL INTO S- BENZO[D]THIAZOLE-2-YL BENZOTHIOATE TOWARDS CORROSION INHIBITION ACTIVITY ON CARBON STEEL IN 0.1 M HCL SOLUTION

• Main Author: Susilawati, Eka
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34699
• Institution: Institut Teknologi Bandung

Corrosion is one of a problem in the industry which has detrimental effects. The best way to prevent corrosion inside the pipe is by the addition of corrosion inhibitor. Benzothiazole-2- thiol is an organic compound that has potent as a corrosion inhibitor. In this study, Benzothiazole-2-thiol compound was modified to S-benzo[d]thiazole-2-yl benzothioate by reaction with Benzoyl chloride and KOH using Microwave Assisted Organic Synthesis (MAOS) method. The product was characterized by TLC test using n-hexane : ethyl acetate = 7 : 3 as eluents which indicates that the product is more nonpolar than the precursor. The melting point of product is 120 - 123?C. Infrared spectrum indicates carbonyl peak from thioester group at 1723,8 cm-1. HRMS TOF ES+, 1H-NMR, and 13C-NMR spectrum confirmed that the product obtained is S-benzo[d]thiazole-2-yl benzothioate. The ability of S-benzo[d]thiazole-2-yl benzothioate as a corrosion inhibitor was tested on carbon steel in 0.1 M HCl solution using electrochemical methods, Electrochemical Impedance Spectroscopy (EIS) and Tafel. The maximum corrosion inhibition efficiency of Benzothiazole-2-thiol was found 96.72% at 30?C and the concentration of 70 ppm, while the S-benzo[d]thiazole-2-yl benzothioate was found 89.72% at 55?C and the concentration of 70 ppm. The activation energy before the addition of inhibitors is 81.70 kJ/mol. The addition of Benzothiazole-2-thiol and S-benzo[d]thiazole-2-yl benzothioate changed the activation energy to 102.45 kJ/mol and 52.86 kJ/mol, respectively. The modification of Benzothiazole- 2-thiol to S-benzo[d]thiazole-2-yl benzothioate shows a decrease in the corrosion inhibition efficiency towards carbon steel in 0.1 M HCl solution.