ISOLATION OF MANGOSTEEN COMPOUND FROM THE PERICARP OF MANGOSTEEN (GARCINIA MANGOSTANA) AS CORROSION INHIBITOR OF CARBON STEEL IN 1% NACL ENVIRONMENT

• Main Author: Ayumaulani, Anindita
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34463
• Institution: Institut Teknologi Bandung

Carbon steel is a material that used in pipelines to carry crude oil or natural gas in oil and gas industry. Corrosion is one of the problems that occurred at the inner-side of carbon steel pipelines. Corrosion inhibitor were added into the crude oil that flow in the pipeline to reduce the corrosion rate. Mangosteen is xanthone derivative compound that found in the mangosteen (Garcinia mangostana) pericarp. In this study, ?-mangosteen was isolated from the pericarp of mangosteen to be used as organic corrosion inhibitors of carbon steel. The FTIR characterization shows the peaks in wave number around 3200, 2900, 1600, 1400, dan 1200 cm-1 that related to the fuctional groups of ?-mangosteen structure. Analysis of 1H- NMR and 13C-NMR confirm that the value of chemical shift (?) from the sample has appropriate to the value of chemical shifts of ?-mangosteen compound. Mangosteen pericarp extract and ?-mangosteen compound were measured by EIS (Electrochemical Impedance Spectroscopy) and Tafel methods as corrosion inhibitor at several temperatures 30, 45, 60 °C and concentrations of 10, 20, 30, 40, dan 50 ppm. At 60 °C and concentration of 40 ppm, the highest inhibiton efficiency of mangosteen pericarp extract is 19.64 % , meanwhile the maximum inhibition efficiency of ?-mangosteen is 8.83 %. Based on Tafel method, mangosteen pericarp extract is an ohmic inhibitor, whereas ?-mangosteen compound is an anodic inhibitor.