Sintesis Metil Oleat dari Asam Oleat dan Metanol pada Variasi Berat Katalis Abu Kulit Telur Ayam dan Waktu Reaksi menggunakan Radiasi Microwave

Abstract

The synthesis of methyl oleate was conducted from the esterification reaction of oleic acid with methanol using a chicken eggshell ash catalyst under microwave irradiation. Chicken eggshell powder was analyzed using Thermogravimetric Analysis (TGA), calcined at a temperature of 900°C for 4 hours, then analyzed using an FT-IR spectrophotometer, X-ray Diffraction (XRD), X-Ray Fluorescence (XRF), and Scanning Electron Microscope. (SEM). The analysis results showed that calcined chicken eggshell ash contained 99.19% CaO compounds. The reaction conditions examined in this research were catalyst weight (3%, 6%, 9%, 12%, 15%, 18%, 21%) and reaction times (1, 5, 10, 20, 30, 40, and 60 minutes) with a molar ratio of oleic acid : methanol of 1:12 and microwave power 60p for each variation. The percent conversion of methyl oleate was determined using alkalimetric titration and analyzed by gas chromatography, while changes in functional groups were determined using an FT-IR spectrophotometer. The maximum conversion of methyl oleate 90.85 ± 0.86% for the catalyst weight parameter was achieved at a catalyst weight of 18%, while for the reaction time parameter it was 91.10 ± 0.85% at a reaction time of 30 minutes. The maximum yield of methyl oleate for the catalyst weight parameter was 73.87 ± 1.36% at a catalyst weight of 12% and for the reaction time parameter it was 83.60 ± 0.80% at a reaction time of 20 minutes. Furthermore, the results of gas chromatography analysis of methyl oleate at maximum reaction conditions obtained a methyl ester conversion of 97.10%. The formation of methyl oleate was confirmed through analysis of changes in functional groups with an FT-IR spectrophotometer which showed the absorption of -C=O stretching ester at wave number 1744.4 cm-1 and there was no stretching vibration of the carboxylic acid -OH group in the wave number area 3400- 2400 cm-1 and is supported by a typical -C-O-C- group stretching absorption band in the 1300-1000 cm-1 area where the absorption band with the smallest wave number on the right experiences a significant increase in absorption intensity. Hence, it can be concluded that there has been a substitution process for the -CH3 group for the H atom of the -OH group of oleic acid.