Sintesis Metil Oleat dari Asam Oleat dengan Metanol pada Variasi Waktu dan Berat Katalis Abu Kulit Durian Menggunakan Radiasi Microwave

Abstract

The synthesis of methyl oleate from esterification oleic acid with methanol using calcined durian peel ash as catalyst under microwave irradiation. Durian powder was calcinated at 600 ˚C for 4 hours. The main component of calcined durian peel ash is K2O of 85,15%. The reaction conditions performed in this study were the catalyst weight (3%, 6%, 9%, 12%, 15%, 18%, 21%) (w/w) and reaction time (1, 5, 10, 20, 30, 40, 60 minutes) with ratio molar of 1:12 and microwave power of 60P in each variation. The methyl oleate conversion was determined using alcalimetric titration and was confirmed gas chromatography while the formation was established using FT-IR spectrophotometer. The conversion and yield of methyl oleate of 91,66% ±0,25% and 78,07% ±1,61%, respectively were achieved at catalyst weight of 6% (w/w), reaction time of 20 minutes, ratio 1:12, and microwave power of 60P. The gas chromatography analysis of methyl oleate showed that the conversion of methyl ester was 93,39% and analysis of changes in functional groups using an FT-IR spectrophotometer showed that there is an absorption of -C=O stretching ester at wave number 1743.65cm-1 and there is no stretching vibration of carboxylic acid -OH groups in the wave number area 3400-2400 cm-1 which was supported by the characteristic stretching absorption band of the -C-O-C- group in the 1300-1000 cm-1 area where the absorption band with the smallest wave number on the right experiences increase in absorption intensity. Hence, it can be concluded that there has been a process of substitution of the OH group on the carboxylic acid with the OCH3 group from methanol..