Wardika, Fitria2022-07-192022-07-192022-01PerpustakaanElfitrahttps://repository.unri.ac.id/handle/123456789/10571Energy reserves derived from oil and natural gas have a limited amount, so alternative renewable energy such as biodiesel is needed. Biodiesel can be derived from vegetable oil or animal fat. Oil from plants is more widely used because it is easier to obtain. Rubber seed is one of the many sources of oil in Riau and has not been widely used. Rubber seeds contain 35-50% oil which has the potential to be used as biodiesel feedstock. Rubber seed oil has a high free fatty acid content, so it is necessary to carry out the esterification stage before proceeding to the transesterification stage. The esterification reaction aims to reduce the free fatty acid content. The esterification step was carried out using a maredan clay catalyst which was activated by 2M sulfuric acid by weight (1%, 2%, 3%), at a temperature of 60°C, 3 hours, and a mole ratio of oil: methanol (1:6, 1:12, 1:18). The results of the esterification were followed by a transesterification step using a blood clam shell catalyst with the reaction conditions: 3% CaO catalyst weight, oil mole ratio: methanol 1:6, reaction temperature 60°C and reaction time of 3 hours. The maximum biodiesel yield obtained was 36.27% on a 3% maredan clay catalyst by weight and an oil:methanol mole ratio of 1:12. The characteristics of the biodiesel produced have a water content of 0.048%, specific gravity 877 kg m-3, viscosity 2.35 mm2 s-1, flash point 184, carbon residue 1.46%, acid number 6.9 mg KOH/g, iodine number 143 .73 g I2/100 g, and a cetane number of 44.22. The results of these characteristics are in accordance with the SNI standard 04-7182-2015 except for acid numbers, carbon residues, iodine numbers and cetane numbers Keywords : esterification, rubber seed oil, transesterification.enesterificationrubber seed oiltransesterificationArticle