Optimasi Proses Metanolisis Dalam Minyak Jarak Pagar (Jatropha Curcas L) Dengan Metode Permukaan Respon

Minyak jarak pagar mempunyai nilai kalor total yang tidak berbeda jauh dengan nilai kalor total bahan bakar minyak konvensional. Namun, viskositas minyak jarak pagar kasar yang tinggi menyulitkan penggunaannya secara langsung sebagai bahan bakar. Untuk menurunkan nilai viskositas minyak nabati ini, dilakukan proses transesterifikasi dengan metanol sehingga dihasilkan metil ester dari asam-asam lemaknya. Penelitian ini bertujuan mendapatkan kondisi optimum nisbah molar metanol terhadap minyak dan waktu reaksi transesterifikasi dalam memproduksi metil ester. Optimasi menggunakan Metode Permukaan Respon dengan rancangan komposit pusat faktorial penuh 2 2 Nisbah metanol terhadap minyak jarak (x 1 ) dan waktu reaksi (X 2 ) berada dalam selang 4,4SNI 04-7102-2006). Optimization Of Methanolysis Of Jatropha Curcas L Crude Oil Applying Response Surface Methodology Jatropha oil possesses t o tal calorific value which is not significantly different from conventional petroleum diesel. However, its high viscosity makes it difficult to be used directly as fuel. The oil has to be converted into methyl ester through methanolysis (transesterification) process before it could be used effectively to substitute diesel fuel. The aim of this research was finding the optimum condition of the methanol molar ratio to oil and reaction time (duration of transesterification process) on the methyl ester yield and the characteristics of methyl ester especially viscosity and acid number. Optimization was conducted using Response Surface Method. Factors tested in this experiment were molar ratio of methanol to jatropha oil (5:1 and 7:1), and reaction times (50 minutes and 120 minutes). Transesterification process was conducted at 60°C in a reactor equipped with stirrer 600 RPM using KOH 0.5% of oil volume as catalyst. Parameters observed were methyl ester content (indicating percent of methyl ester yield), kinematic viscosity and acid number. Optimum conditions was achieved at molar ratio 6.6: I and reaction time 60 minutes. At these optimum points, the characteristics of methyl ester were as follow: percentage of methyl ester yield 99.192%, kinematic viscosity 4.167cSt and acid number 0.112 mg KOH/g oil. These values met the Indonesian National Standard of biodiesel (SNI 04-7102-2006).