IN SITU TRANSESTERIFIKASI MINYAK BIJI MAHONI MENJADI METIL ESTER DENGAN CO-SOLVENT THF (TETRAHYDROFURAN)

Abstract

Tujuan dari penelitian  adalah untuk mengkaji efektifitas penggunaan co-solvent THF pada reaksi transesterifikasi in situ minyak biji mahoni sebagai solusi proses pembuatan biodiesel yang efektif dan efisien. Variabel dan kondisi operasi  meliputi katalis NaOH, kecepatan pengadukan 450 rpm, suhu reaksi suhu kamar, rasio molar minyak:metanol = 1:101,39, rasio molar katalis:minyak = 0,5:1, % FFA minyak 1,42%, kadar air biji 0,8%, waktu reaksi 3, 8, 13, 18, dan 23 menit serta rasio molar minyak:THF 1:47,15, 1:57,85 dan 1:67,85. Biji mahoni yang telah dikeringkan dan dihaluskan ukuran +20/-30 mesh sebanyak 50 gram dimasukkan dalam labu leher tiga yang dilengkapi pendingin balik dan ditambahkan metanol, THF dan katalis NaOH serta dilakukan reaksi sesuai dengan variabel dan kondisi operasi penelitian. Setelah reaksi selesai dipisahkan antara ampas dan filtratnya. Filtrat didistilasi pada suhu ± 70^oC dan residu hasil distilasi dimasukkan dalam corong pemisah dan didiamkan selama ± 12 jam agar terbentuk 2 lapisan. Lapisan atas sebagai metil ester kemudian dianalisis konsentrasi metil oleatnya dengan GC. Dari data hasil penelitian didapatkan hasil terbaik pada rasio molar minyak:THF = 1:67,85 dan waktu reaksi 23 menit dengan  konsentrasi metil oleat 59,10% dan yield metil ester 79,69%. Densitas metil ester 0,8791 g/cm³ memenuhi SNI 04-7182-2006 yaitu 0,85 – 0,89 g/cm³.

Kata kunci : biodiesel, co-solvent, minyak biji mahoni, transesterifikasi in situ

Abstract

The purpose of this research was to assess the effectiveness of the use of co-solvent THF for in situ transesterification reaction mahogany seed oil as a biodiesel manufacturing process solutions that effectively and efficiently. Variables and operating conditions include catalyst NaOH, stirring speed of 450 rpm, room temperature the reaction temperature, molar ratio of oil: methanol = 1: 101.39, the molar ratio of catalyst: oil = 0.5: 1, % FFA oil is 1,42%,  moisture content seed of 0.8%, reaction time is 3, 8, 13, 18, and 23 minutes, and the molar ratio of oil: THF is 1: 47.15, 1: 57.85 and 1: 67.85. Mahogany seeds that have been dried and pulverized size +20/-30 mesh as much as 50 grams included in the three-neck flask equipped condenser and added methanol, THF and catalyst NaOH and the reaction carried out in accordance with the variables and operating conditions. After the reaction is complete, the filtrate and cake was separated. The filtrate is distilled at a temperature of ± 70°C and the residue distilled included in the separating funnel and allowed to stand for ± 12 hours in order to form two layers. The top layer as methyl esters were analyzed by GC to concentrations of methyl oleate. From the research data obtained the best results at a molar ratio of oil: THF = 1: 67.85 and reaction time 23 minutes with methyl oleate concentration of 59.10% and yield methyl ester of 79.69%. Methyl ester density 0.8791 g/cm³ meet SNI 04-7182-2006 from 0.85 to 0.89 g/cm³.
Keywords : biodiesel, co-solvent, in situ transesterification, mahogany seed oil