ABSTRACT Abstrak Biodiesel merupakan bahan bakar alternatif yang dapat dibuat dari minyak nabati melalui proses transesterifikasi, esterifikasi, atau esterifikasi-transesterifikasi dengan alkohol. Minyak dedak padi merupakan salah satu minyak nabati yang mengandung asam lemak bebas tinggi. Pada penelitian ini minyak dedak padi diesterifikasi dengan pelarut methanol. Minyak kemudian diekstraksi dengan menggunakan etanol sebagai solven. Variabel operasi proses esterifikasi adalah suhu reaksi (40; 50; 60°C) dan konsentrasi HCl sebagai katalis (0,5; 1; 1,5; 2; 2,5%-v) Hasil penelitian menunjukkan bahwa konversi asam lemak bebas menjadi ester meningkat seiring meningkatnya suhu dan katalis. Kondisi optimum adalah 50°C dengan 1,5%-v katalis dimana konversi asam lemak bebas yang diperoleh sebesar 78,33% dan konsentrasi metil ester pada produk sebesar76,89%. Kata kunci: asam lemak bebas, biodiesel, esterifikasi, metanol, minyak dedak padi Abstract Biodiesel is a promising alternative fuel which can be made from vegetable oil by trans-etherification, etherification, or etherification-trans etherification process with alcohol. Rice bran oil, one of vegetable oils having high content of free fatty acid, was etherified with methanol in this research. The oil was extracted from rice bran by using methanol as the solvent. The operating variables of the etherification process were temperature (40; 50; 60°C) and concentration of HCl as catalyst for the reaction (0.5; 1; 1.5; 2; 2.5%-v). The experimental results show that conversion of fatty acid to ether increase as temperature and concentration of the catalyst increase. The optimum condition is 50°C with 1,5%-v catalyst, in which the conversion fatty acid is 78.33% and concentration of methyl ester in the product mixture is 76.89%.

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    ABSTRACT: In situ esterifications of high-acidity rice bran oil with methanol and ethanol and with sulfuric acid as catalyst were investigated. In the esterification with methanol, all free fatty acids (FFA) dissolved in methanol were interesterified within 15 min, and it was possible to obtain nearly pure methyl esters. The amount of methyl esters obtained from a given rice bran was dependent on the FFA content of the rice bran oil. In the esterification with ethanol, it was not possible to obtain pure esters as in methanol esterification, because the solubilities of oil components in ethanol were much higher than those in methanol.
    Journal of Oil & Fat Industries 70(2):145-147. · 1.59 Impact Factor
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    ABSTRACT: Rice (Oryza sativa L.) bran contains valuable nutritional constituents, which include lipids with health benefits. A germplasm collection consisting of 204 genetically diverse rice accessions was grown under field conditions and evaluated for total oil content and fatty acid (FA) composition. Genotype effects were highly statistically significant for lipid content and FA profile (P<0.001). Environment (year) significantly affected oil content (P<0.05), as well as stearic, oleic, linoleic, and linolenic acids (all with P<0.01 or lower), but not palmitic acid. The oil content in rice bran varied relatively strongly, ranging from 17.3 to 27.4% (w/w). The major FA in bran oil were palmitic, oleic, and linoleic acids, which were in the ranges of 13.9–22.1, 35.9–49.2, and 27.3–41.0%, respectively. The ratio of saturated to unsaturated FA (S/U ratio) was highly related to the palmitic acid content (r 2=0.97). Japonica lines were characterized by a low palmitic acid content and S/U ratio, whereas Indica lines showed a high palmitic acid content and a high S/U ratio. The variation found suggests it is possible to select for both oil content and FA profile in rice bran.
    Journal of Oil & Fat Industries 05/2003; 80(5):485-490. · 1.59 Impact Factor
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    ABSTRACT: Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. The cost of biodiesel, however, is the main hurdle to commercialization of the product. The used cooking oils are used as raw material, adaption of continuous transesterification process and recovery of high quality glycerol from biodiesel by-product (glycerol) are primary options to be considered to lower the cost of biodiesel. There are four primary ways to make biodiesel, direct use and blending, microemulsions, thermal cracking (pyrolysis) and transesterification. The most commonly used method is transesterification of vegetable oils and animal fats. The transesterification reaction is affected by molar ratio of glycerides to alcohol, catalysts, reaction temperature, reaction time and free fatty acids and water content of oils or fats. The mechanism and kinetics of the transesterification show how the reaction occurs and progresses. The processes of transesterification and its downstream operations are also addressed.
    Bioresource Technology 10/1999; · 5.04 Impact Factor


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