Study of Reaction Conditions for the Synthesis of Methyl Oleic from Used Cooking Oil

Abstract

Abstrak

Penelitian tentang studi kondisi reaksi sintesis metil oleat dari minyak jelantah telah dilakukan. Penelitian ini bertujuan untuk: (1) menurunkan kadar asam lemak bebas (ALB) minyak jelantah dengan menggunakan adsorben arang aktif biji alpukat; (2) menentukan kondisi optimum reaksi sintesis metil oleat dari minyak jelantah; (3) menentukan kualitas metil oleat; (4) mengkarakterisasi metil oleat dengan FTIR. Metil oleat diperoleh melalui dua tahap, yaitu tahap pemurnian dan sintesis. Pada tahap pemurnian, 150 mL minyak jelantah diadsorpsi dengan (2, 4, 6, 8, dan 10) g arang aktif biji alpukat selama 2 jam pada suhu 70^oC. Hasil pemurnian menunjukkan bahwa arang aktif biji alpukat dapat menurunkan kadar ALB minyak jelantah sebesar 93,79% (b/b). Pada tahap sintesis, metil oleat disintesis dengan menggunakan perbandingan mol (triolein : metanol) (1 : 3), (1 : 6), dan (1 : 9), serta konsentrasi NaOH (1, 8, dan 16) % (b/b) dari berat minyak. Hasil penelitian menunjukkan bahwa kondisi optimum reaksi sintesis metil oleat dari minyak jelantah dengan rendemen tertinggi (84,32% b/b) adalah rasio mol (triolein : metanol) (1 : 9) dengan konsentrasi NaOH 1% (b/b). Kualitas metil oleat yang dihasilkan memenuhi syarat sebagai biodiesel menurut SNI 04-7182-2015 dengan nilai bilangan iodin 4,44 g I₂/sampel, angka penyabunan 114,44 mg KOH/g sampel, angka setana 82,96, kadar air 0,03% (b/b), dan bilangan asam 0,71 mg KOH/g sampel. Hasil karakterisasi metil oleat dengan FTIR menunjukkan bahwa metil oleat memiliki tipe serapan gugus fungsi yang khas dari senyawa ester asam lemak tak jenuh.

Abstract

 Research on the study of the reaction conditions for the synthesis of methyl oleic from used cooking oil has been carried out. This study aims to: (1) reduce levels of free fatty acids (FFA) used cooking oil using activated charcoal adsorbent avocado seed; (2) determining the optimum conditions for the synthesis of methyl oleic from used cooking oil; (3) determining the quality of methyl oleic; (4) characterized methyl oleic by FTIR. Methyl oleic was obtained in two stages, namely the purification and synthesis stages. In the purification stage, 150 mL of used cooking oil was adsorbed with (2, 4, 6, 8, and 10) g of avocado seed activated charcoal for 2 hours at 70^oC. The purification results showed that the avocado seed activated charcoal could reduce the FFA content of used cooking oil by 93.79% (w/w). In the synthesis stage, methyl oleic was synthesized using the mol ratio (triolein : methanol) (1 : 3), (1 : 6), and (1 : 9), as well as the concentration of NaOH (1, 8, and 16)% (w/w) by weight of oil. The results showed that the optimum condition for the synthesis of methyl oleic from used cooking oil with the highest yield (84.32% w/w) was the mol ratio (triolein : methanol) (1 : 9) with a concentration of NaOH 1% (w/w). The quality of the resulting methyl oleic meets the requirements as biodiesel according to INS 04-7182-2015 with an iodine number value of 4.44 g I₂/sample, saponification number of 114.44 mg KOH/g sample, cetane number of 82.96, water content of 0.03% (w/w), and the acid number of 0.71 mg KOH/g sample. The results of characterization of methyl oleic by FTIR showed that methyl oleic had a typical functional group absorption type of unsaturated fatty acid esters.