Studi Kinetika Reaksi Pembuatan Biodiesel dari Minyak Nyamplung Menggunakan Iradiasi Microwave

Abstrak

Abstrak -Minyak nyamplung (Calophyllum inophyllum Linn) adalah salah satu bahan baku yang potensial untuk produksi biodiesel karena kandungan minyaknya yang tinggi. Minyak nyamplung mengandung asam lemak bebas yang tinggi, proses pretreatment dalam penelitian ini dapat mereduksi asam lemak bebas dari 27,978 % menjadi 1,269% sehingga minyak dapat dilanjutkan pada proses transesterifikasi. Iradiasi microwave digunakan pada proses transesterifikasi sebagai metode alternatif yang lebih cepat dibandingkan dengan metode refluks konvensional. Tujuan penelitian ini untuk mengidentifikasi metil ester dalam produk, mengkaji kinetika reaksi pembuatan biodiesel dan mengkaji pengaruh penggunaan iradiasi microwave terhadap energi aktivasi dan laju reaksi transesterifikasi dibandingkan dengan metode konvensional. Power microwave (100, 200 dan 400W), waktu iradiasi (5, 7, 10, 12 dan 15 menit) dan suhu reaksi (50, 55, 60, 65 dan 70 ^oC) digunakan sebagai parameter penelitian. Kondisi operasi terbaik menggunakan power microwave 200W pada suhu 65 ^oC selama 5 menit, yield biodiesel maksimal sebesar 84,62% dan sifat fisik biodiesel telah memenuhi standar SNI 04-7182-2006, ASTM 6751-02 dan EN-14214. Biodiesel nyamplung mengandung 30,23% metil oleat, 25,76% metil linolelaidat, 19,21% metil palmitat, 15,75% metil stearat, 2,11% metil lignocerat, 1,41% metil eicosanoic, 0,54% metil behenate dan 0,37% metil palmitoleat. Biodiesel nyamplung dengan iradiasi microwave memiliki energi aktivasi (Ea) sebesar 2579,834 J/mol, faktor tumbukan (A) sebesar 1,0161 L/mol menit, laju reaksi transesterifikasi (r_t) = 1,0161e^{(-2579,834/RT)} [ME] dan waktu reaksi selama 5 menit. Sedangkan biodiesel nyamplung dengan metode konvensional memiliki energi aktivasi (Ea) sebesar 4831,265 J/mol, faktor tumbukan (A) sebesar 0,3772 L/mol, laju reaksi transesterifikasi (r_t)=0,3772 e^{(-4831,265/RT)}[ME] dan waktu reaksi selama 30 menit. Hasil penelitian menunjukkan penggunaan iradiasi microwave dapat meningkatkan laju reaksi transesterifikasi, menurunkan energi aktivasi dan mengurangi waktu reaksi menjadi 1/6 kali lebih cepat dibandingkan metode konvensional.

Abstract - Nyamplung (Calophyllum inophyllum Linn) is an potential feedstock for biodiesel production because of its high oil content. As nyamplung oil contains high free fatty acid, a pretreatment process in this research was carried out to reduce the amount of FFA from 27.498 wt% to 1.269 wt% so that the oil can be resumed in the transesterification process. Microwave irradiation is used in the transesterification process as an alternative method that is faster than the conventional reflux method.The purpose of this research was to study identify methyl ester in the product, examine the kinetics of biodiesel and assess the effect of using microwave irradiation to activation energy and the rate of transesterification reactions compared to conventional methods. Microwave power (100, 200 and 400W), reaction time (5, 7, 10, 12 and 15 minutes) and reaction temperature (50, 55, 60, 65 and 70 ^oC) were selected as experimental parameters. The optimum conditions for transesterification process is using microwave power of 200W at 65 ° C for 5 minutes to obtain yield biodiesel of 84.62% and physical properties biodiesel meet the standard of SNI 04-7182-2006, ASTM 6751-02 and EN-14214. Nyamplung biodiesel contains about 30.23% of methyl oleic, 25.76% of methyl linolelaidate, 19.21% of methyl palmitic, 15.75% of methyl stearic, 2.11% of methyl lignoceric, 1.41 % of methyl eicosanoic, 0.54% of methyl behenate and 0.37% of methyl palmitoleic. Nyamplung biodiesel preparation using microwave irradiation has the activation energy (Ea) of 2579.834 J / mol, collision factor (A) of 1.0161 L/mol min, the rate of transesterification reaction (r_t) = 1,0161e (^{-2,579.834 / RT} ) [ME] and reaction time of 5 minutes. Nyamplung biodiesel preparation using the conventional method has the activation energy (Ea) of 4831.265 J / mol, collision factor (A) of 0.3772 L / mol and the rate of the transesterification reaction (r_t) = 0.3772 e (^{-4,831.265 / RT}) [ME] and reaction time of 30 minutes. The results showed the use of microwave irradiation increases the rate of transesterification reaction, lowering the activation energy and reduce the reaction time becomes 1/6 times faster than conventional methods.