Pengaruh Lama Reaksi terhadap Perubahan Karakteristik Biodiesel Turunan Minyak Jarak Pagar(Jatropha Curcas) dengan Menggunakan Katalis Polistirena Sulfonat (PSS)

Abstract

Production of castor oil derived biodiesel with 7.78% free fatty acid (FAA) has been done by transesterification process. The process was carried out in an autoclave by missing the materials of castor oil such as methanol in 1:6 mole, PSS catalyst 4% of the oil Weight. The reaction procced in 80°C with the varyng time 2 and 6 hours. The transesterification resulted in 2 layers ; upper layer containing methyl ester (FAME) and the lower layer containing residual glycerol and methanol. The upper layer was separated by using a separating funnel, the residual lower layers was added by 100 ml n-hexane incorporated into FAME. The incopration was then neutralized by 100 ml ammoniac followed by the addition of 100 ml aqueos. The fraction was destillated to separate the solvent, and then vacuumed. The residue was weighted an then tested for the physical features such as viscosity, density, Iod grade, fogging point and the water content. Using 50 grs castor oil, 34 grs crude FAME was produced, and convertion of 65.24% for 2 hours, viscosity of 22.65cSt, density of 0.9 gr/cm3 , Iod grade of 67.05% cm², fogging point of 1.76C, and water content of 0.0682%, the crude FAME of 40.04gr with the conversion of 77.52% for 6 hours. Viscosity of 19.26cSt, density of 0.90 gr/cm3 , Iod grade of 67.33 mg/g, fogging point of 1.50°C and water content of 0.0736%. The longer is the reaction, the higher is the reaction conversion that resulted in in important changes in the physical features of biodiesel. The physical features showed that the castor oil-derived biodiesel may be used to be one alternative of substituting solar fuel.

Telah dilakukan pembuatan biodiesel turunan minyak Jarak Pagar berasam lemak bebas ( ALB) 7,78% melalui proses transesterifikasi. Proses ini dilakukan dalam sebuah autoclave dengan mencampurkan bahan bahan minyak jarak pagar : methanol sebanyak 1:6 mol, katalis PSS 4% berat dari minyak. Reaksi ini berlangsung pada suhu 80oC dengan variasi waktu, 2 jam, dan 6 jam. Transesterifikasi ini menghasikan 2 lapisan yaitulapisan atas mengandung metil ester (FAME) dan lapisan bawah gliserol dan metanol sisa. Lapisan atas dipisahkan menggunakan corong pisah, sisa lapisan bawah ditambahkan n-heksan 100 ml dan kemudian digabungkan dengan FAME. Gabungan kemudian dinetralkan dengan amoniak sebanyak 100 ml diikuti penambahan aquadest 100 ml. Fraksi heksan dibubuhi dengan Na2SO4 anhidrat kemudian disaring . Filtrat didestilasi memisahkan pelarut, selanjutnya divakum. Residu ditimbang kemudian diuji sifat fisisnya seperti viscositas, densitas, bilangan Iod, titik kabut dan kadar air. Dengan menggunakan minyak jarak pagar 50 gr , diperoleh bahan FAME crude 34 gr, konversi 65,240% selama 2 jam. Viscositas 22,65cSt, densitas 0,91gr/cm3 , bilangan Iod 67,05g/cm2 , titik kabut 1.76oC, dan kadar air 0,0682%. FAME crude sebanyak 40.04 gr dengan konversi77,52%, untuk 6 jam. Viscositas 19,26 cSt, densitas 0,90 gr/cm3 , bilangan Iod 67,33mg/g, titik kabut 1.50oC, dan kadar air 0,0736%. Makin lama reaksi makin tinggi konversi reaksi sehingga memberi perubaha penting pada sifat fisis biodiesel. Sifat sifat fisis hasil ini menunjukkan biodiesel turunan minyak jarak pagar dapat dipakai sebagai salah satu alternatif pengganti bahan bakar solar.