Document Type : Research Article
Authors
1
Research Center for Advanced Material, National Research and Innovation Agency, The B. J. Habibie Science and Technology Area, South Tangerang, Banten 15314, Indonesia
2
Research Center for Chemistry, National Research and Innovation Agency (BRIN), The B. J. Habibie Science and Technology Area, South Tangerang, Banten 15314, Indonesia
3
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
4
Department of Chemistry, Faculty of Mathematic and Natural Science, Universitas Gadjah Mada, Yogyakarta, Indonesia, 55281
5
Department of Science Education, STKIP Sinar Cendekia, Banten 15310, Indonesia
6
Department of Advanced Materials and Engineering, Hanseo University, Seosan-si, Chungnam-do, 356-706, Korea
Abstract
MgO/γ-alumina and CaO/γ-alumina heterogeneous base catalysts have been prepared by wet impregnation, using 10 wt.% of metal oxide precursors, and used in the transesterification reaction of castor oil (Riccinus communis) into biodiesel. Catalyst characterization includes X-ray diffraction (XRD), Infrared spectroscopy (FTIR), X-ray fluorescence (XRF), Surface area analyzer (SAA), average pore radius (BJH), and basicity. The catalyst performance was observed from the activity and selectivity of the catalyst in converting castor oil into methyl ester with batch system at 60°C for 2 hours. The castor oil biodiesel was analyzed using GC-MS to determine the selectivity of the catalyst towards methyl ricinoleate. The results showed that the addition of MgO and CaO to γ-alumina increased the basicity and average pore radius but decreased the specific surface area of γ-alumina. The FAME yields of γ-alumina, MgO/γ-alumina, CaO/γ-alumina, MgO, CaO, and KOH catalysts with 3 wt.% ratio were 81.15%, 82.17%, 82.45%, 82.02%, 82.16%, and 84.57%. The selectivity to methyl ricinoleate was the highest for CaO/γ-alumina catalyst which was 87.57% area GC. The yield of FAME at various weight ratios of CaO/γ-alumina (1, 2, 3, 4, and 5 wt.%) were 81.81%, 82.13%, 82.45%, 83.57%, and 83.96% and the selectivity to methyl ricinoleate was the largest at 4 wt.% CaO/γ-alumina catalyst which was 90.20% GC area. Castor oil biodiesel was analyzed according to the American Standard of Testing Materials (ASTM) method for biodiesel eligibility. ASTM test results for castor oil biodiesel showed a kinematic viscosity (40°C) of 15.76 mm2/s which is above the biodiesel standard because the kinematic viscosity of castor oil was also high. The flash point of 222.5°C, pour point <27°C, and cloud point of 15°C have fulfilled the requirements of the biodiesel standard.
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