Biodiesel production from soybean and Jatropha oils by magnetic CaFe{sub 2}O{sub 4}–Ca{sub 2}Fe{sub 2}O{sub 5}-based catalyst Xue, Bao-jin [Chinese Academy of Sciences, Biomass Group, Key Laboratory of Tropical Plant Resource and Sustainable Use, Xishuangbanna Tropical Botanical Garden, 88 Xuefulu, Kunming, Yunnan Province 650223 (China)]; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China)]; Luo, Jia [Chinese Academy of Sciences, Biomass Group, Key Laboratory of Tropical Plant Resource and Sustainable Use, Xishuangbanna Tropical Botanical Garden, 88 Xuefulu, Kunming, Yunnan Province 650223 (China)]; Zhang, Fan [Chinese Academy of Sciences, Biomass Group, Key Laboratory of Tropical Plant Resource and Sustainable Use, Xishuangbanna Tropical Botanical Garden, 88 Xuefulu, Kunming, Yunnan Province 650223 (China)]; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049 (China)]; Fang, Zhen [Chinese Academy of Sciences, Biomass Group, Key Laboratory of Tropical Plant Resource and Sustainable Use, Xishuangbanna Tropical Botanical Garden, 88 Xuefulu, Kunming, Yunnan Province 650223 (China)] 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BIODIESEL FUELS; CALCINATION; CATALYSTS; COPRECIPITATION; FERRITES; IRON OXIDES; JATROPHA; METHANOL; SOYBEAN OIL; SOYBEANS; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY Heterogeneous CaFe{sub 2}O{sub 4}–Ca{sub 2}Fe{sub 2}O{sub 5}-based catalyst with weak magnetism was prepared by co-precipitation and calcination. It was characterized by various techniques including X-ray diffraction, X-ray photoelectron spectroscopy and temperature programmed desorption method. Its active components were identified as mainly Ca–Fe composite oxides such as CaFe{sub 2}O{sub 4} for transesterification. The magnetism was further strengthened by reducing its component of Fe{sub 2}O{sub 3} to Fe{sub 3}O{sub 4}–Fe under H{sub 2} atmosphere for better magnetic separation. Both catalysts were used for the catalytic transesterification of soybean and Jatropha oils to biodiesel. The highest biodiesel yields for soybean oil of 85.4% and 83.5% were obtained over the weak and strong magnetic catalysts, respectively under the optimized conditions (373 K, 30 min, 15/1 methanol/oil molar ratio and 4 wt% catalyst). The catalysts could be recycled three times. Biodiesel production from pretreated Jatropha oil was tested with the magnetic CaFe{sub 2}O{sub 4}–Ca{sub 2}Fe{sub 2}O{sub 5}–Fe{sub 3}O{sub 4}–Fe catalyst, and 78.2% biodiesel yield was obtained. The magnetic CaFe{sub 2}O{sub 4}–Ca{sub 2}Fe{sub 2}O{sub 5}-based catalyst shows a potential application for the green production of biodiesel. - Highlights: • Magnetic catalyst was prepared by co-precipitation, calcination and reduction. • The catalyst was composed of CaFe{sub 2}O{sub 4}–Ca{sub 2}Fe{sub 2}O{sub 5}–Fe{sub 3}O{sub 4}–Fe. • Biodiesel yields of 83.5% and 78.2% were achieved for soybean and Jatropha oils. • The catalyst was easily separated by a magnet and used for three cycles. Available from http://dx.doi.org/10.1016/j.energy.2014.02.082 United Kingdom 2014-04-01 English Journal Article Journal Name: Energy (Oxford); Journal Volume: 68; Journal Issue: Complete; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA) Medium: X; Size: page(s) 584-591 https://doi.org/10.1016/J.ENERGY.2014.02.082 PII: S0360-5442(14)00216-3 [] Complete 68 Journal ID: ISSN 0360-5442; CODEN: ENEYDS; Other: PII: S0360-5442(14)00216-3; TRN: GB15R1720022385 INIS 2015-03-19 22316188