Biodiesel Production from Soybean Oil Catalyzed by K2SiO3/C

A solid base catalyst (K2SiO3/C) capable of microwave absorption was used for the transesterification of soybean oil under microwave radiation. The K2SiO3/C catalyst was prepared by an impregnation method that loaded K2SiO3 on carbon particles (1-3.5 mm diameter) followed by drying at 120 °C. The catalysts were characterized by X-ray diffraction, scanning electron microscopy-energy dispersive spectrometry, and the Hammett indicator method. K2SiO3 was well distributed on the support. The effects of reaction variables such as catalyst loading, molar ratio of methanol to oil, and reaction time (under microwave radiation and conventional heating) were studied. When the conventionally heated reaction was carried out at 65 °C with a methanol/oil molar ratio of 30:1 and a catalyst concentration of 24 wt%, the biodiesel conversion was 96.5% after 2.5 h reaction time. The same reaction reached equilibrium after 1.5 h under microwave radiation, and the conversion of biodiesel was 96.7%.

摘要采用浸渍法将钾水玻璃负载于碳颗粒 (粒径 1–3.5 mm) 上, 经 120 °C 烘干后制得 K2SiO3/C 催化剂. 以 X 射线衍射、扫瞄电镜-能量色散 X 射线与 Hammett 指示剂等方法对样品进行了表征. 以 K2SiO3/C 为催化剂, 大豆油为原料, 进行酯交换反应制备生物柴油, 考察了催化剂用量、醇/油摩尔比、反应时间 (微波与传统加热) 等因素对大豆油酯交换率的影响. 当醇/油摩尔比 30:1, 催化剂用量 24 wt% 时, 传统加热反应于 2.5 h 达到 96.5% 酯交换率, 而相同条件下微波加热反应于 1.5 h 达到 96.7% 酯交换率.

Graphical abstractA K2SiO3/C catalyst prepared by an impregnation method had basic sites effective for transesterifcation. It can absorb microwaves and showed high energy efficiency.Figure optionsDownload full-size imageDownload as PowerPoint slide