Solid base catalysis of calcium oxide for a reaction to convert vegetable oil into biodiesel

For the purpose of investigating solid base catalysis of calcium oxide for transesterification of soybean oil with refluxing methanol, the catalyst collected after the reaction was characterized by several instrumental methods: X-ray diffraction, scanning electron microscopy, solid state 13C-NMR. The collected catalyst consisted of calcium glyceroxide, Ca[O(OH)2C3H5]2, due to the direct combination of calcium oxide with glycerol by-produced from soybean oil. Also, the collected catalyst was active in the soybean oil transesterification, and we found that the yield of fatty acid methyl esters reached 70% after 1 h. Although the transformation of the catalytically active phase brought about a slight decrease in the reaction efficiency, calcium glyceroxide was catalytically tolerant to air-exposure.