Tetramethylguanidine covalently bonded onto silica gel surface as an efficient and reusable catalyst for transesterification of vegetable oil Original Research Article

A solid base catalyst was obtained through attachment of tetramethylguanidine onto silica gel surface. Infrared spectroscopy, 13C and 29Si nuclear magnetic resonance data are in agreement with the proposed structure. SEM images showed that the catalyst presented high homogeneous spherical particles of 1 μm with surface area of 216.14 ± 34 m2 g−1. The obtained material was used as catalyst in the transesterification of soybean oil for biodiesel production. The catalytic efficiency was followed and the biodiesel conversion presented a yield of 86.73 ± 2.2% at 3 h of reaction. The catalyst was recovered and reused nine times, maintaining about 62% of its catalytic efficiency.