Sodium Aluminate-Catalyzed Biodiesel Synthesis

Fatty acid methyl esters (FAME) were produced by transesterification of vegetable oil triglycerides, using a cheap, available, and strongly basic catalyst: NaAlO2 (sodium aluminate). Characterization revealed that NaAlO2 displays a high amount of strong basic sites, explaining its record activity compared with other common benchmark basic catalysts (calcined hydrotalcite, supported KI, and Ca and Sr oxides). Importantly, NaAlO2 operates truly as a heterogeneous catalyst and does not leach in the reaction medium. It shows good recyclability and appears more convenient than conventionally used homogeneous NaOH to treat vegetable oil, even in the presence of some free fatty acids.