Transesterificarion of soybean oil using ethanol and mesoporous silica catalyst

Mesoporous silica catalyst was evaluated in the ethanolysis of soybean oil. Ethanol can be environmentally advantageous over methanol (more frequently used as reagent in biodiesel production) because it can be obtained from renewable sources whilst methanol is usually derived from mineral sources. A silica molecular sieve containing lanthanum oxide as active phase (La50SBA-15) was obtained by isomorphous substitution into the SBA-15 network using Pluronic (P123) dissolved in aqueous HCl solution with tetraethyl orthosilicate and a given amount of hydrated lanthanum chloride (Si:La = 50) at 333 K. The reaction was performed using the molar ratio ethanol:soybean oil of 20:1 at inert atmosphere (N2) at 343 K with 1wt% of catalyst mass relative to total oil mass added to the reaction mixture. The reaction was evaluated for ethyl ester conversion after 6 h. The ethyl esters content was measured using low frequency 1H NMR spectroscopy (60 MHz). The La50SBA-15 heterogeneous catalyst presented conversion of soybean oil in ethyl esters as high as 80% after reaction time of 6 h., comparing well with previous reports for methanolysis of soybean oil. Moreover, lixiviation of the active phase was not observed, thus excluding the contribution of the homogeneous catalysis to the studied transesterification process.