Production of compounds to be used as fuel additive: Glycerol conversion using Nb-doped MgAl mixed oxide

Abstract

MgAl mixed oxide from hydrotalcite was modified with niobium and evaluated as a catalyst for a liquid-phase glycerol conversion in the presence of hydrogen peroxide. Niobium oxide exhibited high activity for glycerol conversion via heterogeneous catalysis at 250°C. Gas chromatography with mass spectrometry (GC–MS) analysis of the reaction showed that diglycerol, ethers and ketone were the main products. The results strongly suggest that the glycerol conversion involves acid groups and oxidizing species generated upon reacting with H2O2 and niobium. Furthermore, catalytic tests monitored by electrospray mass spectrometry (ESI-MS) suggest that ethers, such as di, tri and tetra glycerols, are formed during the glycerol condensation (m/z=167, 223, 241, and 315). Preliminary tests using the reaction products as additives for gasoline demonstrate that the octane is increased due to the presence of ether formed from glycerol conversion.