Environmentally friendly lubricants through a zero waste process

Tri-esters of fatty acids with polyols can be easily prepared through direct esterification of different acids with the polyol in the presence of amorphous solid acid catalysts. Conversion close to 100% and very high selectivity to triesters can be obtained in the presence of a silica zirconia amorphous catalyst. Activity and selectivity can be due to the presence of very well dispersed Lewis acid sites consisting in tetrahedrally coordinated Zr ions that are resistant to water formed during reaction as shown by FT IR spectroscopy.