The catalysts separated from the reaction mixture by filtration
were initially washed with hexane to remove non-polar compounds
such as methyl esters on the surface. Further, the catalysts
were washed with methanol to remove polar compounds such as
glycerol and finally dried at 80 8C overnight. The leaching of the
catalyst into the reaction mixture was investigated by inductively
coupled plasma-mass spectrometry (ICP-MS)