Metathesis of unsaturated fatty acid esters derived from South African sunflower oil in the presence of a 3 wt.% Re<inf>2</inf>O<inf>7</inf>/SiO<inf>2</inf>-Al<inf>2</inf>O<inf>3</inf>/ SnBu<inf>4</inf> catalyst

The metathesis of single- and multiple-component fatty acid ester systems derived from South African sunflower oil was investigated using a heterogeneous 3 wt.% Re2O7/SiO2-Al2O3/ SnBu4 catalyst system. A total conversion of the methyl ester of linoleic acid of 86.1% with a total diester yield of 20.4% was obtained. A total conversions of 76.2 and 72.2% with corresponding diester yields of 19.4 and 18.4%, respectively, were obtained in the cross-metathesis of (1) oleate/linoleate methyl esters and (2) a mixture of fatty acid esters derived from South African sunflower oil, respectively. Different reaction products showed varying sensitivity towards reaction temperature with dicarboxylic esters reaching a maximum yield at 60°C. The 3 wt.% Re2O7/SiO2-Al2O3/ SnBu4 catalyst system reached maximum catalytic activity at 60°C, but rapidly deactivated at higher reaction temperatures (80°C). © 2003 Elsevier Science B.V. All rights reserved.