TRANSESTERIFICATION OF SOYBEAN OIL CATALYZED BY ALKYLGUANIDINES HETEROGENIZED ON DIFFERENT SUBSTITUTED POLYSTYRENES

1,5,7-Triazabicyclo[4.4.0]dec-5-ene and 1,1,3,3-tetramethylguanidine w ere heterogenized on different chloromethylated poly(styrene/divinylbe nzene), as well as on linear polystyrene after introduction of a 'spac er-arm'. Furthermore, polymeric 2,3-dicyclohexylguanidines were synthe sized by the reaction of 1,3-dicyclohexylcarbodiimide with p-(6-aminoh exyl)polystyrenes. The guanidine-containing polymers were used in the transesterification of soybean oil with methanol in several consecutiv e catalytic cycles. The guanidines heterogenized on gel-type poly(styr ene/divinylbenzene) with 1 meq Cl/g showed a slightly lower activity t han their homogeneous analogous but reached the same high conversions after prolonged reaction time. On the other hand, they slowly leached from the polymers, allowing only nine catalytic cycles. The guanidines heterogenized on linear polystyrene with the use of a 'spacer-arm' we re less active. Furthermore, they suffered substitution reactions duri ng the recycling experiments to form inactive hexasubstituted guanidin ium compounds.