U. Schuchardt et al., TRANSESTERIFICATION OF SOYBEAN OIL CATALYZED BY ALKYLGUANIDINES HETEROGENIZED ON DIFFERENT SUBSTITUTED POLYSTYRENES, Journal of molecular catalysis. A, Chemical, 109(1), 1996, pp. 37-44
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.