Preparation of a raspberry ketone precursor in the presence of rare earth oxide catalysts

- Acid-base bifunctional rare earth oxides supported on carriers with high BET surface catalyze the aldol addition of acetone and 4-hydroxybenz-aldehyde followed by aldol condensation to form the raspberry ketone precursor 4-(4-hydroxyphenyl)-but-3-ene-2-one.
- The robust and regenerable catalyst titania doped with 1 wt.% La2O3 show highest yield of about 96%.
- The basis sites are responsible for the addition and the acid sites for the dehydration.
- The quality of the starting material has a strong influence on the catalytic performance.