Research progress of catalysts for aldol condensation of biomass based compounds

Abstract

Research progress of catalysts of the aldol condensation reaction of biomass based compounds is summarized for the synthesis of liquid fuel precursors and chemicals. In summary, an acidic catalyst, alkaline catalyst, acid-base amphoteric catalyst, ionic liquid and other catalysts can catalyze the aldol condensation reaction. The aldol condensation reaction catalyzed by an acid catalyst has the problems of low conversion and low yield. The basic catalyst catalyzes the aldol condensation reaction with high conversion and yield, but the existence of liquid alkali is difficult to separate from the product. The reaction temperature needed for oxide and hydrotalcite alkali is relatively high. The basic resin has good catalytic activity and at a low reaction temperature, and is easy to separate from the target product. Acid-base amphoteric catalysts have received extensive attention from researchers for their excellent activity and selectivity. Ionic liquid is a new type of material, which can also be used for the aldol condensation reaction. In the future application of aldol condensation, the development of strong alkaline resin is a good research direction.

Fig. 1. Condensation reaction of furfural and cyclopentanone.

Fig. 2. Preparation of 2-ethyl hexanal by hydrogenation condensation of crotonaldehyde.

Fig. 3. Condensation reaction of benzaldehyde with p-nitroacetophenone.

Fig. 4. Condensation reaction of furfural and acetone.

Fig. 5. Condensation reaction of furfural with 4-heptanone.

Fig. 6. Self-dipolycondensation of levulinic acid.

Fig. 7. Condensation reaction of benzaldehyde and acetone.

Fig. 8. Dehydration and condensation reaction route of ethanol.

Fig. 9. The aldol condensation of vanillin and cyclohexanone.

Fig. 10. Condensation reaction of furfural and acetone.

Fig. 11. Condensation reaction of citral and methyl ethyl ketone.

Fig. 12. Condensation reaction of furfural with methyl isobutyl ketone.

Fig. 13. Condensation reaction of cyclopentanone and butyraldehyde.

Fig. 14. Self-condensation reaction of MIBK.

Fig. 15. Condensation reaction of furfural and levulinic acid.

Fig. 16. Condensation reaction of furfural and levulinic acid.

Fig. 17. Condensation of 5-hydroxymethylfurfural with acetone.

Fig. 18. Aldol condensation of isobutyraldehyde and formaldehyde.

Fig. 19. Self-condensation reaction of propionaldehyde.

Fig. 20. Condensation reaction of acetone with germanial.

Fig. 21. Condensation reaction of furfural and angelica lactone.

Fig. 22. Condensation reaction of cyclopentanone and cyclohexanone.

Fig. 23. Condensation reaction of methyl acetate (Ma) and formaldehyde.

Fig. 24. Condensation reaction of methyl propionate (Ma) and formaldehyde.

Fig. 25. Main reaction pathways in the acetone condensation process.

Fig. 26. Self-aldol condensation of cyclopentanone.

Fig. 27. Intramolecular aldol condensation of 2,5-hexanedione.