Please use this identifier to cite or link to this item:
|Title:||A tandem cyclization and hydrogenation of (±)-citronellal to menthol over bifunctional Ni/Zr-beta and mixed Zr-beta and Ni/MCM-41|
|Authors:||Nie, Y. |
|Citation:||Nie, Y., Niah, W., Jaenicke, S., Chuah, G.-K. (2007-05-15). A tandem cyclization and hydrogenation of (±)-citronellal to menthol over bifunctional Ni/Zr-beta and mixed Zr-beta and Ni/MCM-41. Journal of Catalysis 248 (1) : 1-10. ScholarBank@NUS Repository. https://doi.org/10.1016/j.jcat.2007.02.018|
|Abstract:||The addition of nickel to Zr-beta gave a useful bifunctional catalyst that combines a high rate of cyclization of (±)-citronellal to isopulegols over zirconium sites and subsequent hydrogenation to menthols. The diastereoselectivity to the desired (±)-menthol was 90%. A loading of 4 wt% is optimal; lower loadings led to a low rate of hydrogenation, whereas a higher nickel loading appears to block the zirconium Lewis acid sites essential for the cyclization of citronellal. A mixture of Zr-beta and Ni/MCM-41 also formed an effective bifunctional catalyst system where the selectivity toward menthols remained high even with nickel loadings up to 15 wt%. The yield of (±)-menthol over the dual-catalyst system was 86-89% with < 5 % of byproducts, citronellol and 3,7-dimethyloctanol. Besides nickel, bifunctional Rh/Zr-beta catalysts also formed menthols with selectivity > 93 %, although the diastereoselectivity to (±)-menthol was lower (85%). In comparison, a 2% Pd/Zr-beta catalyst exhibited lower activity and selectivity to menthols, forming substantial amounts of 3,7-dimethyloctanal. © 2007 Elsevier Inc. All rights reserved.|
|Source Title:||Journal of Catalysis|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on Jun 19, 2018
WEB OF SCIENCETM
checked on Jun 12, 2018
checked on Jun 22, 2018
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.