Selective hydrogenation of isophorone in the presence of catalysts containing nanostructured metals
|Piotr Winiarek 1, Elżbieta Fedoryńska 1, Marcin Pisarek 2, Piotr Kędzierzawski 2, Maria Janik-Czachor 2|
1. Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, Warszawa 00-664, Poland
Nanostructures of metals (especially from 10 to 13 group of periodic table of elements) can play an important role as hydrogenation catalysts. In this lecture convenient methods have been presented for the selective hydrogenation of isophorone (3,5,5-trimethylcyclohex-2-enone) to: a. isophorol (3,5,5-trimethylcyclohex-2-enol), b. homomenthol (3,3,5-trimethylcyclohexanol) and c. dihydroisophorone (3,3,5-trimethylcyclohexanone). All of the reactions were performed under the atmospheric pressure using gaseous hydrogen and propan-2-ol as a solvent.
Isophorol synthesis (yield ca. 40 %, selectivity > 90 %) was performed in the flow system with the fixed catalyst’s bed at 423 or 473 K. Au nanoparticles deposited on MgO were used as catalysts. The catalysts were characterized by means of XPS, SEM, TEM and SIMS. A size and shape of Au particles depended on the method and conditions of the catalyst preparation.
Homomenthol was obtained by quantitative hydrogenation of isophorone in the batch system at 353 K over Ni-Al and Ni-Al-Co alloys pretreated with NaOHaq.
Dihydroisophorone synthesis (yield 97 %, selectivity ca. 95 %) was also carried out in a batch system at 315 K over Ni-Al-Cr alloy pretreated with NaOHaq. The surfaces of alloys have been examined by SEM and Auger spectroscopies.
The mechanism of C=O and C=C bonds hydrogenation over above mentioned catalysts has been proposed and discussed in respect to the surface species responsible for the reaction selectivity. The role of solvent has been also discussed.
Presentation: Invited at E-MRS Fall Meeting 2007, Symposium D, by Piotr Winiarek
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-21 22:21 Revised: 2009-06-07 00:44