Support Effects in Nerol Hydrogenation over Pt/SiO2, Pt/H-Y and Pt/H-MCM-41 Catalysts

Abstract

Chemoselective hydrogenation of nerol was investigated over Pt/SiO 2 , Pt/H-Y and Pt/H-MCM-41 catalysts. The initial total reaction rates decreased in following order:Pt/H-Y > Pt/SiO 2 > Pt/H-MCM-41. Nerol hydrogenation was found to be an apparent structure sensitive reaction. The selectivities to citronellol at 30% conversion of nerol were 65%, 55% and 25% over Pt/SiO 2 , Pt/H-MCM-41 and Pt/H-Y, respectively.

Selectivity Enhancement by Catalyst Deactivation in Three-Phase Hydrogenation of Nerol

“…Besides hydrogenation, hydrodeoxygenation 11 and decarbonylation also occur. The confirmed hydrodeoxygenation products in nerol hydrogenation are 3,7-dimethyloctene and 3,7-dimethyloctane . Decarbonylation of an unsaturated alcohol could explain the fast catalyst deactivation during nerol hydrogenation at 100 °C .…”

“…The preliminary results in nerol hydrogenation over Rh/Al 2 O 3 catalyst revealed that the selectivity to a desired, intermediate product, citronellol, increased with increasing conversion . Selectivity enhancement in nerol hydrogenation was not, however, observed over a Pt/SiO 2 catalyst . The main aim in this work was to investigate the origin of the selectivity enhancement over Rh/Al 2 O 3 catalyst in nerol hydrogenation by varying the reaction conditions as well as to investigate the catalyst reuse.…”

“…10 Selectivity enhancement in nerol hydrogenation was not, however, observed over a Pt/SiO 2 catalyst. 11 The main aim in this work was to investigate the origin of the selectivity enhancement over Rh/Al 2 O 3 catalyst in nerol hydrogenation by varying the reaction conditions as well as to investigate the catalyst reuse. Additionally, the reaction mechanism was studied, since besides hydrogenation there also occurs isomerization to citronellal (Figure 1).…”

“…13 Nerol hydrogenation has been very scarcely reported. 10,11,14,15 In the work of Hubaut 14 nerol was hydrogenated over a copper chromium oxide catalyst in decalin at 140 °C under atmospheric pressure. Under these conditions the main product was citronellol, and a substantial amount of citronellal (maximal yield of 25%), the isomerization product of nerol was formed.…”

“…However, no kinetic curves for nerol hydrogenation were presented. 15 Recently Ma ¨ki-Arvela et al 11 investigated different catalysts in nerol hydrogenation in 2-pentanol at 70 °C and 10 bar of hydrogen over Pt/ SiO 2 , Pt/H-Y, and Pt/H-MCM-41 catalysts. The selectivities to citronellol at 30% conversion of nerol were 65%, 55%, and 25% over Pt/SiO 2 , Pt/H-MCM-41 and Pt/ H-Y, respectively.…”