Hydrogenation of Citral Over IrAu/TiO₂ Catalysts. Effect of the Preparation Method

摘要

Hydrogenation of citral over Ir/TiO₂ and IrAu/TiO₂ catalysts was studied. Catalysts were prepared by deposition–precipitation with urea (Ir/TiO₂) and sequential incorporation of the metals using a combined DPU-incipient wetness impregnation approach (IrAu/TiO₂). Samples were reduced in H₂ at 573 K (LT) and 773 K (HT). These materials were characterized by transmission electron microscopy (HAADF), TPR and CO adsorption followed by DRIFT. The liquid phase hydrogenation of citral was studied in a Parr type batch reactor at 363 K and a H₂ pressure of 0.62 MPa. An Ir/TiO₂ catalyst prepared by wet impregnation was used as reference catalyst. High selectivity to unsaturated alcohols was found, the only reaction products were geraniol and nerol for Ir/TiO₂ DPU and IrAu/TiO₂ catalysts. The IrAu/TiO₂ (HT) catalyst showed the higher conversion levels.