Regio selectivity in the hydrogenation of geraniol over platinum containing zeolites

The hydrogenation of 3,7-dimethylocta-2,6-dien-1-ol (geraniol) (1) is performed over different platinum containing zeolitic materials such as beta, Y and MCM-41, prepared by impregnation with Pt(NH3)(4)Cl-2 followed by drying, calcination and reduction. 3,7-dimethyl-6-octen-1-ol (citronellol) (2) and 3,7-dimethyl-2-octen-1-ol (3) are formed in different ratios, depending on the zeolite structure. The mechanism involved points to the existence of a tight host-guest interaction between the zeolitic voids and the substrate. Both shape selectivity and chemical properties of the zeolites play an important role in the induction of regio selectivity during reaction. It is found that geraniol can be converted selectively to citronellol by a proper combination of zeolite structure and metal cluster size.