Methylcyclopentane transformation on Ge-Rh bimetallic catalysts prepared by organometallic grafting

Ge-Rh/Al2O3 catalysts were prepared by organometallic grafting, with nominal Ge loadings of 1/8, 1/4, 1/2 and 1 monolayer and actual loading of 300, 600, 2000 and 2100 ppm. The dispersion decreased proportionally to the Ge loading up to 600 ppm Ge. Methylcyclopentane was used as catalytic test reaction. The selectivity of ring opening was 70-90%. Addition of 300 and 600 ppm Ge divided the contiguous Rh sites to smaller ensembles. Here mostly 2-methylpentane gave C-1-C-5 fragments, its surface intermediate undergoing fragmentation without desorption, like on Rh with D < 60-70%. More Ge (2000 ppm) divided further Rh and also may have penetrated into subsurface layers. Here all primary ring opening products gave fragments, similarly to small Rh particles. (c) 2006 Elsevier B.V. All rights reserved.