Efecto del contenido de Germanio sobre las propiedades de las funciones metálica y ácida del catalizador PtReGe/Al2O3-Cl

V.A. MAZZIERI; C.L. PIECK; C.R. VERA; J.C. YORI; J.M. PARERA; J.M. GRAU

Foz do Iguacu, PR - Brasil

Congreso; 13º Congresso Brasileiro de Catálise 3º MercoCat; 2005

The effect of the content of Ge on the properties of the metal and acid functions of the trimetallic PtReGe/Al2O3-Cl catalyst was studied using the reforming of n-heptane. The elemental concentration of the catalysts were:  Pt=Re=0.3%; Ge=0.1, 0.3, 0.6 and 0.9%. The reaction was performed in a fixed bed flow reactor at 450 ºC, 0.1 MPa, H2/nC7=4 and WHSV=7.3. It was found that the addition of small quantities of Ge (0.1%) decreases both the hydrogenolitic and dehydrogenation activities, by the rupture of Pt-Re ensembles and the modification of the electronic density of Pt as revealed by the decrease in the CO chemisorption capacity. With respect to the acid function upon Ge addition a change in the acid strength distribution, with an increase of the amount of mild and weak acid sites is observed. This modification of the metal/acid balance has an effect over the distribution of products in the reforming of n-heptane. The isomerization and the stability of the catalyst are enhanced while the cracking and dehydrocyclization activity are decreased. The i-heptane/toluene ratio is improved and the product better fullfils the environmental regulations.