Tin/platinum on alumina as catalyst for dehydrogenation of isobutane. Influence of the preparation procedure and of the addition of lithium on the catalytic properties of the catalyst

GUILLERMO J. SIRI, MÓNICA L. CASELLA, GERARDO F. SANTORI, OSMAR A. FERRETTI

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

American Chemical Society

Lugar: Columbus, Ohaio, USA; Año: 1997 vol. 36 p. 4821 - 4826

0888-5885

A series of monometallic and bimetallic Pt and PtSn catalysts, modified or not by the addition of Li, was studied in the dehydrogenation of isobutane to isobutene reaction. Special emphasis was devoted to the behavior of catalysts obtained following different preparation procedures. In relation to the addition of lithium, a strong dependence of the catalytic properties on the order in which Li was added was observed. Two alternatives were analyzed: (a) the support was modified by adding lithium onto it, and then it was impregnated with the metallic precursors; (b) the support was impregnated with the metallic precursors and afterward lithium was added. The application of surface organometallic chemistry on metals (SOMC/M) techniques for the preparation of PtSn bimetallic catalysts led to solids having a better performance than when conventional techniques (successive impregnations with inorganic precursors) were used. Selectivities close to 100% at a high level of activity were obtained when lithium was added on PtSn catalyst (alternative b) prepared from SOMC/M techniques. These systems also showed a good performance in deactivation-regeneration cycles.-regeneration cycles.