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DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE
Citation:
Hill, J. M., R. D. Cortright, D. F. Rudd, AND J. A. Dumesic. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-98/041 (NTIS 98-174717), 1998.
Impact/Purpose:
information
Description:
The objectives of this project were to better understand the effect of different catalyst preparation parameters, the effect of different catalyst treatment parameters, and the mechanism of deactivation. Accordingly, catalysts were made using various preparation methods and with a range of platinum (Pt) and tin (Sn) contents. Catalysts were also tested under a variety of reaction conditions. Catalysts were characterized using kinetic studies, chemisorption, transmission electron microscopy and temperature programmed oxidation. The results indicate that Pt/L-zeolite catalysts are not selective without Sn. Sn reduces the size of the Pt ensembles thus inhibiting the hydrogenolysis, isomerization and coking reactions. At high Sn loadings, or after long periods at high temperature (-873 K) the surface Pt ensembles become enriched with Sn and metal sintering occurs; thus, the number of exposed Pt atoms and subsequently the activity, are decreased. It is difficult to reverse the results of these processes. Reacting isobutane at a lower temperature (-798 K) in the absence of feed hydrogen reduces the Sn enrichment and the metal sintering. At these conditions the main mechanism of deactivation is coking, a process which is relatively easy to reverse with flowing oxygen at a moderate temperature.
