Direct Conversion of n-Butane to Isobutene over Pt–MCM22

MCM22 is a very active and selective catalyst for the skeletal isomerization of butene. At temperatures up to 775 K, Pt–MCM22 gives good results in the dehydroisomerization of n-butane, achieving higher yields of isobutene than does Pt–ZSM5. Most notably, the formation of cracking products is low. Alternatively, MCM22 can also be used as an isomerization catalyst in combination with Pt–ZSM5 in order to increase the yield of isobutene in dehydro-isomerization. A disadvantage of the MCM22 materials, however, is their moderate stability, especially at higher temperatures. During calcination/reduction of Pt–MCM22 partial dealumination of the framework occurs, leading to enhanced deactivation by coking.