Catalytic Activity of ZSM-22 Zeolites in the Skeletal Isomerization Reaction of 1-Butene

Skeletal isomerization of 1-butene was carried out over ZSM-22 zeolites in a fixed-bed reactor system at near atmospheric pressure. The ZSM-22 zeolites obtained after the synthesis and subsequent calcination showed high activity in the transformation of 1-butene even without ion-exchange procedures. There was a great difference in the catalytic activity between catalysts calcined in a separate calcination oven and catalysts calcined using high flows in the reactor. When a selective isomerization catalyst was prepared using calcination in air, a high flow was required in order to efficiently remove steam and heat. Calcination without any possibility of steam formation could be performed in a flow of nitrogen or even in the reactant flow at temperatures as low as 400°C. The effect of temperature, time on stream, weight hour space velocity (WHSV), and partial pressure of 1-butene on the skeletal isomerization reaction of 1-butene was studied over the prepared ZSM-22 catalysts. ZSM-22 demonstrated high activity in the skeletal isomerization of 1-butene at extremely high WHSV, even at temperatures as low as 400°C.