Skeletal isomerization of l-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 l-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 degrees C. The effect of temperature, time on stream, weight hour space velocity (WHSV), and partial pressure of l-butene on the skeletal isomerization reaction of l-butene was studied over the prepared ZSM-22 catalysts. ZSM-22 demonstrated high activity in the skeletal isomerization of l-butene at extremely high WHSV, even at temperatures as low as 400 degrees C.