Acid site density effects in zeolite-catalyzed 1-butene skeletal isomerization

[Display omitted] •Acid site density effects in 1-butene skeletal isomerization over H-HPM-1 are examined.•Changes (⩽0.5 per unit cell) in framework Al atoms lead to notable changes in both conversion and selectivity.•H-HPM-1 with a framework Si/Al ratio of 350 is best among the catalysts tested to date. We have investigated the effect of acid site density on the catalytic performance of high-silica (50⩽Si/Al⩽380) H-HPM-1 zeolite in the 1-butene skeletal isomerization. Changes (⩽0.5) in the number of framework Al atoms, and thus of Brønsted acid sites, per unit cell (60 tetrahedral atoms) led to striking variations in both 1-butene conversion and isobutene selectivity. Combining isobutene yield with catalyst durability, H-HPM-1 with a framework Si/Al ratio of 350 was found to perform better than any of the catalysts studied for this reaction thus far.