Disordered medium-pore zeolite PST-24 as an efficient low-temperature isobutanol dehydration catalyst

Abstract

The synthesis of PST-24 with a relatively high Al content (Si/Al = 47), a disordered medium-pore zeolite, using the seeding technique and its catalytic properties for the low-temperature (250 °C) dehydration of isobutanol to isobutene are presented. This PST-24 was found to be considerably more active and stable for isobutanol dehydration than H-ZSM-5 and H-ferrierite with similar Si/Al ratios, the two most widely studied catalysts for this reaction, revealing its high potential as a new dehydration catalyst for biomass-derived isobutanol. While variable-temperature IR spectroscopy with adsorbed isobutanol reveals stronger interactions of isobutanol molecules with the PST-24 framework than with the latter two zeolite frameworks, ¹H–¹³C CP MAS spectroscopy shows the formation of soft coke only in the former catalyst.