Conversion of Isobutanol to Olefins and Aromatics over HZSM-5-Based Catalysts: Tuning of Product Selectivity

Isobutanol derived from biomass can serve as a potential renewable candidate for the production of light olefins and aromatics, which are the building blocks to manufacture fuels and chemicals in the petrochemical industry. Dependent upon the product requirements, the product selectivity toward olefins or aromatics can be tuned by adjusting the reaction conditions and the properties of HZSM-5 catalysts. On bare HZSM-5, mild conditions (low temperature, low space time, and low acidity) favored the production of olefins and harsh conditions (high temperature, high space time, and high acidity) were more likely to produce aromatics. Ga was impregnated onto HZSM-5 to enhance the production of aromatics. Unexpectedly, Ga introduction only induced the intertransformation between olefins and aromatics without significantly impacting the selectivity of low-value paraffins. The exchanged Ga sites functioning together with Bronsted acid were identified as active Ga species and strengthened the direct dehydrogenatio...