Modulating the Acidity of Y Zeolite Catalyst Toward Selective Oxidation of Tert-Butanol to Acetone with Molecular Oxygen

Abstract

This work proposed a novel two-step process for green synthesis of acetone from C4 hydrocarbon resources, including gas-phase oxidation of isobutane to tert-butanol and its following selective oxidation to acetone. The Y zeolites were demonstrated as selective catalyst for oxidation of tert-butanol to acetone with molecular oxygen. The acidity of Y zeolite catalyst was sensitively modulated by citric acid treatment and CaO modification. The structure-activity relationship analysis results indicated that, a larger amount of Bronsted acid sites benefited the adsorption of isobutene intermediate yielded from tert-butanol dehydration, and a moderate acid strength was required for the facile desorption of acetone product. Under the optimal conditions, the citric acid treated Y zeolites exhibited a stable tert-butanol conversion (28%) and product selectivity (acetone ~33 wt%) for selective oxidation reaction during continuous reaction-regeneration cycles. This work provides both an environmental route for acetone production and a class of selective catalyst for tert-butanol oxidation.

Keywords: Isobutane oxidation to tert-butanol, Tert-butanol selective oxidation to acetone, Y zeolite catalyst, Zeolite acidity modulation, structure-activity relationship