Stability Investigation of a Supported TiO2–Pd Bifunctional Catalyst over the One-Pot Liquid-Phase Synthesis of Methyl Isobutyl Ketone from Acetone and H2

Abstract

The one-pot liquid-phase synthesis of methyl isobutyl ketone (MIBK) from acetone and H2 is a significant process in the fine-chemicals industry. In this paper, we fabricated a series of TiO2–SiO2/SiO2(F)&Pd/Cor bifunctional catalysts and optimized the ratio of TiO2 to SiO2 to be 1. The catalyst with the optimal mole ratio of TiO2 to SiO2 was further investigated in a long-term operation in a trickle-bed reactor, which delivered a stable MIBK selectivity of 83–93% at 26–36% acetone conversion for 300 h. The characterizations of Fourier transform infrared spectra, Raman spectra, thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed desorption of CO2 and NH3, and pyrolysis infrared spectra reveal that the active sites of acetone condensation and dehydrogenation could be attributed to the Ti–O–Si bonds. Deactivation of the catalyst resulted from a decrease of the active sites because of the aggregation of TiO2 and carbonaceous accumulation on the catalyst surface.