ZrO2-MoO3 for the Acetalization of 1,3-Propanediol from Dilute Solutions

A reactive isolation approach for the recovery of 1,3-propanediol (1,3-PD) from dilute aqueous solutions was performed on ZrO2-MoO3 solid heterogeneous catalysts through a cyclic reaction with aldehyde to form acetals (2-methyl-1,3-dioxane, 2MD). The effects of catalyst composition, reaction temperature, reaction time, and optimal dose on the conversion rates of acetalization and hydrolysis were investigated. For ZrO2-10 wt % MoO3 prepared by the precipitation-impregnation method, the conversion rate of 1,3-PD in acetalization reached 95.7% at 60 degrees C for 2 h, and the acetals conversion in the hydrolysis reaction reached 97.0% at 100 degrees C for 10 h. The stability test showed that the 1,3-PD conversion rate still reached 87.3% after five cycles of use. In terms of the catalytic activity in acetalization, the 10 wt % catalyst exhibited much higher selectivity in the simulated fermentation liquid for 1,3-PD than ethanol, 2,3-butanediol, and glycerol. This indicates that ZrO2-10 wt % MoO3 mixed oxide has the best characteristics for the extraction of 1,3-PD from dilute aqueous solutions.