Preparation of the Ru/HZSM-5 catalyst and its catalytic performance for the 2-pentanone hydrodeoxygenation reaction

Levulinic acid is an ideal model compound for complex oxygenated components in bio-oil. To assist the understanding of its hydrodeoxygenation (HDO) performance, it is necessary to investigate separately the HDO property of the ketonic carbonyl group and carboxyl group. Herein, 2-pentanone was selected as a model to study the HDO property of the ketonic carbonyl group. The Ru/HZSM-5 catalyst was prepared by an excessive impregnation method and its structure and acidity were characterized by H-2-TPR, NH3-TPD, HRTEM, SEAD, Py-IR, TG-DSC, and ICP analyses. The effect of preparation conditions on the catalytic performance of Ru/HZSM-5 was studied; the suitable preparation conditions were determined as follows: a calcination temperature of 450 degrees C, a calcination time of 3 h, a reduction temperature of 350 degrees C, and a reduction time of 4 h. The catalytic performance of Ru/HZSM-5 for the 2-pentanone HDO reaction was evaluated; pentane selectivity of 77.7% at a 2-pentanone conversion of 91.8% was achieved under the conditions of a reaction pressure of 5 MPa, a reaction temperature of 190 degrees C, a catalyst amount of 6 wt% and a reaction time of 6 h. 2-Pentanone HDO follows the reaction path of 2-pentanone hydrogenation to 2-pentanol and then 2-pentanol dehydration and hydrogenation to the target product pentane. The acidity of the catalyst plays a certain role in influencing its catalytic performance: Lewis acid sites show high activity for activating C=O bonds and Bronsted acid sites are the key to accelerate the further dehydration of 2-pentanol and hydrogenation to alkanes.

Automated summary

The hydrodeoxygenation (HDO) performance of levulinic acid was studied by investigating the properties of ketonic carbonyl group and carboxyl group separately. Ru/HZSM-5 catalyst was used for the HDO reaction with 2-pentanone as a model compound, showing high pentane selectivity. The acidity of the catalyst plays a crucial role in influencing its catalytic performance.