Effect of Fe addition on the selective hydrogenation of maleic anhydride to succinic anhydride over Ni/SiO2 catalyst

Abstract

Background

Succinic anhydride is a downstream product of the hydrogenation of maleic anhydride and an important intermediate in organic synthesis. Iron was added to Ni-based catalysts to improve the hydrogenation performance under milder reaction conditions.

Methods

A series of 5Ni-Fe/SiO₂ catalysts with varying Ni/Fe molar ratios were prepared, and their catalytic activities for the hydrogenation of maleic anhydride to succinic anhydride were evaluated. The catalysts were characterized using a range of techniques, including N₂ adsorption and desorption, XRD, H₂-TPR, NH₃-TPD, Py-IR, XPS, and CO-TPD.

Significant findings

The optimum performance can be achieved when the molar ratio of Ni/Fe equals to 4/1, with 100 % of maleic anhydride conversion and 87 % of selectivity to succinic anhydride. Fe addition facilitates good dispersion of the active metals, reduces their reduction temperature, modifies the electronic properties of Ni species and increases the amount of Lewis acid sites and active metal sites, resulting in increased selectivity towards succinic anhydride. However, the introduction of excessive amount of Fe could lead to adverse effects such as catalyst surface coverage and pore blockage, leading to a decrease in the hydrogenation performance.