The Catalytic Hydrogenation of Maleic Anhydride on CeO2−δ-Supported Transition Metal Catalysts

Xin Liao,Martyn Hill,Yin Zhang,Junqiu Guo,Zheng Jiang,Lili Zhao,Yongxiang Zhao

doi:10.3390/catal7090272

Abstract

The proper selection of transition metals and support is pivotal to the design of active and selective catalysts for maleic anhydride hydrogenation (MAH). Herein, the M/CeO2−δ (M = Co, Ni, Cu, respectively) catalysts with pre-optimised metal loading of 10 wt % were prepared via a wet impregnation method and well characterized to corroborate their MAH performance with the properties of metal, support and the M/CeO2−δ catalysts. The results revealed that the metal dispersion on the catalyst declines in the order of Ni/CeO2−δ > Co/CeO2−δ > Cu/CeO2−δ, similar to the apparent activity for maleic anhydride (MA) transformation to succinic anhydride (SA). The hydrogenolysis of SA to γ-butyrolactone (GBL) occurs on Ni/CeO2−δ and Co/CeO2−δ only when the MA → SA transformation completing. The Ni/CeO2−δ displays superior activity and selectivity to Co/CeO2−δ in both MA → SA and SA → GBL reactions, while the Cu/CeO2−δ and CeO2−δ are both inert for SA → GBL hydrogenolysis. The MA hydrogenation to SA follows the first order kinetic law on the Ni/CeO2−δ and Co/CeO2−δ catalysts yet a more complex kinetic characteristics observed on the Cu/CeO2−δ. The distinct catalytic hydrogenation behaviours of the M/CeO2−δ catalysts are assigned to the synergism of dispersion and electronic configuration of the transition metals and oxygen vacancies.

Highlights

Catalytic hydrogenation of maleic anhydride (MA) is an essential route for the current industrial production of the succinic anhydride (SA), γ-butyrolactone (GBL) and tetrahydrofuran (THF), which are value-added intermediates for pharmaceuticals and bio-degradable polymers and highly-demanded solvents for various industrial processes [1,2,3]
Ni/CeO2−δ, Co/CeO2−δ and Cu/CeO2−δ catalysts for maleic anhydride hydrogenation were prepared via a simple wet impregnation synthesis and well characterised applying XRD, transition electron microscopy (TEM), Raman, TPR and TPD techniques, in order to unravel the dependence of the MA hydrogenation (MAH) performance over the redox properties and their M-CeO2−δ interaction and, guide the future design of robust and highly selective transition metal catalysts for MAH
It was found that metal dispersion of M/CeO2−δ catalysts declines as Ni/CeO2−δ > Co/CeO2−δ

Summary

Introduction

Catalytic hydrogenation of maleic anhydride (MA) is an essential route for the current industrial production of the succinic anhydride (SA), γ-butyrolactone (GBL) and tetrahydrofuran (THF), which are value-added intermediates for pharmaceuticals and bio-degradable polymers and highly-demanded solvents for various industrial processes [1,2,3]. The main catalysts widely applied in the MAH processes are noble metal catalysts (Pd, Ru and Au) [4] and transition metal copper chromite (Cu-Cr) catalysts [5], though they are either costly, less selective or toxic. MAH catalysts, extensive efforts have been made on: (1) exploring various transition metal Ni [1,2,6], Co [3], Cu [7,8,9] and bimetallic catalysts [10] with controlled particle sizes and surface dispersion;. Catalysts 2017, 7, 272 surface acidity and redox properties [8,15,16]; and (3) employing new catalyst supports, for example the structure-defective TiO2 [17] and CeO2 [1] have emerged as excellent supports for metallic Ni catalysts and demonstrated exceptional selectivity in MAH. The systematic and comparative studies of the influence of transition metals and their supports on the MAH performance have not been well documented in literature, in particular the emerging ceria and titania supports

Methods

Results

Conclusion