A CuMg-MOF-74 derived stable Cu/MgO@SiO2 for the hydrogenation of bis(2-hydroxyethyl) cyclohexane-1,4-dicarboxylate

Abstract

Cu-based catalysts play an important role in the hydrogenation of carboxylate, however, its application under high temperature is restricted due to the low Hüttig temperature of Cu. Promoting the activity and stability of Cu catalysts at high temperature is a challenge. In this work, a highly stable Cu/MgO@SiO2 was calcined and reduced controllably from CuMg-MOF-74 modified by SiO2, and applied in the hydrogenation of poly(ethylene terephthalate) degraded bis(2-hydroxyethyl) cyclohexane-1,4-dicarboxylate (BHCD) to CHDM. Characterizations found that Cu/MgO@SiO2 possessed enlarged surface area and pore volume (104 m2/g and 0.52 cm3/g), highly dispersed Cu (22.7%), strong metal–support interactions, and abundant basicity (480 μmol/g). It was confirmed that the conversion of BHCD and selectivity of CHDM over Cu/MgO@SiO2 reached 99.2% and 97.1% at 260 °C, 2.5 MPa H2, 0.8 g-BHCD/g-cat./h, 155 mol-H2/mol-BHCD, which was superior to reference Cu/MgO and other Cu-MgO-SiO2 catalysts. And also, Cu/MgO@SiO2 could remain its activity within 100 h at 280 °C due to the MgO decorated Cu nanoparticles encapsulated by SiO2 hollow in well-designed Cu/MgO@SiO2.