Highly Dispersed Ruthenium Nanoparticle-Embedded Mesoporous Silica as a Catalyst for the Production of γ-Butyrolactone from Succinic Anhydride

In this study, a novel, strategic method was developed for the synthesis of a mesoporous silica catalyst embedded with ruthenium nanoparticles (RuNPs/SiO₂) by combining the polyol and modified sol–gel methods. By applying this new procedure, uniformly synthesized ruthenium nanoparticles with an average size of 3.8 nm and 95% spherical shape were highly dispersed in the mesoporous silica support material. Coordinated carbonyl groups of PVP remaining from the synthesis of the RuNPs were effectively removed by the thermal treatment (calcined at 573 K for 4 h) and the sythesized RuNPs/SiO₂ catalysts were reduced under hydrogen at 20 bar for 2 h. These catalysts were analyzed using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), N₂ adsorption–desorption, and X-ray diffraction (XRD). After the thermal treatment and the reduction procedure, the size and shape of the embedded RuNPs were nearly unchanged, and the catalyst was active in the liquid-phase hydrogenation of succinic anhydride (SAN) to selectively form γ-butyrolactone (GBL) with a maximum yield of 90.1%. This novel catalyst preparation is a potentially useful method for the synthesis of metal nanoparticles as heterogeneous catalysts.