Selective Hydrogenation of Dimethyl Oxalate to Methyl Glycolate over Boron-Modified Ag/SiO2 Catalysts

The addition of boron (B) as a promoter to the Ag/SiO2 catalyst for the selective hydrogenation of dimethyl oxalate (DMO) to methyl glycolate (MG) was investigated. A comparison of the preparation method for incorporation of B found that the addition during the ammonia evaporation deposition-precipitation synthesis of the Ag/SiO2 catalyst (Ag-B/SiO2) was inferior to incipient wetness impregnation introduction of the Ag/SiO2 catalyst (B/Ag/SiO2). Moreover, the effects of B contents (0.5-5 wt %) on the physicochemical properties and catalytic performance of the B/Ag/SiO2 catalysts were investigated by XRF, N2- physisorption, XRD, FTIR, TEM, EDX mapping, H2-TPR, NH3-TPD, XPS, and catalytic testing. The results indicated that both the catalytic activity and stability of the Ag/SiO2 catalyst were noticeably enhanced after the introduction of B. The B/Ag/SiO2 catalyst with 1 wt % B showed the best catalytic performance of 100% DMO conversion and 88.3% MG selectivity, which could be attributed to the highest dispersion of the active metal and the smallest Ag particle size stabilized by the strong interaction between silver and boron species.

Automated summary

The addition of boron as a promoter to the Ag/SiO2 catalyst for the selective hydrogenation of dimethyl oxalate to methyl glycolate was investigated. Two methods of incorporating boron were compared, and it was found that impregnation introduction of boron yielded better results. The effects of different boron contents on the properties and catalytic performance of the catalyst were studied, and it was observed that the introduction of boron significantly enhanced the activity and stability of the catalyst, with 1 wt % boron showing the best performance.