Catalyst For Hydrogenation Of Dimethyl Oxalate Research Articles

Synergistic Effect of a Boron-Doped Carbon-Nanotube-Supported Cu Catalyst for Selective Hydrogenation of Dimethyl Oxalate to Ethanol.

Heteroatom doping is a promising approach to improve the properties of carbon materials for customized applications. Herein, a series of Cu catalysts supported on boron-doped carbon nanotubes (Cu/xB-CNTs) were prepared for the hydrogenation of dimethyl oxalate (DMO) to ethanol. The structure and chemical properties of boron-doped catalysts were characterized by XRD, TEM, N2 O pulse adsorption, CO chemisorption, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption, which revealed that doping boron into CNT supports improved the Cu dispersion, strengthened the interaction of Cu species with the CNT support, introduced more surface acid sites, and increased the surface area of Cu0 and especially Cu+ sites. Consequently, the catalytic activity and stability of the catalysts were greatly enhanced by boron doping. 100 % DMO conversion and 78.1 % ethanol selectivity could be achieved over the Cu/1B-CNTs catalyst, the ethanol selectivity of which was almost 1.7 times higher than that of the catalyst without boron doping. These results suggest that doping CNTs with boron is an efficient approach to improve the catalytic performance of CNT-based catalysts for hydrogenation of DMO. The boron-doped CNT-based catalyst with improved ethanol selectivity and catalytic stability will be helpful in the development of efficient Cu catalysts supported on non-silica materials for selective hydrogenation of DMO to ethanol.

The influence of B-doping on the catalytic performance of Cu/HMS catalyst for the hydrogenation of dimethyloxalate

The influence of boron introduction on the performance of 20 wt.% Cu/HMS catalysts for the catalytic hydrogenation of dimethyloxalate was systematically investigated. It is shown that the boron loading, boron source and the preparation method all have great effect on the catalytic behaviors of the catalyst. Characterization methods including N 2-physisorption, X-ray diffraction, H 2-temperature-programmed reduction, N 2O titration, NH 3 temperature-programmed desorption, and X-ray photoelectron spectroscopy were carried out to elucidate the structure evolution of the catalyst with the introduction of boron. Experimental results showed that the B 2O 3 modified catalyst prepared via the ammonia-evaporation-induced synthesis method exhibited the highest conversion and ethylene glycol selectivity because of the higher metallic copper surface area and copper dispersion. The optimum Cu/B mole ratio, which strongly affects the surface composition of the catalyst, was found to be 2/1. 100% DMO conversion and 98% EG selectivity could be obtained over the CuB/HMS(2/1) catalyst under 2.5 h −1 liquid hour space velocity, which is almost four times higher than that of the one without boron introduction.

Synthesis of Methyl Glycolate by Hydrogenation of Dimethyl Oxalate over Cu-Ag/SiO 2 Catalyst

Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate (DMO) over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO 2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous cuprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO 2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate (MG) were optimized: temperature at 468-478 K, 40-60 mesh catalyst diameter, H 2/DMO ratio 40, and 1.0 h −1 of LHSV.