Nanoporous Ni₃P Evolutionarily Structured onto a Ni Foam for Highly Selective Hydrogenation of Dimethyl Oxalate to Methyl Glycolate

Abstract

Methyl glycolate (MG) is a versatile platform molecule to produce numerous important chemicals and materials, especially new-generation biocompatible and biodegradable poly­(glycolic acid). In principle, it can be massively produced from syngas (CO + H2) via gas-phase hydrogenation of CO-derived dimethyl oxalate (DMO), but the groundbreaking catalyst represents a grand challenge. Here, we report the discovery of a Ni-foam-structured nanoporous Ni3P catalyst, evolutionarily transformed from a Ni2P/Ni-foam engineered from nano- to macro-scale, being capable of nearly fully converting DMO into MG at >95% selectivity and stable for at least 1000 h without any sign of deactivation. As revealed by kinetic experiments and theoretical calculations, in comparison with Ni2P, Ni3P achieves a higher surface electron density that is favorable for MG adsorption in a molecular manner rather than in a dissociative manner and has much higher activation energy for MG hydrogenation to ethylene glycol (EG), thereby markedly suppressing its overhydrogenation to EG.

Synthesis of methyl glycolate by hydrogenation of dimethyl oxalate with a P modified Co/SiO2 catalyst

“…S7, ESI †), which is higher than that of the Cu-based catalyst (49.0 kJ mol À1 ) 45 but lower than that of the reported Ni 3 P/SiO 2 catalyst (76.0 kJ mol À1 ). 37 What's more, the E a of the MG-to-EG process for the Co 8 P/SiO 2 catalyst was 91.5 kJ mol À1 (Fig. S7, ESI †), much higher than that of the Cu-based catalyst (54.0 kJ mol À1 ) 45 which can explain the higher MG selectivity of the P-modified Co-based catalyst than the Cu-based catalysts.…”

“…The catalyst displayed an unexceptionable stability with 100% conversion of DMO and 76% selectivity to MG during the 3600 h time-on-stream. Furthermore, Lu et al 37 have found that Ni 3 P/Ni-foam can provide 495% selectivity at nearly 100% conversion in the DMO to MG reaction and they also proposed that Ni 3 P with a higher surface electron density showed higher catalyst performance than the Ni 2 P catalyst. Nowadays, transition metal phosphides (TMPs) with unique and desirable physicochemical properties have attracted much attention.…”

Ni-Modified Ag/SiO2 Catalysts for Selective Hydrogenation of Dimethyl Oxalate to Methyl Glycolate

“…Methyl glycolate (MG), containing both hydroxyl and ester groups, is an important fine chemical [ 1 , 2 , 3 ]. As it has similar chemical properties to alcohol and ester, MG can undergo various reactions such as carbonylation, hydrolyzation, and oxidation [ 4 , 5 ].…”

“…As it has similar chemical properties to alcohol and ester, MG can undergo various reactions such as carbonylation, hydrolyzation, and oxidation [ 4 , 5 ]. Many traditional synthetic technologies, such as the carboxylation of formaldehyde and condensation of methyl formate with formaldehyde [ 2 , 6 , 7 ], have been applied for the synthesis of MG. However, disadvantages such as environmental pollution, harsh production process, and low stability of catalyst are obvious [ 2 , 6 , 7 ].…”

“…Many traditional synthetic technologies, such as the carboxylation of formaldehyde and condensation of methyl formate with formaldehyde [ 2 , 6 , 7 ], have been applied for the synthesis of MG. However, disadvantages such as environmental pollution, harsh production process, and low stability of catalyst are obvious [ 2 , 6 , 7 ]. Thus, the development of a green synthetic method with high efficiency is warranted.…”