Importance of Magnesium in Cu-Based Catalysts for Selective Conversion of Biomass-Derived Furan Compounds to Diols

Abstract

Selectively hydrogenating the carbonyl of furfural and opening of the furan ring is challenging but crucial for efficient conversion of furfural to pentanediols, the valuable chemicals. In this study, CuMgAl catalysts with highly dispersed Cu particles and tunable basic sites were synthesized with layered double hydroxides as precursors for hydrogenation of furfural to furfuryl alcohol (FA) and the subsequent hydrogenolysis of FA to 1,2-pentanediol and 1,5-pentanediol. The presence of varied content of Mg in the catalyst promoted dispersion of copper oxide and exposure of metallic copper species, weakened interaction between copper oxides and the carrier, suppressed sintering of metallic copper species, and increased abundance of the basic sites, promoting the catalytic activity/selectivity/stability. Strong chemical adsorption of the furan ring in FA on basic sites of the catalyst suppressed hydrogenation of the furan ring and facilitated opening of the furan ring in FA, the rate-determining step for formation of the diols.

Recent advances in the catalytic transfer hydrogenation of furfural to furfuryl alcohol over heterogeneous catalysts

“…Shao et al synthesized a Cu 0.3 Mg 2.7 Al catalyst with highly dispersed copper particles and abundant basic sites using layered double hydroxides as precursors, giving nearly complete FF conversion with 98.3% FFA selectivity with a TOF of 13.5 h −1 in isopropanol at 373 K and 4 MPa H 2 for 3 hours. 72 The addition of Mg to CuAl forms a LDH structure, which improved the surface area (193.4 m 2 g −1 ) and the pore volume (1.2 cm 3 g −1 ), thus promoting the dispersion of CuO and metallic Cu species. Mg had a weaker interaction with copper oxides, alleviating the interaction of copper oxide with alumina and making the reduction of CuO much easier.…”

In Situ Ruthenium Catalyst Modification for the Conversion of Furfural to 1,2-Pentanediol

“…Noble metal-based catalysts have been described to be highly efficient to produce these two diols from furfural or its hydrogenated derivatives, Pt- [8][9][10][11][12][13][14] and Ru-based [15][16][17][18][19] catalysts producing mainly 1,2-PeD, and Rh-and Ir-based [20][21][22] catalysts, 1,5-PeD. Cu-based [23][24][25] catalysts produce a mixture of both diols usually needing harsher reaction conditions. Pt-based catalysts efficiently cleavage the C-O bond of FA to produce 1,2-PeD, several of these catalysts producing this diol in high yields [8][9][10].…”

“…Similarly, a 10 wt % Cu/Al 2 O 3 catalyst gave a 86% conversion of FA with a 70% selectivity towards the pentanediols (48% 1,2-PeD and 22% 1,5-PeD) at 140 • C and 80 bar of H 2 [24]. A series of CuMgA catalysts, whose properties were modulated by controlling the Mg content, were able to efficiently convert FR or FA at 140 • C and 60 bar of H 2 to pentanediols [25]. Cu 1.8 Mg 1.2 Al converted 95% of FA into 46% of 1,2-PeD and 16% of 1,5-PeD, together with other minor by-products.…”

“…A series of CuMgA catalysts, whose properties were modulated by controlling the Mg content, were able to efficiently convert FR or FA at 140 °C and 60 bar of H2 to pentanediols [25]. Cu1.8Mg1.2Al converted 95% of FA into 46% of 1,2-PeD and 16% of 1,5-PeD, together with other minor by-products.…”

In Situ Hybridizing Cu3(BTC)2 and Titania to Attain a High‐Performance Copper Catalyst: Dual‐Functional Role of Metal‐Support Interaction on the Activity and Selectivity

“…[7] Zhao et al have announced that sulfonate modified active carbon can improve copper dispersion and reducibility, generating 100 % FOL yield at 378 K and 0.4 MPa. [8] Other support modification strategies, including alkali metal (K, Mg), [9] porosity confinement, [10] etc. have also been conceived by several scientists.…”