Tunable and Selective Conversion of 5‐HMF to 2,5‐Furandimethanol and 2,5‐Dimethylfuran over Copper‐Doped Porous Metal Oxides

Abstract

Tunable and selective hydrogenation of the platform chemical 5-hydroxymethylfurfural into valuable C6 building blocks and liquid fuel additives is achieved with copper-doped porous metal oxides in ethanol. A new catalyst composition with improved hydrogenation/hydrogenolysis activity is obtained by introducing small amounts of ruthenium dopant into the previously reported Cu(0.59) Mg2.34 Al1.00 structure. At a mild reaction temperature (100 °C), 2,5-furandimethanol is obtained with excellent selectivity up to >99%. Higher reaction temperatures (220 °C) favor selective deoxygenation to 2,5-dimethylfuran and minor product 2,5-dimethyltetrahydrofuran with a combined yield as high as 81%. Notably, these high product yields are maintained at a substrate concentration up to 10 wt% and a low catalyst loading. The influence of different alcohol solvents on product selectivity is explored. Furthermore, reaction intermediates formed at different reaction temperatures are identified. The composition of these product mixtures provides mechanistic insight into the nature of the reduction pathways that influence product selectivity. The catalysts are characterized by elemental analysis, TEM, and BET techniques before and after the reaction. Catalyst recycling experiments are conducted in batch and in a continuous-flow setup.

Selective hydrogenation of 5-hydroxymethylfurfural to 2,5-bis-(hydroxymethyl)furan using Pt/MCM-41 in an aqueous medium: a simple approach

“…16 While preparing this manuscript another group detected a 99% yield of BHMF at 100°C after 3 h of reaction in ethanol over a copper-doped porous metal oxide prepared by the calcination of hydrotalcite. 17 Thus, in most of the cases, higher hydrogen pressure, longer reaction time, organic solvents or additional metal oxide additive were used to achieve a high yield of BHMF.…”

Rational design of Ni-based catalysts derived from hydrotalcite for selective hydrogenation of 5-hydroxymethylfurfural

“…To produce DMF, a CuRu/C catalyst was firstly proposed with a yield of 76~79%. 18,19 Recently, a bifunctional Ni-W 2 C/AC catalyst was proposed for DMF synthesis with high yield 19 , indicating the potential of non-noble catalysts. mainly focused on the noble metal catalysts (e.g., Pt 10, 15 , Ru 9, 16 , Pd 17 ).…”

Efficient synthesis of 2,5-dihydroxymethylfuran and 2,5-dimethylfuran from 5-hydroxymethylfurfural using mineral-derived Cu catalysts as versatile catalysts

“…Many subsequent reports were also mainly conducted on noble metals (e.g., Pd, 12 Ru, 14,15 and Pt 16 ). 20,21 Nevertheless, the development of non-noble catalysts still requires considerable effort prior to their commercial applications. Ni-based (e.g., RANEY® Ni, 17 Ni/Al 2 O 3 (ref.…”

“…To obtain high yields of DHMF/DMF, the efficiency of CO hydrogenation and/or C-O hydrogenolysis needs to be promoted. 20 However, Ru sites would also promote CC hydrogenation reactions and lower the DMF yield. 17,18,22 For example, DHMF yield would be reduced by the formation of DHMTHF over RANEY® Ni and Ni-Al 2 O 3 catalysts.…”

“…Commonly used noble metal (e.g., Ru, Pd) and Ni catalysts are good candidates, whereas the saturation of the furan ring easily proceeds over these catalysts with strong CC hydrogenation abilities. 20,23 Besides, excessive amounts of acid sites would catalyze the ringopening reactions and etherification, and thus lower the selectivity to DHMF and DMF. 17,18 Ru-modified Cu/MgO/Al 2 O 3 catalysts were reported for HMF hydrogenation with high reactivity.…”