Fast Catalytic Hydrogenation of 2,5-Hydroxymethylfurfural to 2,5-Dimethylfuran with Ruthenium on Carbon Nanotubes

Abstract

We have found that the utilization of carbon nanotubes as support for ruthenium nanoparticles increases hydrogenation activity over 40 times in terms of turnover frequency (TOF) when compared to activated carbon in the transformation of hydroxymethylfurfural to dimethylfuran. Catalysts based on carbon nanotubes produced 83.5% yield of dimethylfuran (TOF 819.7 h −1 ) in under 1 h at 150 °C and less than 20 bar hydrogen pressure, whereas the activated carbon catalyst required more than 3 h to give an 80% yield of dimethylfuran (TOF 36 h −1 ). The superior accessibility of pores in carbon nanotubes, plus an electronic promotional effect in the carbon nanotubes, appear to be responsible for the superior activity of the catalysts supported on carbon nanotubes. The catalysts were synthesized by impregnation and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen physisorption, temperature-programmed reduction, electron microscopy and pulse CO chemisorption to propose the structure−activity relationships. This work highlights the importance of the support in hydrogenating reactions with ruthenium and the potential applicability of carbon nanotubes as supports for the hydrogenation of other bioderivatives.

Bimetallic platinum/iridium modified mesoporous catalysts applied in the hydrogenation of HMF

“…PdAu/C catalyst was tested with high conversion (96%) using several Pd/Au molar ratios in the presence of hydrochloric acid, under atmospheric hydrogen pressure [9]. In addition, DMF yield of 76% was achieved by Yang et al [10] over Ni/Co3O4 catalyst at 130 °C and 10 atm, while 92% yield was attained by using CoPt over carbon nanotubes at 160 °C and 10 atm after 10 h of reaction [11].…”

Catalytic Hydrogenation/Hydrogenolysis of 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran

“…When considering the economical feasibility of this process, it should also be kept in mind, that noble metal catalysts are more expensive, not necessarily, on the other hand, requiring high reaction temperature and pressure [20] contrary to alternative options. Monometallic Pd/C (Table 1, entry 22) [44] and Ru/C (Table 1, entry 18), [46] in which carbon facilitates electron transfer [38,44] have been quite good candidates for selective production of DMF, while Pt/SiO 2 and Pt/Al 2 O 3 promoted mainly formation of products other than DMF from HMF at 180 °C in 8 h in n‐ butanol under 10 bar hydrogen [48] . One challenge with monometallic catalysts is overhydrogenation, because these catalysts exhibit very high hydrogenation activity, as for example Ru/C [25,38] .…”

“…Transformation of HMF to DMF is scientifically an interesting reaction with a complex reaction network and this reaction has been intensively studied [14–62] . In the first step HMF is hydrogenated to BHMF followed by its hydrogenolysis to methylfurfuryl alcohol (MFA) and further hydrogenolyses to DMF.…”

“…In additional the challenge to maximize the yield of DMF is to suppress its overhydrogenation to 2,5‐dimethyltetrahydrofuran (DMTHF) and further cracking reactions, e. g. formation of furans and furan ring opening forming diketones and alcohols (Figure 1). [38] HMF transformations require typically a bifunctional catalyst both with hydrogenation and hydrogenolysis activity. The catalyst should have an optimized metal content, desired support properties which facilitate an intimate contact between the metal and the support.…”

Separation procedures in the identification of the hydrogenation products of biomass-derived hydroxymethylfurfural

“…When it comes to the subject of this review, the product identification efficiency depends on many factors, of which one of the most important is the selectivity of HMF hydrodeoxygenation reaction and therefore the number of products to analyze, and their difference in volatility. There are some limited examples where only one GC detector was used for analysis (FID) [38,39] and for selective reactions with the presence of only a few products (HMF, DMF, BHMF, 5-MFA) without many impurities it proved fully sufficient, practically allowing to close the carbon balance of the reaction [40][41][42]. However, where a wide range of by-products is present, FID is often combined with MS detector or NMR spectroscopy analysis, which allow the structure confirmation [42][43][44][45][46][47][48] and therefore more complete detection.…”