5-Hydroxymethylfurfural Hydrodeoxygenation to 2,5-Dimethylfuran in Continuous-Flow System over Ni on Nitrogen-Doped Carbon

Abstract

Waste lignocellulosic biomass is sustainable and an alternative feedstock to fossil resources. Among the lignocellulosic derived compounds, 2,5-dimethylfuran (DMF) is a promising building block for chemicals, e.g., p-xylene, and a valuable biofuel. DMF can be obtained from 5-hydroxymethylfurfural (HMF) via catalytic deoxygenation using non-noble metals such as Ni in the presence of H2. Herein, we present the synthesis of DMF from HMF using 35 wt.% Ni on nitrogen-doped carbon pellets (35Ni/NDC) as a catalyst in a continuous flow system. The conversion of HMF to DMF was studied at different hydrogen pressures, reaction temperatures, and space times. At the best reaction conditions, i.e., 423 K, 8.0 MPa, and space time 6.4 kgNi h kgHMF−1, the 35Ni/NDC catalyst exhibited high catalytic activity with HMF conversion of 99 mol% and 80 mol% of DMF. These findings can potentially contribute to the transition toward the production of sustainable fine chemicals and liquid transportation fuels.

Controlled lignosulfonate depolymerizationviasolvothermal fragmentation coupled with catalytic hydrogenolysis/hydrogenation in a continuous flow reactor

“…The liquid-phase LS depolymerization using water/alcohols solvent mixtures was conducted in a continuous flow fixed bed reactor, similar to our previously described system (Figure S2 in ESI). [68][69][70] This system consists of: (A) an HPLC pump equipped with a pressure sensor (Knauer Azura P 4.1S Series), (B) a mass-flow controller to supply a specific H 2 flow (Model SLA58050 from Brooks), (C) T-piece for gas-liquid mixer (Swagelok SS-400-30) to mix the supplied H 2 with the reaction solution before reaching the pre-heating unit and the catalyst bed (D) a two-side opened heating unit equipped with a heat controller (D) a two-side opened heating unit equipped with a heat controller (Model # 4848 from Parr Instrument Company), (E) a sampling unit equipped with proportional relief valves also used as a pressure regulator (Swagelok SS-RL4M8F8-EP), cf., Figure S2 in ESI. To ensure efficient heating, a cylindrical aluminium adapter with three boreholes was matched inside the heating unit.…”

“…Furthermore, the latter step was coupled to hydrogenolysis/hydrogenation fragmentation (SHF) in a continuous flow system using water/alcohol solvent and 35 wt.-% Ni supported on NDC as a catalyst. 68,69 Finally, the advantage of operating the catalytic depolymerization of LS in a continuous flow system is highlighted with respect to batch system.…”

New (and Old) Monomers from Biorefineries to Make Polymer Chemistry More Sustainable

“…[ 45–48 ] Certainly, this numbers showed that there is a great potential for the isomer‐pure synthesis of p XL as a premonomer from renewable resources. In this context, there are reported studies for the synthesis of p XL from biomass‐derived 2,5‐dimethylfuran (DMF), [ 49 ] which involves a Diels‐Alder cycloaddition of ethylene to form the intermediate 1,4 dimethyl‐7‐oxabicyclo[2.2.1] hept‐2‐ene, followed by a dehydration step to p XL using different types of zeolites as a catalyst. [ 45–48,50–52 ] For this reaction usually batch systems are used, combined with high reaction temperature (523–623 K), high ethylene pressure (5.0–7.0 MPa) and long reaction times (24–48 h).…”

Resin-supported iridium complex for low-temperature vanillin hydrogenation using formic acid in water

“…[8][9][10] Typically, a biomass heterogeneously-catalyzed hydrogenation reaction is conducted using relatively high temperature (100-200 C), external pressurized H 2 as reductive agent and supported metals as catalyst, such as Pt, Pd, Ru and Ni. 8,9,[11][12][13][14] Heterogeneous catalysis is the preferred method because it allows for the implementation of more economically efficient and environmentally benign reactor designs. However, bio-renery processes are expensive when compared to traditional reneries.…”