p-Xylene from 2,5-dimethylfuran and acrylic acid using zeolite in continuous flow system

The continuous flow synthesis of p-Xylene (pXL) via Diels-Alder cycloaddition of lignocellulosic biomass-derivable 2,5-dimethylfuran (DMF) and acrylic acid (AA) was performed over different type of zeolites, i.e. Beta, ZSM-5 and Y. Among the tested zeolites, Beta zeolite showed an optimum catalytic performance in pXL synthesis from DMF and AA. In this context, Beta zeolite with a Si/Al molar ratio of 150 which is abbreviated Beta(150), resulted in a complete DMF conversion with a pXL yield of 83, and 2,5-dimethylbenzoic acid (DMBA) with yield of 17 as the second product, at 473 K and 10.1 min residence time (τ) and excess of AA (0.7 M). This high catalytic activity is attributed to the high specific surface area of 1180 m2 g-1 with a three-dimensional porous architecture with pore diameter of (6.6 × 6.7 Å) and an acid sites density above 40 µmol g-1. The utilized Beta(150) showed a very stable performance up to 10 h time on stream with minor deactivation after 8 h of TOS, while pXL yield stayed above 70. The original catalytic performance of Beta(150) in DMF upgrading to pXL was restored by applying a regeneration step for the spent catalyst, which is simple in continuous flow reactors. Finally, this sustainable continuous flow process enables an efficient and selective pXL production from DMF and AA as a dienophile at lower reaction temperature (473 K) and shorter residence time (τ = 10.1 min) with respect to batch fashion

Nickel on nitrogen doped carbon pellets for continuous flow hydrogenation of biomass derived compounds in water

Hydrogenation reactions in water at elevated temperatures are challenging for heterogeneous catalyst. Thus, we present a simple, cheap, scalable, and sustainable approach for synthesizing an efficient and water-tolerant Ni catalyst supported on highly porous nitrogen-doped carbon (NDC) in pellet shape. The performance of this catalyst was evaluated in the aqueous-phase hydrogenation of lignocellulosic biomass-derived compounds, i.e., glucose (Glu), xylose (Xyl) and vanillin (V), using a continuous-flow system. The prepared 35 wt.- Ni on NDC catalyst exhibited a high catalytic performance in all three different aqueous-phase hydrogenation reactions, i.e., conversion of Glu, Xyl and V was 96.3 mol, 85 mol and 100 mol and yield of sorbitol (Sor), xylitol (Xyt) and 2-methoxy-4-methylphenol (MMP) was 82 mol, 62 mol and 100 mol, respectively. This high activity was attributed to heterojunction effects stabilizing and adjusting the homogenously dispersed Ni nanoparticles on the surface of NDC. Changing the electron density in the Nickel nanoparticle allows high performance of the catalyst under long time of stream (7 to 30 h) with minimized Ni leaching

5-Hydroxymethylfurfural hydrodeoxygenation to 2,5-dimethylfuran in continuous-flow system over Ni on nitrogen-doped carbon

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

Conformal carbon nitride thin film inter-active interphase heterojunction with sustainable carbon enhancing sodium storage performance

Sustainable, high-performance carbonaceous anode materials are highly required to bring sodium-ion batteries to a more competitive level. Here, we exploit our expertise to control the deposition of a nm-sized conformal coating of carbon nitride with tunable thickness to improve the electrochemical performance of anode material derived from sodium lignosulfonate. In this way, we significantly enhanced the electrochemical performances of the electrode, such as the first cycle efficiency, rate-capability, and specific capacity. In particular, with a 10 nm homogeneous carbon nitride coating, the specific capacity is extended by more than 30% with respect to the bare carbon material with an extended plateau capacity, which we attribute to a heterojunction effect at the materials' interface. Eventually, the design of (inter)active electrochemical interfaces will be a key step to improve the performance of carbonaceous anodes with a negligible increase in the material weight