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Construction of N-substituted pyrrolidones from biomass-derived levulinic acid (LA) via reductive amination is a highly attractive route for biomass valorization. However, realizing this transformation using H2 as the hydrogen source under mild conditions is still very challenging. Herein, we designed porous TiO2 nanosheets-supported Pt nanoparticles (Pt/P-TiO2) as the heterogeneous catalyst. The prepared Pt/P-TiO2 was highly efficient for reductive amination of LA to produce various N-substituted pyrrolidones (34 examples) at ambient temperature and H2 pressure. Meanwhile, Pt/P-TiO2 showed good applicability for reductive amination of levulinic esters, 4-acetylbutyric acid, 2-acetylbenzoic acid, and 2-carboxybenzaldehyde. Systematic studies indicated that the strong acidity of P-TiO2 and the lower electron density of the Pt sites as well as the porous structure resulted in the excellent activity of Pt/P-TiO2.

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Development of high-performance catalysts for carbon dioxide (CO2) hydrogenation is crucial for CO2 utilization. Herein, a heterogeneous catalyst for CO2 hydrogenation to formate was developed by coordinating the mononuclear Ru3+ center (Ru hereafter) with a N,P-containing polymer, which was synthesized from phosphonitrilic chloride trimer and 2,6-diaminopyridine. Multiple nitrogen functionalities in the polymer (N content: 25.9 wt %) containing pyridine nitrogen and phosphazene nitrogen not only provided an electron-rich coordination environment for stabilizing mononuclear Ru center but also facilitated CO2 conversion by interacting with CO2 molecules. The polymer-coordinated mononuclear Ru catalysts (Ru/p-dop-POMs) could promote the hydrogenation of CO2 to formate with a turnover number (TON) up to 25.4 × 103 in aqueous solutions, and the concentration of formate in the solution could reach 3.4 mol/L. DFT calculations revealed that the electron-rich mononuclear Ru site could promote H2 dissociation, which is the rate-determining step in the reaction, thereby enhancing the catalytic activity. Systemic studies demonstrated that the synergistic effect between individually electron-rich Ru centers and nitrogen-rich polymer enhanced catalytic efficiency.

High-performance bifunctional catalysts (Ni–Cu/Al2O3–ZrO2) have been investigated in the selective hydrogenolysis of levulinic acid into 2-methyltetrahydrofuran.

Phenol is an important commodity chemical in the industry, which is currently produced using fossil feedstocks. Here, we report a strategy to produce phenol from lignin by directly deconstructing Csp2–Csp3 and C–O bonds under mild conditions. It was found that zeolite catalyst could efficiently catalyze both the direct Csp2–Csp3 bond breakage to remove propyl structure and aliphatic β carbon–oxygen (Cβ–O) bond hydrolysis to form OH group on the aromatic ring. The yield of phenol could reach 10.9 weight % with a selectivity of 91.8%. In this unique route, water was the only reactant besides lignin. A scale-up experiment showed that 4.1 g of pure phenol could be obtained from 50.0 g of lignin. The reaction pathway was proposed by a combination of control experiments and density functional theory studies. This work opens the way for producing phenol from lignin by direct transformation of Csp2–Csp3 and C–O bonds in lignin.

Levulinic acid is an important platform molecule from biomass-based renewable resources. A sustainable manufacturing process for this chemical and its derivatives is the enabling factor to harness the renewable resource. An integrated catalytic process to directly convert furfural to levulinate ester was developed based on a bifunctional catalyst of Pt nanoparticles supported on a ZrNb binary phosphate solid acid. The hydrogenation of furfural and the following alcoholysis of furfuryl alcohol were performed over this catalyst in a one-pot conversion model. Mesoporous ZrNb binary phosphate was synthesized by a sol-gel method and had a high surface area of 170.1 m(2) g(-1) and a large average pore size of around 8.0 nm. Pt nanoparticles remained in a monodisperse state on the support, and the reaction over Pt/ZrNbPO4 (Pt loading: 2.0 wt%; Zr/Nb, 1:1) gave a very high selectivity to levulinate derivatives (91% in total). The sustainability of this conversion was greatly improved by the process intensification based on the new catalyst, mild reaction conditions, cost abatement in separation and purification, and utilization of green reagents and solvents.