•The one-pot reductive amination for the synthesis of secondary amines was developed with CO/H2O.•The nitrogen-doped carbon supported Co catalyst was active toward this transformation.•Both nitrogen and Co nanoparticles were important for the transfer hydrogenation.•A plausible mechanism was proposed for this reaction.The one-pot reductive amination of carbonyl compounds with nitro compounds over heterogeneous non-noble metal catalysts was developed for the first time by transfer hydrogenation with CO/H2O as the hydrogen donor. Nitrogen-doped carbon supported cobalt nanoparticles were observed to be active toward this reaction, affording structurally-diverse secondary amines with high yields. Kinetic studies revealed that the transfer hydrogenation of imines (CN bonds) was the rate-determining step. Reaction mechanism studies indicated that both nitrogen and cobalt nanoparticles were important for the transfer hydrogenation with CO/H2O to generate the proton (NH+) and hydride (CoH−) as the active species. Furthermore, the heterogeneous cobalt catalyst was highly stable without the loss of its catalytic activity during the recycling experiments.Download high-res image (77KB)Download full-size image

The paper deals with oxidation of the biomass-derived model molecule 5-(hydroxymethyl)furfural (HMF) catalyzed by the trimetallic mixed oxide RuCo(OH)2CeO2. The catalyst RuCo(OH)2CeO2 was prepared through alkali hydrolysis of RuCl3, Co(NO3)2, and Ce(NO3)2 and characterized by X-ray diffraction and transmission electron microscopy techniques. RuCo(OH)2CeO2 showed high catalytic activity for aerobic oxidation of HMF under mild conditions (in the case of atmospheric oxygen pressure). Various reaction parameters such as the reaction temperature, catalyst amount, solvent, and oxidant were explored. Results demonstrated that the oxidant and solvent showed a remarkable effect on the aerobic oxidation of HMF to 2,5-diformylfuran (DFF). Under optimal conditions, DFF was obtained in a high yield of 82.6% with HMF conversion of 96.5% after 12 h at 120 °C. More importantly, the catalyst could be reused several times without significant loss of its catalytic activity.

In this study, aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) was studied over a magnetic catalyst [Fe3O4@SiO2-NH2-Ru(III)]. Various reaction parameters were optimized for the oxidation of HMF into DFF. A high DFF of 86.4% and HMF conversion of 99.3% were obtained after 4 h at 120 °C. More importantly, the catalyst also showed high catalytic activity in air, and high HMF conversion of 99.7% and DFF yield of 86.8% were obtained after 16 h. The high catalytic performance of Fe3O4@SiO2-NH2-Ru(III) in air makes this method much more convenient and economical. Moreover, the procedure of the catalyst recycle was simple as the Fe3O4@SiO2-NH2-Ru(III) catalyst could be readily recovered from the reaction mixture by a permanent magnet. The catalyst could be reused several times without significant loss of its catalytic activity.

In this study, prepared silica supported sulfonic acid was used as a heterogeneous catalyst for the production of 5-ethoxymethylfurfural (EMF) from fructose based carbohydrates and the synthesis of ethyl D-glucopyranoside from glucose based carbohydrates in ethanol. EMF was obtained in a high yield of 83.8% from 5-hydroxymethylfurfural (HMF) after 10 h, and a 63.1% yield was obtained from fructose at 100 °C for 24 h. Temperature experiments demonstrated that a higher reaction temperature (in the case of 120 °C) resulted in side reactions such as polymerization of HMF and alcoholysis of HMF into ethyl levulinates. When di- and poly-saccharides (sucrose and inulin) were used, the fructose moieties in sucrose and inulin were also successfully converted into EMF. However, the silica supported sulfonic acid catalyst was inert for the production of EMF from aldose based carbohydrates such as glucose and cellobiose. Ethyl D-glucopyranoside was formed in a high yield of 91.7% from glucose. More importantly, the catalyst could be reused several times without losing its catalytic activity with an average EMF yield of around 60% from a one-pot reaction of fructose. This work provides a good outlook for the conversion of carbohydrates into fine chemicals and biofuel additive.