Yifeng Zhu

Production of bioadditives from glycerol esterification over zirconia supported heteropolyacids.

The synthesis of bioadditives for biofuels from glycerol esterification with acetic acid was performed over zirconia supported heteropolyacids catalysts using H(4)SiW(12)O(40) (HSiW), H(3)PW(12)O(40) (HPW) and H(3)PMo(12)O(40) (HPMo) as active compounds. The as-prepared catalysts were characterized by N(2)-physisorption, XRD, Raman spectroscopy, NH(3)-TPD, FTIR of pyridine adsorption and H(2)O-TPD. Among the catalysts tested, HSiW/ZrO(2) achieved the best catalytic performance owing to the better combination of surface Brønsted acid sites and hydrothermal stability. A 93.6% combined selectivity of glyceryl diacetate and glyceryl triacetate with complete glycerol conversion was obtained at 120°C and 4h of reaction time in the presence of HSiW/ZrO(2). This catalyst also presented consistent activity for four consecutive reaction cycles, while HPW/ZrO(2) and HPMo/ZrO(2) exhibited distinct deactivation after reusability tests. In addition, HSiW/ZrO(2) can be resistant to the impurities present in bulk glycerol.

Rational design of Ni-based catalysts derived from hydrotalcite for selective hydrogenation of 5-hydroxymethylfurfural

Selective hydrogenation of 5-hydroxymethylfurfural (HMF) is of great importance for future energy and chemical supply. Herein, we propose for the first time that non-noble Ni-Al2O3 catalysts derived from hydrotalcite-like compounds can efficiently and selectively convert HMF into 2,5-dimethylfuran (DMF), 2,5-dimethyltetrahydrofuran (DMTHF) and 2,5-dihydroxymethyltetrahydrofuran (DHMTHF). Homogeneous elemental distributions of the hydrotalcite-like precursor facilitate good dispersion of Ni and Al2O3 species and strong interaction between them over the resulting catalysts. The catalysts therefore exhibited superior reactivity. Through fine modulation of surface metal–acid bifunctional sites and control of reaction conditions, high yields of DMF (91.5%), DMTHF (97.4%) and DHMTHF (96.2%) can be diversely achieved. The results demonstrate the feasibility of Ni catalysts for selective hydrogenation of CO, CC and C–O bonds, which have great potential for biomass utilization.

Efficient synthesis of 2,5-dihydroxymethylfuran and 2,5-dimethylfuran from 5-hydroxymethylfurfural using mineral-derived Cu catalysts as versatile catalysts

Selective conversion of 5-hydroxymethylfurfural (HMF) can produce sustainable fuels and chemicals. Herein, Cu–ZnO catalysts derived from minerals (malachite, rosasite and aurichalcite) were employed for selective hydrogenation of HMF for the first time. High yields of 2,5-dihydroxymethylfuran (~99.1%) and 2,5-dimethylfuran (~91.8%) were obtained tunably over the catalyst with a Cu/Zn molar ratio of 2, due to the well-dispersed metal sites tailored by mineral precursors, well-controlled surface sites and optimized reaction conditions. The relationship between catalytic performance and catalyst properties was elucidated by characterization based on the composition and the structural and surface properties, and catalytic tests. The catalyst can also be extended to selective hydrogenation of other bio-derived molecules (furfural and 5-methylfurfural) to target products. The construction of mineral-derived Cu–ZnO catalysts and the revelation of the structure–performance relationship can be applied to further rational design and functionalization of non-noble Cu catalysts for selective conversion of bio-derived compounds.

Switchable synthesis of 2,5-dimethylfuran and 2,5- dihydroxymethyltetrahydrofuran from 5- hydroxymethylfurfural over Raney Ni catalyst†

Raney-type metals (Cu, Co and Ni) were employed to catalyze hydrogenation of 5-hydroxymethylfurfural. Switchable synthesis of 2,5-dimethylfuran and 2,5-dihydroxymethyltetrahydrofuran was achieved with 96% and 88.5% yield respectively over Raney Ni, demonstrating high feasibility for industrialization. The excellent yields can be explained by the fact that Raney Ni facilitates the hydrogenation reaction but has limited deoxygenation ability at low temperature, while high temperature promotes the deoxygenation step. The reaction pathway was analyzed by time course experiments and HMF hydrogenation over model catalysts was performed. The reaction mechanism related to the respective catalytic sites was discussed and proposed, which has great implications in the design of efficient and non-noble metal catalysts.

Catalytic conversion of 5-hydroxymethylfurfural to some value-added derivatives

5-Hydroxymethylfurfural (HMF) is a platform chemical derived from C6 sugars, which can be transformed into various important chemicals and fuels because of the presence of CO, C–O and furan ring functional groups. In this review, the selective tailoring of these groups in HMF to form 2,5-dimethylfuran, 2,5-dihydromethylfuran, 2,5-dihydromethyltetrahydrofuran, 5-ethoxymethylfurfural, 1,6-hexanediol, long-chain alkanes, 3-(hydroxy-methyl)cyclopentanone, p-xylene, 2,5-diformylfuran, 2,5-furandicarboxylic acid and maleic anhydride will be described to gain more insight into the transformation of HMF under various conditions. The focus of this review is on the mechanisms of the catalytic processes and potential design strategies for future catalysts. The activation of the functional groups and the key challenges involved in the precise design of bifunctional catalysts are highlighted. Some examples of “one-pot” transformations of fructose into various chemicals using the HMF platform are also presented.