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Sulfonated (SO3H-bearing) activated carbon (AC-SO3H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO3H density of 0.64 mmol·g−1 and a specific surface area of 602 m2·g−1. The catalytic properties of AC-SO3H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO3H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO3H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g−1). However, AC-SO3H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO3H is the leaching of SO3H group during the reactions.

The full potential energy surface of the catalytic conversion of furfural to 2-methylfuran on the Cu(111) surface has been systematically computed on the basis of density functional theory, including dispersion and zero-point energy corrections. For furfuryl alcohol formation, the more favorable step is the first H addition to the carbon atom of the CO group, forming an alkoxyl intermediate (F-CHO +H → F-CH2O); the second H atom addition, leading to furfuryl alcohol formation (F-CH2O + H → F-CH2OH), is the rate-determining step. For 2-methylfuran formation from furfuryl alcohol dissociation into surface alkyl (F-CH2) and OH groups, H2O formation is the rate-determining step (OH + H → H2O). Our results explain perfectly the experimentally observed selective formation of furfuryl alcohol and the equilibrium of furfural/furfuryl alcohol conversion under hydrogen-rich conditions as well as the effect of H2O suppressing furfural conversion. In addition, it is found that dispersion correction (PBE-D3) overestimates the adsorption energies of furfural, furfuryl alcohol, and 2-methylfuran considerably, whereas those of H2 and H2O can be reproduced nearly quantitatively. Our results provide insights into Cu-catalyzed furfural selective conversion and broaden our fundamental understanding into deoxygenation reactions of oxygenates involved in the refining of biomass-derived oils.

ARTICLE This journal isSelective 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-Al 2 O 3 catalysts derived from hydrotalcite-like compounds can efficiently and selectively convert HMF to 2,5-dimethylfuran (DMF), 2,5-dimethyltetrahydrofuran (DMTHF) and 2,5dihydroxymethyltetrahydrofuran (DHMTHF). Homogeneous elemental distributions of hydrotalcite-like precursor facilitate the good dispersion of Ni and Al 2 O 3 species and strong interaction between them over the resulted 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 C=O, C=C and C-O bonds, which have great potential for biomass utilization. ARTICLEThis journal is © The Royal Society of Chemistry 2015Green Chem., 2015, 00, 1-3 | 9 TPD) and CO temperature programmed desorption (CO-TPD) were performed on a Tianjin XQ TP-5080 instrument. Temperature programmed desorption of NH 3 (NH 3 -TPD) experiments were conducted on the AutoChem II. 2920 instrument (Micromeritics, USA) equipped with a mass spectrum detector. (See supporting information for details about the characterizations). Catalyst tests:The tests were performed over a 100 mL tank reactor. For a typical procedure, the reactor was fed with HMF (1.5 g), NiAl-CT and 1,4-dioxane (35 mL), then sealed and purged by H 2 (5 times). After that, the reactor was filled with H 2 in desired pressure and heated to objective temperature. After the test, the reactor was quenched in icewater, and then the liquid and gas products were analysed by a GC instrument with a FID detector. Notes and references