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5-Hydroxymethylfurfural (HMF) is one of the most important intermediate platforms for production of both chemicals and liquid fuel derived from biomass. The one-pot production of HMF from cellulose was conducted in a batch reactor in the presence of various solid acid catalysts. The prepared catalysts were characterized by means of Brunauer–Emmett–Teller measurement and pyridine adsorption FT-IR to investigate their pore structure and acidic properties. The presence of gaseous hydrogen enhanced the formation of HMF by suppressing the formation of byproducts. Increasing the acid amount of the catalyst caused an increase in the conversion and selectivity for organic acid and a decrease in the HMF selectivity. A Brønsted-type catalyst (Al-SBA-15) favored the formation of HMF. The reaction conditions of 220 °C, 5 min, and a hydrogen pressure of 1 MPa resulted in the highest yield of HMF, and selectivity of 26.9% was achieved when the Al-SBA-15 catalyst was used. Moreover, under the same conditions, cellulose extracted from eucalyptus, a practical biomass, was converted to HMF in a one-pot synthesis with a yield of 13.0 C-mol.%. [ABSTRACT FROM AUTHOR]

Abstract: Ceria-supported chromium, molybdenum, and tungsten catalysts were prepared by impregnation. The prepared catalysts were characterized using N2 adsorption, X-ray diffraction (XRD), the temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS) measurements. The catalytic activity in CO hydrogenation was evaluated using a fixed-bed pressurized flow reaction system under the following conditions: 260–300°C, 5.0MPa, GHSV of 5000h−1, and a H2/CO ratio of 1.0–2.0. The effects of ceria support, group VI metals, and catalyst activation methods on C2+ alcohol synthesis were investigated. The use of ceria supports resulted in a decrease in the selectivity for CO2, and in increases in the selectivity for C2+ alcohols and CO conversion. The selectivity for alcohols on the Mo-based catalysts was higher than those on the corresponding Cr or W-based catalysts. A comparison of the methods of activation for the K005Co0620MoCe catalyst demonstrated that sulfidation produced the highest CO conversion and selectivity for C2+ alcohols, as well as the lowest, hydrocarbon selectivity. XPS and H2-TPR measurements show that the mixed metal sulfide phases, e.g., the Co–Mo–S phase, and the thiol group on the catalysts enhanced the formation of C2+ alcohols. [Copyright &y& Elsevier]

We prepared activated carbon-based solid acid catalysts derived from coconut shells via chemical activation with phosphoric acid under air and subsequent sulfonation. Their catalytic activities were evaluated in the saccharification of cellulose, and the parameters required for the activation and sulfonation processes were investigated. A catalyst activating temperature of 400 °C was found to be optimal, and the catalyst treated with chlorosulfuric acid exhibited a similar monosaccharide yield to that treated with fuming sulfuric acid. The prepared catalysts were characterized by various analytical techniques. The catalysts exhibited high specific surface areas and micropore volumes but low external specific surface areas. The catalysts had high contents of acidic functional groups when low activating temperatures were employed. For these catalysts, the surface chemical structure had a more dominant effect on the catalytic activity than that caused by the porous texture, while high acidic group contents led to high catalytic activities. Unlabelled Image • Activated carbon-based solid acid catalysts were prepared from coconut shells. • Preparation was via chemical activation with phosphoric acid and sulfonation. • Lower activating temperatures yielded higher acid amounts. • A higher acid amounts contributed to a higher catalytic activity. [ABSTRACT FROM AUTHOR]