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Sustainable production of bio-fuels: hydroxyapatite nanowires rich in [Ca–O–P] sites catalyze the direct coupling of ethanol to higher aliphatic alcohols.

Aromatic alcohols, often used for the synthesis of plasticizers, coatings and pharmaceuticals, are currently produced from the oxidation of petroleum-derived aromatic hydrocarbons. Herein, we report a non-petroleum and environmentally friendly route for the production of aromatic alcohols: cofeeding methanol with ethanol over cobalt-hydroxyapatite catalyst, in which the distribution of aromatic alcohols products can be regulated by varying methanol pressure. Co species on hydroxyapatite can activate both methanol and ethanol to yield their corresponding aldehydes (formaldehyde and acetaldehyde). The followed cross-and self-condensations of aldehydes are catalyzed by hydroxyapatite to produce acrolein and 2-butenal, which are the key intermediates for the formation of aromatic oxygenates. The sequential cross-condensation and dehydrocyclization of acrolein and 2-butenal yield benzaldehyde, which is then hydrogenated to benzyl alcohol. The direct production of benzyl alcohol from methanol and ethanol could be regarded as a cutting-edge example, which ensures a promising route for sustainable aromatic alcohols production.

Enhancing liquid hydrocarbons selectivity and simultaneously suppressing CO2 formation are highly desirable yet challenges in iron-based Fischer-Tropsch synthesis. Herein, we report an in-situ oxidation method for the fabrication of a...

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Catalytic upgrading of ethanol, as a platform molecule from biomass to higher alcohols (C4–12), is a low-carbon route for value-added chemical production. However, the products are generally obtained in low selectivity due to the uncontrollable reactivity of intermediates that cause a complex reaction network. In this study, we show that unsaturated intermediates of aldehydes can be rapidly hydrogenated by surface hydrogen species during the ethanol upgrading process, thereby greatly inhibiting the cyclization reaction of aldehydes. Specifically, the product distributions on the Cu-hydroxyapatite (Cu-HAP) catalyst shift stepwise to higher alcohols from aromatic oxygenates with the partial pressure of hydrogen increasing from 0 to 95 kPa. Kinetic measurements and in situ ethanol infrared results indicated that the intermediates during this process are acetaldehyde and 2-butenal. Combined with physical structure and chemical state analysis of the catalyst, we found that Cu sites catalyze the hydrogenation of the CC bond of 2-butenal under a hydrogen atmosphere. The C–C coupling of ethanol to higher alcohols over Cu-HAP follows the Guerbet mechanism. In comparison, on bare HAP, n-butanol is formed as a primary product even though little amount of acetaldehyde was detected, indicating that ethanol proceeds mainly in a direct coupling process to yield higher alcohols. This study introduces an efficient ethanol valorization approach that is enabled by subtle control of the intermediate conversion over the Cu-HAP catalyst by the hydrogen partial pressure.

Catalytic upgrading of biomass-derived ethanol to C4+ compounds through C-C coupling is an essential green and sustainable approach towards value-added fine chemicals. Developing catalysts to improve the selectivity of C4+...

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