Developing a green and highly efficient method for CO 2 reduction into value-added chemicals with earth-abundant materials and facile hydrogen source is crucial to the practical application of CO 2 conversion and utilization. In this study, a new method of reduction of NaHCO 3 , a model compound of CO 2 , to formate as a hydrogen storage material by splitting water with waste Al-can as a reductant is proposed. A formate yield up to 65% from bicarbonate was successfully obtained with waste raw Al-can strips as a reductant and water as a hydrogen source. The Al-can converted to powdered AlO(OH) with a surface area of 129.3 m 2 •g −1 after the reaction, which is a valuable substrate for preparing adsorbents, catalysts, and alumina-derived ceramics. The proposed method not only provides a simple and efficient way to reduce CO 2 into value-added chemicals but also develops a new way to produce functional Al materials from waste Al-can.
The base‐free transfer hydrogenation of biomass derived furanic aldehydes with ruthenium and iridium pincer complexes was studied using bio‐alcohols as the hydrogen source. The furanic substrates, such as 5‐hydroxymethyl furfural (HMF) and thiophene‐2‐carboxaldehyde (TC), were reduced under mild conditions (35–80 °C) affording the desired alcohols with excellent conversions and yields. It was also possible to extend this methodology for the transfer hydrogenation of 5‐formylfurfural (DFF) at 130 °C. Deuterium labelling of C−H functions in the furanic alcohols was also investigated in the presence of ethanol‐d6. Finally, proposed catalytic resting species derived from the interactions between one of the catalysts and furanic reagents/product as well as the solvent during the transfer hydrogenation (TH) reaction were analysed.
Ethanol is one of the most promising renewable resources for the production of key industrial commodities. Herein, we present the first direct and selective conversion of ethanol to either primary or secondary alcohols, or to hydrocarbons, using ruthenium PNP pincer complexes [(RPNP)RuHXCO] (R= iPr, Ph, Cy, tBu; X = Cl, H-BH3) as catalysts. Using phenyl substituted phosphines leads to the selective produc-tion of secondary alcohols. Hence, employing [(PhPNP)RuH(Cl)CO] (Ru-1) as a catalyst in ethanol, containing 20 mol% of NaOEt, at 115 ⁰C leads to 89% selective production of secondary alcohols over pri-mary alcohols. A yield of 12% of 2-butanol, and in total 22% of secondary alcohols, was achieved. In addition, minor amounts of 2 butenes/butane (≤5%) were observed in the gas phase. On the contrary, when using bulky phosphine substituents, such as t-butyl, the selectivity completely shifts toward primary alcohols. Thus, using [(tBuPNP)RuH(Cl)CO] (Ru 5) leads to >99% selectivity of 1 butanol (13% yield) over secondary alcohols at 115 ⁰C. In fact, the catalytic system is highly competitive for producing 1-butanol with 22% yield obtained at 130 ⁰C, a temperature significantly lower than previously re-ported systems. Our methodology unveils the potential for using bulk bio-alcohols to selectively produce primary or secondary alcohols and hydrocarbons under mild conditions.
Ethanol is one of the most promising renewable resources for producing key industrial commodities. Herein, we present the direct conversion of ethanol to either primary or secondary alcohols, or to hydrocarbons, using ruthenium PNP pincer complexes [(RPNP)RuHXCO] (R = iPr, Ph, Cy, tBu; X = Cl, H–BH3) as catalysts. Using phenyl-substituted phosphines leads to the selective production of secondary alcohols over primary alcohols. Hence, employing [(PhPNP)RuH(Cl)CO] (Ru-1) as a catalyst in ethanol, containing 20 mol % of NaOtBu, at 115 °C leads to 89% selective production of the secondary alcohols. A yield of 12% of 2-butanol, and in total 22% of secondary alcohols, was achieved. In addition, minor amounts of 2-butenes/butane (≤5%) were observed. On the contrary, when using bulky phosphine substituents, such as t-butyl, the selectivity completely shifts toward primary alcohols. Thus, using [( tBuPNP)RuH(Cl)CO] (Ru-5) leads to >99% selectivity of 1-butanol (13% yield) over secondary alcohols at 115 °C. The catalytic system is highly competitive for producing 1-butanol with 22% yield obtained at 130 °C. Our methodology unveils the potential for developing methods to use bulk bio-alcohols to selectively produce primary or secondary alcohols and hydrocarbons under mild conditions.
The Front Cover shows the schematic diagram of converting bio‐based furanic alcohols using transfer hydrogentaion. In their Research Article, R. Padilla, M. Nielsen and co‐workers disclose the catalytic performance of different pincer complexes for the base‐free transfer hydrogenation (TH) of bio‐based furanic aldehydes in presence of EtOH, iPrOH or MeOH as hydrogen sources and solvents under mild reaction conditions. Furanic derivatives such as 5‐hydroxymethyl furfural (HMF), furfural (FAL), 5‐methylfurfural (MF), and thiophene‐2‐carboxaldehyde (TC) were reduced under mild conditions (35‐80 °C) affording the desired alcohols with excellent conversions and yields. It was also possible to extend this methodology for the transfer hydrogenation of the challenging substrate 5‐formylfurfural (DFF) at 130 °C. Deuterium labelling studies of the C−H functionality in the furanic alcohols as well as NMR and IR studies for the generated resting species shed light on the mechanisms. More information can be found in the Research Article by R. Padilla, M. Nielsen and co‐workers.
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