Synthesis of Renewable Triketones, Diketones, and Jet‐Fuel Range Cycloalkanes with 5‐Hydroxymethylfurfural and Ketones

Abstract

A series of renewable C -C triketones with repeating [COCH CH ] units were synthesized in high carbon yields (ca. 90 %) by the aqueous-phase hydrogenation of the aldol-condensation products of 5-hydroxylmethylfurfural (HMF) and ketones over an Au/TiO catalyst. Compared with the reported routes, this new route has many advantages such as being environmentally friendly, having fewer steps, using a cheaper and reusable catalyst, etc. The triketones as obtained can be used as feedstocks in the production of conducting or semi-conducting polymers. Through a solvent-free intramolecular aldol condensation over solid-base catalysts, the triketones were selectively converted to diketones, which can be used as intermediates in the synthesis of useful chemicals or polymers. As another application, the tri- and diketones can also be utilized as precursors for the synthesis of jet-fuel range branched cycloalkanes with low freezing points (224-248 K) and high densities (ca. 0.81 g mL ).

Bio‐Based Cycloalkanes: The Missing Link to High‐Performance Sustainable Jet Fuels

“…[102,103] Li et al recently studied the solvent-free aldol condensation of 5-HMF with acetone, 2-pentanone, and MIBK, using a CaObased catalyst. [104] Carbon yields above 90 % were obtained under mild conditions (140 or 130°C, 6 h) (Scheme 6). Aqueous-phase hydrogenation of the condensed products was then examined over a series of TiO 2 -supported noblemetal catalysts.…”

“…Compared to methods by Poirier and Dujardin, [106] Alder et al, [107] Waidmann et al, [108] and Xu et al [109] this method for the synthesis of triketones has a number of benefits, including low-cost, an easily separable heterogeneous catalyst, and reduced environmental impact. [104] The triketones were converted to cyclic di-ketones by solvent-free intramolecular aldol condensation over a solid base catalyst. CaO or magnesium-aluminum hydrotalcite (MgAlÀ HT) facilitated this conversion in high yields (89-94 %) at 150°C (Scheme 7).…”

“…Li et al. recently studied the solvent‐free aldol condensation of 5‐HMF with acetone, 2‐pentanone, and MIBK, using a CaO‐based catalyst [104] . Carbon yields above 90 % were obtained under mild conditions (140 or 130 °C, 6 h) (Scheme 6).…”

Upgrading of Biomass-Derived Feedstocks to Liquid Transportation Fuel Precursors by Aldol Condensation

“…The HMF yields were as high as 96% and 81% for fructose and glucose, respectively [22]. Typically, aldol condensation furfural and ketones is catalyzed by solid base catalysts [23] [24].…”

Catalyst Stability Assessment in a Lab-Scale Liquid-Solid (LS)² Plug-Flow Reactor

“…Hence, to evaluate heterogeneous catalyst stability in a batch reactor, the spent catalyst should be recycled in a subsequent experiment. Yet, all too often, catalyst stability is concluded from repeated high yields that are either at full reactant conversion or at the thermodynamic equilibrium [8][9][10][11][12][13][14][15][16][17][18][19]. As a result, such experimental information does not provide any indication of the catalyst stability.…”