Highly Selective Condensation of Biomass-Derived Methyl Ketones as a Source of Aviation Fuel

• Published in: ChemSusChem Vol. 8; no. 10; pp. 1726 - 1736
• Main Authors: Sacia, Eric R., Balakrishnan, Madhesan, Deaner, Matthew H., Goulas, Konstantinos A., Toste, F. Dean, Bell, Alexis T.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 22-05-2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc; ChemPubSoc Europe
• Subjects: Alkanes - chemistry; Alternative energy sources; Aluminum Hydroxide - chemistry; biofuels; Biomass; C-C coupling reactions; Catalysis; Condensation; CC coupling reactions; Energy-Generating Resources; heterogeneous catalysis; hydrogenation; jet fuel; Ketones - chemistry; Magnesium Hydroxide - chemistry; CC coupling reactions; biofuels; jet fuel; heterogeneous catalysis; hydrogenation
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201500002

Aviation fuel (i.e., jet fuel) requires a mixture of C9–C16 hydrocarbons having both a high energy density and a low freezing point. While jet fuel is currently produced from petroleum, increasing concern with the release of CO2 into the atmosphere from the combustion of petroleum‐based fuels has led to policy changes mandating the inclusion of biomass‐based fuels into the fuel pool. Here we report a novel way to produce a mixture of branched cyclohexane derivatives in very high yield (>94 %) that match or exceed many required properties of jet fuel. As starting materials, we use a mixture of n‐alkyl methyl ketones and their derivatives obtained from biomass. These synthons are condensed into trimers via base‐catalyzed aldol condensation and Michael addition. Hydrodeoxygenation of these products yields mixtures of C12–C21 branched, cyclic alkanes. Using models for predicting the carbon number distribution obtained from a mixture of n‐alkyl methyl ketones and for predicting the boiling point distribution of the final mixture of cyclic alkanes, we show that it is possible to define the mixture of synthons that will closely reproduce the distillation curve of traditional jet fuel.
Cool your jets! Aviation fuel requires a mixture of hydrocarbons having both a high energy density and a low freezing point. It is demonstrated that biomass‐derived n‐alkyl methyl ketones undergo selective, base‐catalyzed reactions to form cyclic trimer condensates in >94 % selectivity. These products are then quantitatively hydrodeoxygenated to form aviation fuels having a broad range of volatility and exceptional freezing points and energy densities when utilizing multiple starting ketones.