A communication titled "Synthesis of diesel and jet fuel range alkanes with furfural and ketones from lignocellulose under solvent free conditions" by Jinfan Yang was published in Green Chemistry ( DOI: 10.1039/C4GC01314J).
In this work, we reported, for the first time, the solvent-free synthesis of diesel and jet fuel range alkanes by the aldol condensation of furfural with 2-pentanone and 2-heptanone which can be obtained from lignocellulose. By the aldol condensation of furfural with 2-pentanone (or the mixture of 2-pentanone and 2-heptanone) over solid base catalysts, followed by the one-step hydrodeoxygenation (HDO) process over Pd catalysts, C9-C12 alkanes were obtained at high overall carbon yield (~80%). Among the solid base catalysts which were used for the aldol condensation, CaO exhibited the highest activity, which can be rationalized by the stronger basicity of this material. The products from the aldol condensation of furfural and 2-pentanone (or a mixture of 2-pentanone and 2-heptanone) are liquid at room temperature. Therefore, they can be directly hydrodeoxygenated to alkanes over a series of Pd catalysts. Among them, Pd/H-ZSM-5 demonstrated the best catalytic performance and good stability, which makes it a promising catalyst in future application.
By taking advantage of the good intersolubility of these aldol condensation products, we successfully prepared C9-C12 straight alkanes without using of any external solvent during the whole process. Compared with previous furfural-acetone route, the new protocol has many advantages such as solvent-free, fewer steps, lower energy consumption, etc.