Synthesis of jet fuel and diesel range cycloalkanes with 2-methylfuran and benzaldehyde

Jet fuel and diesel range C12 and C17 cycloalkanes were synthesized for the first time by a two-step process with 2-methylfuran and benzaldehyde, two platform compounds which can be derived from lignocellulose. In the first step, 5,5′-(phenylmethylene)bis(2-methylfuran) was obtained by the acid-catalyzed hydroxylalkylation/alkylation (HAA) of 2-methylfuran and benzaldehyde. Among the investigated commercial acidic resins, Nafion resin demonstrated the highest activity for the HAA of 2-methylfuran and benzaldehyde, which can be rationalized by the highest acid strength of Nafion resin. In the second step, the 5,5′-(phenylmethylene)bis(2-methylfuran) from the HAA reaction was further hydrodeoxygenated to jet fuel and diesel range C12 and C17 cycloalkanes. Among the investigated catalyst systems, the combination of H-ZSM-5 and Ru/hydroxyapatite (denoted as H-ZSM-5 + Ru/HAP) exhibited the best hydrodeoxygenation (HDO) performance. Over it, a high total carbon yield (87.3%) of jet fuel and diesel range C12 and C17 cycloalkanes was obtained under mild conditions (453 K and 4 MPa H2). According to our measurements, the mixture of C12 and C17 cycloalkanes obtained from the HDO process has high density (0.816 g mL−1) and low freezing point (240 K). Therefore, it can be blended into current bio-diesel and bio-jet fuel to increase their volumetric heat values. As another option, the C12 and C17 cycloalkanes can also be dehydrogenated to produce alkylbenzenes that can be used as feedstock in the production of surfactants.