Synthesis of a high-density jet fuel with creosol and formaldehyde

Abstract

A new two-step process was developed for the synthesis of jet fuel range high-density bicycloalkanes with creosol and formaldehyde, two platform compounds that can be derived from lignocellulose. In the first step, C₁₇ oxygenate was obtained by the phenolic condensation of creosol and formaldehyde. Among the investigated catalysts, 40% HPW/SiO₂ (a SiO₂-loaded phosphotungstic acid catalyst with a phosphotungstic acid weight percentage of 40%) exhibited the highest activity for this reaction. Over it, a high yield (64%) and good selectivity (92%) of C₁₇ oxygenate were achieved under mild reaction conditions (323 K, 6 h). In the second step, the C₁₇ oxygenate was hydrodeoxygenated to C₁₄ and C₁₅ bicycloalkanes over Ru-based bifunctional catalysts. Under the optimized conditions, a high total yield of C₁₄ and C₁₅ bicycloalkanes (89%) was achieved. According to our measurements, the C₁₄ and C₁₅ bicycloalkane mixture as obtained had a high density (0.90 g mL⁻¹), low freezing point (246.5 K), and high heat value (46.2 MJ kg⁻¹ or 41.6 MJ L⁻¹). It has potential to be used as a fuel additive to improve the volumetric heat value of current bio-jet fuels.