Synthesis Of Polycyclic Hydrocarbon And Alkyl-Diamondoid High-Density Liquid Fuels

High-density-energy liquid fuels are essential for promoting the performance of volume-limited aircrafts. In this dissertation, the synthesis of low-cost polycyclic and alkyl-diamondoidsfuels based on dicyclopentadiene (DCPD) and butadiene(BD) were studied.Isomerization of low-purity endo-tetarhydrodicyclopentadiene (endo-THDCPD) was investigated using AICl3 as acid catalyst and 1,2-dichloroethane as solvent. In AICl3 catalytic addition, the optimized reaction condition is:temperature 70?,3wt% AICl3 and reaction time 1h. Under this condition, the yield of exo-THDCPD is 98.8% and the purity of isomerization product is 88.4%. Compared with the isomerization without solvent, the addition of 1,2-dichloroethane as solvent can promote the isomerization greatly with the optimal reaction condition:temperature of 50?, 3wt% of AICl3 and 1,2-dichloroethane concentration 50 wt%. And less adamantane and no tar are formed under this condition.Hydrogenation of ethylidene norbornene derived heavy oil into polycyclic hydrocarbon fuels was studied using Pd/C as catalyst. The heavy oil consisting of C10?C15 polycyclic olefins was synthesized by DCPD and BD with Diels-Alder reaction. The saturated hydrogenation product mixture shows good performance with high density(0.99g/cm3) and volumetric energy(42.21MJ/L) and low freezing point(<-60?). But the resulting fuel cannot be used alone due to the high viscosity at low temperature.Isomerization of the hydrogenation product of heavy oil to alkyl-adamantanes was investigated using chloroaluminate ionic liquid(IL) as acid catalyst. According to the literature and experimental analysis, the reaction pathway of each compound was illustrated. Although having different molecular structure, the saturated hydrocarbons of heavy oil undergo conformational isomerization and then skeletal rearrangement towards alkyl-adamantanes. The effect of reaction conditions including IL acidity (AICl3 fraction), IL dosage, reaction temperature and time was also investigated in order to optimize the yield of alkyl-adamantanes. The hydrocarbon fuel containing 90% of diamondiods was obtained at the optimal condition and the performance was improved compared with that before isomerization, especially the viscosity at low temperature(<300 mm2/s,-40?). The synthesis of diamondoid-based fuel not only recycles the heavy oil byproduct, but also provides a new path for the preparation of high density liquid fuel.