High Density Alkyl Diamondoid Fuels Synthesized by Catalytic Cracking of Alkanes in the Presence of Adamantane

Abstract

Alkyl diamondoid fuel mixtures have been prepared under moderate conditions by AlBr3 catalyzed cracking of nonane and heptane in the presence of adamantane. The fuel mixture prepared with heptane as the alkyl source (HA) contains primarily 1-ethyl-3-methyl adamantane and 1-propyladamantane, while the mixture prepared from nonane (NA) contains primarily C13–C15 alkyl diamondoids. Both fuel mixtures exhibit densities greater than 0.9 g/mL and volumetric net heats of combustion approximately 10 and 6% higher than conventional jet and diesel fuels, respectively. The structural diversity of the fuel blends and presence of multiple branch sites lead to lower viscosities compared to pure alkyl diamondoid fuels. The lower molecular weight blend, HA, exhibits a 40 °C kinematic viscosity of 3.22 mm2 s–1, well within the specification for diesel fuel, and both blends have derived cetane numbers of >42, suggesting that they can be used directly in conventional diesel engines.

Synthesis and Characterization of High-Performance Renewable Diesel Fuel from Bioderived 1-Octen-3-ol

“…A more direct comparison with representative C 16 cycloalkanes is not currently viable, given the lack of literature data. However, recent work has shown that C 12 -C 15 alkyl diamondoids (highly branched multicyclic alkanes with fused cyclohexane ring systems and short alkyl chains) have reported DCNs ranging from 43 to 49, − suggesting that cyclohexane ring systems do not have a significant negative impact on the DCN of parent hydrocarbons.…”

“…One route to improve the density of renewable diesel fuel is to focus on the synthesis of cycloalkanes (naphthenes) instead of linear and branched alkanes. Although most cycloalkanes have low to moderate cetane numbers, the incorporation of modest length alkyl chains can enhance the cetane number and allow for the isolation of full performance fuels. − A straightforward and atom-economic route to cycloalkane synthesis is through [4 + 2] Diels–Alder cycloaddition, suggesting that a sustainable conjugated diene derived from a renewable source would be an ideal substrate.…”

Synthesis of Polycyclic Hydrocarbons C14H20by Hydrogenation ofexo–exo-,exo–endo-,endo–exo-, andendo–endo-Hexacyclo[9.2.1.02,10.03,8.04,6.05,9]tetradec-12-enes with H2SO4and Isomerization of the Products to Diamantane Induced by Ionic Liquids

“…It should be especially noted that in recent years, the researchers have widely studied alkyl derivatives of diamondoids, including penta- and hexacyclotetradecane, due to their unique properties, such as high density, thermal stability, high calorific value, and good low-temperature characteristics, which make them promising as high-energy rocket fuels. − …”

Density, Viscosity, and Refractive Index for Binary Mixtures of Three Adamantane Derivatives with n-Nonane or n-Undecane at T = 293.15–343.15 K and Atmospheric Pressure

“…High-energy-density hydrocarbon fuels have relative high density and volumetric energy content; so, these kinds of fuels are very attractive. , High-energy-density hydrocarbon fuels are critical for volume-limited aircraft to increase the effective load and extend the flight range . It has been reported that adamantane fuels derived from some reservoirs exhibit a high density and volumetric heating value, and they are regarded as one new kind of high-energy-density hydrocarbon fuel.…”