Chemoselective Hydrogenation of Ring‐Strained Monoterpenes: A Route to High‐Performance Sustainable Aviation Fuels

Abstract

Sabinene and 3‐carene, bio‐based monoterpene precursors to high‐performance jet fuels, are chemoselectively hydrogenated with reduced PtO2 at low temperatures (263–298 K), to yield products in which the alkene groups are saturated, whereas cyclopropane rings from the parent hydrocarbons are conserved. Sabinene is selectively converted to a 79:21 mixture of cis:trans‐thujane (1), whereas 3‐carene is converted to a 72:28 mixture of cis:trans‐carane (3). For comparison, the fully hydrogenated species tetrahydrosabinene (2) and 1,1,4‐trimethylcycloheptane (4) are prepared by hydrogenation with Pd/C. To evaluate 1−4 as advanced jet fuel blendstocks, several key fuel properties are measured. Compared with conventional jet fuel, the hydrogenated monoterpenes exhibit up to 8.6% higher density, 1.3% higher gravimetric net heat of combustion (NHOC), 9.7% higher volumetric NHOC, and 64% lower kinematic viscosity at −20 °C. These properties suggest that 1−4 are valuable blendstocks for conventional jet fuel or sustainable aviation fuel, providing enhanced operability and performance.

Is aromatic plants environmental health engineering (APEHE) a leverage point of the earth system?

“…Meanwhile, on the premise of meeting indoor needs, redundant BVOCs can be considered by some methods of enrichment and transformation and the recovery of MAPs [ 74 ], research and development of new fuels [ 75 ] or hybrid fuels [ 76 ] and applications in other fields, such as gas-powered nanosynthesizers for automatic production of polymers on demand [ 77 ].…”

Solvent-free dehydration, cyclization, and hydrogenation of linalool with a dual heterogeneous catalyst system to generate a high-performance sustainable aviation fuel

“…All chemicals were used as received. 1 H NMR spectra were collected as previously described 24 and are displayed in Figures S4 , S6 , S8 , S10 , and S 11 . Experimental parameters for GC-FID, GC-MS, and the measurement of kinematic viscosity, density, and heat of combustion are included in the Supplementary Methods.…”

“…Terpenes have also been studied as precursors to high-density fuels for rocket and missile propulsion. This was accomplished through a variety of techniques including dimerization 22 , 23 , chemoselective hydrogenation of ring-strained terpenes 24 , and cyclopropanation 19 . Recent work by Harvey et al demonstrated that pinene, limonene, and sabinene, once hydrogenated, could be blended with synthetic paraffinic kerosenes to generate jet fuel that exceeded Jet-A standards 14 .…”

Designer Biosynthetic Jet Fuels Derived from Isoprene and α-Olefins

“…1 H NMR spectra were collected as previously described. 72 1 H and 13 C NMR spectra for the products described below as well as experimental parameters for GC-FID, GC-MS, and the measurement of kinematic viscosity, density, and heat of combustion are included in the Supporting Information.…”