Pd/C catalytic cyclopropanation of polycyclic olefins for synthesis of high‐energy‐density strained fuels

Abstract

Cyclopropane derivates are appealing to synthesis of high-energy-density fuels because of the high strained energy of the three-numbered ring. The catalytic cyclopropanation of olefin with diazomethane is very effective to construct the carbocycle. The majority of the catalysts employed are nonrecyclable homogeneous compounds. Herein, we report cyclopropanation of polycyclic olefins catalyzed by heterogeneous Pd/C. The optimal cyclopropanation conditions were explored utilizing dicyclopentadiene as model substrate and a series of polycyclic olefins were cyclopropanated with high yield. Additionally, the catalyst has good recyclability and stability, as shown by characterizations as well as the fact that no inactivation happens after cyclopropanation. The synthesized cyclopropane derivates exhibit good fuel characteristics like high density (1.006-1.087 g/cm 3 ), high volumetric net heat of combustion (42.58-46.45 kJ/cm 3 ), good low-temperature and combustion performance. This work shows industrial potential for cyclopropanation of polycyclic olefins with diazomethane.

Mechanism and kinetics of self‐sensitized photocycloaddition of cyclohexenone and norbornene

“…First, for self-cycloaddition, its reaction rate equation is described as Equation ( 5) and can be converted to Equation (6). According to the initial concentration method, CHOE with different initial concentrations are selected to conduct [2 + 2] photoreaction under the light flux of 100 mW/cm 2 , and the reaction rate of initial reaction is obtained by differentiating the correlation line between concentration and time.…”

“…Generally, the classic high‐density hydrocarbon fuels such as RJ‐4 and JP‐10 are usually derived from petroleum‐based raw materials via Diels–Alder cyclization, olefin polymerization, alkylation or hydroisomerization. Furthermore, some highly strained three‐numbered ring fuels can be synthesized through cyclopropanization 6 . Recently, strategies based on renewable biomass resources are developed to synthesize green hydrocarbon fuels, like the Aldol condensation of acetone with 5‐hydroxymethyl furfural 7 or cyclopentanone, 8 alkylation of cyclohexanone with 2‐methyl furan, 9,10 hydroxyl alkylation/alkylation of 2‐methylfuran with cyclohexanone (cyclopentanone and cyclohexanone) 11 .…”