Thermal Stability and Isomerization Mechanism of exo-Tetrahydrodicyclopentadiene: Experimental Study and Molecular Modeling

Abstract

Thermal stability and the primary initiation mechanism of exo-tetrahydrodicyclopentadiene (exo-THDCP, C10H16) were investigated in a batch-type reactor. The catalytic role of the stainless steel inside the reactor was eliminated by inserting a quartz flask. exo-THDCP decomposed at temperatures over 623 K and 1-cyclopentylcyclopentene (1-CPCP, C10H16) and 4-methyl-2,3,4,5,6,7-hexahydro-1H-indene (4-MHI, C10H16) were the primary decomposition products of exo-THDCP. C10 hydrocarbons were determined to be the major products. The amount of C5−C7 hydrocarbons, such as cyclopentene, benzene, and toluene, were relatively small. We performed the molecular modeling (MM) on some of the compounds, including 1-CPCP and 4-MHI produced from exo-THDCP to evaluate the activation energy and molecular structure of the intermediates. The experimental and MM results showed that 1-CPCP and 4-MHI were independently formed from exo-THDCP. The experimental results closely corresponded with the MM result; the products that were only minimally produced after the reaction had qualitatively higher activation energies than the other products.

Quasi-homogeneous catalytic cracking of JP-10 over high hydrocarbon dispersible nanozeolites

“…Generally, there are many components in the liquid residuals as a result of its cracking. In the light fractions, C5-C6 products of cycloalkenes and aromatics are observed, whereas a little amount of polycyclic aromatic hydrocarbons are also observed, which agrees well with the results reported in the literature [36][37][38][39][40][41].…”

Catalytic Effects of Zeolite Socony Mobil-5 (ZSM-5) on the Oxidation of Acoustically Levitated exo-Tetrahydrodicyclopentadiene (JP-10) Droplets

“…10,22 Overall, the pyrolysis of JP-10 was found to be mostly efficient at temperatures exceeding 873 K due to the high activation energies of at least 397 kJ mol −1 to cleave the carbon−hydrogen bond(s) (Scheme 2). 10,[14][15][16][17]20,21 Distinct catalysts have been proposed to decrease the activation energy in the decomposition of JP-10. Li et al 27 explored the effects of gold nanoparticles, but the improvement of the cracking rate of JP-10 only achieved 10% with the dispersion stability of metal nanoparticles, limiting the use as a catalyst in JP-10 decomposition.…”

“…Over the past decades, researchers exploited a great variety of approaches to study the thermal decomposition and oxidation of JP-10 such as distinct reactor types (flow tube, jet stirred, and batch), ,− shock tubes, ,, and high-temperature chemical reactors (Table ) with identified products compiled in Table S1. ,, The majority of these products were reported in a chemical microreactor setup by Zhao et al by exploiting vacuum ultraviolet photoionization detection along with studies by Johnson et al, Pan et al, and Huang et al Electronic structure calculations by Morozov et al provided a theoretical framework of these findings and yielded in-depth mechanistical insights into the feasible pathways, leading to the pyrolysis products of JP-10. These studies revealed that the decomposition of JP-10 is initiated by distinct C–H bond cleavages ,, followed by C–C bond β-scissions via biradical intermediates; these pathways are consistent with the cleavage of strained C–C bonds eventually initiating the unimolecular decomposition of the carbon skeleton of JP-10 (Scheme ).…”

“… Zhao et al revealed that R1, R4, R5, and R6 represent favorable channels due to the lower endoergicities of the C–H bond cleavages. , Overall, the pyrolysis of JP-10 was found to be mostly efficient at temperatures exceeding 873 K due to the high activation energies of at least 397 kJ mol –1 to cleave the carbon–hydrogen bond(s) (Scheme ). ,− ,, …”

Oxidation of Levitated exo-Tetrahydrodicyclopentadiene Droplets Doped with Aluminum Nanoparticles

“…Air-breathing propulsion systems rely on the combustion of hydrocarbon fuels such as of Jet Propellant-10 (JP-10). , The exo -tetrahydrodicyclopentadiene molecule (C 10 H 16 ; Scheme ) represents the major component of JP-10 and is defined by a high volumetric energy (39.6 kJ cm –3 ) due to three five-membered ring moieties incorporated into a single molecule along with the inherent ring strain energy. This makes JP-10 not only an attractive fuel for missiles, pulse-detonation engines, and ramjets ,, but also interesting for the physical (organic) chemistry, combustion, and theoretical chemistry communities to explore its decomposition and oxidation experimentally, theoretically, and in combustion models. − Exploiting shock tubes, flow tubes, ,− and high-temperature chemical reactors, ,, a detailed understanding of the decomposition of pure JP-10 is beginning to emerge. The unimolecular decomposition (“pyrolysis”) of JP-10 leads to smaller hydrocarbon molecules and reactive transient species, among them aliphatic radicals, resonantly stabilized free radicals (RSFRs), and aromatic radicals (ARs), , which initiate the complex chemistry in the oxidation of JP-10 based jet fuel.…”