Propylcyclohexane

• CAS: 1678-92-8
• Catalog Number: ACM1678928-2
• Category: Alkanes
• Molecular Weight: 126.24
• Molecular Formula: C9H18
• Synonyms: Cyclohexane, propyl-
• Complexity: 60
• Defined Atom Stereocenter Count: 0
• Exact Mass: 126.1408
• Formal Charge: 0
• Hazard Statements: H225-H304-H315-H336-H410
• Heavy Atom Count: 9
• Hydrogen Bond Acceptor Count: 0
• Hydrogen Bond Donor Count: 0
• Isotope Atom Count: 0
• Monoisotopic Mass: 126.1408
• RIDADR: UN 3077 9 / PGIII
• Rotatable Bond Count: 2
• Symbol: GHS02
• Topological Polar Surface Area: 0 Ų
• XLogP3-AA: 4.6

Case Study

Comparative Study on the Combustion Performance of n-Propylcyclohexane, Ethylcyclohexane and Cyclohexane

Tian, Zemin, et al. Energy & fuels, 2014, 28(11), 7159-7167.

Cycloalkanes serve as vital components for both traditional automotive fuels like gasoline, diesel and jet fuel. Researchers tested ignition delay times for ethylcyclohexane (ECH), n-propylcyclohexane (PCH), and n-butylcyclohexane (BCH) at atmospheric pressure across equivalence ratios 0.5 to 2.0 and temperatures ranging from 1110 to 1650 K behind reflected shock waves with fuel concentration set at 0.5%. The research conducted computational simulations by applying three widely acknowledged mechanisms.
Key findings
· The branching chain promoting unimolecular reactions results in shorter ignition delay times for ECH and PCH compared to CH at high temperatures (T > 1450 K), when these reactions primarily influence fuel decomposition.
· H-abstraction reactions control fuel consumption at lower temperatures and make the H radical a crucial factor for CH decomposition.
· The observed ignition delay times for ECH, PCH, and BCH follow the order of PCH < ECH ≈ BCH, which can be attributed to their molecular structures. PCH facilitates faster H-radical generation due to its simpler pathways, while the more complex pathways for H production in BCH oxidation make it slower to generate H radicals. Consequently, BCH exhibits a longer ignition delay time than PCH.

Study on the Pyrolysis Chemistry of n-Propylcyclohexane

Wang, Qianpeng, et al. Fuel, 2021, 283, 118847.

Researchers performed n-propylcyclohexane (n-PCH) pyrolysis experiments inside a flow reactor by applying synchrotron VUV photoionization mass spectrometry techniques. The experiment achieved temperatures between 950 and 1300 K while sustaining pressures at levels of 30 and 760 Torr with a starting fuel concentration at 0.5% in the gas mixture. The mole fractions of more than thirty pyrolytic species were determined through quantitative measurements.
Key Findings
· The kinetic analysis shows that n-PCH mainly breaks down via H-abstraction reactions which lead to the formation of seven different C9H17 intermediates. The radicals C3H7S2XcC6H10 and C3H7S3XcC6H10 together make up over 34% of fuel usage across both evaluated pressures.
· A comparison of the pyrolysis behavior of four alkylcyclohexanes indicates the order of primary decomposition temperatures as follows: n-PCH < ethylcyclohexane (ECH) < methylcyclohexane (MCH) < cyclohexane (CH). n-PCH experiences lower decomposition temperatures because its propyl group contains weak C-H bonds and H-abstractions play a major role during initial fuel consumption.
· The ring-opening decomposition of C9H17 and alkylcyclohexyl radicals by β-scission produces unsaturated olefins and diolefins which exist in cyclic and linear structures.
· The formation pathways related to the six-membered naphthenic structure led to substantial amounts of aromatic compounds such as benzene, toluene, and ethylbenzene.