cis-1,2-Dimethylcyclohexane

• CAS: 2207-01-4
• Catalog Number: ACM2207014-1
• Category: Other Products; Alkanes
• Molecular Weight: 112.21
• Molecular Formula: C8H16
• Synonyms: (1S,2R)-1,2-dimethylcyclohexane
• Complexity: 56
• Defined Atom Stereocenter Count: 2
• Exact Mass: 112.1252
• Formal Charge: 0
• Hazard Statements: H225-H315-H319-H335 + H336
• Heavy Atom Count: 8
• Hydrogen Bond Acceptor Count: 0
• Hydrogen Bond Donor Count: 0
• Isotope Atom Count: 0
• Monoisotopic Mass: 112.1252
• RIDADR: UN 2263 3 / PGII
• Rotatable Bond Count: 0
• Symbol: GHS02
• Topological Polar Surface Area: 0 Ų
• XLogP3-AA: 3.8

Case Study

Study on the Isomerization of cis-1,2-Dimethylcyclohexane

Rosado-Reyes, et al. The Journal of Physical Chemistry A, 2014, 118(36), 7707-7714.

Cyclic hydrocarbons are the main components of jet fuel and are also reference compounds for jet fuel substitutes. In order to study the kinetics and thermal stability of the fuel molecules and the reaction mechanism, this work uses single-pulse shock tube experiments to conduct a detailed study and analysis of the pyrolysis chemistry of cis-1,2-dimethylcyclohexane. The experimental temperature range is 1100 to 1200 K and the pressure is about 2.5 atmospheres.
Key findings
· The major product is trans-1,2-dimethylcyclohexane. At the same time, small amounts of trans-2-octene and cis-2-octene were detected in the products, as well as a much lower yield of 1-octene. Product formation follows biradical initiation combined with disproportionation reactions that prefer hydrogen transfer through six-membered transition states compared to eight-membered ones.
· The internal disproportionation reactions result in the formation of the three octene isomers. The total rate expression for isomerization k_C-C = 10^15.5±0.8 exp(-38644 ± 2061 K/T) s^-1 results from assuming a diradical mechanism and that cis-1,2-dimethylcyclohexane forms equally with its trans isomer. Transition state rate constants show more than tenfold reduction compared to those in noncyclic hydrocarbon systems. The detection of isomeric octenes demonstrates that internal disproportionation serves as a critical element of the isomerization process.

Gas Hydration Reaction of trans-1,2-Dimethylcyclohexane with Synergistic Effect of Methane and cis-1,2-Dimethylcyclohexane

Nakamura, Toshiyuki, et al. Chemical engineering science, 2004, 59(1), 163-165.

The formation of structure-H (sH) gas hydrates reduces natural gas hydrate stability pressure which has generated extensive interest for natural gas transportation systems. It has been regarded that the maximum cage occupancy limit for the sH hydrate falls between the 1,2-dimethylcyclohexane stereo-isomers since only the cis-isomer can produce sH hydrate with methane present while the trans-isomer fails to do so. The research identified gas hydrate formation of trans-1,2-dimethylcyclohexane (trans-1,2-DMCH) with methane and cis-1,2-dimethylcyclohexane (cis-1,2-DMCH) using the stability boundaries of the structure-H hydrate system.
Key Findings
· The equilibrium pressure rises with the mole fraction of trans-1,2-DMCH and it appears that a specific trans-1,2-DMCH concentration range exists which enables the formation of sH gas hydrate with the assistance of methane and cis-1,2-DMCH.
· On this prospect, in a mixture of cis-1,2-DMCH and methane trans-1,2-DMCH can settle into the U-cage. The U-cage within s-H hydrate becomes distorted through cis-1,2-DMCH molecule entrapment which allows trans-1,2-DMCH to occupy this expanded U-cage.