Recoil tritium reactions with methylcyclohexene. A test of the assumption of energy randomization prior to unimolecular decomposition

Journal Article · Thu Feb 14 04:00:00 EDT 1974 · J. Phys. Chem., v. 78, no. 4, pp. 354-360

DOI:https://doi.org/10.1021/j100597a007· OSTI ID:4319705

Fee, D C; Markowitz, S S

The reactions of recoil tritium atoms with the three methylcyclohexene isomers were studied in the gas phase at 135 deg C. T was produced by /sup 3/ He(n,p)T. Recoil tritium atom abstraction, addition, or T-for-H substitution reactions accounted for 90% of the gas-phase products. Following activation by T- for-H substitution, the unimolecular decomposition of 4-methylcyclohexene-t (to give propylene-t or butadiene-t) and the unimolecular decomposition of 3- methylcyclohexene-t (to give ethylene-t or 1,3- pentadiene-t) was established from the pressure dependence of the product yield in the 300-1200-torr pressure range. The apparent rate constants for these unimolecular decomposition processes were determined as 1 x 10/sup 7/ and 3 x 10/sup 6/ sec/sup -1/, respectivel y. The rate constants for the unimolecular decomposition of cyclohexene1-t and cyclohexene-3-t (formed by T-for-methyl substitution on 1- methylcyclohexene and 3-methylcyclohexene, respectively) were nearly equivalent. In addition, the average energy of excitation following T-for-methyl substitution is the same in cyclohexene-1-t and cyclohexene-3-t, namely, 6.0 to 6.5 cV. It was concluded that the RRKM (Rice, Ramsperger, Kassel, and Marcus) assumption of energy randomization prior to unimolecular decomposition is valid for the recoil tritium initiated unimolecular decomposition of cyclohexene. (44 references) (auth)

• Research Organization: Univ. of California, Berkeley
• Sponsoring Organization: USDOE
• NSA Number: NSA-29-018205
• OSTI ID: 4319705
• Journal Information: J. Phys. Chem., v. 78, no. 4, pp. 354-360, Journal Name: J. Phys. Chem., v. 78, no. 4, pp. 354-360; ISSN JPCHA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*CYCLOALKENES-- HOT ATOM CHEMISTRY
*TRITIUM-- HOT ATOM CHEMISTRY
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ISOMERS
N40410* --Chemistry--Radiochemistry & Nuclear Chemistry--Hot Atom Chemistry
PRESSURE DEPENDENCE
RECOILS