title: Infrared absorption of 1-chloro-2-methyl-2-propyl [⋅C(CH3)2CH2Cl] and 2-chloro-2-methylpropyl [⋅CH2C(CH3)2Cl] radicals produced in the addition reactions of Cl with isobutene (i-C4H8) in solid para-hydrogen.
abstract: The addition reactions of chlorine atom with isobutene (i-C4H8) in solid para-hydrogen (p-H2) were investigated with infrared (IR) absorption spectra. When a p-H2matrix containing Cl2and isobutene was irradiated with ultraviolet light at 365 nm, intense lines in a set at 534.5, 1001.0, 1212.9, 1366.0, 2961.6, and 2934.7 cm-1, and several weaker others due to the 1-chloro-2-methyl-2-propyl radical,⋅C(CH3)2CH2Cl, and those in a second set including intense ones at 642.7, 799.2, 1098.2, 1371.8, and 3027.3 cm-1due to the 2-chloro-2-methylpropyl radical,⋅CH2C(CH3)2Cl, appeared; the ratio of⋅C(CH3)2CH2Cl to⋅CH2C(CH3)2Cl was approximately (3 ± 1):1. The observed wavenumbers and relative intensities agree with the vibrational wavenumbers and IR intensities predicted with the B3PW91/aug-cc-pVTZ method. That the Cl atom adds to both carbons of the C=C bond of isobutene with the terminal site slightly favored is consistent with the energies of products predicted theoretically, but is in contrast to the reaction of Cl + propene in solid p-H2in which the addition of Cl to mainly the central C atom was previously reported. The role of the p-H2matrix in affecting the reaction paths is discussed. Absorption lines of the complex i-C4H8⋅Cl2and the dichloro-product anti-1,2-dichloro-2-methylpropane, a-CH2ClCCl(CH3)2, are also characterized.
authors: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.
authors: Ching-Yin
authors: CY
authors: Chou
authors: Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.
authors: Yuan-Pern
authors: YP
authors: Lee