Crossed molecular beam studies of substitution and exchange reactions. [F + C/sub 2/H/sub 4/; Br + R-Cl (R = aromatic); Br + C/sub 2/H/sub 2/Cl/sub 2/; CH/sub 3/ radical + iodoalkanes]
Atom + alkene/aromatic and radical + iodoalkane reactions have been studied. F + C/sub 2/H/sub 4/ ..-->.. (C/sub 2/H/sub 4/F)* ..-->.. H + C/sub 2/H/sub 3/F was studied at low collision energies. The substitution cross section decreases with increasing E/sub c/, suggesting that long-range attractive forces dominate the F-C/sub 2/H/sub 4/ interaction. The CM frame C/sub 2/H/sub 3/F angular distributions may reflect unusual angular momentum partitioning in the C/sub 2/H/sub 4/F collision complex. Chapters 2 and 3 describe studies of endoergic substitution reactions, Br + R-Cl ..-->.. R-Br + Cl, where R-Cl = 0-, m-, and p-CH/sub 3/C/sub 6/H/sub 4/Cl, C/sub 6/X/sub 5/Cl (X = H, F), and 1,1- and trans-C/sub 2/H/sub 2/Cl/sub 2/ in the collision energy range 15 to 35 kcal/mol. Br adds to the double bond to form a weakly bound collision complex which then decomposes through Cl elimination. Competition between intramolecuar vibrational modes and Cl elimination results in translational energy distributions and excitation functions that can be modeled by a limited number of vibrational modes participating in energy sharing prior to bond fission. Substituents influence the orientation and probability of Br addition as well as energy redistribution. The first crossed beam studies of CH/sub 3/ radicals with polyatomic molecules are reported in Chapter 4. The CH/sub 3/I products from the reactions CH/sub 3/ + R-I ..-->.. CH/sub 3/I + R (R = CF/sub 3/, (CH/sub 3/)/sub 3/C) are strongly backward scattered, indicating a preferred collinear CH/sub 3/-I-R configuration. Most of the 15 kcal/mol of available energy is channeled into product translation (50% for R = (CH/sub 3/)/sub 3/C and 70% for R = CF/sub 3/). This large repulsive energy release is rationalized in terms of stability of the CH/sub 3/-I-R transition structures. 199 refs., 47 figs., 8 tabs.
- Research Organization:
- California Univ., Berkeley (USA). Dept. of Chemistry; Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5523173
- Report Number(s):
- LBL-24635; ON: DE88006322
- Resource Relation:
- Other Information: Thesis (Ph.D.). Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BROMINE
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
CHLORINATED AROMATIC HYDROCARBONS
ETHYLENE
FLUORINE
IODINATED ALIPHATIC HYDROCARBONS
METHYL RADICALS
ATOMS
COLLIDING BEAMS
MOLECULAR BEAMS
ALKENES
ALKYL RADICALS
AROMATICS
BEAMS
ELEMENTS
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
HALOGENS
HYDROCARBONS
NONMETALS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
RADICALS
400201* - Chemical & Physicochemical Properties