2672-01-7Relevant articles and documents
The dynamics of hydrogen abstraction reactions: Crossed-beam reaction Cl+n-C5H12→C5H11+HCl
Hemmi, Naoki,Suits, Arthur G.
, p. 5338 - 5343 (2007/10/03)
We present a crossed molecular beam study of the dynamics of the metathesis reaction Cl+n-C5H12→HCl+C5H11 at a collision energy of 16.8 kcal/mol. The experiments were conducted on the Chemical Dynamics Beamline at the Advanced Light Source, using tunable undulator radiation to effect soft ionization of the pentyl radical product. Laboratory angular distributions and time-of-flight spectra at many laboratory angles were used to obtain the center-of-mass translational energy and angular distributions. These distributions were found to be strongly coupled, with the forward scattered pentyl radical formed extremely cold, while the backscattered radicals were formed leaving nearly 15 kcal/mol in internal energy in the products. These results are contrasted with recent studies on the analogous reaction with propane, suggesting in this case direct involvement of the carbon skeleton in the collision process.
Reactions of Atomic Oxygen (3P) with Selected Alkanes
Miyoshi, Akira,Tsuchiya, Kentaro,Yamauchi, Noboru,Matsui, Hiroyuki
, p. 11452 - 11458 (2007/10/02)
Rate constants for the reactions of atomic oxygen (3P) with selected alkanes (C2-C6 straight chain alkanes, c-C6H12, neo-C5H12, and i-C4H10) have been determined directly by a laser photolysis-shock tube-atomic resonance absorption method at hi
ON THE REMOVAL OF METALLIC MIRRORS BY FREE RADICALS.
Rice,Tweedell
, p. 995 - 997 (2007/10/02)
Large radicals can be formed by passing chlorinated organic compounds at pressures of a few mm. , through a furnace containing a pellet of sodium and heated to 350-400 degree C. It is found that the only radicals that will remove metallic mirrors (of tellurium or antimony, etc. , previously deposited beyond the furnace) are those that can decompose into methyl or ethyl radicals plus an unsaturated molecule, without undergoing any transmigration of atoms. The authors also found, especially in the case of larger monochlorinated molecules, that there was some decomposition, approximately half, even in the absence of metallic sodium.
Absolute Rate Constants for the Reaction of Triethylsilyl Radicals with Organic Halides
Chatgilialoglu, C.,Ingold, K. U.,Scaiano, J. C.
, p. 5123 - 5127 (2007/10/02)
The absolute rate constants for the reactions of Et3Si. radicals with a number of organic halides have been measured in solution by using laser flash photolysis techniques.The reactivities cover a wide range; e.g., the rate constants at ca. 300 K are 4.3 * 109, 1.1 * 108, 2.5 * 106, and 5 M-1 s-1 for CH3CH2I, C6H5Br, (CH3)3CCl, and C6H5CH2F, respectively.Arrhenius parameters were determined for a few representative substrates.Thus, for CCl4, Ea = (0.78 +/- 0.24) kcal/mol and log (A/M-1 s-1) = 10.2 +/- 0.2, data which can be combined with relative rates from the literature to yield absolute rate constants for some additional substrates.Comparison of the Arrhenius parameters for halogen abstraction from several substrates suggests the involvment of charge-transfer interactions in some of these reactions.Such rate-enhancing interactions can have a greater influence on the preexponential factor than on the activation energy.An explanation for this phenomenon is advanced.Combination of our rate constants with data from literature also allows evaluation of the rates of inversion at the silicon center in triorganosilyl radicals as being in the range (3-12) * 109 s-1 at temperatures from 0 to 80 deg C which implies that a considerable activation barrier is involved in such process.
