Mechanistic and kinetic study of alkane activation by Ti/sup +/ and V/sup +/ in the gas phase. Lifetimes of reaction intermediates

Journal Article · Wed Nov 26 04:00:00 EST 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00284a012· OSTI ID:7203899

Tolbert, M A; Beauchamp, J L

The reactions of Ti/sup +/ and V/sup +/ with several deuterium-labeled alkanes are studied by using an ion beam apparatus. The dominant reactions observed for both of these metal ions are single and double dehydrogenations. Alkane loss reactions are also observed for Ti/sup +/ but may be due to electronically excited states. The dehydrogenation mechanisms are investigated by using partially deuterated alkanes. The results are consistent with 1,2-eliminations for both V/sup +/ and Ti/sup +/, where deuterium scrambling may occur in the latter case. It is proposed that some 1,3-elimination of hydrogen also occurs in the reaction of Ti/sup +/ with n-butane. Although the dehydrogenation reactions of V/sup +/ and Ti/sup +/ appear to be similar to those of Ru/sup +/ and Rh/sup +/, there are some important differences in the reactivity of V/sup +/. Extensive adduct formation and large deuterium isotope effects are consistent with reaction intermediates which are relatively long-lived for V/sup +/ in comparison to Ti/sup +/, Ru/sup +/, and Rh/sup +/. Collisional stabilization studies are used to estimate dissociation rates of reaction intermediates formed when Ti/sup +/ and V/sup +/ interact with n-butane. The measured upper limits to the unimolecular decomposition rates are 1.47 x 10/sup 5/ s/sup -1/ and 1.23 x 10/sup 7/ s/sup -1/ for V/sup +/ and Ti/sup +/, respectively. Model RRKM calculations are able to reproduce these rates and provide an explanation of isotope effects observed when n-butane-d/sub 10/ is employed as the neutral reactant.

• Research Organization: California Institute of Technology, Pasadena
• OSTI ID: 7203899
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 108:24; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADDUCTS
ALKANES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DEHYDROGENATION
DEUTERIUM COMPOUNDS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
FLUIDS
GASES
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
LABELLED COMPOUNDS
LIFETIME
METALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
REACTION INTERMEDIATES
REACTION KINETICS
TITANIUM
TRANSITION ELEMENTS
VANADIUM