3675-63-6Relevant articles and documents
Alkyl Substituent Effect in the Deprotonation of Unsymmetrical Ketones
Johnson, Cris E.,Sannes, Kristin A.,Brauman, John I.
, p. 8827 - 8835 (1996)
The effect of various degrees of alkyl substitution on the relative rates of deprotonation from the two distinct sites in several unsymmetrical ketones in the gas phase is examined.The infrared multiple photon activation of an appropriately deuterium-labeled alkoxide ion generates the ion-molecule complex for the half-reaction of the bimolecular proton transfer process between an alkyl anion and an unsymmetrical ketone with one deprotonation site selectively deuterated.The resulting products are enolate ions generated by the removal of either a deuteron or a proton and, thus, are distinguishable by mass.The measurement of the enolate ion product ratios, along with an independent measurement of the kinetic isotope effect, allowed the kinetic effect of the alkyl environment on the relative proton transfer rates to be determined.The primary and secondary isotope effects are also estimated from the enolate ion product ratios.By examining the magnitude of the kinetic alkyl effect, the primary isotope effect, and the secondary isotope effect, we learn about the transition state for proton transfer.
On the Pyrolysis of Pent-1-ene-4,4,5,5,5-d5
Kopinke, F.-D.,Bach, G.,Ondruschka, B.,Zimmermann, G.
, p. 699 - 707 (2007/10/02)
The distribution of deuterium in the main products of thermal decomposition of pent-1-ene-4,4,5,5,5-d5 at 550 to 650 deg C was studied and interpreted.The results include conclusions on kinetic isotope effects, on relative reactivities of different C-H-bonds, on the proportion of terminal and nonterminal addition of methyl radicals, and on the importance of a radical isomerisation reaction.It was shown that the molecular decomposition (Retro-En-Reaction) cannot successfully compete with the radical way in the temperature range above 600 deg C.
