133673-06-0Relevant articles and documents
Decompositions of Ionized Isopropyl Methyl Ether: Complex-Mediated and Direct Processes in Unimolecular Dissociations
McAdoo, David J.,Traeger, John C.,Hudson, Charles E.,Griffin, Lawrence L.
, p. 1524 - 1530 (2007/10/02)
Methane and methyl losses from ionized isopropyl methyl ether (1) were characterized to improve our understanding of ion-neutral-complex-mediated dissociations in the gas phase.Photoionization appearance energies demonstrate that the onsets for the two reactions differ by only 2+/-1 kJ mol-1, consistent with the two processes being related by a common bond cleavage.Isotope effects confirm that the transition states for bond scission to form the complex and subsequent hydrogen transfer to form methane are at very similar energies.Loss of methane becomes insignificant 20-30 kJ mol-1 above its onset, whereas loss of methyl increases rapidly for at least 100 kJ mol-1 above threshold.From this it is concluded that the decompositions of 1 are complex-mediated near threshold but shift to a direct mechanism at higher energies, i. e., that decomposition is ion-neutral-complex-mediated over only a narrow range of energies just above threshold.
Formation and transformations of cations obtained from 1,1-dialkoxyalkanes in fluorosulfonic acid
Akhmatdinov, R. T.,Kantor, E. A.,Imashev, U. B.,Yasman, Ya. B.,Rakhmankulov, D. L.
, p. 626 - 630 (2007/10/02)
The reaction of 1,1-dialkoxyalkanes with fluorosulfonic acid at -75 deg C leads to the formation of alkoxycarbenium ions and protonated alcohols.The methoxy- and ethoxymethylcarbenium ions are stable at room temperature.Methoxycarbenium undergoes further reactions at -5 deg C.At -15 deg C ethoxycarbenium is converted by a 1,3-hydride shift into methoxymethylcarbenium.At this temperature the latter reacts with ethanol, forming ethoxymethylcarbenium and methanol.At -45 deg C isopropoxycarbenium is converted also by a 1,3-hydride shift into methoxydimethylcarbenium.Methyl, ethyl, and isopropyl alcohols are converted into the corresponding fluorosulfonic esters.
