20717-76-4Relevant academic research and scientific papers
Effect of a Hydrogen Pretreatment on the Mechanism of Deuterium Addition Exchange of Propene over Ni-Cu Alloy Catalysts
Naito, Shuichi,Tanimoto, Mitsutoshi
, p. 1253 - 1260 (2007/10/02)
The effects of a hydrogen pretreatment on the activity and reaction intermediate in a C3H6-D2 reaction over a Ni-Cu alloy as well as Ni metal catalysts were investigated in detail by applying an isotope tracer technique.Ni metal and Ni-rich alloy catalysts, cooled down to the reaction temperature under a hydrogen atmosphere (D-surface), exhibited low activity compared to that of a surface evacuated before cooling (E-surface).For Cu-rich alloy catalysts, however, the E-surface exhibited a lower activity and a higher activation energy than did the D-surface.A comparison of the TPF spectra of adsorbed hydrogen with the dependence of the activity upon the evacuation temperature suggests that strongly adsorbed hydrogen retards the reaction over Ni and Ni-rich alloy catalysts at lower temperature.Microwave spectroscopic analysis demonstrated that the reaction intermediates over D- and E-surfaces of Cu-rich alloy catalysts were similar to those over Cu and Ni metals, respectively.This result suggests that a hydrogen pretreatment of Cu-rich alloys forms a specific surface structure which is destroyed by evacuation at elevated temperatures.
Reactions of FeCH2(+) and CoCH2(+) with Aliphatic Alkanes in the Gas Phase. Activation of C-H and C-C Bonds by Naked Transition-Metal Carbene Ions
Jacobson, D. B.,Freiser, B. S.
, p. 4373 - 4378 (2007/10/02)
Gas-phase reactions of the title carbenes with several aliphatic alkanes using Fourier transform mass spectrometry (FTMS) ,are described.CoCH2(+) reacts with alkanes larger than methane whereas FeCH2(+) reacts with alkanes larger than ethane.Both FeCH2(+) and CoCH2(+) react predominantly by initial C-H bond insertion with some C-C bond insertion also observed.As a consequence of facile carbene-alkyl coupling, C-C bond cleavage processes proceed predominantly with elimination of the original carbene incorporated into the departing alkane neutral.In addition a small amount of C-C bond formation product is also observed.Finally, a greater degree of H/D scrambling is observed for CoCD2(+) than for FeCD2(+).
