Title page for etd-0809111-120608


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URN etd-0809111-120608
Author Kuo-Chen Ma
Author's Email Address No Public.
Statistics This thesis had been viewed 5571 times. Download 1437 times.
Department Chemistry
Year 2010
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Thermal Chemistry of Benzyl Isocyanate and Phenyl Isocyanate on Cu(111)
Date of Defense 2011-07-28
Page Count 64
Keyword
  • RAIRS
  • TPD
  • benzyl isocyanate
  • Cu(111)
  • UHV
  • XPS
  • benzyl azide
  • Abstract Nitrenes are reactive intermediates for many organic reactions, such
    as Curtius rearrangement. The thermo- or photochemical- decomposition
    of azides or isocyanates was known to generate nitrenes. We investigated
    the thermal chemistry of nitrene adsorbed on Cu(111) using benzyl azide
    (Bz-N=N=N), benzyl isocyanate (Bz-N=C=O) and phenyl isocyanate
    (ph-N=C=O) as precursors under ultrahigh vacuum conditions using
    temperature-programmed reaction/desorption (TPR/D), reflectionabsorption
    infrared spectroscopy (RAIRS) and X-ray photoelectron
    spectroscopy (XPS). Our study shows that despite of the isoelectronic
    functionalities (-N=N=N vs. -N=C=O) these molecules undergo different
    reaction pathways. For benzyl azide (Bz-N=N=N), the azido group losses
    N2 ,and the phenyl group migrates from nitrogen to carbon, forming
    surface bound H2C=N-Ph at 210 K. Eventually, H2 elimination and a
    carbon-to-nitrogen phenyl shift give the thermally stable ph-CN final
    product. XPS reveals that benzyl isocyanate (Bz-N=C=O) rearranges to
    form amide intermediate on the surface, which breaks into CO2, HCN
    and toluene at 410 K. RAIRs suggests that phenyl isocyanate
    (ph-N=C=O) undergoes cyclodimerization, cyclotrimerization and
    condensation to remove CO2 at 170 K, and phenyl group shifts from
    nitrogen to carbon to produce a metal bound acyl nitrene species
    (Ph-(C=O)-N---Cu) at 410 K.
    Advisory Committee
  • Hsiu-Wei Chen - chair
  • Chia C. Wang - co-chair
  • CHAO-MING CHIANG - advisor
  • Files
  • etd-0809111-120608.pdf
  • Indicate in-campus at 1 year and off-campus access at 1 year.
    Date of Submission 2011-08-09

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