REDUCTIVE COUPLING OF CYCLIC-KETONES ON REDUCED TIO2(001) SINGLE-CRYSTAL SURFACES

Hicham Idriss, M A BARTEAU

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Abstract

Reactions of cyclohexanone, cyclohexenone, and p-benzoquinone were investigated on TiO2(001) single crystal surfaces. On the reduced, sputtered surfaces, the following reactions were observed: partial reduction of the cycloketones to their corresponding alcohols and of p-benzoquinone to phenol; reductive coupling to form C6H10=C6H10 and C6H8=C6H8 from cyclohexanone and cyclohexenone respectively; and reductive coupling/reduction of p-benzoquinone to benzene, biphenyl, and terphenyl. The reduced surface was oxidized upon adsorption of the ketones as evidenced by an increase of the intensity of the XPS Ti(2p(3/2)) peak at 459.1 eV corresponding to Ti+4 cations. The population of Ti+4 cations in the region sampled by XPS increased by 6.8%, 11.2%, and 16.8% upon adsorption at 300 K of cyclohexanone, cyclohexenone, and p-benzoquinone, respectively. The activity of the reduced surface for reductive coupling was highest for p-benzoquinone and lowest for cyclohexanone. The observation of reductive coupling on single crystal surfaces in ultrahigh vacuum suggests that gas-solid contact catalysis of this reaction may be feasible.

Original languageEnglish
Pages (from-to)463-470
Number of pages8
JournalStudies in Surface Science and Catalysis
Volume78
Publication statusPublished - 1991

Keywords

  • CARBON BOND FORMATION
  • FORMALDEHYDE

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