Support effects in the selective gas phase hydrogenation of p-chloronitrobenzene over gold

Fernando Cardenas-Lizana, Santiago Gómez-Quero, Noemie Perret, Mark A. Keane

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

The catalytic continuous gas phase hydrogenation of p-chloronitrobenzene (P = 1 atm; T = 423 K) has been investigated over a series of oxide (Al2O3, TiO2, Fe2O3 and CeO2) supported Au (1 mol %) catalysts. The application of two catalyst synthesis routes, i.e. impregnation (IMP) and deposition-precipitation (DP), has been considered where the DP route generated smaller mean Au particle sizes (1.5-2.8 nm) compared with the IMP preparation (3.5-9.0 nm). The catalysts have been characterised in terms H2 chemisorption and BET area measurements where the formation of metallic Au post-activation has been verified by diffuse reflectance UV-Vis, XRD and HRTEM analyses. p -Chloroaniline was generated as the sole reaction product over all the Au catalysts with no evidence of C-Cl and/or C-NO2 bond scission and/or aromatic ring reduction. The specific hydrogenation rate increased with decreasing Au particle size (from 9 to 3 nm), regardless of the nature of the support. This response extends to a reference Au/TiO2 catalyst provided by the World Gold Council. A decrease in specific rate is in evidence for smaller particles (< 2 nm) and can be attributed to a quantum size effect. The results presented establish the basis for the design and development of a versatile catalytic system for the clean continuous production of high value amino compounds under mild reaction conditions.

Original languageEnglish
Pages (from-to)124-132
Number of pages9
JournalGold Bulletin
Volume42
Issue number2
Publication statusPublished - 2009

Keywords

  • Au particle size
  • Catalyst support effect
  • Gold catalysts
  • p-chloroaniline
  • p-chloronitrobenzene hydrogenation

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