Gas phase hydrogenation of nitrocyclohexane over supported gold catalysts

Xiaodong Wang, Noémie Perret, Mark Keane

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

We report the first continuous (gas phase) hydrogenation of nitrocyclohexane over oxide (Al2O3, TiO2, CeO2 and ZrO2) supported Au catalysts. Thermochemical analysis has established possible thermodynamic constraints and product distribution at equilibrium. The catalysts have been characterised by temperature-programmed reduction (TPR), H2/O2 chemisorption/temperature-programmed desorption (TPD), BET surface area/porosity, X-ray diffraction (XRD) and scanning/transmission electron microscopy (STEM/TEM) measurements. The effects of space velocity (2–6 × 104 h−1), temperature (353 and 473 K) and H2 partial pressure (8 × 10−4–0.93 atm) on catalyst performance have been examined. Selectivity to the target cyclohexanone oxime is sensitive to H2 pressure, where an increase in temperature favours cyclohexanone with amine/ketone condensation and subsequent reduction to dicyclohexylamine. An increase in turnover frequency was observed with decreasing (surface area weighted) mean Au size (from 7.0 to 4.3 nm) but a lower value was obtained for 3.0 nm Au (on CeO2) that is linked to suppressed H2 chemisorption (under reaction conditions) resulting from strong interaction with the partially reduced support. We establish a critical surface interplay between imine, H and –OH that governs selectivity. Au/Al2O3 exhibited the highest activity and oxime selectivity (maximum = 95%), Au/CeO2 promoted near exclusive production of cyclohexanone whereas Au/TiO2 and Au/ZrO2 generated a cyclohexylamine/cyclohexanone mixture.
Original languageEnglish
Pages (from-to)575-584
Number of pages10
JournalApplied Catalysis A: General
Volume467
Early online date16 Aug 2013
DOIs
Publication statusPublished - 2 Oct 2013

Fingerprint

Gold
Hydrogenation
Gases
Chemisorption
Catalysts
Cyclohexylamines
Transmission electron microscopy
Imines
Oximes
Catalyst selectivity
Temperature programmed desorption
Ketones
Catalyst supports
Partial pressure
Temperature
Oxides
Amines
Condensation
Porosity
Thermodynamics

Keywords

  • gas phase hydrogenation
  • nitrocyclohexane
  • cyclohexanone oxime
  • supported AU catalysts
  • thermochemical analysis
  • hydrogen partial pressure

Cite this

Gas phase hydrogenation of nitrocyclohexane over supported gold catalysts. / Wang, Xiaodong; Perret, Noémie; Keane, Mark.

In: Applied Catalysis A: General, Vol. 467, 02.10.2013, p. 575-584.

Research output: Contribution to journalArticle

Wang, Xiaodong ; Perret, Noémie ; Keane, Mark. / Gas phase hydrogenation of nitrocyclohexane over supported gold catalysts. In: Applied Catalysis A: General. 2013 ; Vol. 467. pp. 575-584.
@article{49faa4f12ac544aa93682f2f368d2fc0,
title = "Gas phase hydrogenation of nitrocyclohexane over supported gold catalysts",
abstract = "We report the first continuous (gas phase) hydrogenation of nitrocyclohexane over oxide (Al2O3, TiO2, CeO2 and ZrO2) supported Au catalysts. Thermochemical analysis has established possible thermodynamic constraints and product distribution at equilibrium. The catalysts have been characterised by temperature-programmed reduction (TPR), H2/O2 chemisorption/temperature-programmed desorption (TPD), BET surface area/porosity, X-ray diffraction (XRD) and scanning/transmission electron microscopy (STEM/TEM) measurements. The effects of space velocity (2–6 × 104 h−1), temperature (353 and 473 K) and H2 partial pressure (8 × 10−4–0.93 atm) on catalyst performance have been examined. Selectivity to the target cyclohexanone oxime is sensitive to H2 pressure, where an increase in temperature favours cyclohexanone with amine/ketone condensation and subsequent reduction to dicyclohexylamine. An increase in turnover frequency was observed with decreasing (surface area weighted) mean Au size (from 7.0 to 4.3 nm) but a lower value was obtained for 3.0 nm Au (on CeO2) that is linked to suppressed H2 chemisorption (under reaction conditions) resulting from strong interaction with the partially reduced support. We establish a critical surface interplay between imine, H and –OH that governs selectivity. Au/Al2O3 exhibited the highest activity and oxime selectivity (maximum = 95{\%}), Au/CeO2 promoted near exclusive production of cyclohexanone whereas Au/TiO2 and Au/ZrO2 generated a cyclohexylamine/cyclohexanone mixture.",
keywords = "gas phase hydrogenation, nitrocyclohexane, cyclohexanone oxime, supported AU catalysts, thermochemical analysis, hydrogen partial pressure",
author = "Xiaodong Wang and No{\'e}mie Perret and Mark Keane",
year = "2013",
month = "10",
day = "2",
doi = "10.1016/j.apcata.2013.07.061",
language = "English",
volume = "467",
pages = "575--584",
journal = "Applied Catalysis A: General",
issn = "0926-860X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Gas phase hydrogenation of nitrocyclohexane over supported gold catalysts

AU - Wang, Xiaodong

AU - Perret, Noémie

AU - Keane, Mark

PY - 2013/10/2

Y1 - 2013/10/2

N2 - We report the first continuous (gas phase) hydrogenation of nitrocyclohexane over oxide (Al2O3, TiO2, CeO2 and ZrO2) supported Au catalysts. Thermochemical analysis has established possible thermodynamic constraints and product distribution at equilibrium. The catalysts have been characterised by temperature-programmed reduction (TPR), H2/O2 chemisorption/temperature-programmed desorption (TPD), BET surface area/porosity, X-ray diffraction (XRD) and scanning/transmission electron microscopy (STEM/TEM) measurements. The effects of space velocity (2–6 × 104 h−1), temperature (353 and 473 K) and H2 partial pressure (8 × 10−4–0.93 atm) on catalyst performance have been examined. Selectivity to the target cyclohexanone oxime is sensitive to H2 pressure, where an increase in temperature favours cyclohexanone with amine/ketone condensation and subsequent reduction to dicyclohexylamine. An increase in turnover frequency was observed with decreasing (surface area weighted) mean Au size (from 7.0 to 4.3 nm) but a lower value was obtained for 3.0 nm Au (on CeO2) that is linked to suppressed H2 chemisorption (under reaction conditions) resulting from strong interaction with the partially reduced support. We establish a critical surface interplay between imine, H and –OH that governs selectivity. Au/Al2O3 exhibited the highest activity and oxime selectivity (maximum = 95%), Au/CeO2 promoted near exclusive production of cyclohexanone whereas Au/TiO2 and Au/ZrO2 generated a cyclohexylamine/cyclohexanone mixture.

AB - We report the first continuous (gas phase) hydrogenation of nitrocyclohexane over oxide (Al2O3, TiO2, CeO2 and ZrO2) supported Au catalysts. Thermochemical analysis has established possible thermodynamic constraints and product distribution at equilibrium. The catalysts have been characterised by temperature-programmed reduction (TPR), H2/O2 chemisorption/temperature-programmed desorption (TPD), BET surface area/porosity, X-ray diffraction (XRD) and scanning/transmission electron microscopy (STEM/TEM) measurements. The effects of space velocity (2–6 × 104 h−1), temperature (353 and 473 K) and H2 partial pressure (8 × 10−4–0.93 atm) on catalyst performance have been examined. Selectivity to the target cyclohexanone oxime is sensitive to H2 pressure, where an increase in temperature favours cyclohexanone with amine/ketone condensation and subsequent reduction to dicyclohexylamine. An increase in turnover frequency was observed with decreasing (surface area weighted) mean Au size (from 7.0 to 4.3 nm) but a lower value was obtained for 3.0 nm Au (on CeO2) that is linked to suppressed H2 chemisorption (under reaction conditions) resulting from strong interaction with the partially reduced support. We establish a critical surface interplay between imine, H and –OH that governs selectivity. Au/Al2O3 exhibited the highest activity and oxime selectivity (maximum = 95%), Au/CeO2 promoted near exclusive production of cyclohexanone whereas Au/TiO2 and Au/ZrO2 generated a cyclohexylamine/cyclohexanone mixture.

KW - gas phase hydrogenation

KW - nitrocyclohexane

KW - cyclohexanone oxime

KW - supported AU catalysts

KW - thermochemical analysis

KW - hydrogen partial pressure

U2 - 10.1016/j.apcata.2013.07.061

DO - 10.1016/j.apcata.2013.07.061

M3 - Article

VL - 467

SP - 575

EP - 584

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

SN - 0926-860X

ER -