Evidence of furan formation from acetaldehyde over beta-UO3

H Madhavaram, Hicham Idriss

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Furan, C4H4O, has been observed from acetaldehyde over beta -UO3 during temperature programmed desorption (TPD) with a high yield (ca. 40%) at low surface coverage. At high surface coverage crotonaldehyde, CH3CH=CHCHO (formed by beta -aldolisation of acetaldehyde), was the most dominant product. Flow experiments at P = 30 atm have indicated that one can achieve high reaction selectivity to furan. The catalyst deactivated, however, after a few hours of time on stream. X-ray diffraction analyses have shown that beta -UO3 has been reduced to a mixture of alpha -U3O8 and UO2. The catalysts could be regenerated by gas-phase O-2 at 673-773 K, 30-40 atm for 2 h. The comparison between furan formation from acetaldehyde to that from ethylene as well as fi om ethanol [J. Catal. 184 (1999) 553; Stud. Surf. Sci. Catal. 110 (1997) 265] over U oxides indicates the following. (1) beta -UO3 was far more active than alpha -U3O8 (2) Acetaldehyde gave the highest reaction yield. (3) The reaction appears to be driven by the high oxidation state of U cations (U+6) as well as the potential presence of these U+6 cations in a sixfold coordination environment, i.e. containing two vacancies to accommodate the coupling of two C2 molecules to the C4 furan product. (C) 2000 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Pages (from-to)309-315
Number of pages7
JournalCatalysis Today
Volume63
Issue number2-4
DOIs
Publication statusPublished - 25 Dec 2000

Keywords

  • furan
  • TPD
  • X-ray diffraction
  • acetaldehyde
  • URANIUM OXIDE CATALYSTS
  • TRIOXIDE PHASES
  • MIXED CATALYSTS
  • CARBON-MONOXIDE
  • SINGLE-CRYSTAL
  • OXIDATION
  • SURFACES
  • MECHANISM
  • REDUCTION
  • NEUTRON
  • Furan
  • Acetaldehyde
  • NEUTRON

Cite this

Evidence of furan formation from acetaldehyde over beta-UO3. / Madhavaram, H ; Idriss, Hicham.

In: Catalysis Today, Vol. 63, No. 2-4, 25.12.2000, p. 309-315.

Research output: Contribution to journalArticle

Madhavaram, H ; Idriss, Hicham. / Evidence of furan formation from acetaldehyde over beta-UO3. In: Catalysis Today. 2000 ; Vol. 63, No. 2-4. pp. 309-315.
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AU - Idriss, Hicham

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N2 - Furan, C4H4O, has been observed from acetaldehyde over beta -UO3 during temperature programmed desorption (TPD) with a high yield (ca. 40%) at low surface coverage. At high surface coverage crotonaldehyde, CH3CH=CHCHO (formed by beta -aldolisation of acetaldehyde), was the most dominant product. Flow experiments at P = 30 atm have indicated that one can achieve high reaction selectivity to furan. The catalyst deactivated, however, after a few hours of time on stream. X-ray diffraction analyses have shown that beta -UO3 has been reduced to a mixture of alpha -U3O8 and UO2. The catalysts could be regenerated by gas-phase O-2 at 673-773 K, 30-40 atm for 2 h. The comparison between furan formation from acetaldehyde to that from ethylene as well as fi om ethanol [J. Catal. 184 (1999) 553; Stud. Surf. Sci. Catal. 110 (1997) 265] over U oxides indicates the following. (1) beta -UO3 was far more active than alpha -U3O8 (2) Acetaldehyde gave the highest reaction yield. (3) The reaction appears to be driven by the high oxidation state of U cations (U+6) as well as the potential presence of these U+6 cations in a sixfold coordination environment, i.e. containing two vacancies to accommodate the coupling of two C2 molecules to the C4 furan product. (C) 2000 Elsevier Science B.V. All rights reserved.

AB - Furan, C4H4O, has been observed from acetaldehyde over beta -UO3 during temperature programmed desorption (TPD) with a high yield (ca. 40%) at low surface coverage. At high surface coverage crotonaldehyde, CH3CH=CHCHO (formed by beta -aldolisation of acetaldehyde), was the most dominant product. Flow experiments at P = 30 atm have indicated that one can achieve high reaction selectivity to furan. The catalyst deactivated, however, after a few hours of time on stream. X-ray diffraction analyses have shown that beta -UO3 has been reduced to a mixture of alpha -U3O8 and UO2. The catalysts could be regenerated by gas-phase O-2 at 673-773 K, 30-40 atm for 2 h. The comparison between furan formation from acetaldehyde to that from ethylene as well as fi om ethanol [J. Catal. 184 (1999) 553; Stud. Surf. Sci. Catal. 110 (1997) 265] over U oxides indicates the following. (1) beta -UO3 was far more active than alpha -U3O8 (2) Acetaldehyde gave the highest reaction yield. (3) The reaction appears to be driven by the high oxidation state of U cations (U+6) as well as the potential presence of these U+6 cations in a sixfold coordination environment, i.e. containing two vacancies to accommodate the coupling of two C2 molecules to the C4 furan product. (C) 2000 Elsevier Science B.V. All rights reserved.

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KW - MIXED CATALYSTS

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KW - SINGLE-CRYSTAL

KW - OXIDATION

KW - SURFACES

KW - MECHANISM

KW - REDUCTION

KW - NEUTRON

KW - Furan

KW - Acetaldehyde

KW - NEUTRON

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EP - 315

JO - Catalysis Today

JF - Catalysis Today

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ER -