Hydrophobic titania-silica mixed oxides for the catalytic epoxidation of cyclooctene

Lucia E. Manangon-Perugachi, Alvise Vivian, Pierre Eloy, Damien P. Debecker, Carmela Aprile, Eric M. Gaigneaux

Research output: Contribution to journalReview article

Abstract

Titania-silica (TiO 2 -SiO 2 ) mixed oxides are known catalysts for the epoxidation of olefins. It has been demonstrated that their active sites consist in isolated framework Ti atoms. However, the latter species are only obtained when Ti loading is low, limiting the number of active sites and the catalytic performances. Thus, the need to search other approaches to boost them. We succeeded improving the catalytic activity of TiO 2 -SiO 2 mixed oxides in the epoxidation of cyclooctene with hydrogen peroxide by introducing hydrophobic organic moieties at their surface. Hydrophobic TiO 2 -SiO 2 mixed oxides were prepared through a one-pot sol-gel method. Titanium butoxide (TiBut) and tetraethoxy silane (TEOS) were used as the Ti and Si precursors respectively. Hydrophobization was achieved by substituting a fraction of TEOS in the synthesis by methyltriethoxy silane (MTES). The characterization of the Ti species was performed by FTIR, DRUV, and XPS, confirming the presence of significant amount of the active framework Ti. The methylation degree was evaluated by Solid State 29 Si-NMR and TGA-MS. Hydrophobic TiO 2 -SiO 2 performed better in the epoxidation reaction than a fully inorganic more hydrophilic TiO 2 -SiO 2 prepared without MTES. A too high methylation degree of the catalysts is however detrimental. Our contribution allows elucidating the debate in literature about the consequence of hydrophobization of epoxidation catalysts on their performance.

Original languageEnglish
Number of pages9
JournalCatalysis Today
DOIs
Publication statusPublished - 1 Jan 2019

Fingerprint

Silanes
Epoxidation
Silicon Dioxide
Oxides
Titanium
Silica
Methylation
Catalysts
Alkenes
Hydrogen peroxide
Hydrogen Peroxide
Sol-gel process
Olefins
Catalyst activity
X ray photoelectron spectroscopy
Nuclear magnetic resonance
Atoms
titanium dioxide

Keywords

  • Framework-titanium
  • Methyl-functionalization
  • Olefin epoxidation
  • One-pot hydrolytic sol-gel
  • Surface hydrophobicity
  • TiO -SiO mixed oxide

Cite this

Manangon-Perugachi, Lucia E. ; Vivian, Alvise ; Eloy, Pierre ; Debecker, Damien P. ; Aprile, Carmela ; Gaigneaux, Eric M. / Hydrophobic titania-silica mixed oxides for the catalytic epoxidation of cyclooctene. In: Catalysis Today. 2019.
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abstract = "Titania-silica (TiO 2 -SiO 2 ) mixed oxides are known catalysts for the epoxidation of olefins. It has been demonstrated that their active sites consist in isolated framework Ti atoms. However, the latter species are only obtained when Ti loading is low, limiting the number of active sites and the catalytic performances. Thus, the need to search other approaches to boost them. We succeeded improving the catalytic activity of TiO 2 -SiO 2 mixed oxides in the epoxidation of cyclooctene with hydrogen peroxide by introducing hydrophobic organic moieties at their surface. Hydrophobic TiO 2 -SiO 2 mixed oxides were prepared through a one-pot sol-gel method. Titanium butoxide (TiBut) and tetraethoxy silane (TEOS) were used as the Ti and Si precursors respectively. Hydrophobization was achieved by substituting a fraction of TEOS in the synthesis by methyltriethoxy silane (MTES). The characterization of the Ti species was performed by FTIR, DRUV, and XPS, confirming the presence of significant amount of the active framework Ti. The methylation degree was evaluated by Solid State 29 Si-NMR and TGA-MS. Hydrophobic TiO 2 -SiO 2 performed better in the epoxidation reaction than a fully inorganic more hydrophilic TiO 2 -SiO 2 prepared without MTES. A too high methylation degree of the catalysts is however detrimental. Our contribution allows elucidating the debate in literature about the consequence of hydrophobization of epoxidation catalysts on their performance.",
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Hydrophobic titania-silica mixed oxides for the catalytic epoxidation of cyclooctene. / Manangon-Perugachi, Lucia E.; Vivian, Alvise; Eloy, Pierre; Debecker, Damien P.; Aprile, Carmela; Gaigneaux, Eric M.

In: Catalysis Today, 01.01.2019.

Research output: Contribution to journalReview article

TY - JOUR

T1 - Hydrophobic titania-silica mixed oxides for the catalytic epoxidation of cyclooctene

AU - Manangon-Perugachi, Lucia E.

AU - Vivian, Alvise

AU - Eloy, Pierre

AU - Debecker, Damien P.

AU - Aprile, Carmela

AU - Gaigneaux, Eric M.

PY - 2019/1/1

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N2 - Titania-silica (TiO 2 -SiO 2 ) mixed oxides are known catalysts for the epoxidation of olefins. It has been demonstrated that their active sites consist in isolated framework Ti atoms. However, the latter species are only obtained when Ti loading is low, limiting the number of active sites and the catalytic performances. Thus, the need to search other approaches to boost them. We succeeded improving the catalytic activity of TiO 2 -SiO 2 mixed oxides in the epoxidation of cyclooctene with hydrogen peroxide by introducing hydrophobic organic moieties at their surface. Hydrophobic TiO 2 -SiO 2 mixed oxides were prepared through a one-pot sol-gel method. Titanium butoxide (TiBut) and tetraethoxy silane (TEOS) were used as the Ti and Si precursors respectively. Hydrophobization was achieved by substituting a fraction of TEOS in the synthesis by methyltriethoxy silane (MTES). The characterization of the Ti species was performed by FTIR, DRUV, and XPS, confirming the presence of significant amount of the active framework Ti. The methylation degree was evaluated by Solid State 29 Si-NMR and TGA-MS. Hydrophobic TiO 2 -SiO 2 performed better in the epoxidation reaction than a fully inorganic more hydrophilic TiO 2 -SiO 2 prepared without MTES. A too high methylation degree of the catalysts is however detrimental. Our contribution allows elucidating the debate in literature about the consequence of hydrophobization of epoxidation catalysts on their performance.

AB - Titania-silica (TiO 2 -SiO 2 ) mixed oxides are known catalysts for the epoxidation of olefins. It has been demonstrated that their active sites consist in isolated framework Ti atoms. However, the latter species are only obtained when Ti loading is low, limiting the number of active sites and the catalytic performances. Thus, the need to search other approaches to boost them. We succeeded improving the catalytic activity of TiO 2 -SiO 2 mixed oxides in the epoxidation of cyclooctene with hydrogen peroxide by introducing hydrophobic organic moieties at their surface. Hydrophobic TiO 2 -SiO 2 mixed oxides were prepared through a one-pot sol-gel method. Titanium butoxide (TiBut) and tetraethoxy silane (TEOS) were used as the Ti and Si precursors respectively. Hydrophobization was achieved by substituting a fraction of TEOS in the synthesis by methyltriethoxy silane (MTES). The characterization of the Ti species was performed by FTIR, DRUV, and XPS, confirming the presence of significant amount of the active framework Ti. The methylation degree was evaluated by Solid State 29 Si-NMR and TGA-MS. Hydrophobic TiO 2 -SiO 2 performed better in the epoxidation reaction than a fully inorganic more hydrophilic TiO 2 -SiO 2 prepared without MTES. A too high methylation degree of the catalysts is however detrimental. Our contribution allows elucidating the debate in literature about the consequence of hydrophobization of epoxidation catalysts on their performance.

KW - Framework-titanium

KW - Methyl-functionalization

KW - Olefin epoxidation

KW - One-pot hydrolytic sol-gel

KW - Surface hydrophobicity

KW - TiO -SiO mixed oxide

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DO - 10.1016/j.cattod.2019.05.020

M3 - Review article

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JO - Catalysis Today

JF - Catalysis Today

SN - 0920-5861

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