Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home prepared titanium dioxide. 1: Selectivity enhancement by aliphatic alcohols

Vincenzo Augugliaro, Leonardo Palmisano, Vittorio Loddo, Giovanni Palmisano, Francesco Parrino, María José López-Muñoz, Horst Kisch, Sedat Yurdakal, Francesco Parrino, Carlos Márquez-Álvarez

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Abstract

Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterisation of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28% (BA conversion: 50%) and 41% (MBA conversion: 65%), about four times higher than those of commercial TiO2. The addition of an aliphatic alcohol (methanol, ethanol, 2-propanol or tert-butanol) in small amounts with respect to water decreased the overall oxidation rate of aromatic alcohols but enhanced the selectivity for aldehyde formation up to 1.5 times. The reactivity results suggest that: (i) the aromatic alcohol molecules interact with the TiO2 surface in different ways that eventually determine two parallel reaction pathways (partial oxidation or mineralization); and (ii) the aliphatic alcohols preferentially compete with aromatic alcohols for the mineralizing pathway.
Lingua originaleEnglish
pagine (da-a)182-188
Numero di pagine7
RivistaApplied Catalysis A: General
Volume349
Stato di pubblicazionePublished - 2008

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Aldehydes
Titanium dioxide
Suspensions
Alcohols
Oxidation
Benzyl Alcohol
Catalysts
tert-Butyl Alcohol
2-Propanol
Catalyst selectivity
titanium dioxide
Methanol
Hydrolysis
Ethanol
Porosity
Propanol
Butenes
Scanning electron microscopy
Molecules
Water

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Process Chemistry and Technology

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title = "Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home prepared titanium dioxide. 1: Selectivity enhancement by aliphatic alcohols",
abstract = "Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterisation of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28{\%} (BA conversion: 50{\%}) and 41{\%} (MBA conversion: 65{\%}), about four times higher than those of commercial TiO2. The addition of an aliphatic alcohol (methanol, ethanol, 2-propanol or tert-butanol) in small amounts with respect to water decreased the overall oxidation rate of aromatic alcohols but enhanced the selectivity for aldehyde formation up to 1.5 times. The reactivity results suggest that: (i) the aromatic alcohol molecules interact with the TiO2 surface in different ways that eventually determine two parallel reaction pathways (partial oxidation or mineralization); and (ii) the aliphatic alcohols preferentially compete with aromatic alcohols for the mineralizing pathway.",
keywords = "Photocatalysis, TiO2, Aromatic alcohols, Aliphatic alcohol, Selective oxidation",
author = "Vincenzo Augugliaro and Leonardo Palmisano and Vittorio Loddo and Giovanni Palmisano and Francesco Parrino and L{\'o}pez-Mu{\~n}oz, {Mar{\'i}a Jos{\'e}} and Horst Kisch and Sedat Yurdakal and Francesco Parrino and Carlos M{\'a}rquez-{\'A}lvarez",
year = "2008",
language = "English",
volume = "349",
pages = "182--188",
journal = "Applied Catalysis A: General",
issn = "0926-860X",
publisher = "Elsevier",

}

TY - JOUR

T1 - Photocatalytic oxidation of aromatic alcohols to aldehydes in aqueous suspension of home prepared titanium dioxide. 1: Selectivity enhancement by aliphatic alcohols

AU - Augugliaro, Vincenzo

AU - Palmisano, Leonardo

AU - Loddo, Vittorio

AU - Palmisano, Giovanni

AU - Parrino, Francesco

AU - López-Muñoz, María José

AU - Kisch, Horst

AU - Yurdakal, Sedat

AU - Parrino, Francesco

AU - Márquez-Álvarez, Carlos

PY - 2008

Y1 - 2008

N2 - Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterisation of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28% (BA conversion: 50%) and 41% (MBA conversion: 65%), about four times higher than those of commercial TiO2. The addition of an aliphatic alcohol (methanol, ethanol, 2-propanol or tert-butanol) in small amounts with respect to water decreased the overall oxidation rate of aromatic alcohols but enhanced the selectivity for aldehyde formation up to 1.5 times. The reactivity results suggest that: (i) the aromatic alcohol molecules interact with the TiO2 surface in different ways that eventually determine two parallel reaction pathways (partial oxidation or mineralization); and (ii) the aliphatic alcohols preferentially compete with aromatic alcohols for the mineralizing pathway.

AB - Oxygenated aqueous suspensions of home-prepared (HP) and commercial TiO2 catalysts were used in a batch photoreactor for carrying out the oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) under different operative conditions. HP catalysts were synthesized from TiCl4 and underwent a hydrolysis treatment of different times under mild conditions. The textural characterisation of catalysts was carried out with XRD, SEM observations, BET surface area and porosity measurements. For both alcohols the main oxidation products were the corresponding aromatic aldehydes and CO2. The HP catalysts exhibited selectivity values towards the aldehyde production up to 28% (BA conversion: 50%) and 41% (MBA conversion: 65%), about four times higher than those of commercial TiO2. The addition of an aliphatic alcohol (methanol, ethanol, 2-propanol or tert-butanol) in small amounts with respect to water decreased the overall oxidation rate of aromatic alcohols but enhanced the selectivity for aldehyde formation up to 1.5 times. The reactivity results suggest that: (i) the aromatic alcohol molecules interact with the TiO2 surface in different ways that eventually determine two parallel reaction pathways (partial oxidation or mineralization); and (ii) the aliphatic alcohols preferentially compete with aromatic alcohols for the mineralizing pathway.

KW - Photocatalysis, TiO2, Aromatic alcohols, Aliphatic alcohol, Selective oxidation

UR - http://hdl.handle.net/10447/47984

M3 - Article

VL - 349

SP - 182

EP - 188

JO - Applied Catalysis A: General

JF - Applied Catalysis A: General

SN - 0926-860X

ER -