Selective photocatalytic oxidation of 4-substituted aromatic alcohols in water with rutile TiO2 prepared at room temperature

Yurdakal, Sedat; Palmisano, Giovanni; Loddo, Vittorio; Alagöz, Oğuzhan; Augugliaro, Vincenzo; Palmisano, Leonardo

doi:10.1039/b819862d

Cited by 168 publications

(112 citation statements)

References 27 publications

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“…Merck performance in term of selectivity was similar to P25, but reaction rate was slower. This behavior is in accord with previous results obtained for selective oxidation of other alcohols to the corresponding aldehyde [2,24,25].…”

Section: Resultssupporting

confidence: 82%

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Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

Bellardita

Loddo

Palmisano

et al. 2014

Applied Catalysis B: Environmental

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a b s t r a c tPiperonal (heliotropine or 3,4-methylenedioxybenzaldehyde) has been synthesized by oxidizing piperonyl alcohol in aqueous UV-irradiated TiO 2 suspensions. This compound was identified by GC-MS chromatography, 1 H NMR and melting point determination. The other products of the photoprocess were 1,3-bis(3,4-(methylenedioxy)benzyl) ether (found in traces) and CO 2 , derived from the parallel pathway of photo-mineralization. Commercial and home-prepared TiO 2 samples have been tested and the best selectivity (ca. 35%) was obtained by using the home-prepared ones. The reported green process allows to obtain an added value product (piperonal), upon partial oxidation of a cheap reagent.

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Section: Resultssupporting

confidence: 82%

“…Home prepared samples were obtained from an aqueous TiO 2 sol synthesized by controlled hydrolysis of TiCl 4 , later being either boiled [24] (HP0.5) or kept at room temperature (HPRT) [25]. Another sample was obtained by heating at 373 K an aqueous TiO 2 sol obtained from TiOSO 4 (HP873S) [26].…”

Section: Samples Preparationmentioning

confidence: 99%

Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

Bellardita

Loddo

Palmisano

et al. 2014

Applied Catalysis B: Environmental

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“…[28,29] By using the most selective HPR photocatalyst, the selective photocatalytic oxidation of benzyl alcohol (BA), 4-methylbenzyl alcohol (MeBA), and 4-nitrobenzyl alcohol (NBA) to the corresponding benzaldehydes was also carried out in order to investigate the influence of the substituent group on the partial oxidation rate and selectivity. [30] The results are reported in Table 3, together with those obtained with a commercial rutile TiO 2 sample (Sigma Aldrich, SA). In reference to the oxidation rate, the reaction times needed to achieve 50 % conversion of alcohol decreased in the order BA > MeBA > MBA, while time was longer from BA to NBA.…”

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confidence: 98%

“…The selectivity to aldehyde was determined for 50 % conversion of alcohol. [30] [a] Reaction time needed for 50 % alcohol conversion.…”

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confidence: 99%

Green Oxidation of Alcohols to Carbonyl Compounds by Heterogeneous Photocatalysis

Augugliaro

Palmisano

2010

ChemSusChem

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The selective conversion of alcohols to carbonyl compounds is essential for the preparation of fragrances, food additives, and many organic intermediates.[1] This transformation is carried out by catalytic processes that are of fundamental importance in synthetic chemistry.[2] Catalytic oxidation has long been carried out in environmentally harmful organic solvents (often chlorinated ones) at high temperatures and pressures by employing stoichiometric amounts of various inorganic oxidants, for example chromate and permanganate species, that play the role of oxygen donors. The latter oxidants are not only expensive and toxic but also produce large amounts of dangerous wastes, so that investigations have been concerned with substituting them for safer systems.In recent years, significant progress has been made in the development of effective catalytic processes for the aerobic oxidation of alcohols [3] with environmentally benign and inexpensive oxidants such as oxygen or air. Typically, the aerobic oxidation of alcohols involves the use of catalysts based on platinum-group metals and transition metal compounds. The latter are (1) transition metal complexes, which comprise a central metal atom and surrounding organic ligand(s); and (2) inorganic catalysts, mainly polyoxometalates [4,5] (POMs), typically oxides of molybdenum, tungsten, and vanadium. POMs are well-defined early transition metal-oxygen clusters with unique structural characteristics and catalytic properties. [6,7] Interestingly, many POMs share photochemical characteristics very similar to those of semiconductor photocatalysts, so that POMs represent the analogues of semiconductor metal oxides.[8] According to thermodynamics, an alcohol molecule with singlet electronic configuration cannot directly react with an unactivated dioxygen molecule, which has a triplet electronic configuration.[9] The working mechanism for all metal oxidation catalysts is that the metal atom mediates the electron transfer, and thereby induces the formation of singlet oxygen.In this respect, a wide range of homogeneous metal catalysts has been found capable to use molecular oxygen as the only oxidant. [10][11][12][13] For example, a water-soluble palladium(II) batho-phenanthroline complex has been used as catalyst at a pressure of 30 bar and a temperature of 373.16 K for the aerobic oxidation of a wide range of alcohols to aldehydes, ketones, and carboxylic acids in a biphasic water/alcohol system.[14] The alcohol conversion was almost complete and the yield of carbonyl compounds was in the range 79-90 %, depending on the substrate.The use of homogeneous catalysts, however, offers obvious disadvantages over heterogeneous systems with respect to ease of handling and catalyst recycling. A wide range of supported platinum and palladium catalysts has long been reported to exhibit high catalytic performance in the oxidation of alcohols.[15-17] Au/Pd-TiO 2 catalysts showing high turnover frequencies (up to 270 000 turnovers per hour) have been also proposed.[18] These catalysts, u...

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“…Metal oxide based catalysts such as TiO2, [11][12][13] Nb2O5, 14 and ZnO 15 have been well explored for the alcohol oxidation in presence of UV irradiation. Incorporation of various noble metals including Au, 16 Pd, 17 and Pt 18,19 on different photoactive catalyst supports has been reported to achieve improved activities even under visible light conditions.…”

Section: Introductionmentioning

confidence: 99%

Mild ultrasound-assisted synthesis of TiO 2 supported on magnetic nanocomposites for selective photo-oxidation of benzyl alcohol

Colmenares

Ouyang

Ojeda

et al. 2016

Applied Catalysis B: Environmental

115

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Mild ultrasound-assisted synthesis of TiO2 supported on magnetic nanocomposites for selective photo-oxidation of benzyl alcohol, Applied Catalysis B, Environmental http://dx.doi.org/10. 1016/j.apcatb.2015.10.034 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Selective photocatalytic oxidation of 4-substituted aromatic alcohols in water with rutile TiO2 prepared at room temperature

Cited by 168 publications

References 27 publications

Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

Green Oxidation of Alcohols to Carbonyl Compounds by Heterogeneous Photocatalysis

Mild ultrasound-assisted synthesis of TiO 2 supported on magnetic nanocomposites for selective photo-oxidation of benzyl alcohol

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