Solvent-free liquid phase oxidation of benzyl alcohol to benzaldehyde by molecular oxygen using non-noble transition metal containing hydrotalcite-like solid catalysts

Choudhary, Vasant R.; Chaudhari, Pankaj A.; Narkhede, Vijay

doi:10.1016/s1566-7367(03)00027-x

Cited by 194 publications

(64 citation statements)

References 14 publications

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“…The advantage of using such oxidants lies in the formation of water as the sole co-product and the low cost of the oxygen/air. Different catalysts (homogeneous and heterogeneous) have been investigated in the alcohol oxidation using molecular oxygen or hydrogen peroxide in the liquid phase [4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Au–Pd/AC as catalysts for alcohol oxidation: Effect of reaction parameters on catalytic activity and selectivity

Villa

Janjic

Spontoni

et al. 2009

Applied Catalysis A: General

153

119

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The oxidation of different alcohols with molecular oxygen in water has been investigated using a range of activated carbon-supported Au-Pd bimetallic catalysts. The effect of the Au-Pd ratio on the conversion and selectivity was observed and a synergistic effect is present in a large range of the Au-Pd ratio, being maximized for Au80-Pd20 composition instead of Au90-Pd10 shown in glycerol oxidation [1]. Moreover the enhancement of conversion observed by adding a base resulted greater for gold-rich catalysts rather than for palladium-rich ones. The effect of the alcohol concentration and the metal/substrate ratio in the presence or the absence of the base was also studied revealing substantial differences in terms of both activity and selectivity. At 1 M concentration under biphasic conditions benzyl alcohol has been selectively oxidized to benzaldehyde (S90=98%) even in the presence of NaOH with a TOF of 18000h -1 using Au60-Pd40/AC as the catalyst.

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Section: Introductionmentioning

confidence: 99%

Au–Pd/AC as catalysts for alcohol oxidation: Effect of reaction parameters on catalytic activity and selectivity

Villa

Janjic

Spontoni

et al. 2009

Applied Catalysis A: General

153

119

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“…The influence of reaction temperature on the aerial oxidation of benzyl alcohol is also explored by varying the temperature from 20 • C to 100 • C while using ZnO x (1%)-MnCO 3 /(1%)HRG as catalyst. The obtained results including benzyl alcohol conversion, specific activity, and benzaldehyde selectivity at various temperatures (20,40,60,80, and 100 • C) were compiled in Table 4 and represented in Figure 8. According to Table 4, the benzyl alcohol conversion strongly depends on the reaction temperature.…”

Section: Influence Of Temperaturementioning

confidence: 99%

“…The oxidation rate of the reaction is slower for derivatives of benzyl alcohol containing electron-withdrawing substituents such as (-Cl, -F, -NO2, and -CF3) ( Table 7, entries 9, 10, 14 and 17). Steric hindrance is also a significant factor that affects the rate of the oxidation processes, the bulky groups such as (4-CF3, 2,3,4-TriOMe, 2,4-DiCl, and 2,3,4,5,6-Pentaflouro) attached to the benzyl alcohol decreases the rate of oxidation reaction and required longer reaction time owing to the steric resistance that hinder the oxidation of the bulky substituents benzylic alcohols (Table 7, entries [17][18][19][20] [115]. Moreover, the results clearly revealed that the position (para-, ortho-and meta-) of electron donating groups in benzylic alcohols played also an important role in the activity of the catalytic oxidation of alcohols [85,98].…”

Section: Oxidation Of Wide Range Of Benzylic and Aliphatic Alcoholsmentioning

confidence: 99%

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

et al. 2017

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Nanocomposites of highly reduced graphene oxide (HRG) and ZnO x nanoparticles doped manganese carbonate containing different percentages of HRG were prepared via a facile co-precipitation method.The prepared sample calcined at 300 • C yielded i.e., ZnO x (1%)-MnCO 3 /(X%)HRG (where X = 0-7), calcination at 400 • C and 500 • C, yielded different manganese oxides i.e., ZnO x (1%)-MnO 2 /(X%)HRG and ZnO x (1%)-Mn 2 O 3 /(X%)HRG respectively. The prepared catalyst were subjected to catalytic evaluation and a comparative catalytic study between carbonates and oxides for the liquid-phase aerobic oxidation of benzylic alcohols to corresponding aldehydes using molecular oxygen as an eco-friendly oxidant without adding additives or bases. The influence of various parameters such as percentage of HRG, reaction time, catalyst amount, calcination and reaction temperature was systematically examined to optimize reaction conditions using oxidation of benzyl alcohol as a substrate model. It was found that the catalytic performance is remarkably enhanced after using HRG as catalyst co-dopant for the aerobic oxidation of alcohols, possibly owing to the presence of carbon defects and oxygenated functional groups on HRG surface. The as-synthesized catalysts were characterized by SEM, EDX, XRD, Raman, TGA, BET, and FT-IR. Under optimal conditions, the catalyst with composition ZnO x (1%)-MnCO 3 /(1%)HRG calcined at 300 • C exhibited remarkable specific activity (57.1 mmol·g −1 ·h −1 ) with 100% conversion of benzyl alcohol and more than 99% product selectivity within extremely short time (7 min). The as-prepared catalyst was re-used up to five consecutive times without significant decrease in its activity and selectivity. To the best of our knowledge, the achieved specific activity is the highest so far compared to the earlier reported catalysts used for the benzyl alcohol oxidation. A wide range of substituted benzylic and aliphatic alcohols were selectively oxidized into their corresponding aldehydes with complete convertibility and selectivity in short reaction times without over-oxidation to the acids. Due to their significant low cost, superior reproducibility, excellent catalytic efficiency, the ZnO x (1%)-MnCO 3 /(X%)HRG nanocomposites possess several application prospect in other organic chemistry reactions.

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“…8,9 Most of this recent research though is devoted to solvent-free processes. 10,11 Nevertheless, solvents can play beneficial roles in promoting the solubility of oxygen in the reaction media 12 or by promoting the reactivity of functional groups over metal or metal oxide interfaces. 13 However, these studies are mainly centred on polarity effects.…”

Section: Introductionmentioning

confidence: 99%

Water as a catalytic switch in the oxidation of aryl alcohols by polymer incarcerated rhodium nanoparticles

Weston

Miyamura

Yasukawa

et al. 2017

Catal. Sci. Technol.

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One of the major goals in the oxidation of organic substrates, and especially for alcohol oxidation, is the use of molecular oxygen as the oxidant under mild conditions. Here we report the synthesis and testing of Rh polymer incarcerated catalysts, using a metal so far not used for alcohol oxidation reactions, in which the catalytic activity towards aryl alcohol oxidation, for substrates like 1-phenylethanol and benzyl alcohol, is switched on by the addition of water as co-solvent in toluene. This is done by using air as oxidant at atmospheric pressure, in one of the mildest reaction conditions reported for this class of reaction. The promoting effect of water to higher conversions was observed also for rhodium over alumina supported catalysts, which were used as a benchmark allowing in all cases high conversion and selectivity to the ketone or the aldehyde within a short reaction time. The effect of water was explained as a medium capable to promote the oxidation of the alcohol to the ketone in a biphasic system assisted by phase transfer catalysis. This is particularly relevant for alcohols like 1-phenylethanol or benzyl alcohol that are not soluble in water at room temperature, and for which alternative oxidation routes are needed, as well as to switch on the catalytic activity of metal nanoparticles in a facile and green manner for the activation of molecular oxygen. Aliphatic alcohols like 1-octanol and 3-octanol were also tested, still showing Rh based catalysts as promising materials for this reaction if toluene only was used as solvent instead.2

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Solvent-free liquid phase oxidation of benzyl alcohol to benzaldehyde by molecular oxygen using non-noble transition metal containing hydrotalcite-like solid catalysts

Cited by 194 publications

References 14 publications

Au–Pd/AC as catalysts for alcohol oxidation: Effect of reaction parameters on catalytic activity and selectivity

Au–Pd/AC as catalysts for alcohol oxidation: Effect of reaction parameters on catalytic activity and selectivity

Mixed Zinc/Manganese on Highly Reduced Graphene Oxide: A Highly Active Nanocomposite Catalyst for Aerial Oxidation of Benzylic Alcohols

Water as a catalytic switch in the oxidation of aryl alcohols by polymer incarcerated rhodium nanoparticles

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