Direct Oxidation of Benzene to Phenol Catalyzed by Vanadium Substituted Heteropolymolybdic Acid

Tang, Ying; Zhang, Jin

doi:10.1007/s11243-005-6412-1

Cited by 27 publications

(14 citation statements)

References 30 publications

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“…Further increasing vanadium content leads to decrease the yield of phenol. The high vanadium content of 14.0V-HMS is responsible for the high decomposition and low efficiency of H 2 O 2 , leading to low phenol yield as well as over-oxidation of phenol [21]. Lemke et al [11] reported that mesoporous siliceous catalysts with low vanadium content are more efficient than the catalysts with high vanadium content, which is believed that the consecutive oxidation reactions are suppressed by isolated VO x sites on the catalysts with low vanadium content.…”

Section: Catalytic Testmentioning

confidence: 99%

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Synthesis and Characterization of V-HMS Employed for Catalytic Hydroxylation of Benzene

et al. 2009

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V-HMS catalysts with different vanadium content have been prepared by co-synthesis method using dodecylamine as template. The isolated VO 4 species are successfully incorporated into the framework of HMS for the samples with low vanadium content. The effect of various reaction conditions on the hydroxylation of benzene to phenol with H 2 O 2 as oxidant in aqueous acetic acid solvent was investigated where the yield of phenol achieves 11.1% under the optimized condition.

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Section: Catalytic Testmentioning

confidence: 99%

“…But the conversion of benzene nearly increases with increasing reaction temperature. The high reaction temperature may results in deep oxidation of phenol [21]. be consumed during the deep oxidation of benzene and its self-decomposition [22].…”

Section: Catalytic Testmentioning

confidence: 99%

Synthesis and Characterization of V-HMS Employed for Catalytic Hydroxylation of Benzene

et al. 2009

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“…Hence the synthesis of phenol by direct hydroxylation of benzene is attractive both economically and energetically. Benzene oxidation using hydrogen peroxide has been explored by various researchers [1][2][3]. Transition metal catalysts have also been demonstrated by researchers for the reaction in presence of comparatively costly oxygen as the oxidant, and a reducing agent [4,5].…”

Section: Introductionmentioning

confidence: 99%

Single step conversion of benzene to phenol using hydrogen peroxide over modified V2O5–Al2O3 systems

Shijina

Renuka

2009

React Kinet Catal Lett

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Alumina supported vanadia catalysts were prepared by the wet impregnation method. The effect of vanadium content was investigated with 1.92-16.93 wt% V 2 O 5 loading over the support. Physical characterization of the catalysts was done by techniques such as energy dispersive X-ray (EDX), X-ray diffraction (XRD), BET surface area measurement, FTIR spectroscopy and temperature programmed reduction (TPR) studies. Characterization techniques have revealed that vanadia is well dispersed over alumina up to 13.91 wt%, after which aggregation into vanadia crystallites was observed. Single step liquid-phase hydroxylation of benzene to phenol by hydrogen peroxide was studied over these catalysts. The phenol selectivity can be attributed to amorphous surface vanadyl units in the catalysts. The supported analogues were modified with oxides of iron and cerium. Ceria incorporation to alumina enhanced the activity towards hydroxylation of benzene.

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“…Therefore, POMs are useful catalysts for liquid-phase oxidation of hydrocarbons. In recent years, there has been an increasing interest in transition metal-substituted polyoxometalates (TMSPs) as catalysts for the oxidation of organic substrates, in which the substituted vanadium is known as the most active metal species for the hydroxylation of benzene [12,13] . Liu et al used TMSP compounds [(C 4 H 9 ) 4 N] 5 [PW 11 CuO 39 (H 2 O)] as the catalyst for the liquid-phase hydroxylation of benzene to phenol by molecular oxygen with ascorbic acid as a reducing agent in an acetone/sulfolane/water-mixed solvent, showing 9.2% of benzene conversion and 91.8% of selectivity to phenol at 323 K for 12 h [14] .…”

Section: Introductionmentioning

confidence: 99%

Pyridine-H5PMo10V2O40 hybrid catalysts for liquid-phase hydroxylation of benzene to phenol with molecular oxygen

Zhang

Piao

et al. 2009

Sci. China Ser. B-Chem.

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Pyridine(Py)-modified Keggin-type vanadium-substituted heteropoly acids (Py n PMo 10 V 2 O 40 , n=1 to 5) were prepared by a precipitation method as organic/inorganic hybrid catalysts for direct hydroxylation of benzene to phenol in a pressured batch reactor and their structures were detected by FT-IR. Among various catalysts, Py 3 PMo 10 V 2 O 40 exhibits the highest catalytic activity (yield of phenol, 11.5%), without observing the formation of catechol, hydroquinone and benzoquinone in the reaction with 80 vol% aqueous acetic acid, molecular oxygen and ascorbic acid used as the solvent, oxidant and reducing reagent, respectively. Influences of reaction temperature, reaction time, oxygen pressure, amount of ascorbic acid and catalyst on yield of phenol were investigated to obtain the optimal reaction conditions for phenol formation. Pyridine can greatly promote the catalytic activity of the Py-free catalyst (H 5 PMo 10 V 2 O 40 ), mostly because the organic π electrons in the hybrid catalyst may extend their conjugation to the inorganic framework of heteropoly acid and dramatically modify the redox properties, at the same time, pyridine adsorbed on heteropoly acids can promote the effect of "pseudo-liquid phase", thus accounting for the enhancement of phenol yield.hydroxylation, benzene, organic/inorganic hybrid catalyst, phenol, heteropoly acid, pyridine

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Direct Oxidation of Benzene to Phenol Catalyzed by Vanadium Substituted Heteropolymolybdic Acid

Cited by 27 publications

References 30 publications

Synthesis and Characterization of V-HMS Employed for Catalytic Hydroxylation of Benzene

Synthesis and Characterization of V-HMS Employed for Catalytic Hydroxylation of Benzene

Single step conversion of benzene to phenol using hydrogen peroxide over modified V2O5–Al2O3 systems

Pyridine-H5PMo10V2O40 hybrid catalysts for liquid-phase hydroxylation of benzene to phenol with molecular oxygen

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