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Choudhary, Vasant R.; Dumbre, Deepa K.; Narkhede, Vijay; Jana, Suman K.

doi:10.1023/a:1022620203071

Cited by 68 publications

(38 citation statements)

References 5 publications

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“…Comparison of the catalytic activity of PS-(QBIM) 2 Cu(II) with other reported systems (Table 7) reveals that the present system exhibits superior catalytic activity [8,21,33,34]. Heterogeneity and recycling tests A heterogeneity test was performed by taking 0.02 mmol of the catalyst plus 5.0 mmol of cyclohexanol with a 1:1 substrate/TBHP ratio at 60°C in acetonitrile.…”

Section: Scheme 1 Oxidation Of Various Alcoholsmentioning

confidence: 96%

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A polymer-supported diacetatobis(2-quinolylbenzimidazole)copper(II) complex as an efficient catalyst for oxidation of alcohols with tert-butyl hydroperoxide

Shilpa

Gayathri

2012

Transition Met Chem

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A polymer-supported diacetatobis(2-quinolylbenzimidazole)copper(II) complex [PS-(QBIM) 2 Cu(II)] was synthesized by functionalization of chloromethylated polystyrene cross-linked with 6.5 % divinyl benzene with 2-(2 0 -quinolyl)benzimidazole and subsequent treatment with Cu(OAc) 2 in methanol. The complex was characterized by physical, analytical and spectroscopic techniques. Electronic and ESR spectra, together with magnetic susceptibility measurements, indicated that the complex was paramagnetic with distorted octahedral geometry around the copper. The complex was found to be active toward oxidation of various alcohols including phenol, benzyl alcohol and cyclohexanol using 70 % aqueous tert-butyl hydroperoxide under mild conditions. Under the optimized reaction conditions, cyclohexanol gave 100 % conversion to cyclohexanone, benzyl alcohol gave 98 % yield of benzaldehyde and phenol gave 89 % yield of catechol and 4 % of hydroquinone. The complex was recycled five times without much loss in catalytic activity.

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Section: Scheme 1 Oxidation Of Various Alcoholsmentioning

confidence: 96%

“…Selective oxidation of benzaldehyde is important for the production of chlorine-free benzaldehyde required in the perfume and pharmaceutical industries [21]. The applicability of polymer-supported Cu(II) complexes as catalysts in the degradation of phenol is innovative [22].…”

Section: Introductionmentioning

confidence: 99%

A polymer-supported diacetatobis(2-quinolylbenzimidazole)copper(II) complex as an efficient catalyst for oxidation of alcohols with tert-butyl hydroperoxide

Shilpa

Gayathri

2012

Transition Met Chem

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“…In order to prepare highly active hydrotalcite derived acylation catalyst, recently we modified MgGahydrotalcite by reacting with gaseous hydrogen chloride before its use in the acylation reaction [55]. Pretreatment of hydrogen chloride to MgGa-hydrotalcite was performed by bubbling gaseous HCl (20 mol% HCl in N 2 ) through a mixture containing powered hydrotalcite and liquid aromatic substrate at 110°C for 1.0 h followed by flushing with pure N 2 in order to (without HCl pretreatment) shows no catalytic activity in the benzoylation by benzoyl chloride of substituted benzenes even when the reaction was carried over a period of 5.0 h. However, after HCl pretreatment, the catalyst is activated for benzoylation reaction, showing almost no induction period for the acylation reaction.…”

Section: Catalysis By Claysmentioning

confidence: 99%

Advances in liquid-phase Friedel-Crafts acylation of aromatics catalyzed by heterogeneous solids

Jana

2006

Catal Surv Asia

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In the last few decades, significant improvements toward the development of environmentally benign processes have been achieved in the liquid-phase Friedel-Crafts acylation reactions. Many efforts have been devoted to the research on solid catalysts adequate to substitute homogeneous protonic acids or Lewis acids as traditionally employed catalysts in the acid-catalyzed FriedelCrafts acylation processes. This short article describes the recent developments on catalysis by gallium (Ga), indium (In) and thallium (Tl) based novel heterogeneous solids for the liquid-phase Friedel-Crafts acylation of aromatics by acyl halide. The above heterogeneous catalysts are efficient for Friedel-Crafts acylation reaction and exhibited superior activity than the traditionally employed strongly acidic solid catalysts. Unlike conventional acidic catalyst, the acylation activity of Ga, In and Tl based solids, additionally having redox functions, does not depend solely on their acidic properties, even present. These solids in their non-acidic or basic form also show high acylation activity. Based on the catalytic results over these novel solids a plausible reaction mechanism for the acylation is proposed.

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“…Oxidation of benzoin is a practically important reaction for the production of benzil or benzaldehyde required in the perfumery and pharmaceutical industries [12][13][14][15][16][17]. Few heterogeneous catalytic methods have been developed for the oxidation of ethylbenzene, benzoin and cyclohexanol [18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Zeolite encapsulated Ru(III), Cu(II) and Zn(II) complexes of benzimidazole as reusable catalysts for the oxidation of organic substrates

Bhagya

Gayathri

2013

J Porous Mater

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Ru(III), Cu(II) and Zn(II) complexes of benzimidazole (BzlH) have been synthesized in the supercages of zeolite-Y by the flexible ligand method and were characterized by spectroscopic (IR, UV-Vis and ESR) studies, XRD and thermogravimetric analysis, surface area, and pore volume measurements. The zeolite encapsulated complexes catalyzed the oxidation of ethylbenzene, benzoin, and cyclohexanol. Various parameters, such as concentration of oxidant and catalyst, reaction time, temperature of the reaction and type of solvents have been optimized to obtain the maximum transformation of ethylbenzene to a mixture of acetophenone, benzaldehyde and styrene. Under the optimized reaction conditions, [Ru(BzlH)]-Y gave 80.4 % conversion of ethylbenzene in 1 h. All these zeolite encapsulated complexes were more selective towards acetophenone formation. Oxidation of benzoin catalyzed by [Cu(BzlH)]-Y, [Ru(BzlH)]-Y and [Zn(BzlH)]-Y encapsulated complexes resulted in 75.5, 78.7 and 59.9 % conversion respectively to give benzaldehyde as exclusive product. A maximum conversion of 39.1 % cyclohexanol with [Cu(BzlH)]-Y was achieved to give cyclohexanone. The activity of neat complexes towards these reactions was also carried out. The encapsulated catalysts were significantly more active than neat complexes and recyclable without much loss in catalytic activity.

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Cited by 68 publications

References 5 publications

A polymer-supported diacetatobis(2-quinolylbenzimidazole)copper(II) complex as an efficient catalyst for oxidation of alcohols with tert-butyl hydroperoxide

A polymer-supported diacetatobis(2-quinolylbenzimidazole)copper(II) complex as an efficient catalyst for oxidation of alcohols with tert-butyl hydroperoxide

Advances in liquid-phase Friedel-Crafts acylation of aromatics catalyzed by heterogeneous solids

Zeolite encapsulated Ru(III), Cu(II) and Zn(II) complexes of benzimidazole as reusable catalysts for the oxidation of organic substrates

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