Hydrodechlorination and Hydrogenation over Raney–Ni under Multiphase Conditions: Role of Multiphase Environment in Reaction Kinetics and Selectivity

Zinovyev, Sergei; Perosa, Alvise; Yufit, S. S.; Tundo, Pietro

doi:10.1006/jcat.2002.3755

Cited by 17 publications

(33 citation statements)

References 10 publications

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“…We have previously reported some of our data for the same system [14]. Reaction of 1,3,5-TCB is a simple scheme with only two intermediates and imitates well the general reactivity of polychlorinated aromatics.…”

Section: Introductionsupporting

confidence: 54%

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On the promoting effect by quaternary ammonium salts in the multiphase hydrodechlorination with hydrogen gas on Raney nickel catalyst

Zinovyev

Tundo

2007

Applied Catalysis B: Environmental

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Hydrodechlorination of 1,3,5-trichlorobenzene with hydrogen gas on Raney nickel catalyst in the biphasic system composed of isooctane, aqueous KOH, and a quaternary ammonium compound as a promoter at 70 8C and atmospheric pressure was studied. The promoter increased the rate of reaction above two orders of magnitude. Several quaternary chloride salts were studied, such as Aliquat 336, trioctylmethylammonium, tridodecylmethylammonium, cetyltrimethylammonium, tetrabutylammonium and tetraethylammonium. The relationship of the reaction rate with adsorption, micelle formation, and the structural properties of the promoter are discussed. #

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Section: Introductionsupporting

confidence: 54%

“…Reaction of 1,3,5-TCB is a simple scheme with only two intermediates and imitates well the general reactivity of polychlorinated aromatics. In this case, Raney nickel is interesting owing to the more pronounced effect that is induced by the quaternary salt, compared with the Pd/C system [1,14].…”

Section: Introductionmentioning

confidence: 99%

On the promoting effect by quaternary ammonium salts in the multiphase hydrodechlorination with hydrogen gas on Raney nickel catalyst

Zinovyev

Tundo

2007

Applied Catalysis B: Environmental

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“…(1)), to compare the activity of different catalysts (Pd/C, Pt/C, Raney-Ni), with and without A336, under the standard multiphase conditions. 10,11 (1)…”

Section: Resultsmentioning

confidence: 99%

“…11 The multiphase system proves advantageous over monophasic ones, as demonstrated in a number of instances, 10 in particular for the case of Raney-Ni, where in the absence of A336, or of the alkaline aqueous phase, the reactions are inhibited. 11 From the green chemistry standpoint, heterogeneous catalysis is an attractive synthetic tool, particularly: when it allows to selectively (chemo-, regio-, stereo-) conduct different transformations by tuning some simple reactions parameters, when the reaction conditions are easily accessible (e.g. low temperature and pressure), when the catalyst system can be conveniently recovered and recycled, and when the product can be easily separated.…”

Section: Introductionmentioning

confidence: 99%

Mild catalytic multiphase hydrogenolysis of benzyl ethers

2002

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A preliminary study was conducted on the multiphase (aqueous KOH-isooctane-Aliquat ® 336) hydrogenolysis of benzyl methyl ether using Pd/C, Pt/C and Raney-Ni as catalysts, under mild conditions (T = 50 °C, pH 2 = 1 atm). Using ethanol as solvent, the Pd/C system is very efficient, while the same catalyst under multiphase conditions is almost inactive. With Pt/C, the reaction is always sluggish, and ring hydrogenation kicks in under multiphase conditions. The Raney-Ni system has an opposite behavior, while debenzylation is slow in ethanol, under multiphase conditions the reaction is quite fast. Other O-benzyl protected substrates undergo debenzylation with Raney-Ni as well, with varying chemoselectivity.

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“…[21][22][23][24][25][26] The A336 layer was shown to modify catalyst properties such as selectivity and kinetics. [27][28][29][30] Since this system is highly active and selective for the activation of aryl halides, the goal was to establish whether the presence of A336 promotes the heterogeneous Heck reaction as well. Next, to test it in the multiphase system made by the aqueous/organic solvents, and the heterogeneous catalyst suspended in the A336 phase.…”

Section: Homogeneous Catalyst Immobilized In Ionic Liquidsmentioning

confidence: 99%

Heck reaction catalyzed by Pd/C, in a triphasic—organic/Aliquat 336/aqueous—solvent system

et al. 2004

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The rate of the Pd/C catalyzed Heck coupling of Ar-I with CH 2 CH-R is accelerated tenfold by the presence of Aliquat 336 (A336), a well known phase transfer catalyst, and an ionic liquid. Both when conducted in A336 as solvent, and in an isooctane/A336/aqueous triphasic mixture, the Heck reaction of aryl iodides with electron deficient olefins, catalyzed by Pd/C, proceeds with high yields and selectivity. When KOH is used instead of Et 3 N, selective formation of the biphenyl rather than the Heck product, is observed. Aryl bromides react more sluggishly, and only the more activated ones undergo the Heck reaction. In the absence of the olefin, aryl halides possessing an electron withdrawing group are reduced to the corresponding Ar-H.

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Hydrodechlorination and Hydrogenation over Raney–Ni under Multiphase Conditions: Role of Multiphase Environment in Reaction Kinetics and Selectivity

Cited by 17 publications

References 10 publications

On the promoting effect by quaternary ammonium salts in the multiphase hydrodechlorination with hydrogen gas on Raney nickel catalyst

On the promoting effect by quaternary ammonium salts in the multiphase hydrodechlorination with hydrogen gas on Raney nickel catalyst

Mild catalytic multiphase hydrogenolysis of benzyl ethers

Heck reaction catalyzed by Pd/C, in a triphasic—organic/Aliquat 336/aqueous—solvent system

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