Catalytic hydrogenation behaviours of palladium complexes of chitosan-polyacrylic acid and chitosan-polymethacrylic acid

Jin, Jing-Ji; Guo-cheng, Chen; Huang, Mei‐Yu; Jiang, Ying‐Yan

doi:10.1016/0923-1137(94)90006-x

Cited by 26 publications

(10 citation statements)

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“…Natural polymers have recently been the subject of many studies for their application in catalysis. For example, chitosan has recently been used as a support for catalysis. − Indeed, this amino-polysaccharide is characterized by its high affinity for metal ions, which can be adsorbed either by chelation mechanisms (metal cations in near-neutral solutions) or by ion-exchange mechanisms (metal anions in acidic solutions). − High sorption capacities have been achieved for precious metals and platinum group metals: sorption levels as high as 3 mmol Me g -1 are commonly reached with gold, platinum, and palladium, under mild experimental conditions. , The reduction of loaded metals by a suitable procedure (using sodium borohydride and/or in situ generated hydrogen) enables loaded metals to be present on the support at the zerovalent oxidation state, which is appropriate for many hydrogenation procedures . This kind of catalyst has been investigated for chromate reduction using sodium formate as the electron donor: chromate reduction may result from a hydrogen transfer mechanism and/or by production of hydrogen from formic acid oxidation .…”

Section: Introductionmentioning

confidence: 99%

Chitosan-Supported Palladium Catalyst. 3. Influence of Experimental Parameters on Nitrophenol Degradation

2003

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Glutaraldehyde cross-linked chitosan was loaded with palladium and then reduced by means of an in situ hydrogen generation procedure (Zn in sulfuric acid solution) to prepare a chitosan-supported palladium catalyst. This catalyst was successfully used to degrade nitrophenol in dilute solutions in the presence of sodium formate as the hydrogen donor. The optimum initial pH was below pH 4. The pH strongly increased during the reaction. The influence of the initial concentration of nitrophenol and sodium formate was studied in order to determine the minimum molar ratio between these compounds to achieve the complete conversion of the nitrogenous product. The pseudo-first-order equation was shown to fit degradation kinetics in most cases; however, in some cases it was necessary to use a variable-order equation in order to model the kinetics. Decreasing catalyst particle size increased degradation rate; the kinetic parameter varied linearly with the reciprocal of the diameter, indicating that film diffusion may partially contribute to the kinetic control of the reaction. The kinetic parameter linearly increased with catalyst dosage, while increasing the palladium loading in the catalyst slightly increased degradation kinetics but the catalytic activity did not increase proportionally. Catalytic activity appears to be restricted to external catalyst layers.

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Section: Introductionmentioning

confidence: 99%

Chitosan-Supported Palladium Catalyst. 3. Influence of Experimental Parameters on Nitrophenol Degradation

2003

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“…Recently, research into supported catalysis has been carried out on chitosan. − Chitosan is obtained by deacetylation of chitin (the most abundant biopolymer in nature after cellulose). Chitosan is characterized as a heteropolymer consisting of d -glucosamine and N -acetyl d -glucosamine units.…”

Section: Introductionmentioning

confidence: 99%

Chitosan-Supported Palladium Catalyst. II. Chlorophenol Dehalogenation

Vincent

Spinelli

Guibal

2003

Ind. Eng. Chem. Res.

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Preliminary treatment with glutaraldehyde increased the stability of chitosan in acidic solution and the sorption of palladium from HCl solutions at high loading. A reduction procedure was used to partially reduce the palladium. The resulting chitosan-supported palladium catalyst was efficiently used for the hydrodehalogenation and partial dehydrodearomatization of 2-chlorophenol (2-CP). The reaction proceeds via hydrogen transfer using sodium formate. The optimum pH for the degradation of 2-CP was close to pH 3. The effects of catalyst dosage, formate concentration, 2-CP concentration, and temperature were studied to define the optimum conditions for the conversion of 2-chlorophenol into phenol and cyclohexanone. A limit on the formate/2-CP molar ratio was found to be required to achieve the complete dehalogenation of 2-CP: The formate excess needed to be higher than 50 times the 2-CP concentration. Increasing the temperature from 20 to 60 °C continuously increased the degradation rate, and the activation energy ranged between 20 and 25 kJ mol -1 under nonlimiting experimental conditions (formate excess at the required level and pH 2.7).

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“…The use of biopolymer matrix increases the activity, selectivity and stability for hydrogenation. [91] Galletti et al adopted a very interesting approach in which microwave irradiation was used for synthesizing the catalyst as well as for the reaction. Pdchitosan was prepared using microwaves which was superior to conventional heating method in terms of milder conditions and short reaction times.…”

Section: Hydrogenation Reactionsmentioning

confidence: 99%

Valorization of Oceanic Waste Biomass: A Catalytic Perspective

Lucas

Athawale

Rode

2019

The Chemical Record

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Efficacious waste utilization is vital in context of sustainability. The past decade has witnessed attempts of usage of land biomass and wastes for various applications, contributing towards a sustainable society. Exploitation of the marine biomass, which does not compete with habitation and food production like land biomass has been largely unnoticed and therefore not being utilized judiciously. Researchers have mainly exploited these resources as functional materials having significant potential applications. However, a catalytic perspective for the valorisation of these polymers arising from oceanic waste widens their scope and ameliorates its use. The objective of the present review is to demonstrate the effectiveness of chitin/chitosan as a catalyst and as a feedstock for deriving important fuels and chemicals. It displays all the reactions heterogeneously catalyzed by them along with the strategic methodology. Their important catalytic organic transformations attempted so far, have also been discussed. The future perspectives are also presented which if inculcated would improve the value addition of the waste, paving a way for greener and imperishable world.

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Catalytic hydrogenation behaviours of palladium complexes of chitosan-polyacrylic acid and chitosan-polymethacrylic acid

Cited by 26 publications

References 1 publication

Chitosan-Supported Palladium Catalyst. 3. Influence of Experimental Parameters on Nitrophenol Degradation

Chitosan-Supported Palladium Catalyst. 3. Influence of Experimental Parameters on Nitrophenol Degradation

Chitosan-Supported Palladium Catalyst. II. Chlorophenol Dehalogenation

Valorization of Oceanic Waste Biomass: A Catalytic Perspective

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