Catalytic activity of anionic iron(III) porphyrins immobilized on grafted disordered silica obtained from acidic leached chrysotile

Halma, Matilte; Bail, Alesandro; Wypych, Fernando; Nakagaki, Shirley

doi:10.1016/j.molcata.2005.08.019

Cited by 73 publications

(33 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The white disordered silica solid was obtained by treating chrysotile with hydrochloric acid, as previously described. 21,23 Iodosylbenzene (PhIO) was synthesized by hydrolysis of iodosylbenzenediacetate. 26 The solid was carefully dried under reduced pressure and kept at 5 °C.…”

Section: Methodsmentioning

confidence: 99%

“…20 The mismatch of the brucite-like octahedral sheet with the silica tetrahedral sheet causes the curvature of the layers, which can roll into tight tubes, the characteristic chrysotile fibers. 21 A drastic leaching of chrysotile fibers by concentrated acid transforms this natural polymer by removing the brucite-like layer, resulting in an excellent source of hydrated disordered silica 23,24 with physico-chemical characteristics similar to silica gel.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Nakagaki¹,

Castro²,

Machado³

et al. 2006

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

Crisotila natural e quimicamente modificada foi usada como matrizes para imobilização de ferroporfirinas de segunda geração. As atividades catalíticas dos sólidos obtidos foram avaliadas em reações de oxidação de cicloexano, usando iodosilbenzeno como oxidante. Os resultados de catálise foram analisados e comparados aos obtidos pela imobilização das mesmas ferroporfirinas em sílica funcionalizada com 3-APTS, derivadas do tratamento ácido da crisotila. Os resultados preliminares mostraram que os catalisadores são eficientes e seletivos para a obtenção de álcool.Natural and grafted chrysotile were used as matrices for the immobilization of second generation iron porphyrins. The catalysts obtained were evaluated in the oxidation reaction of cyclohexane, using iodosylbenzene as oxidant agent. The catalyst activity for different conditions was compared with results for the same porphyrins immobilized with 3-APTS grafted disordered silica, obtained from acid-leached chrysotile. Preliminary results have shown that high activity can be obtained with short reaction times, and that the reaction is specific for alcohol.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Nakagaki¹,

Castro²,

Machado³

et al. 2006

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…17,[33][34][35][36][37][38][39] This is particularly attractive from an economical and environmental viewpoint. In this context, layered double hydroxides (LDHs) have emerged as interesting supports to immobilize a variety of MPs.…”

Section: -33mentioning

confidence: 99%

“…The morphology and textural properties of the support can direct the substrates to the catalytically active center in a different way. 18,36,50,[76][77][78] Besides that, FeP immobilization protects the catalyst from the oxidative attack of another catalytically activated FeP, which avoids destruction of the catalytic species. In the specific case of FeP-LDHME, the microporous structure of the support may have conferred better protection to the FeP, whereas the immobilized FeP remained on the surface of the layered crystals in FeP-LDH-NO 3 , as indicated by XRD analysis (Figure 2c).…”

Section: Catalytic Oxidation Reactionsmentioning

confidence: 99%

“…[22][23][24][25][26][27][28][29][30][31][32][33] Catalyst immobilization can facilitate catalyst recovery from the reaction medium, to enable their reuse and recycling. 17,[33][34][35][36][37][38][39] This is particularly attractive from an economical and environmental viewpoint. In this context, layered double hydroxides (LDHs) have emerged as interesting supports to immobilize a variety of MPs.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Anionic Iron(III) Porphyrin Immobilized on/into Exfoliated Macroporous Layered Double Hydroxides as Catalyst for Oxidation Reactions

Nakagaki¹,

Castro²,

Ucoski³

et al. 2014

Journal of the Brazilian Chemical Society

Self Cite

View full text Add to dashboard Cite

A oxidação de substratos orgânicos é uma importante classe de reações explorada visando a produção de insumos industriais tais como epóxidos, álcoois e cetonas. As metaloporfirinas são compostos com reconhecida atividade catalítica que mimetizam processos de oxidação que ocorrem em seres vivos. A sua imobilização em diferentes sólidos robustos e inertes permite a recuperação e reuso do catalisador em processos catalíticos heterogêneos. Hidróxidos duplos lamelares (LDHs) são materiais inorgânicos constituídos de hidróxidos de metais di e trivalentes, resultando em lamelas bidimensionais carregadas positivamente. Neste trabalho reportamos a preparação de catalisadores baseados na imobilização de ferroporfirina (FeP) em LDH macroporoso (LDHM) obtido pelo método de co-precipitação usando poliestireno como template, reconstrução de óxidos e esfoliação (LDHME). A imobilização da FeP no LDH intercalado com ânions nitrato obtido pelo método de co-precipitação também é reportada. Os sólidos obtidos foram caracterizados e investigados como catalisadores na oxidação do cicloocteno e cicloexano.The oxidation of organic substrates via catalytic routes is an important class of reactions to produce industrial input materials such as epoxides, alcohols, and ketones. Metalloporphyrins display recognized catalytic activity that mimics oxidation processes in living organisms. Their immobilization in different inert supports allows their recovery and reuse in heterogeneous catalytic processes. Layered double hydroxides (LDHs) are inorganic materials consisting of di-and trivalent metal hydroxides that afford bidimensional positively charged layers. This work reports on the preparation of the solid based on macroporous LDHs (LDHMs) by the co-precipitation method, which involved the use of polystyrene as template, oxides reconstruction, and exfoliation, to furnish LDHME. We also describe the immobilization of an iron(III) porphyrin (FeP) in LDHME and in LDH intercalated with nitrate anions, obtained by the co-precipitation method. Application of the immobilized catalysts in (Z)-cyclooctene and cyclohexane oxidation will help to assess their catalytic activity. Keywords: porphyrin, macroporous LDH, oxidation, biomimetic reaction, heterogeneous catalysis IntroductionThe family of enzymes collectively known as cytochrome P450 monooxygenases bear a heme prosthetic group and participate in different catalytic processes, mainly oxidative metabolism of endogenous/exogenous products in mammals. [1][2][3][4][5] Over the last years, researchers have made great efforts to develop routes that can generate robust synthetic metalloporphyrins (MPs), 6-10 aiming to mimic biological enzymes such as cytochrome P450 (biomimetic approach). Indeed, MPs can efficiently and selectively catalyze hydrocarbon oxidation.11 Some of these MPs are based on the structure of meso-tetraphenylporphyrin [H 2 (TPP)].The high efficiency and selectivity of MPs have motivated the proposition of technological catalytic systems based on this versatile family of oxidation ca...

show abstract

A Novel Charge Transfer Channel to Simultaneously Enhance Photocatalytic Water Splitting Activity and Stability of CdS

Ning

et al. 2019

Adv Funct Materials

104

View full text Add to dashboard Cite

It is highly desirable to develop durable photocatalysts for efficiently boosting water splitting, but it is challenging for CdS to realize the expected result without using any hole sacrificial agents. Herein, improved photocatalytic hydrogen evolution and enhanced stability are simultaneously realized in the absence of any sacrificial agents by introducing Zinc 5-, 10-, 15-, 20-mesotetra (4-hydrazidephenyl) porphyrin (ZnTHPP) onto CdS nanosheets (CdS NSs). In this system (ZnTHPP/CdS NSs), a novel hole transfer channel is achieved by an internal chemical reaction using the functional group of acylhydrazine in ZnTHPP. Compared with CdS NSs, the ZnTHPP/CdS NSs exhibit excellent photostability (15 h) and efficient photocatalytic activity for pure water splitting (≈6.4 times). Furthermore, it is found that the rate constant for photogenerated holes is about 1.7 times higher than the pure CdS NSs under light irradiation. This suggests that the promising charge transfer channel can efficiently suppress charge recombination and photocorrosion of pure CdS NSs. The pattern via internal charge transfer channel not only can solve the stability of CdS based materials, but also design more semiconductors for efficient photocatalytic water splitting.

show abstract

Catalytic activity of anionic iron(III) porphyrins immobilized on grafted disordered silica obtained from acidic leached chrysotile

Cited by 73 publications

References 32 publications

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Catalytic activity in oxidation reactions of anionic iron(III) porphyrins immobilized on raw and grafted chrysotile

Anionic Iron(III) Porphyrin Immobilized on/into Exfoliated Macroporous Layered Double Hydroxides as Catalyst for Oxidation Reactions

A Novel Charge Transfer Channel to Simultaneously Enhance Photocatalytic Water Splitting Activity and Stability of CdS

Contact Info

Product

Resources

About