Oxidations involving phosphate species supported on TS-1: a novel class of grafted catalysts

Duprey, E.; Maquet, Jocelyne; Man, Pascal P.; Manoli, Jean‐Marie; Delamar, Michel; Brégeault, Jean‐Marie

doi:10.1016/0926-860x(95)00078-x

Cited by 27 publications

(13 citation statements)

References 20 publications

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“…The usual approaches include immobilization on polymers, silica, and magnetic particles. [18][19][20] However, owing to the limited phase-transfer between solid catalyst and substrates, heterogeneous catalysts afford relatively poor yield compared with the homogeneous analogues. Thus, in order to combine the advantages of homogenous catalysts (activity and selectivity) with the facility of heterogeneous systems (recycling), some "smart catalysts" sensitive to A tungsten peroxo complex stabilized by the bidentate picolinato ligand has been synthesized and then immobilized successfully on imidazole-functionalized silica.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins

Chen

et al. 2015

ChemPlusChem

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A tungsten peroxo complex stabilized by the bidentate picolinato ligand has been synthesized and then immobilized successfully on imidazole‐functionalized silica. The immobilized tungsten‐based catalyst was employed as an efficient catalyst for the one‐pot synthesis of β‐alkoxy alcohols from olefins and methanol with H2O2. Regarding the catalyst evaluation and the results of characterization by the various methods, it was demonstrated that the immobilization of tungsten peroxo complex was highly temperature‐dependent. The tungsten peroxo complex can dissociate and diffuse into the liquid phase at reaction temperature, resulting in a homogeneous reaction. Nevertheless, the catalytically active species was anchored on the imidazole‐functionalized silica by hydrogen bonding as the temperature was lowered to 0 °C after the reaction, which thus offered a highly effective approach for recycling the catalyst for consecutive cycles. In addition, various olefins can be converted to the corresponding β‐alkoxy alcohols with good conversion and selectivity under relative mild conditions by H2O2.

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Section: Introductionmentioning

confidence: 99%

Temperature‐Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins

Chen

et al. 2015

ChemPlusChem

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“…This indicates that most of the phosphine species have decomposed, while the remaining phosphine species migrated and adsorbed onto the TS‐1, and slowly oxidise to phosphates with increasing time‐on‐stream. It has been previously reported that phosphate grafting onto TS‐1 can be used to enhance epoxidation [49] . Therefore, the increasing trend in the PO production rate is linked to more accessible Au‐Ti sites with the gradual release of the bound phosphine species at 200 °C from the Au surface.…”

Section: Resultsmentioning

confidence: 98%

Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation

et al. 2021

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Designing a stable and selective catalyst with high H2 utilisation is of pivotal importance for the direct gas‐phase epoxidation of propylene. This work describes a facile one‐pot methodology to synthesise ligand‐stabilised sub‐nanometre gold clusters immobilised onto a zeolitic support (TS‐1) to engineer a stable Au/TS‐1 catalyst. A non‐thermal O2 plasma technique is used for the quick removal of ligands with limited increase in particle size. Compared to untreated Au/TS‐1 catalysts prepared using the deposition precipitation method, the synthesised catalyst exhibits improved catalytic performance, including 10 times longer lifetime (>20 days), increased PO selectivity and hydrogen efficiency in direct gas phase epoxidation. The structure‐stability relationship of the catalyst is illustrated using multiple characterisation techniques, such as XPS, 31P MAS NMR, DR‐UV/VIS, HRTEM and TGA. It is hypothesised that the ligands play a guardian role in stabilising the Au particle size, which is vital in this reaction. This strategy is a promising approach towards designing a more stable heterogeneous catalyst.

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“…It has been previously reported that phosphate grafting onto TS‐1 can be used to enhance epoxidation. [49] Therefore, the increasing trend in the PO production rate is linked to more accessible Au‐Ti sites with the gradual release of the bound phosphine species at 200 °C from the Au surface. The subsequent decrease in the PO production rate after 11 days can be associated to partial aggregation of Au particles caused by the loss of ligands.…”

Section: Resultsmentioning

confidence: 99%

Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation

et al. 2021

View full text Add to dashboard Cite

Designing astable and selective catalyst with high H 2 utilisation is of pivotal importance for the direct gas-phase epoxidation of propylene.This work describes afacile one-pot methodology to synthesise ligand-stabilised sub-nanometre gold clusters immobilised onto az eolitic support (TS-1) to engineer as table Au/TS-1 catalyst. An on-thermal O 2 plasma technique is used for the quickremoval of ligands with limited increase in particle size. Compared to untreated Au/TS-1catalysts prepared using the deposition precipitation method, the synthesised catalyst exhibits improved catalytic performance,i ncluding 10 times longer lifetime (> 20 days), increased PO selectivity and hydrogen efficiency in direct gas phase epoxidation. The structure-stability relationship of the catalyst is illustrated using multiple characterisation techniques,s uch as XPS, 31 PM AS NMR, DR-UV/VIS,H RTEM and TGA. It is hypothesised that the ligands play ag uardian role in stabilising the Au particle size, whichi sv ital in this reaction. This strategy is ap romising approach towards designing amore stable heterogeneous catalyst.

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Oxidations involving phosphate species supported on TS-1: a novel class of grafted catalysts

Cited by 27 publications

References 20 publications

Temperature‐Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins

Temperature‐Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins

Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation

Precisely Engineered Supported Gold Clusters as a Stable Catalyst for Propylene Epoxidation

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