Highly efficient recyclable hydrated-clay supported catalytic system for atom transfer radical polymerization

Munirasu, Selvaraj; Aggarwal, Ravi; Baskaran, Durairaj

doi:10.1039/b908118f

Cited by 30 publications

(26 citation statements)

References 20 publications

(30 reference statements)

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“…Baskaran et al performed a highly robust AGET ATRP of methacrylates using hydrated natural clay as a support for a CuBr 2 /PMDETA complex, and the supported clay catalyst was recycled for 21 batch polymerizations without loss of its activity. They discovered that an optimum amount of water and reducing agent (AsAc‐Na) are necessary for the polymerization to proceed in a controlled manner.…”

Section: Catalyst Separation and Recycling Methods In Atrpmentioning

confidence: 99%

Recent Progress on Transition Metal Catalyst Separation and Recycling in ATRP

Ding

Jiang

Zhang

et al. 2015

Macromol. Rapid Commun.

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Atom transfer radical polymerization (ATRP) is a versatile and robust tool to synthesize a wide spectrum of monomers with various designable structures. However, it usually needs large amounts of transition metal as the catalyst to mediate the equilibrium between the dormant and propagating species. Unfortunately, the catalyst residue may contaminate or color the resultant polymers, which limits its application, especially in biomedical and electronic materials. How to efficiently and economically remove or reduce the catalyst residue from its products is a challenging and encouraging task. Herein, recent advances in catalyst separation and recycling are highlighted with a focus on (1) highly active ppm level transition metal or metal free catalyzed ATRP; (2) post-purification method; (3) various soluble, insoluble, immobilized/soluble, and reversible supported catalyst systems; and (4) liquid-liquid biphasic catalyzed systems, especially thermo-regulated catalysis systems.

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Section: Catalyst Separation and Recycling Methods In Atrpmentioning

confidence: 99%

Recent Progress on Transition Metal Catalyst Separation and Recycling in ATRP

Ding

Jiang

Zhang

et al. 2015

Macromol. Rapid Commun.

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“…When it comes to researches of metal catalysts, ATRP processes using various transition metal complexes, such as copper,27–29 iron,30–32 ruthenium,33 and other transition metals,34, 35 have been investigated. Considering of the large amount of metal catalysts and vital toxicity of the metal catalysts (e.g., copper) in normal ATRP, a number of excellent works have been carried out to reduce the amount of the metal catalysts used in ATRP36–40 or to remove the residual metals from final products 41–44…”

Section: Introductionmentioning

confidence: 99%

Upfront observation versus radiation for adult pilocytic astrocytoma

Ishkanian

Laperrière

et al. 2011

Cancer

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BACKGROUND: Although pilocytic astrocytoma accounts for up to 40% of all childhood brain tumors, it is a rare disease in adults. Consequently, there are few mature data on the impact of up-front treatment options after surgery that include observation or adjuvant radiotherapy. METHODS: Ten women and 20 men were identified who were diagnosed with pilocytic astrocytoma from 1971 to 2007 and were retrospectively reviewed. The median patient age was 30 years (range, 18-64 years), and the median follow-up was 87 months (range, 16-420 months). Initial surgery included biopsy (10% of patients), subtotal resection (57% of patients), or gross-total resection (33% of patients). Nineteen patients were observed postoperatively, whereas 11 patients received up-front postoperative adjuvant radiotherapy (50 grays in 25 fractions). No patient received adjuvant or concurrent chemotherapy. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Differences between survival curves were analyzed with the log-rank test. RESULTS: For the entire cohort, the 5-year and 10-year OS rates were 95% and 85%, respectively, and the 5-year and 10-year PFS rates were 63% and 35%, respectively. The median PFS was 8.4 years. Initial radiation, compared with observation, did not have an impact on OS but significantly improved PFS. The 5-year PFS rate for patients who were observed versus those who received radiation was 42% versus 91%, respectively; and, at 10 years, the PFS rate was 17% versus 60%, respectively (P ¼ .005). Patients who progressed after observation (11 of 19 patients) received various salvage therapies, resulting in a 2-year PFS rate of 68% compared with 33% for patients who progressed after initial radiation (3 of 11 patients) and were salvaged with either chemotherapy or surgery (P ¼ .1). CONCLUSIONS: Adjuvant radiotherapy for pilocytic astrocytoma significantly prolonged PFS at both 5 years and 10 years compared with observation. However, equivalent OS was observed, which reflected the efficacy of salvage therapies. Cancer 2011;117:4070-

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“…This can not only help limit the residual metal concentration in the final polymer, simplifying purification, but also allows for recycling of the catalyst to decrease material costs. Various types of substrates such as silica, polymer beads, ion exchange resin, and organic clay have been explored …”

Section: Conventional Atrp With Continuous Tubular Reactorsmentioning

confidence: 99%

Copper‐mediated controlled radical polymerization in continuous flow processes: Synergy between polymer reaction engineering and innovative chemistry

Chan

Cunningham

Hutchinson

2013

J. Polym. Sci. Part A: Polym. Chem.

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Copper(0)-mediated controlled radical polymerization (CRP), or single-electron transfer-living radical polymerization (SET-LRP) is a robust and dynamic technique that has attracted considerable academic and industrial interest as a synthetic tool for novel value-added materials. Although SET-LRP possesses many advantages over other forms of CRP, this novel chemistry still requires concurrent engineering solutions for successful commercial application. In this highlight, the evolution of atom-transfer radical polymerization chemistry and development in continuous processes is presented, leading to recent research on the use of SET-LRP in continuous flow tubular reactors. The proofs of concept are reviewed, and remaining challenges and unexplored potential on the use of continuous flow processes with SET-LRP as a powerful platform for the synthesis of novel polymeric materials are discussed.

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Highly efficient recyclable hydrated-clay supported catalytic system for atom transfer radical polymerization

Abstract: Atom transfer radical polymerization of methacrylates has been performed using hydrated natural clay as a support for a CuBr(2)-ligand complex and the supported clay catalyst has been recycled for 21 batch polymerizations without losing its activity.

Cited by 30 publications

References 20 publications

Recent Progress on Transition Metal Catalyst Separation and Recycling in ATRP

Recent Progress on Transition Metal Catalyst Separation and Recycling in ATRP

Upfront observation versus radiation for adult pilocytic astrocytoma

Copper‐mediated controlled radical polymerization in continuous flow processes: Synergy between polymer reaction engineering and innovative chemistry

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