Polyacrylic acid supported TEMPO for selective catalytic oxidation of cellulose: recovered by its pH sensitivity

Li, Shaojie; Sun, Tingting; Yang, Desheng; Cao, Meng; Liang, Huazhe

doi:10.1007/s10570-018-2012-z

Cited by 17 publications

(3 citation statements)

References 25 publications

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“…As described in Equation 2, the initial 4-hydroxy-TEMPO compound possesses a -N-O bond, which corresponds to the FTIR stretching vibration peaks at 1167 cm −1 and 1295 cm −1 . 50,51 After charging to 1.4 V, the peak at 1167 cm −1 disappeared, and a peak at 1542 cm −1 emerged. The peak at 1542 cm −1 corresponds to the N=O stretching vibration, indicating the transition of 4-hydroxy-TEMPO to 4-hydroxy-TEMPO + , as displayed in Equation 2.…”

Section: Resultsmentioning

confidence: 99%

An Aqueous Rechargeable Fluoride Ion Battery with Dual Fluoride Electrodes

Hou

Zhang

Shen

et al. 2019

J. Electrochem. Soc.

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An anion flow battery has recently emerged as an option to store electricity with high volumetric energy densities. In particular, fluoride ions are attractive for these batteries because they have the smallest size among anions, which is beneficial for charge transport. To date, reported fluoride ion batteries either operate with an ionic liquid, organic electrolyte or solid-state electrolyte at high temperatures. Herein, an aqueous fluoride ion flow battery is proposed that consists of bismuth fluoride as the anode, 4-hydroxy-TEMPO (TEMPO) as the cathode, and NaF salt solution as the aqueous electrolyte. During the charging process, bismuth fluoride electrochemically releases fluoride ions with the formation of bismuth metal, while TEMPO captures the fluoride ions. A reversible and stable discharge capacity of 89.5 mAh g −1 was achieved at 1000 mA g −1 after 85 cycles. The fluoride ion battery possesses excellent rate performance. To the best of our knowledge, this is the earliest demonstration that fluoride ion batteries can work in aqueous solutions, which can be used for future clean energy applications.

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Section: Resultsmentioning

confidence: 99%

An Aqueous Rechargeable Fluoride Ion Battery with Dual Fluoride Electrodes

Hou

Zhang

Shen

et al. 2019

J. Electrochem. Soc.

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“…The DPv of PEG4000-NHPI oxidized cellulose is 1.1 times higher than that of TEMPO oxidized cellulose, and the degradation degree is only 18%. Compared with the reported macromolecular TEMPO catalysts of P(AA-co-TA) (Liu et al 2018a) and P(AM-co-VAm)-T (Liu et al 2018b), the oxidation performance of PEG4000-NHPI is higher than P(AA-co-TA) and can reach 84% of P(AM-co-VAm)-T level. The cellulose degradation rates of these two macromolecular TEMPO catalysts (41% and 21%, respectively) are higher than that of PEG4000-NHPI (18%).…”

Section: Resultsmentioning

confidence: 66%

“…However, because TEMPO itself has good water solubility, loading it on water-soluble macromolecules such as PEG cannot further increase its water solubility. Its large molecular weight tends to reduce its catalytic activity when used to oxidize cellulose (Liu et al 2017(Liu et al , 2018a.…”

Section: Introductionmentioning

confidence: 99%

Recoverable Water-soluble Polyethylene Glycol-immobilized N-hydroxyphthalimide Mediated Oxidation of Cellulose in the Presence of NaBr and NaClO

Wang

Sun

et al. 2021

Preprint

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As a highly efficient nitroxide radical catalyst for selective catalytic oxidation of cellulose, N-hydroxyphthalimide (NHPI) has attracted much attention because of its low price and light cellulose degradation. However, NHPI is insoluble in water and is difficult to recycle because of its small molecular weight. To address the above issues, the water-soluble polyethylene glycol (PEG)-immobilized NHPI catalyst (PEG-NHPI) was designed and prepared in this work. Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and UV-vis light spectroscopy were used to characterize PEG-NHPI. The results showed that PEG-NHPI catalysts with good water solubility and adjustable NHPI loading amounts were successfully synthesized. Using NaBr as promoter and NaClO as oxidant, PEG-NHPI mediated oxidation of cellulose was carried out and good catalytic performance was found. The catalytic performance of PEG-NHPI mediated oxidation of cellulose in water was higher than that in acetonitrile-water. The carboxyl content of PEG-NHPI oxidized cellulose could reach the level of free NHPI oxidized cellulose, and was equivalent to 68% of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidized cellulose, while the degradation degree of cellulose was greatly reduced by more than 40%. The catalytic performance did not decrease significantly after six oxidation cycles. The structure of recycled PEG-NHPI was not changed. These results indicated that immobilizing NHPI onto PEG can achieve the unification of high catalytic performance and good recyclability.

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Recoverable acrylamide-vinylamine copolymer immobilized TEMPO mediated oxidation of cellulose with good catalytic performance and low cellulose degradation

et al. 2021

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In this work, a recoverable acrylamide-vinylamine copolymer immobilized TEMPO (P(AM-co-VAm)-T) catalyst for selective oxidation of cellulose with good catalytic performance and low cellulose degradation was developed. Firstly, the acrylamide-vinylamine copolymer (P(AM-co-VAm)) was prepared by Hofmann degradation of polyacrylamide (PAM). Then, the condensation reduction reaction between amine groups of P(AM-co-VAm) and carbonyl groups of 4-oxo-TEMPO yielded P(AM-co-VAm)-T. P(AM-co-VAm)-T was used as a catalyst for selective oxidation of C6 primary hydroxyl groups of cellulose to carboxyl groups. The carboxyl content of obtained oxidized cellulose was up to 1.114 mmol/g, which was equivalent to 76% of the free TEMPO level. This macromolecular catalyst was easily recycled and the recycling performance was excellent. Interestingly, it was found that P(AM-co-VAm)-T could effectively reduce the degradation of oxidized cellulose. The corresponding degradation degree was 21%-27%, which was much lower than the degradation degree of free TEMPO (61%-66%) and other macromolecular TEMPO catalysts, such as polyacrylic acid immobilized-TEMPO (41%-53%) and polyamidoamine supported TEMPO (28%-44%). P(AM-co-VAm)-T with positive charge and suitable size could effectively inhibit the formation of C6 aldehydes and C2/C3 ketones, which was the main reason that it could signi cantly inhibit cellulose degradation.

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Polyacrylic acid supported TEMPO for selective catalytic oxidation of cellulose: recovered by its pH sensitivity

Cited by 17 publications

References 25 publications

An Aqueous Rechargeable Fluoride Ion Battery with Dual Fluoride Electrodes

An Aqueous Rechargeable Fluoride Ion Battery with Dual Fluoride Electrodes

Recoverable Water-soluble Polyethylene Glycol-immobilized N-hydroxyphthalimide Mediated Oxidation of Cellulose in the Presence of NaBr and NaClO

Recoverable acrylamide-vinylamine copolymer immobilized TEMPO mediated oxidation of cellulose with good catalytic performance and low cellulose degradation

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