A recoverable dendritic polyamidoamine immobilized TEMPO for efficient catalytic oxidation of cellulose

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

doi:10.1016/j.carbpol.2018.09.016

Cited by 21 publications

(7 citation statements)

References 60 publications

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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: 65%

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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Section: Resultsmentioning

confidence: 65%

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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“…Under the oxidation conditions, the cellulose can be oxidized and depolymerized into water soluble derived compounds (Isogai et al 2018). The decrease of yield at low oxidation degree is probably due to the fact that the increased de brillation degree cannot offset the increase of amorphous region hydrolysis of cellulose, while higher oxidation degree leads to an easier de brillation by ball milling, thus resulting in an increase of yield (Liu et al 2018).…”

Section: Resultsmentioning

confidence: 99%

Tuning the properties of pineapple peel cellulose nanofibrils by TEMPO-mediated oxidation and ball milling

Luo²,

Chen

et al. 2022

Cellulose

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In this study, the oxidized cellulose nano brils from pineapple peel (PP-TOCNF) were prepared by TEMPOmediated oxidation followed by ball milling. The in uence of oxidation degree on the structure and properties of PP-TOCNF were investigated, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and thermogravimetry (TG), as well as the potential application in aerogels. The results suggested that TEMPO oxidation facilitated the dispersion of PP-TOCNF due to the strong electrostatic repulsion between -COO − groups. Regulating oxidation degree by varying NaClO concentration could effectively adjust the -COO − content (0.167 ~ 0.550 mmol/g), zeta potential (-18 ~ -34 mV) and rheological properties. The obtained PP-TOCNF showed a long brillar structure, whose average diameter and CrI values gradually decreased with the increase of oxidation degree. The PP-TOCNF-based aerogels exhibited a light weight, good porosity, water absorption, and mechanical properties, which also can be easily adjusted by oxidation degree of PP-TOCNF. Furthermore, TEMPO oxidation improved the stability and shape recovery ability of aerogels in water.

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“…The aspect ratio (length divided by diameter) was around 9 for Form I and 30 for Form II. Higher aspect ratios for Form II show a greater potential in the reinforcement capabilities when incorporated into composite materials [22]. The important difference regarding the current study, however, is that the fully functionalized Form II product from the TEMPO/Oxone ® synthetic procedure requires no mechanical treatment to create smaller nanoparticulates, as illustrated through Supplemental Figure S1.…”

Section: Tem Microscopy Of Oxone ® -Mediated Tempo-oxidized Cellulosementioning

confidence: 87%

Oxone®-Mediated TEMPO-Oxidized Cellulose Nanomaterials form I and form II

et al. 2020

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The 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation of cellulose, when mediated with Oxone® (KHSO5), can be performed simply and under mild conditions. Furthermore, the products of the reaction can be isolated into two major components: Oxone®-mediated TEMPO-oxidized cellulose nanomaterials Form I and Form II (OTO-CNM Form I and Form II). This study focuses on the characterization of the properties of OTO-CNMs. Nanoparticle-sized cellulose fibers of 5 and 16 nm, respectively, were confirmed through electron microscopy. Infrared spectroscopy showed that the most carboxylation presented in Form II. Conductometric titration showed a two-fold increase in carboxylation from Form I (800 mmol/kg) to Form II (1600 mmol/kg). OTO-CNMs showed cellulose crystallinity in the range of 64–68% and crystallite sizes of 1.4–3.3 nm, as shown through XRD. OTO-CNMs show controlled variability in hydrophilicity with contact angles ranging from 16 to 32°, within or below the 26–47° reported in the literature for TEMPO-oxidized CNMs. Newly discovered OTO-CNM Form II shows enhanced hydrophilic properties as well as unique crystallinity and chemical functionalization in the field of bio-sourced material and nanocomposites.

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A recoverable dendritic polyamidoamine immobilized TEMPO for efficient catalytic oxidation of cellulose

Cited by 21 publications

References 60 publications

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

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

Tuning the properties of pineapple peel cellulose nanofibrils by TEMPO-mediated oxidation and ball milling

Oxone®-Mediated TEMPO-Oxidized Cellulose Nanomaterials form I and form II

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