4-OH-TEMPO radical grafted onto a novel polyaromatic ether sulfone containing carboxyl side chains as solid catalyst for alcohol oxidation |
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Authors: | Wenyu Zhang Yu Zhang Weijie Cai Dazhi Wang Shaoyin Zhang |
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Affiliation: | 1. Faculty of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, China;2. Faculty of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, China
Contribution: Data curation (supporting);3. Faculty of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, China
Contribution: Resources (equal), Supervision (lead);4. Faculty of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, China
Contribution: Supervision (supporting) |
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Abstract: | 2,2,6,6-Tetramethylpiperidinium-nitroxide (TEMPO) is a mild and efficient catalyst, which is important in the industrial production of selective oxidation of alcohols to the corresponding aldehyde or ketone compounds. However, it is a challenge to recover the expensive TEMPO catalyst in homogeneous catalytic systems. In this study, a novel polymer-supported catalyst was prepared using 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxy (4-OH-TEMPO) and polyaromatic ether sulfone (PAES). The successful grafting of 4-OH-TEMPO in PAES-C was demonstrated by 1H nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR), load capacity can be calculated by elemental analysis (EA). BET and scanning electron microscopy (SEM) to depict the structure-performance relationship. Herein, SEM images revealed the existence of porous structure. This structure can effectively adsorb NO molecules to form a PAES-TEMPO/NOx catalytic system to selectively oxidize benzyl alcohol. The experimental results indicated the high activity, the subsequent benzyl alcohol oxidation cycle can reach more than 93% conversion without showing a large loss of selectivity. More importantly, the as-prepared catalyst exhibited the attractive recyclability (recovery rate is 98%). After 10 consecutive runs, no significant loss of conversion and selectivity was observed (the conversion rate of benzyl alcohol was more than 93% and the selectivity was more than 95%). This study might provide some recommendation on the development of highly efficient catalysts for alcohol oxidation. |
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Keywords: | alcohol oxidation immobilization molecular oxygen Nitroxide free radical poly (arylene ether sulfone) |
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