Abstract

Homogeneous chitosan/poly(methacrylic acid) solution containing Pd²⁺ cations was successfully prepared by addition of pyridine-2-carboxaldehyde. Then, this homogeneous solution was smoothly electrospun into uniform composite nanofibers with mean diameter of 442 ± 163 nm, followed by annealing at elevated temperature to improve the solvent resistance. Scanning electron microscopy (SEM) analysis shows that the solvent resistance of the composite nanofibers was improved with the increment of annealing temperature. FT-IR spectra demonstrate that the chemical structure of the composite nanofibers was not oxidized after annealing process. Moreover, the palladium species were homogeneously incorporated inside the composite nanofibers. The catalytic performance of these novel composite nanofibers was evaluated by Heck reaction. The catalysis result shows that these composite nanofibers were very efficient to catalyze the Heck reaction of aromatic iodides with acrylates with yields over 86%. Moreover, these composite nanofibers can be reused for 10 times with little decrement of yield.

Graphic abstract

A novel palladium embedded chitosan composite nanofiber mat has been prepared by electrospinning and thermal techniques. This novel fiber palladium catalyst exhibited high catalytic activity and stability for Heck reaction.

中文翻译：

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壳聚糖/聚（甲基丙烯酸）负载钯纳米纤维的制备，作为高效稳定的Heck反应催化剂

摘要

含Pd ^2+的均相壳聚糖/聚（甲基丙烯酸）溶液通过添加吡啶-2-羧醛成功制备了阳离子。然后，将该均质溶液平滑地电纺成平均直径为442±163 nm的均匀复合纳米纤维，然后在高温下退火以提高耐溶剂性。扫描电子显微镜（SEM）分析表明，随着退火温度的升高，复合纳米纤维的耐溶剂性得到提高。FT-IR光谱表明，复合纳米纤维的化学结构在退火过程后没有被氧化。此外，钯物质被均匀地掺入复合纳米纤维内部。通过Heck反应评价了这些新型复合纳米纤维的催化性能。催化结果表明，这些复合纳米纤维非常有效地催化芳族碘化物与丙烯酸酯的Heck反应，收率超过86％。而且，这些复合纳米纤维可以在不降低产量的情况下重复使用10次。

图形摘要

通过静电纺丝和热技术制备了一种新型的钯嵌入壳聚糖复合纳米纤维毡。这种新型的纤维钯催化剂表现出高的催化活性和对Heck反应的稳定性。