Abstract:
Cobalt-aluminum-layered double hydroxides containing carboxymethyl β-cyclodextrin (CMβCD) were synthesized by coprecipitation and evaluated as a cobalt source for the 4-nitrophenol reduction in an aqueous medium. Several physicochemical techniques (XRD, FTIR, TGA) indicated the intercalation of the anionic cyclodextrin without damages to the hydrotalcite-type structure. These lamellar cobalt-aluminum hybrid materials (CoAl_CMβCD) were evaluated in the 4-nitrophenol reduction and showed higher activities in comparison with the CMβCD-free standard material (CoAl_CO3). To rationalize these results, a set of experimental controls going from physical mixtures of CoAl_CO3 with different cyclodextrins to other cobalt-based materials were investigated, highlighting the beneficial effects of both the layered double hydroxide and CMβCD-based hybrid structures. CMβCD also showed a beneficial effect as an additive during the 4-nitrophenol reduction. CoAl_CO3, dispersed in a fresh CMβCD solution could be re-used for five successive cycles without the loss of activity.
摘要:
通过共沉淀合成了含有羧甲基β-环糊精(CMβCD)的钴-铝层状双氢氧化物,并评估了其作为在水性介质中还原4-硝基苯酚的钴源。几种物理化学技术(XRD,FTIR,TGA)表明阴离子环糊精的嵌入没有破坏水滑石型结构。这些层状钴铝杂化材料(CoAl_CMβCD)在4-硝基苯酚还原评价和显示更高的活性与无CMβCD标准材料(CoAl_CO3)相比。为了使这些结果合理化,研究了从CoAl_CO3与不同环糊精的物理混合物到其他钴基材料的一组实验对照,强调了层状双氢氧化物和基于CMβCD的混合结构的有益效果。CmβCD在4-硝基苯酚还原过程中也显示出作为添加剂的有益效果。CoAl_CO3,分散在一个新鲜的CMβCD溶液可以重复使用五个连续的循环没有活性的损失。