Economical and efficient aqueous reductions of high melting-point imines and nitroarenes to amines: promotion effects of granular PTFE
作者:Tao Li、Xiaoxue Cui、Lili Sun、Chunbao Li
DOI:10.1039/c4ra04528a
日期:——
The reductions of high melting-point imines and nitroarenes to amines in aqueous media using Zn powder, granular PTFE (polytetrafluoroethylene), catalytic Aliquat 336 and NH4Cl or 5% NaOH at room temperature have been achieved. A major advantage of this procedure is that the cost of the catalyst is only 1/7200 of that of a previously reported nitroaromatic aqueous reduction catalyst. Altogether 13 imines and 11 nitroarenes were reduced to the corresponding amines with excellent yields. The effects of the amount of granular PTFE, and solubilities and melting points of the substrates, and melting points of the products on the reaction rates are discussed. For the first time, the relationship between the aqueous reaction rates and melting points of the products was investigated, which leads to a conclusion that lower melting-point products form faster than higher melting-point ones in the aqueous reductions. The Aliquat 336, granular PTFE and water are all recyclable.
使用 Zn 粉末、颗粒状 PTFE(聚四氟乙烯)、催化剂 Aliquat 336 和 NH4Cl 或 5%NaOH,在室温下实现了高熔点亚胺和硝基烯烃在水介质中还原成胺的过程。这种方法的一个主要优点是催化剂的成本仅为之前报道的硝基芳烃水还原催化剂的 1/7200。总共有 13 个亚胺和 11 个硝基烯烃被还原成相应的胺,而且收率极高。讨论了颗粒状聚四氟乙烯的用量、底物的溶解度和熔点以及产物的熔点对反应速率的影响。首次研究了水反应速率与产物熔点之间的关系,从而得出结论:在水还原反应中,低熔点产物的形成速度快于高熔点产物。Aliquat 336、粒状聚四氟乙烯和水均可回收利用。