The industrially relevant reaction between nitriles and hydroxylamine yielding amidoximes was studied in different molecular solvents and in ionic liquids. In industry, this procedure is carried out on the ton scale in alcohol solutions and the above transformation produces a significant amount of unexpected amide by-product, depending on the nature of the nitrile, which can cause further analytical and purification issues. Although there were earlier attempts to propose mechanisms for this transformation, the real reaction pathway is still under discussion. A new detailed reaction mechanistic explanation, based on theoretical and experimental proof, is given to augment the former mechanisms, which allowed us to find a more efficient, side-product free procedure. Interpreting the theoretical results obtained, it was shown that the application of specific imidazolium, phosphonium and quaternary ammonium based ionic liquids could decrease simultaneously the reaction time while eliminating the amide side-product, leading to the targeted product selectively. This robust and economic procedure now affords a fast, selective amide free synthesis of amidoximes.
在不同分子溶剂和
离子液体中,对腈与
羟胺生成脒基
肟的工业相关反应进行了研究。在工业上,这一过程在吨级的醇溶液中进行,而上述转化过程会产生大量意外的酰胺副产物,这取决于腈的性质,可能导致进一步的分析和纯化问题。尽管之前有人尝试提出这一转化的机理,但真正的反应途径仍在讨论之中。基于理论和实验证据,给出了一个新的详细反应机理解释,以增强先前的机理,这使我们能够找到一种更高效、无副产物的方法。通过对所获得理论结果的解释,结果显示,使用特定的
咪唑鎓、
磷鎓和季
铵盐基
离子液体,不仅可以同时缩短反应时间,还能消除酰胺副产物,从而选择性地得到目标产物。这一稳健且经济的程序现在提供了一种快速、选择性的无酰胺脒基
肟合成方法。