Highly Efficient Epoxidation of Allylic Alcohols with Hydrogen Peroxide Catalyzed by Peroxoniobate-Based Ionic Liquids
作者:Chen Chen、Haiyang Yuan、Haifeng Wang、Yefeng Yao、Wenbao Ma、Jizhong Chen、Zhenshan Hou
DOI:10.1021/acscatal.6b00786
日期:2016.5.6
characterized by elemental analysis, HRMS, NMR, IR, TGA, etc. With hydrogen peroxide as an oxidant, these ILs exhibited excellent catalytic activity and recyclability in the epoxidation of various allylic alcohols under solvent-free and ice bath conditions. Interestingly, subsequent activity tests and catalyst characterization together with first-principles calculations indicated that the parent [Nb═O(O-O)(OH)2]−
这项工作报告了已制备的新型单体过氧杂酸根阴离子官能化离子液体(IL),命名为[A + ] [Nb═O(OO)(OH)2 ](A + =四丙基铵,四丁基铵或四己基铵阳离子)。用过氧化氢作为氧化剂,这些IL在无溶剂和冰浴条件下,在各种烯丙基醇的环氧化反应中表现出出色的催化活性和可回收性。有趣的是,随后的活性测试和催化剂表征以及第一性原理计算表明,母体[Nb═O(OO)(OH)2 ] -阴离子已被氧化为阴离子[Nb(OO)2(OOH)2 ] -在H 2 O 2存在下,H 2 O 2在反应过程中构成了真正的催化活性物质;与类似的过氧钨酸根阴离子相比,该阴离子具有更高的活性。此外,通过DFT(密度泛函理论)计算,在原子水平上探索了由[Nb(OO)2(OOH)2 ] -催化的底物(烯丙醇)的环氧化过程,发现它更有利于通过氢键机理发生,其中[Nb(OO)2(OOH)2 ]的过氧基团-通过形成氢键,HOH