氨基醇杂多酸类离子液体催化环酮的Baeyer-Villiger氧化反应

合成了一系列氨基醇杂多酸类离子液体,并将其用于催化环酮的Baeyer-Villiger氧化反应.以2-庚基环戊酮为模板底物,H₂O₂为氧化剂,探究了此类氨基醇杂多酸类离子液体的催化活性,筛选出催化活性最高的催化剂为[Pro-ps]H₂PW₁₂O₄₀,最佳反应条件:n(2-庚基环戊酮)∶n(催化剂)∶n(H₂O₂)=1∶0. 03∶4,反应温度40℃,反应时间8 h,无溶剂.在最佳条件下,2-庚基环戊酮的转化率为98. 19%,产物δ-十二内酯的选择性可达82. 84%.水相中的离子液体[Pro-ps]H₂PW₁₂O₄₀经干燥后可以重复使用.经过5次循环使用后催化活性未见明显下降.[Pro-ps]H₂PW₁₂O₄₀还可用于催化其它多种环酮的Baeyer-Villiger氧化反应,结果表明,该催化剂具有良好的...     

Atomically Dispersed Zn-Pyrrolic-N4 Cathode Catalysts for Hydrogen Fuel Cells

To achieve practical application of fuel cell, it is vital to develop highly efficient and durable Pt-free catalysts. Herein, we prepare atomically dispersed ZnNC catalysts with Zn-Pyrrolic-N₄ moieties and abundant mesoporous structure. The ZnNC-based anion-exchange membrane fuel cell (AEMFC) presents an ultrahigh peak power density of 1.63 and 0.83 W cm⁻² in H₂-O₂ and H₂-air (CO₂-free), and also exhibits long-term stability with more than 120 and 100 h for H₂-air (CO₂-free) and H₂-O₂, respectively. Density functional calculations further unveil that the Zn-Pyrrolic-N₄ structure is the origin of high activity of as-synthesized ZnNC catalyst, while the Zn-Pyridinic-N₄ moiety is inactive for oxygen reduction reaction (ORR), which successfully explain the puzzle why most Zn-metal-organic framework -derived ZnNC catalysts in previous reports did not present good ORR activity because of their Zn-Pyridinic-N₄ moieties. This work offers a new route for speeding up development of AEMFCs.