Ionic liquids can be designed by varying a great deal of anions and cations offering efficient CO₂ capture or CO₂ utilization. Generally, the anion played a key role, but the cation did not have a significant impact. Here, a strategy for rational design of functionalized ionic liquids for efficient synthesis of quinazoline-2,4(1H,3H)-diones from CO₂ has been developed through tuning the cations of aprotic ionic liquids. The basicity of cation affects its catalytic activity dramatically and the hydrogen bond from cation can promote this reaction. Then, hydroxyl functionalized ionic liquid [Ch][Im] was designed, which exhibited the best catalytic activity in this reaction. Through the combination of quantum-chemical calculations, NMR spectroscopic investigations, and controlled experiments, the results indicate that in situ generated [Ch][Im]-CO₂ complex is the real catalyst. Furthermore, aprotic IL [Ch][Im] exhibits good generality and reuseability. Remarkably, quinazoline-2,4(1H,3H)-dione can also be obtained under simulated flue gas system on a gram scale with excellent yield using [Ch][Im] as catalyst. As we know, this is the first time that obtains quinazoline-2,4(1H,3H)-dione in excellent yield under flue gas condition.

中文翻译：

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羟基官能化的非质子离子液体高效从CO ₂合成喹唑啉-2,4（1 H，3 H）-二酮

离子液体可通过改变阳离子和阴离子，提供高效的CO的大量被设计₂捕获或CO ₂的利用率。通常，阴离子起关键作用，但阳离子没有显着影响。在这里，一种合理设计功能化离子液体以从CO ₂有效合成喹唑啉-2,4（1 H，3 H）-二酮的策略通过调节非质子离子液体的阳离子已经开发出了N-己内酰胺。阳离子的碱性会极大地影响其催化活性，而阳离子中的氢键可促进该反应。然后，设计了羟基官能化的离子液体[Ch] [Im]，其在该反应中表现出最佳的催化活性。通过结合量子化学计算，NMR光谱研究和受控实验，结果表明原位生成的[Ch] [Im] -CO ₂络合物是真正的催化剂。此外，非质子IL [Ch] [Im]具有良好的通用性和可重复使用性。值得注意的是，喹唑啉-2,4（1 H，3 H使用[Ch] [Im]作为催化剂，也可以在模拟烟气系统下以克级以优异的收率获得二酮。众所周知，这是在烟气条件下首次以优异的收率获得喹唑啉-2,4（1 H，3 H）-二酮。