酰胺类酸性离子液体催化Oxa-Michael加成反应

设计合成并表征了N-甲基吡咯烷酮磷酸盐(NMPH]H2PO4)、己内酰胺磷酸盐(NHCH]H2PO4)、N,N'-二甲基甲酰胺磷酸盐(DMFH]H2PO4)和N,N'-二甲基乙酰胺磷酸盐(DMEH]H2PO4)等酰胺类质子酸离子液体;将其用于β-苯乙醇和丁烯酮的Oxa.Michael加成反应中,考察了离子液体阳...

Oxa-Michael Addition Catalyzed by Amide-Based Acidic Ionic Liquids

A series of acidic ionic liquids, including N-methyl-2-pyrrolidonium dihydrogen phosphate (NMPH]H₂PO₄), caprolactam dihydrogen phosphate (NHCH]H₂PO₄), N,N′-dimethylformamide dihydrogen phosphate (DMFH]H₂PO₄), and N,N′-dimethylacetamide dihydrogen phosphate (DMEH]H₂PO₄), were synthesized and characterized. Oxa-Michael addition of β-phenylethanol to methyl vinyl ketone (MVK) was used as a model reaction. The effects of cation structure, ionic liquid amount, β-phenylethanol/MVK ratio, reaction temperature, and reaction time were measured. Under the optimized conditions of n(β-phenylethanol):n(MVK) = 1:2, 25 °C, 24 h and using NMPH]H₂PO₄ as catalyst, the β-phenylethanol conversion was 95%. The ionic liquid was stable and could be reused at least 5 times with a slight loss of activity. All the amide-based acidic ionic liquids gave higher conversion compared with imidazolium acidic ionic liquid, which showed that the effect of cation structure was important. A possible reaction mechanism was proposed and the evidence for the role of amide-based acidic ionic liquids in Oxa-Michael addition was given.