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本工作研究的Knorr-Paal逆反应是吡咯化合物和羰基试剂羟胺作用生成γ-二肟的反应。对这一对应机制的动力学研究得出:1.反应受特殊酸催化;2.pH-速率关系为一“钟型”曲线;3.羟胺在反应中是一级的,整个反应为二级;4.反应可以在无水有机溶剂中进行;5.1-烷基-2,5-二甲基吡咯的反应速率比2,5-二甲基吡咯慢,6.极性大的溶剂中反应速率较快;7.1-取代苯基-2,5-二甲基吡咯化合物与羟胺作用其Hammett关系在pH4.5时除取代基为P-Meu外为-ρ=-0.309的直线,在pH6.5时为一向下弯的曲线。
The work Knorr-Paal reverse reaction is pyrrole compound and carbonyl reagent hydroxylamine generated γ-dioxime reaction. Kinetic studies on this mechanism show that: 1. The reaction is catalyzed by a special acid; 2. The pH-rate relationship is a “bell-shaped” curve; 3. The hydroxylamine is one-stage in the reaction and the whole reaction is two-stage ; 4. The reaction can be carried out in anhydrous organic solvent; the reaction rate of 5.1-alkyl-2,5-dimethylpyrrole is slower than that of 2,5-dimethylpyrrole; 6. The reaction rate Faster; the Hammett relationship of 7.1 -substituted phenyl-2,5-dimethylpyrrole compounds to hydroxylamine at-4.5 at pH 4.5 with a -ρ = -0.309 outside the P-Meu substituent at pH 6.5 When the curve has always been down.