【摘要】 丙酮氰醇的分解反应是有机溶剂中一锅化法制备具杀虫活性的 (S)-a-氰基-3-苯氧基苄醇的第一步反应。丙酮氰醇能被碱催化分解。考虑到生物催化剂与化学催化剂的相容性,并便于反应器中进行连续反应,阴离子交换树脂被用作本反应的催化剂。研究了两种国产碱性树脂D296与D301催化性能的优劣,发现弱碱性树脂D301优于强碱性树脂D296。通过比较两种极性不同的溶剂对同一种树脂催化性能的影响发现,极性低的溶剂条件下D301的催化性能好。不同溶剂条件下, 温度对树脂催化性能的影响结果显示:在实验温度范围内,55C为最适反应温度。转速试验发现,当转速达到190 r min-1 时, 外扩散对反应的影响可以忽略。更多还原

【Abstract】 Acetone cyanohydrin was used as the hydrogen cyanide donor in the one-pot reaction——the decomposing reaction of acetone cyanohydrin in organic media which is the first-step reaction of preparing the important intermidate of bio-insecticide pyrethroids. In order to study the kinetic characteristics of the one-pot reaction, and to serve for designing appropriate reactor, the kinetics of the decomposing reaction of acetone cyanohydrin was studied. Since the acetone cyanohydrin can be decomposed by bases and considering the compatibility of biocatalyst with chemical catalyst and the convenience of successive operation in bioreactor, anion exchange resins were used as the catalyst in this reaction. Two domestic base resins, D296 and D301 were used respectively and the results showed that the weak basic resin, D301 is better than the strong basic resin, D296. Two kinds of solvent with different polarities (anhydrous diisopropyl ether and vinyl acetate) were used respectively and it was found that D301 showed better catalytic chacteristics in the lower polarity solvent, diisopropyl ether. The reaction was studied at different temperatures and the optimal temperature was found to be 55℃ under the experimental conditions. It was also found that in both solvents the effect of the catalyst external surface diffusion resistant on the reaction rate can be neglected if the rotation speed is over 190rmin-1.更多还原