Kinetic study on the effect of solvent in ‘vapor-phase’ Beckmann rearrangement of cyclohexanone oxime on silicalite-1
Kinetic study on the effect of solvent in ‘vapor-phase’ Beckmann rearrangement of cyclohexanone oxime on silicalite-1
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DOI：
10.1016/s1387-1811(99)00218-8
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发表时间：
2000-04
影响因子：
5.2
通讯作者：
T. Komatsu;T. Maeda;T. Yashima
中科院分区：
文献类型：
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作者：
T. Komatsu;T. Maeda;T. Yashima
用动力学方法研究了溶剂对Silicalite-1催化剂上环己酮肟气相Beckmann重排反应的影响。检测了具有各种极性的溶剂的反应。结果表明，中等极性的乙醇对ε-己内酰胺的生成是有效的。ε-己内酰胺的生成速率符合Langmuir型速率方程。该实验速率方程由反应方案解释，其中溶剂分子的攻击引起的ε-己内酰胺的脱附是速率决定步骤。红外光谱测定证实了ε-己内酰胺的脱附是由乙醇分子的进攻引起的。乙醇和甲醇对ε-己内酰胺的产率有特定的提高，这可能是由于OH基团的影响。然而，具有较高碳数的醇由于其疏水性质而降低产率。因此，乙醇和甲醇是环己酮肟在silicalite-1上进行Beckmann重排反应的最有效溶剂。
The effect of solvents in the ‘vapor-phase’ Beckmann rearrangement of cyclohexanone oxime was studied on silicalite-1 catalyst through kinetic measurements. Solvents with various polarities were examined for the reaction. It was found that ethanol, which has medium polarity, was effective in the formation of ε-caprolactam. The rate of ε-caprolactam formation fitted the Langmuir-type rate equation for the various solvents. This experimental rate equation was explained by the reaction scheme where the desorption of ε-caprolactam caused by the attack of a solvent molecule was the rate-determining step. IR measurements confirmed the desorption of ε-caprolactam induced by the attack of the ethanol molecule. Ethanol and methanol gave specific improvements in the yield of ε-caprolactam probably due to the effect of OH groups. However, alcohols with higher carbon numbers lowered the yield owing to their hydrophobic nature. Therefore, ethanol and methanol are the most effective solvents for the ‘vapor-phase’ Beckmann rearrangement of cyclohexanone oxime on silicalite-1.