微反应器内邻氨基苯甲酸甲酯的连续重氮化工艺

Continuous-flow diazotization of methyl anthranilate in microreactor system

邻氨基苯甲酸甲酯(MA)的重氮盐是一种典型的重氮化合物,因其具有高化学选择性可高效合成结构复杂分子被广泛应用于现代有机合成领域。传统半间歇合成工艺中的固有缺陷以及MA重氮盐的潜在爆炸性,限制了其在工业规模上的应用。本文基于此提出了在“心形结构”的高通量微通道反应器内合成MA重氮盐的连续流工艺。在单因素实验的基础上,采用Box-Behnken design(BBD)中心组合原理构建响应面模型对工艺进行优化,研究了不同反应条件之间交互效应对反应的影响并与实验室规模的半间歇合成工艺进行了比较。结果表明,微反应器内连续重氮化合成工艺对降低因素交互效应、提高工艺可控性、抑制平行副反应有显著的效果。经优化后的最佳工艺条件为n(MA)∶n(亚硝酸钠)∶n(盐酸)=1∶1.15∶2.67,反应温度为34.62℃,停留时间为45.07s,在此条件下MA重氮盐收率可达92%,相比于半间歇合成工艺提高了10%。这种新的合成方式可有效解决传统半间歇工艺中重氮化合成体系对温度的高敏感性,避免了反应温度控制困难、高潜在热失控风险带来的安全隐患。

The diazonium salt of methyl anthranilate(MA)is an typical diazo compound,which has been widely used in the field of modern organic synthesis due to its high chemical selectivity and high efficiency in the synthesis of complex molecules.The inherent defects in the traditional semi-batch synthesis process and the potential explosiveness of MA diazonium salt limit its application on industrial scale.In this paper,a continuous flow process for the synthesis of MA diazonium salt was proposed in a high-throughput microchannel reactor with“heart-cell”structure.Based on the single factor experiment,Box-Behnken design(BBD)center combination principle was used to construct the response surface model to optimize the process.The effects of interaction between different reaction conditions on the reaction were studied and compared with the laboratory scale semi-batch synthesis process.The results showed that the continuous diazotization process in micro reactor had significant effect on reducing the interaction effect of factors,improving the process controllability and inhibiting the parallel side reactions.The yield of MA diazonium salt of 92%was achieved under the optimized reaction conditions of n(MA)∶n(sodium nitrite)∶n(hydrochloric acid)=1∶1.15∶2.67,reaction temperature 34.62℃and residence time 45.07s,which is 10%higher than the semi-batch synthesis process.The high sensitivity to temperature of the diazotization synthesis system in the traditional semi-batch process can be effectively solved by this new synthesis method,which avoided the security hidden danger caused by the difficulty of reaction temperature control and the risk of high potential thermal runaway.