基于杂化相变纳米微胶囊的格氏试剂制备引发阶段热失控抑制机理研究

Grignard reagent is one of the common chemicals in fine chemicals. The safety of preparation process of Grignard reagent is one of issues of fine chemicals currently. The increasing induction period is the core problem which can lead to inappropriate operations (e.g., excessive addition of reactants or raising the operation temperature to accelerate the reaction) that could also result in a runaway reaction. Therefore, this project proposed a novel strategy which the critical criterion of thermal runaway of Grignard reagent formation is used to detect the thermal runaway phenomenon in the early and the hybrid nanoencapsulated phase change materials (H-NanoPCMs) is used to inhibit thermal runaway. This project will study the effect of main factors which influence the induction period lag on thermal evolution of initiating stage. The critical criterion of thermal runaway of initiating stage of Grignard reagent formation is established by the nonlinear fitting and parameter sensitivity analysis. The hybrid nanoencapsulated phase change materials are prepared by miniemulsion in situ polymerization, sol-gel and self-assembly. The mechanism of multilevel molecular interactions is discussed. The prepared (H-NanoPCMs) is used for the shortstopping of thermal runaway of Grignard reagent formation. The implementation of this project will provide new ideas and theoretical basis for the safety of preparation process of Grignard reagent.

格氏试剂是精细化工领域常用的化学试剂之一，其制备过程的热安全性是精细化工领域关注的问题之一。格氏试剂制备反应引发阶段，由于物料中金属镁表面氧化膜、微量水分以及引发剂等影响，导致反应引发阶段诱导期较长，造成物料累积，从而引起热失控事故是影响制备过程安全性的核心问题。为此，本项目提出“通过建立格氏试剂制备反应引发阶段热失控临界判据辨识早期热失控，研究利用杂化相变纳米微胶囊抑制热失控事故”的新思路。深入研究影响反应诱导期滞后的相关因素对引发阶段热演化的作用机制，建立引发阶段热失控临界判据模型；采用细乳液原位聚合法等方法制备有机-无机杂化壁材液固相变纳米微胶囊；将制备的微胶囊与建立的临界判据相结合，探索液固相变纳米微胶囊对格氏试剂制备反应失控抑制的影响规律，揭示纳米相变微胶囊混合分散和相变换热协同抑制机理，为提高格氏试剂制备引发阶段的安全性提供新的思路与理论依据。

格氏试剂是精细化工领域常用的化学试剂之一，其制备过程的热安全性是精细化工领域关注的问题之一。格氏试剂制备反应引发阶段，由于物料中金属镁表面氧化膜、微量水分以及引发剂等影响，导致反应引发阶段诱导期较长，造成物料累积，从而引起热失控事故是影响制备过程安全性的核心问题。本项目针对正丁基溴化镁格氏试剂（n-BuMgBr）合成反应引发阶段为对象，采用反应量热、在线红外监测、高斯理论计算等技术研究了引发阶段放热机理和反应风险，根据密度泛函理论计算，结合实验了解该反应的路径和活化能；其次，制备壁材是二氧化硅，芯材是正十八烷的相变纳米胶囊，以及壁材为聚苯乙烯-二氧化硅杂化，芯材为正十八烷的相变微胶囊，对其微观形貌、化学结构、晶体结构、相变性能、热稳定性进行了测试表征，将相关相变胶囊用于引发阶段热失控抑制，揭示相变胶囊对反应热失控抑制机理，验证了相变胶囊对反应热失控抑制的相变潜热储能与对流换热强化效应的协同作用，为格氏试剂制备反应热失控监测预警、早期抑制提供新的思路与理论依据。