Lukin Stipe, Stolar Tomislav, Tireli Martina, Blanco Maria Valeria, Babić Darko, Friščić Tomislav, Užarević Krunoslav, Halasz Ivan
Ruđer Bošković Institute, Bijenička 54, 10000, Zagreb, Croatia.
ESRF, the European Synchrotron, Grenoble, France.
Chemistry. 2017 Oct 9;23(56):13941-13949. doi: 10.1002/chem.201702489. Epub 2017 Aug 15.
We report herein quantitative in situ monitoring by simultaneous PXRD and Raman spectroscopy of the mechanochemical reaction between benzoic acid and nicotinamide, affording a rich polymorphic system with four new cocrystal polymorphs, multiple phase transformations, and a variety of reaction pathways. After observing polymorphs by in situ monitoring, we were able to isolate and characterize three of the four polymorphs, most of which are not accessible from solution. Relative stabilities among the isolated polymorphs at ambient conditions were established by slurry experiments. Using two complementary methods for in situ monitoring enabled quantitative assessment and kinetic analysis of each studied mechanochemical reaction, even when involving unknown crystal structures, and short-lived intermediates. In situ Raman monitoring was introduced here also as a standalone laboratory technique for quantitative assessment of mechanochemical reactions and understanding of mechanochemical reactivity. Our results provide an important step toward a complete and high-throughput quantitative approach to mechanochemical reaction kinetics and mechanisms, necessary for the development of the mechanistic framework of milling reactions.
我们在此报告通过同步PXRD和拉曼光谱对苯甲酸与烟酰胺之间的机械化学反应进行定量原位监测，该反应产生了一个丰富的多晶型体系，包括四种新的共晶多晶型物、多个相变以及多种反应途径。通过原位监测观察到多晶型物后，我们能够分离并表征四种多晶型物中的三种，其中大多数无法从溶液中获得。通过淤浆实验确定了分离出的多晶型物在环境条件下的相对稳定性。使用两种互补的原位监测方法能够对每个研究的机械化学反应进行定量评估和动力学分析，即使涉及未知晶体结构和短寿命中间体。原位拉曼监测在此也作为一种独立的实验室技术被引入，用于机械化学反应的定量评估和机械化学反应活性的理解。我们的结果朝着机械化学反应动力学和机理的完整且高通量定量方法迈出了重要一步，这是研磨反应机理框架发展所必需的。
