Michalchuk Adam A L, Hope Karl S, Kennedy Stuart R, Blanco Maria V, Boldyreva Elena V, Pulham Colin R
EaStCHEM School of Chemistry and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh, UK.
Chem Commun (Camb). 2018 Apr 17;54(32):4033-4036. doi: 10.1039/c8cc02187b.
Resonant acoustic mixing (RAM) is a new technology designed for intensive mixing of powders that offers the capability to process powders with minimal damage to particles. This feature is particularly important for mixing impact-sensitive materials such as explosives and propellants. While the RAM technique has been extensively employed for the mixing of powders and viscous polymers, comparatively little is known about its use for mechanosynthesis. We present here the first in situ study of RAM-induced co-crystallisation monitored using synchrotron X-ray powder diffraction. The phase profile of the reaction between nicotinamide and carbamazepine in the presence of a small amount of water was monitored at two different relative accelerations of the mixer. In marked contrast to ball-milling techniques, the lack of milling bodies in the RAM experiment does not hinder co-crystallisation of the two starting materials, which occurred readily and was independent of the frequency of oscillation. The reaction could be optimised by enhancing the number of reactive contacts through mixing and comminution. These observations provide new insight into the role of various experimental parameters in conventional mechanochemistry using liquid-assisted grinding techniques.
共振声学混合（RAM）是一种专为粉末的强化混合而设计的新技术，它能够在对颗粒造成最小损害的情况下处理粉末。这一特性对于混合诸如炸药和推进剂等对冲击敏感的材料尤为重要。虽然RAM技术已被广泛应用于粉末和粘性聚合物的混合，但对于其在机械合成中的应用了解相对较少。我们在此展示了首次使用同步加速器X射线粉末衍射对RAM诱导的共结晶进行的原位研究。在混合器的两种不同相对加速度下，监测了在少量水存在的情况下烟酰胺和卡马西平之间反应的相分布。与球磨技术形成显著对比的是，RAM实验中没有研磨体并不妨碍两种起始原料的共结晶，共结晶很容易发生且与振荡频率无关。通过混合和粉碎增加反应接触次数可以优化该反应。这些观察结果为使用液体辅助研磨技术的传统机械化学中各种实验参数的作用提供了新的见解。
