Reliable Mechanochemistry: Protocols for Reproducible Outcomes of Neat and Liquid Assisted Ball-mill Grinding Experiments.
Reliable Mechanochemistry: Protocols for Reproducible Outcomes of Neat and Liquid Assisted Ball-mill Grinding Experiments.
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可靠的机械化学：纯和液体辅助球磨机研磨实验的可重复结果的协议。
DOI：
10.3791/56824
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
J. Sanders
中科院分区：
文献类型：
--
作者：
Ana M. Belenguer;G. Lampronti;J. Sanders
球磨机研磨的平衡结果可以作为实验条件中甚至微小变化的函数而显著改变，例如存在非常少量的添加溶剂。为了可重复地和准确地捕获这种灵敏度，实验人员需要仔细考虑可能影响所研究的球磨机研磨反应的每一个因素，从确保研磨罐在使用前清洁和干燥，到准确地添加起始材料的化学计量，到验证溶剂体积的输送是准确的，以确保很好地理解溶剂和粉末之间的相互作用，并且如果需要，将特定的浸泡时间添加到该过程中。初步的动力学研究对于确定达到平衡所需的研磨时间至关重要。只有这样，才能在球磨机液体辅助研磨（LAG）下获得作为溶剂浓度函数的精细相组成曲线。通过使用类似于这里所提出的严格和仔细的程序，可以获得几乎所有铣削系统的铣削平衡曲线。我们用来证明这些程序的系统是一个二硫键交换反应，从两个同二聚体的等摩尔混合物开始，以获得平衡定量的异二聚体。后者通过球磨机研磨形成两种不同的多晶型物，形式A和形式B。研磨平衡时的比率R = [晶形B] /（[晶形A] + [晶形B]）取决于研磨罐中溶剂的性质和浓度。
The equilibrium outcomes of ball mill grinding can dramatically change as a function of even tiny variations in the experimental conditions such as the presence of very small amounts of added solvent. To reproducibly and accurately capture this sensitivity, the experimentalist needs to carefully consider every single factor that can affect the ball mill grinding reaction under investigation, from ensuring the grinding jars are clean and dry before use, to accurately adding the stoichiometry of the starting materials, to validating that the delivery of solvent volume is accurate, to ensuring that the interaction between the solvent and the powder is well understood and, if necessary, a specific soaking time is added to the procedure. Preliminary kinetic studies are essential to determine the necessary milling time to achieve equilibrium. Only then can exquisite phase composition curves be obtained as a function of the solvent concentration under ball mill liquid assisted grinding (LAG). By using strict and careful procedures analogous to the ones here presented, such milling equilibrium curves can be obtained for virtually all milling systems. The system we use to demonstrate these procedures is a disulfide exchange reaction starting from the equimolar mixture of two homodimers to obtain at equilibrium quantitative heterodimer. The latter is formed by ball mill grinding as two different polymorphs, Form A and Form B. The ratio R = [Form B] / ([Form A] + [Form B]) at milling equilibrium depends on the nature and concentration of the solvent in the milling jar.