Michalchuk AAL, Tumanov IA, Konar S, Kimber SAJ, Pulham CR, Boldyreva EV. Challenges of Mechanochemistry: Is In Situ Real-Time Quantitative Phase Analysis Always Reliable? A Case Study of Organic Salt Formation.
ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2017;
4:1700132. [PMID:
28932677 PMCID:
PMC5604370 DOI:
10.1002/advs.201700132]
[Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Indexed: 05/21/2023]
Abstract
Mechanochemical methods offer unprecedented academic and industrial opportunities for solvent-free synthesis of novel materials. The need to study mechanochemical mechanisms is growing, and has led to the development of real-time in situ X-ray powder diffraction techniques (RI-XRPD). However, despite the power of RI-XRPD methods, there remain immense challenges. In the present contribution, many of these challenges are highlighted, and their effect on the interpretation of RI-XRPD data considered. A novel data processing technique is introduced for RI-XRPD, through which the solvent-free mechanochemical synthesis of an organic salt is followed as a case study. These are compared to ex situ studies, where notable differences are observed. The process is monitored over a range of milling frequencies, and a nonlinear correlation between milling parameters and reaction rate is observed. Kinetic analysis of RI-XRPD allows, for the first time, observation of a mechanistic shift over the course of mechanical treatment, resulting from time evolving conditions within the mechanoreactor.
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