In-situ reaction monitoring of a mechanochemical ball mill reaction with solid state NMR

Sustainability Assessment of Mechanochemistry by Using the Twelve Principles of Green Chemistry

“…[212,213] On the other hand, the formation of bulk atomic and electronic structure during a mechanochemical reactions have been recently monitored by coupling X-ray absorption spectroscopy and X-ray diffraction, [214] and in 2020 in situ monitoring of mechanochemical reactions with solid state NMR was also described. [215] In the case of mechanochemical reactions triggered by pulsed ultrasonication experiments (Figure 6e), synchronous optical measurements by real-time UV-vis spectroscopy have enabled to acquire kinetic information to understand the influence of polymer structure and composition on mechanochemical activity (Figure 6e). [216] As mentioned above, the adoption of in-process monitoring (GC 11) in the field of mechanochemistry has permitted the elucidation of mechanistic steps in mechanochemical reactions, [205] as well as the correlation of milling parameters on the course of mechanochemical reactions, [217] the observation of short-lived polymorphic materials, [90] reaction intermediates, [91] and a better understanding of the effect caused by milling additives.…”

“…Complementarily, formation of volatile products in ball milling reactions has been monitored by gas chromatography (Scheme 10), [168] while online spectroscopic identification of gaseous products generated by ball milling has been achieved by nondispersive infrared spectroscopy [212,213] . On the other hand, the formation of bulk atomic and electronic structure during a mechanochemical reactions have been recently monitored by coupling X‐ray absorption spectroscopy and X‐ray diffraction, [214] and in 2020 in situ monitoring of mechanochemical reactions with solid state NMR was also described [215] …”

Role of Mixing and Milling in Mechanochemical Synthesis (Review)

“…Interest in the study of mechanochemical reactions directly in apparatuses in the in-situ/operando mode has splashed in recent years. There is a very wide range of instrumental methods that allow one to monitor the composition and structure of the reaction mixture at all transformation stages, detect intermediate products, and control the temperature; it includes, in particular, diffraction [96, 170-174, 192, 193, 197-212], Raman spectroscopy [154,[213][214][215], X-ray spectroscopy [216,217], and solid-state NMR [218]. Special designs of apparatuses for mechanical exposure have been proposed to be both combined with laboratory instruments and installed at workstations in synchrotron research centers [218][219][220][221].…”

“…There is a very wide range of instrumental methods that allow one to monitor the composition and structure of the reaction mixture at all transformation stages, detect intermediate products, and control the temperature; it includes, in particular, diffraction [96, 170-174, 192, 193, 197-212], Raman spectroscopy [154,[213][214][215], X-ray spectroscopy [216,217], and solid-state NMR [218]. Special designs of apparatuses for mechanical exposure have been proposed to be both combined with laboratory instruments and installed at workstations in synchrotron research centers [218][219][220][221]. But with all the obvious advantages of in situ/operando methods in terms of continuous monitoring of processes without interfering in their course for sampling [222], a serious problem has been identified due to the fact that the researcher's field of view is not the entire sample, but a small part of it, and far from being always representative part.…”

In situ monitoring of mechanochemical covalent organic framework formation reveals templating effect of liquid additive

“…[34,35] Bulk mechanochemical reactions are usually performed by either direct grinding of reactants (neat grinding), or in the presence of grinding additives, as in liquid-assisted grinding (LAG). [36] Recently, mechanistic studies of mechanochemistry have been facilitated by the development of methods for in situ monitoring using synchrotron X-ray powder diffraction (XRPD), [37,38] Raman spectroscopy, [39,40] X-ray absorption spectroscopy, [41] solid-state nuclear magnetic resonance spectroscopy (ssNMR), [42] and/or thermal measurements. [43] This has enabled rapid progress in fundamental understanding of mechanochemical processes and the discovery of new materials.…”