In Situ Monitoring of Mechanochemical Synthesis of Calcium Urea Phosphate Fertilizer Cocrystal Reveals Water-Based Autocatalysis

Using the mechanosynthesis of the calcium phosphate and urea fertilizer cocrystal as a model, we provide the first in situ investigation of autocatalysis in a mechanochemical reaction. The application of in situ Raman spectroscopy and synchrotron X-ray diffraction provided the first direct evidence of a mechanochemical system in which a reaction product (water) mediates the rate of transformation and underpins positive feedback kinetics.