Experimental and Theoretical Study of Selectivity in Mechanochemical Cocrystallization of Nicotinamide with Anthranilic and Salicylic Acid

Selectivity in mechanochemical cocrystal formation between nicotinamide and anthranilic acid or salicylic acid was studied using tandem in situ reaction monitoring by powder X-ray diffraction (PXRD) and Raman spectroscopy. Selectivity was probed by offering a competing cocrystal coformer to a previously prepared cocrystal or under competitive reaction conditions where all cocrystal coformers, in different stoichiometric ratios, were introduced together in the starting reaction mixture. Reaction paths were dependent on the starting mixture composition, and we find that the formation of intermediates and the final product can be predicted possible reaction mixtures. In some cases, quantitative assessment Raman monitoring, directly indicating, for the first time, different crystalline level of the reaction mixture.