In Situ Monitoring Of A Quasi Solid-State Diffusion-Driven Cocrystallization In The Diphenylamine-Benzophenone System

Diphenylamine reacts with benzophenone in the solid state through the formation of a eutectic liquid intermediate, from which the final product, in the form of a hydrogen-bonded cocrystal, is finally formed. By a simple experiment, the phase diagram of the benzophenone/diphenylamine system is effectively divided into two parts, which enabled monitoring of the overall process from the side of each reactant separately. Accompanied by isothermal and nonisothermal spectroscopic monitoring of the system, this provides additional details of the mechanistic pathway of the process of cocrystal formation through a metastable liquid intermediate phase.