Solvent-free synthesis of diketopyrrolo [3,4-c] pyrrole pigments

The paper describes environmentally friendly and cost effective solvent-free multistep & multi-reagent process of the synthesis of.diketopyrrolo[3,4-c]pyrrole/2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP) pigments, a new class of most recently introduced high-performance pigments, now in use for a variety of applications, beyond colour appearance , such as liquid crystal displays (LCD) of electronic equipments & TV monitors. Silent features of the process versus state-of-the-art of process, reaction mechanism of the in-situ multistep synthesis and mechanism of the formation of by-products are discussed. Moreover, the process provides the only approach to the stepwise synthesis of unsymmetrical diketopyrrolo pyrrole molecules. The process is particularly aimed at reducing carbon emissions and for energy saving in chemical processes.