Mixture of Ionic Liquids as Novel Media for Green Synthesis of Diketopyrrolopyrrole Pigments

A green method for the synthesis of high-performance diketopyrrolopyrrole pigments using diethyl succinate in the presence of mixture of ionic liquids is reported. Although, alkaline condition is needed in the succinate ester route for synthesis of the pigments, in the present study, the replacement possibility of conventional organic base by mixture of BMIMOH and BMIMBF4 ionic liquids was investigated. One of the points in this approach is utilization of diethyl succinate, a commercially available and low-cost reagent instead of di-t-butyl or t-amyl succinate as bulky esters which are recommended in conventional methods. The obtained results were compared with the results of synthesis in presence of each ionic liquid solely with sodium t-amyloxide.