Tetrabutylammonium bromide: An efficient, green and novel media for polycondensation of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione with diisocyanates

This is the first report of application of molten ionic liquid (MIL) for the synthesis of heterocyclic polyureas. An inexpensive and readily available MIL, tetrabutylammonium bromide (TBAB) was used for the synthesis of polymers. Therefore, polycondensation of 4-(4-dimethylaminophenyl)-1,2,4-triazolidine-3,5-dione (DAPTD) with various commercially available diisocyanates was performed in molten TBAB with or without dibutyltin dilurate (DBTDL) as a catalyst. The polymerization reaction gave similar results in the presence or absence of DBTDL, indicating that, the catalyst was not needed in this process. Various polyureas were obtained with high yields and moderate inherent viscosities ranging from 0.26 to 0.38 dL/g. This method was compared with the polymerization reaction in conventional solvent and in the presence of DBTDL as a catalyst. In the case of using TBAB, higher yields and inherent viscosities were obtained. This process was safe and green since toxic and volatile solvent such as N,N-dimethylacetamide (DMAc) was eliminated.