Preparation of Carbodiimides Using Phase-Transfer Catalysis

Article abstract of DOI:10.1055/s-1987-27992

A new method is described for the preparation of carbodiimides by dehydration of ureas with arenesulfonyl chlorides under solid-liquid phase-transfer catalytic (PTC) conditions using solid potassium carbonate as a base and a lipophilic quaternary ammonium salt as a catalyst.The method is generally applicable for the synthesis of disubstituted carbodiimides, but is especially useful for unsymmetrically substituted carbodiimides.The basic carbodiimides prepared were identified in the form of the more stable, crystalline quaternary salts.