3-Hydroxypropylammonium acetate (HPAA) ionic liquid: an effective acidic media in efficient conversion of anilines into aryl isocyanates

A simple and mild procedure for the conversion of anilines into aryl isocyanates is described using the 3-hydroxypropylammonium acetate (HPAA) ionic liquid as a novel and efficient media has been explored in the synthesis of aryl isocyanates from the reaction of substituted urea with sodium nitrite in a water immiscible solvent. This ionic liquid can be easily recovered and reused for many times without noticeable loss of activity.