Process for preparing squaraines

摘要

A process for forming finely divided squaraine particles is disclosed comprising dissolving squaraine material in an organic base selected from the group consisting of primary organic amines and secondary organic amines, neutralizing the organic base with an acid selected from the group consisting of organic acids and inorganic acids thereby precipitating the squaraine material as finely divided particles in a liquid medium, and separating the finely divided particles from the liquid medium.