In this work, fluorescein was incorporated with an equal molar of 1-chloro-4-nitrobenzene and double potassium carbonate (molar ratio), the solvent of this reaction is dimethylacetamide (50 ml for 5 g of fluorescein). The solution was stirred in at 110 °C for 24 h, after that cooled to the room temperature and precipitated in cold water, but a solid, similar to potassium carbonate, remains at the bottom of the reaction vessel, and the efficiency is very low (25%). I don't know the cau