Method for production of pyromellitic dianhydride

摘要

A method for producing crystals of pyromellitic dianhydride is disclosed which is characterized by setting the water content of an atmosphere used in handling the crystals of pyromellitic dianhydride at a temperature of not higher than 120° C. at a level of not more than 4 vol. %. Particularly by supplying an inert gas having a water content of not more than 4 vol. % to the step of production, it is made possible to prevent the conversion of pyromellitic dianhydride by hydration very efficiently.