Method for producing pyromellitic dianhydride, pyromellitic dianhydride produced by the method, and apparatus therefor

摘要

A method for producing a highly pure PMDA comprises at least the following steps: (1) a step of preparing a raw material solution by dissolving a raw material of a pyromellitic dianhydride in an acetic acid solvent, (2) a step of preparing a precursor pyromellitic dianhydride by recrystallizing the pyromellitic dianhydride in the prepared raw material solution and separating the acetic acid solvent, (3) a step of performing a degassing treatment on the precursor pyromellitic dianhydride by stirring the precursor pyromellitic dianhydride in a fluidized state while heating under reduced-pressure conditions, and (4) a step of taking out the pyromellitic dianhydride subjected to the degassing treatment.