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.

主权项

1. A method for producing a pyromellitic dianhydride comprising at least the following steps:
(1) a step of preparing a raw material solution by dissolving a raw material of 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 while stirring the raw material solution, (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, (4) a step of taking out the pyromellitic dianhydride subjected to the degassing treatment, and (5) a step of preparing powder and granular pyromellitic dianhydride in an inert gas atmosphere.