It is mainly used as a solvent for synthetic fiber (acrylonitrile) and polyurethane spinning and synthesis of polyamide resin, and also used as an extractive distillation solvent for the separation of phenethylenes from C8 fraction, and widely used in polymer films and coatings. It can be used as catalyst of reaction, electrolytic solvent, paint remover and many kinds of crystalline solvent adducts and complexes.