Acetic Anhydride Method of Purifying Crude Acetic Anhydride and Method of Producing Polyoxytetramethylene Glycol Using Acetic Anhydride

摘要

PURPOSE: Provided is a method for purifying the crude acetic anhydride which can improve quality of polyoxytetramethylene glycol(PTMG). Also, a method for producing polyoxytetramethylene glycol is provided by using the same. CONSTITUTION: In the method for producing polyoxytetramethylene glycol by the ring-opening polymerization of tetrahydrofuran in the presence of acetic anhydride and an acid catalyst, it is characterized by carrying out the ring-opening polymerization using the acetic anhydride having a diketene concentration of = 10 ppm. Thereby, the polyoxytetramethylene glycol having improved transparency and an excellent color tone can be obtained.