Method of regenerating a catalyst for synthesis of alkylene carbonate and/or alkylene glycol, and a method for producing alkylene carbonate and/or alkylene glycol

The present invention relates to a method of regenerating a catalyst and a method for producing alkylene carbonate and/or alkylene glycol which can be used by regenerating a deactivated catalyst. The method of regenerating a catalyst comprises the steps of: concentrating, through the use of a thin film evaporation apparatus, a resultant product obtained by the reaction between alkylene oxide and carbon dioxide in the presence of a catalyst of a quaternary phosphonium iodide compound and/or quaternary phosphonium bromide compound; and allowing the concentrate to react with an iodine salt and/or bromine salt.