I have some strange phenomena, usually it well known that ethylene carbonate will be freeze in room temperature, because it melting point is 34 degree celcius. But Why my ethylene carbonate does not freeze in the nearest room temperature?
It is possibly not dry. You may consider to dry ethylene carbonate over P2O5, and fractionally distil over fresh P2O5 under vacuum (e.g. 65―67 ºC; 1mm Hg).