The synthesis of 5-membered carbonate from 4-vinyl-a-cyclohexene-1,2-epoxide(VCHO) and carbon dioxide was performed without using any solvent in the presence of ionic liquid as catalyst. The reaction was carried out in a batch autoclave reactor. The conversion of VCHO was affected by the structure of the ionic liquid ; the one with the cation of bulkier alkyl chain length and with more nucleophilic anion showed better reactivity. The conversion of VCHO increased as the temperature increased from 60℃ to 140℃ probably due to the increase of the absorption of carbon dioxide into the mixture of VCHO and the ionic liquid.