Carbonated vegetable oils were synthesized from epoxidized oils and CO2 using microwave heating with tetrabutyl ammonium bromide as catalyst. The reaction proceeded faster when microwaves were used; reaction times using microwaves were ca. 1/4-1/3 of reaction times required using conventional heating under similar reaction conditions. Other important finding was that the addition of water favors the reaction. Besides, selectivity towards the cyclocarbonate was improved by using microwaves because of the lower reaction time required. Conversions of ca. 90% were obtained at 70 h and 40 h with conventional and microwave heating, respectively. (C) 2012 Elsevier B.V. All rights reserved.