The addition of sucrose on two fatty epoxides, 1,2-epoxydodecane and 1,2-epoxydodecan-3-ol, has been studied in DMSO and water. The study of the kinetics of the reaction showed that the 1,2-epoxydodecan-3-ol is more reactive for both interfacial and electronic reasons. In water, the induction time normally necessary is dramatically reduced with an immediate emulsification of the mixture which is beneficial to the interfacial formation of sucrose ethers. The comparison of the reaction in DMSO allowed to estimate the assistance of the alpha-hydroxyl group through intramolecular hydrogen bonding in 1,2-epoxydodecan-3-ol, revealing that both aspects are involved in the catalysis of the reaction in aqueous medium. (C) 2002 Elsevier Science B.V. All rights reserved.