Green synthesis of glycerol 1,3-bromo- and iodohydrins under solvent-free conditions

ABSTRACT

New eco-friendly conditions for Finkelstein reaction employing homogeneous media or alumina-supported reagents, both solventless, were utilized in the bromohydrins and iodohydrins synthesis from 1,3-dichlorohydrin (1,3-DCH), obtained from glycerol. Thus, the trans-halogenation of glycerol-1,3-dichlorohydrin (1) in homogeneous media, using NaI, NaBr salts and organic additives (TBAI, TBAB), led to the synthesis of four different glycerol halohydrins (2a, 2b, 3a, 3b) in regular to excellent conversions (43–96%) and good selectivities to 3a and 2b. Already, the alumina-supported reagents such as KI, KBr, NaBr were used for glycerol-1,3-dichlorohydrin trans-halogenation, in the absence of solvent, producing halohydrin mixtures in high conversions (77–99%) and very good selectivity (82%) to 1,3-diiodo-2-propanol (2b).