Synthesis of sucrose-based surfactants through regioselective sulfonation of acylsucrose and the nucleophilic opening of a sucrose cyclic sulfate

Abstract

Synthesis of a new class of anionic and amphoteric sucrose-based surfactants is described. Direct sulfonation of 6- O-acylsucrose using the pyridine–sulfur trioxide complex led to a mixture of the regioisomeric monosulfates, 6- O-acyl-4′– O-sulfosucrose and 6- O-acyl-1′- O-sulfosucrose, while sulfonation of 1′- O-acylsucrose afforded a mixture of 1′- O-acyl-6′- O-sulfosucrose and 1′- O-acyl-6- O-sulfosucrose. The ratio of regioisomers ranged from 4.7:1.0 to 7.5:1.0, depending on reaction time and the size of the fatty acyl chain. The regiospecific synthesis of 6- O-acyl-4- O-sulfosucrose derivatives was accomplished by nucleophilic substitution of the sucrose 4,6-cyclic sulfate using various fatty acids. The amphoteric 6-alkylamino-6-deoxy-4- O-sulfosucrose surfactants were also synthesized by nucleophilic substitution of the sucrose cyclic sulfate by different fatty amines. All the newly synthesized sucrose-based surfactants displayed excellent surface-active properties.