Direct and one-pot conversion of polyguluronates and alginates into alkyl-L-guluronamide-based surfactant compositions

We describe here an efficient one-pot process for the synthesis of 100% bio-based L-guluronic acid based surfactant compositions as emulsion stabilizers, directly from L-polyguluronate or whole alginate, a renewable polysaccharide extracted from brown seaweeds. The transformation of these polymers into long-chain alkyl-L-guluronamides associated with D-mannuronamides when the alginate was used, has been achieved through the preparation of n-butyl uronate monosaccharide intermediates involving methane sulfonic acid-promoted hydrolysis, Fisher glycosylation and esterification reactions, followed by an in situ solvent-free aminolysis reaction with fatty amines.