Catalytic Hydrogenation of Macroalgae-Derived Alginic Acid into Sugar Alcohols.

Alginic acid, a major constituent of macroalgae, iss hydrogenated into sugar alcohols over carbon-supported noble metals for the first time. Mannitol and sorbitol are the major products of the catalytic hydrogenation of alginic acid, which consists of two epimeric uronic acids. The main reaction pathway is the consecutive hydrogenations of the aldehyde and carboxyl ends of alginic acid dimers, followed by the cleavage of the C-O-C linkage into monomeric units by hydrolysis.