EQUILIBRATION OF ALDITOL ANHYDRIDES IN ACETIC ACID

Article abstract of DOI:10.1016/0008-6215(83)88168-3

Dehydration of pentitols in acetic acid containing an acidic catalyst parallels that in aqueous sulfuric acid; 1,4(2,5)-dehydration occurs with inversion of configuration at C-2 or C-4.Acetylated alditols undergo similar processes via intermediates having free hydroxyl groups.Configurational inversion of 1,4- or 1,5-anhydroalditols is attributed to intermediate acyloxonium ions that are also proposed as intermediates in the structural isomerisation.Drastic treatment of each alditol gives equilibrium mixtures.The equilibrium concentrations are used to calculate free-energy differences.