Ruthenium-catalysed epimerisation of secondary carbohydrate alcohols was used to determine the thermodynamic equilibrium between non-anomeric epimers of partially protected glucose, mannose and allose derivatives. A cyclopentadienylruthenium catalyst was used to epimerise each of two pure epimeric alcohols in two separate experiments. The epimerisation reactions were run until the same ratio of epimers was obtained from the two experiments.