Interaction of d-glucono-1,5-lactone with water

Abstract Some studies of the interconversion of d -glucono-1,5-lactone, d -gluconic acid and d -glucono-1,4-lactone have been undertaken. High-performance liquid chromatography on reversed-phase supports was successfully used to resolve these components in water solution. There are no interactions between the 1,5-lactone and gluconic acid manifested as optical rotation effects. The course of hydrolysis of d -glucono-1,5-lactone, as measured by optical rotation is corroborated by the hplc data. The 1,4-lactone is predictably more stable than the 1,5-lactone and rate constants for the hydrolysis of the 1,5-lactone, and the lactonisation of d -gluconic acid were determined in d -gluconic acid solution which had a constant pH of 2·4. At 20°C the rate constants were found to be 1·730 × 10 −4 s −1 and 3·807 × 10 −5 s −1 , respectively. The specific rotation of d -gluconic acid was affected by the presence of inorganic ions; its value in the absence of interfering ions was determined to be −5·11° (c, 4·5, 20°C, water).