Analysis of the formose reaction system.

A kinetic analysis of the formose reaction, a calcium hydroxide-catalyzed condensation of formaldehyde to carbohydrates in aqueous homogeneous media, was carried out and the performance of the reaction was studied on the basis of a dynamic treatment of the complex reaction system taking into consideration all the species expected to be formed from formaldehyde. The analytical results were compared with the kinetic characteristics experimentally observed. It was found that the carbonyl rearrangement and retro-aldol reaction steps played a substantial role in the autocatalytic nature of the formose reaction. The rates of these reactions were found to be large and the product distribution stayed nearly in equilibrium. The calculated results showed good agreement with the experimental ones, assuming that the species which can afford the foranose or pyranose ring become much less reactive in the subsequent reactions.