Abstract By means of liquid chromatographic analysis, UV, 13C NMR and GC-MS spectroscopy it is possible to determine quantitatively the most important intermediate and final products of the formose reaction. As stable main products xylose, glucose and dendroketose, as stable side products ribose, lyxose, arabinose, mannose, dendroaldose, fructose and sorbose are identified. Instable intermediates are glycolaldehyde, glycerolaldehyde, dihydroxiacetone, erythrose, threose and pentuloses. Cannizzaro reaction, oligomerization and the primary formose reaction are catalyzed by a calcium hydroxide bismethylene glycolate complex.

Abstract New insights into the autocatalytic primary reaction step of the formose reaction are obtained by using soluble calcium hydroxide bismethylene glycolate complexes for kinetic investigations in homogeneous phase. The reaction kinetics follows between 20% and 80% formaldehyde consumption a nonlinear rate equation. Specific co-catalytic activities are determined for the most important intermediates and end products of the formose reaction. By correlation of the kinetic results with solubility experiments, ultraviolet, 13C NMR spectroscopic measurements and rates of oxidation and acid formation, a mechanism for the autocatalytic primary reaction is given. The main catalytic effects for the formaldehyde activation are caused by calcium enediolate complexes in an autocatalytic cycle and competition with the Cannizzaro and oligomerisation reaction. Further, but less probable mechanisms are also discussed.