Selective synthesis of erythrulose and 3-pentulose from formaldehyde and dihydroxyacetone catalyzed by phosphates in a neutral aqueous medium
The aldol condensation of formaldehyde and the lower carbohydrate dihydroxyacetone in a neutral aqueous medium is effectively catalyzed by solid compounds (hydroxylapatite and calcium phosphate and carbonate), natural minerals (apatite and vivianite), and soluble phosphates. In excess formaldehyde, the decrease in the concentration of the lower carbohydrate is described by a first-order rate law with respect to dihydroxyacetone. The major products of the reaction between formaldehyde and dihydroxyacetone in the presence of the above catalysts are erythrulose (45–50% selectivity) and 3-pentulose (35–40% selectivity). Branched pentulose and hexulose are also identified among the reaction products.