Synthesis of Erythrulose from Dihydroxyacetone and Formaldehyde Using Zinc Zeolitic Imidazolate Frameworks

Abstract: A study is performed for the aldol condensation of formaldehyde with dihydroxyacetone (DHA) in an aqueous medium (pH 7.54–8.71) at 65–80°C using zinc zeolitic imidazolate frameworks based on 2-methylimidazole (ZIF-8) and 2-ethylimidazole (MAF-5 and MAF-6). It is shown that the selectivity of the process depends on the pH of the reaction solution, which is controlled by the temperature of the reaction and the amount of catalyst in the reaction mixture. There are high yields of C₆ sugars when the reaction is conducted at pH 8.36 and 80°C. The sugars are accompanied by high yields of erythrulose (39–60%) at a temperature of 65°C and. It is found that the yield of erythrulose when using the studied catalytic systems depends on the pore radius and grows in the order MAF-6 > MAF-5 > ZIF-8. The advantages of the studied systems are compared to those of homogeneous and heterogeneous phosphate systems proposed in the literature.