It was found that a formose reaction in the presence of small amounts of calcium and D- fructose gave rise to three products, 2-(hydroxymethyl) glycerol, 3-(hydroxymethyl) pentitol, and 2, 4-bis (hydroxymethyl) pentitol, with a high selectivity. Various factors affecting the selectivity were also discussed:[Ca], pH,[D-fructose], the reaction temperature, co-catalysts, and metal hydroxides. The amount of formaldehyde relative to [Ca] is the most important ...