The invention discloses a new method for preparing 1, 3-
dihydroxyacetone from
glycerol, which comprises the following steps: (1) acetalation reaction, which is to perform acetalation reaction of the
glycerol and
benzaldehyde in the presence of a water-carrying agent and under the action of an acid catalyst A so as to obtain
glycerol benzaldehyde acetal ester having a structure as shown in the formula (I); (2) oxidation reaction, which is to oxidize the glycerol
benzaldehyde acetal ester in an
organic solvent and under the action of an oxidizer so as to obtain 5-carbonyl-2-phenyl -1, 3-dioxane having a structure as shown in the formula (II); and (3)
hydrolysis reaction, which is to hydrolyze the obtained 5-carbonyl-2-phenyl -1, 3-dioxane in the presence of an acid catalyst B so as to prepare a 1, 3-
dihydroxyacetone dimer having a structure as shown in the formula (III). The synthetic
route of the method uses the glycerin as a
raw material, thus both the selectivity and the yield are higher than that by a method of direct oxidation, the target product is simple and convenient to separate, and the product purity can reach 99 percent; and compared with the prior art, the synthetic
route of the method has stronger market competitiveness.