Preparation method of 2,5-furan diformaldehyde

The invention discloses a preparation method of 2,5-furan diformaldehyde, and relates to the technical field of organic synthesis. The product, that is, 2,5-furan diformaldehyde is prepared by carrying out a reaction on 5-hydroxymethyl furfural (HMF) serving as a raw material and sodium nitrite (NaNO2) serving as an oxidant in an organic solvent at 0 to 100 DEG C for 1 to 4 hours, wherein the mole ratio of sodium nitrite to 5-hydroxymethyl furfural is (0.25 to 1.5): 1. According to the preparation method disclosed by the invention, no catalyst is needed; the used oxidant adopts sodium nitrite, so that the oxidant is cheap and readily available; the reaction conditions are mild, the reaction time is short, and the reaction temperature is room temperature; the preparation method is efficient and energy-saving; the yield of a target product is relatively high (up to 90 percent); and the preparation method is low in equipment requirement, small in equipment investment, low in production cost and relatively high i