The invention relates to a nicosulfuron
crystal form and a preparation method thereof. A characteristic endothermic peak at 187 + / - 2 DEG C exists in the DSC map of the nicosulfuron
crystal form. Themethod adopts a constant temperature suspension
crystal transformation technology, and concretely comprises the following steps: adding crude nicosulfuron to
ethanol according to a
mass ratio of nicosulfuron to the
solvent ethanol of 0.12-0.17, stirring the nicosulfuron and
ethanol at a constant temperature suspension
crystal transformation temperature of 40-50 DEG C for 36-48 h to generate a white
solid, filtering the obtained product while hot, and
drying the filtered product to obtain the nicosulfuron crystal. The product is a well-growth block crystal, has a good fluidity, is not prone tocoalesce, has a high
bulk density reaching 0.6421 g / ml, and has an
angle of repose of 24 DEG, and the method is beneficial to the preparation production,
filtration and other operations, and solves the problems of easiness in coalescence and difficulty in preparation production of existing
acicular crystals.