A production process and purification method for
furosemide. The process comprises the following steps: S1, adding a crude
furosemide product to an inorganic alkali solution, sufficiently reacting same, decolorizing and filtering same, adjusting the pH value of a filtrate with an acid solution to create acidic conditions, subjecting same to
crystallization, and then filtering and washing same to obtain a
solid substance; and S2, adding the
solid substance to a recrystallization
solvent, heating same to
reflux same in a boiling state until the temperature of the solution is constant, then filtering same while the solution is still hot, transferring the resulting filtrate into a
crystallization kettle, heating the solution to the
boiling point temperature thereof, stopping heating, setting the pressure of the
crystallization kettle to be 3-60 kPa, conducting crystallization, extracting the evaporated
solvent, and after the solution in the crystallization kettle stops boiling, cooling the solution to 10-15ºC by using circulating cooling water, continuing crystallization, and then conducting filtering, washing and
drying to obtain a finished
furosemide product. The purification method provided can avoid the cold wall
precipitation of crystals, reduce the generation of waste liquid, and significantly improve the purity and yield of furosemide.