Methods for production of 1,2,4-triazol-3-one

1. A method for producing 1,2,4-triazol-3-one comprising (i) combining semicarbazide hydrochloride and formic acid to form an initial composition, wherein the formic acid is combined in an amount greater than 3.3 and up to about 7 equivalents as to the semicarbazide hydrochloride, (ii) heating the initial composition to a temperature of at least about 70° C. and maintaining the temperature for at least about 1 hour to form a product composition, (iii) distilling the product composition to remove unreacted formic acid and form a concentrated product composition, (iv) combining water and the concentrated product composition to form a diluted product composition, (v) heating the diluted product composition to at least about 70° C. to dissolve crude 1,2,4-triazol-3-one to form a product solution, (vi) cooling the product solution to lower than about 10° C., and (vii) collecting produced 1,2,4-triazol-3-one from the cooled product solution, all absent use of a catalyst.

2. The method according to claim 1 wherein (v) is replaced with the following: (v-a) distilling the diluted product composition to remove additional unreacted formic acid, (v-b) combining additional water and the distilled diluted product composition to form a further diluted product composition; (v-c) heating the further diluted product composition to a crystallization temperature high enough to dissolve crude 1,2,4-triazol-3-one to form a product solution.

3. The method of claim 1 wherein the cooling is conducted over a period of at least about 2.5 hours.

4. The method of claim 2 further comprising (ix) drying the produced 1,2,4-triazol-3-one under vacuum.