PROCESSO PER OTTENERE SALI DI DIAZONIO DEL 3-AMMINO-PIRAZOLO

3-Diazonium salts of pyrazole, useful as intermediates in the preparation of azo dyes are obtained by an oxidative diazotization of 3-amino-pyrazolines with nitrous acid or with nitrosyl-sulphuric acid. The 3-diazonium salts of pyrazole have the following structure: (I) wherein: X is a radical -CO- or -COO-, n is 0 or 1, R is hydrogen (in such case n is always 0), a normal or ramified alkyl C1-C4, an aromatic or heterocyclic, optionally substituted, radical, in particular a phenyl radical having the structure: in which m may vary from 0 to 3 and substituents R3, either like or unlike one another for m>1, are alkyls C1-C4 with linear or ramified chain, halogens, a cyano, nitro, sulphonic or carboxylic group, carboxyesters having a linear or ramified chain C1-C4, alkoxyls having a linear or ramified chain C1-C4, trifluoro-methyl groups, acylamino groups having a linear or ramified aliphatic chain C1-C4, or sulphonamide groups of the type wherein substituents R4 and R5, like or unlike each other, are hydrogen, or linear or ramified aliphatic chains C1-C4, and R1 and R2, either like or unlike each other, are hydrogen, linear or ramified aliphatic chains C1-C4, or non-substituted or substituted benzene residues.