Process for the manufacture of easily dispersible, solid n'-hydroxy-n-cyclohexyl-diazenium oxide salts

A process for the manufacture of solid Mn+(HDO)n salts, wherein HDO is the anion of N′-hydroxy-N-cyclohexyldiazenium oxide, Mn+ is a cation with the exception of alkali metal cations, and n has a value of 1 to 4 comprising at least the following steps:

• (1) Providing an aqueous mixture comprising at least
• an aqueous soluble Mn+-salt,
• a compound M(I)(HDO), wherein M(I) is at least one monovalent cation in an amount of n to 1.5 n moles per mole of Mn+, and wherein the cation is selected from the group of H+, alkali metal ions, ammonium ions N(R1)4+ and/or phosphonium ions P(R2)4+, wherein R1 and R2 are selected—independently of each other—from H and hydrocarbon substituents comprising 1 to 30 carbon atoms and/or hydroxy-substituted hydrocarbon substituents comprising 1 to 30 carbon atoms, with the proviso that the M(I) cations and the Mn+-cations used are different,
• at least one aqueous soluble amine in an amount of 1 to 6 moles of amino groups per mole of Mn+,
• and adjusting the pH-value of the aqueous mixture to 10 to 14,
• (2) mixing the components at a temperature from 30 to 70° C. to obtain a substantially homogeneous mixture,
• (3) precipitating solid Mn+(HDO)n salt by cooling to a temperature below a temperature of 30° C. and adjusting the pH-value of the mixture using an acid to a pH-value from 5 to 9.5,
• (4) Collecting the formed precipitate of Mn+(HDO)n,
• (5) Drying the precipitate at a temperature below 45° C.