Process of bleaching

An aqueous solution of a preformed transition metal catalyst salt, which salt is a mononuclear or dinuclear complex of a Mn(III) or Mn(IV) transition metal catalyst having a non-coordinating counter ion selected to provide a preformed transition metal catalyst salt that has a water solubility of at least 30 g/l at 20 ° C. and wherein the ligand of the transition metal catalyst is of formula (I):

• wherein:
• p is 3;
• R is independently selected from:
• hydrogen or C1-C6-alkyl;
• and
• R1, R2, R3, and R4 are independently selected from:
• H, C1-C4-alkyl, and C1-C4-alkylhydroxy,
• which aqueous solution is present in a buffer system that maintains the solution in a pH range of 4 to 6.