Method of preparing stable dilute solutions of aliphatic carboxylic peracids, and the resulting solutions

A method of preparing a dilute solution, containing a rated concentration between 1 and 20% by weight, of an aliphatic carboxylic peracid with a stable concentration titer in time, notwithstanding the possible presence of trace amounts of decomposition catalysts, comprising the steps of:

• preparing a concentrated solution of aliphatic peracid from the corresponding carboxylic acid or anhydride and hydrogen peroxide in a concentration of between 60 and 90% in the presence of the substantially minimal amount of a strong acid catalyst necessary to obtain equilibrium of the system in a maximum period of 48 hours;
• and
• diluting the concentrated solution of aliphatic peracid, prepared in said preparing step, with a solution containing at least one of the reagents used in said preparing step in an amount and concentration sufficient to bring the concentration of aliphatic peracid at least to the rated concentration of the mixture and such that (a) the maximum concentration of peracid during storage at ambient temperature is at most 10% above the rated concentration of peracid and (b) the concentration after storage for 12 months is at least equal to the rated concentration of aliphatic peracid.