Method for making diperoxyacids

DETAILED DESCRIPTION OF THE INVENTION The process of the present invention involves the following steps: A.
forming a solution containing from about 6% to about 14% hydrogen peroxide, about 69% to about 82% sulfuric acid and about 6% to about 21% water.
B.
adding to the solution of A an aliphatic dibasic carboxylic acid having the formula ##STR1## wherein R is an alkylene group having from about 10 to about 18 carbon atoms to form a mixture.
In a preferred process the dibasic caroxylic acid is added slowly over a time period of from about 30 to about 120 minutes.
C.
maintaining the mixture of B at a temperature of from about 10.
degree.
C.
to about 50.
degree.
C.
until the diperoxyacid crystals are formed.
Preferably the mixture is maintained at the desired temperature for a period of from about 1 to about 4 hours after all of the dibasic acid has been added.
D.
recovering the diperoxyacid crystals of step C by means of filtration.
E.
washing the crystals with water and drying said crystals.
The diperoxyacid formed using the above-described method is formed quickly and under certain conditions (e.
g.
, low temperature, slow addition of the dibasic acid, and/or small amount of hydrogen peroxide) the crystals formed are very easily filtered.
The method also provides for a safer, more easily controlled reaction since the strongly exothermic mixing of hydrogen peroxide, water and sulfuric acid can be done before the unstable diperoxy acid is formed.
For example, the mixing of the three liquid components can be done in a vessel separate from the one in which the diperoxyacid is formed.
The ingredients used in the process of the present invention are all readily available in commerce.
Hydrogen peroxide can be of any concentration, but is preferably from about 35% to about 70%, while sulfuric acid is preferably used in a concentration of from about 92% to about 98%.
The percentages of these materials in the reaction mixture described above are based on pure materials.
The acids suitable for use herein are those aliphatic dibasic carboxylic acids having from about 12 to about 20 carbon atoms