Preformed peracids

Peracid Analysis. Peracid concentrations can be measured in a product or in the bath by use of a standard iodide / thiosulfate titration (60). With preformed peracids or peracids formed via perhydrolysis care must be exercised to minimize the interference of hydrogen peroxide, present intentionally as a component of the perhydrolysis reaction or as a result of the hydrolysis of the peracid (87,88) as shown in equation 18. 

Preformed Peracids. Peracids can be generated at a manufacturing site and direcdy incorporated into formulations without the need for m situ generation. Two primary methods are utilized for peracid manufacture. The first method uses the equiUbrium shown in equation 22 to generate the peracid from the parent acid. 

In contrast to sensitive preformed peracids, bleach activators are safe to handle and, in granulated form, reasonably storage-stable in alkaline detergent powders or tablets. Bleach activators are organic compounds having at least one reactive acyl group R-CO (peracid precursor group), which... 

The use of volume-effective preformed peracids should be facilitated by the current trend toward more compact formulations. Stability problems in alkaline compositions and economic reasons, however, still prevent more widespread use. The only peracid of commercial importance is PAP. In mid-2007, a color detergent powder containing PAP was introduced in Switzerland, claiming the color-safe properties of the peracid. The future of PAP is currently seen in liquid applications, especially when dual-chamber bottles are used. A PAP-containing HDL was intensively test-marketed some years ago in North America, and a similar concept has been used successfully in a Swiss liquid detergent since 2006. 

Reinhardt, G., Nitrogen-containing preformed peracids. Proceeding 5th World Surfactants Congress Cesio 2000, Federchimica Milano, pp. 1244-1252, 2000. 

In contrast to equilibrium peracids, preformed peracids refer to percarboxylic acids that were isolated from the reaction mixture and purified for use in formulations. The development of these peracids offers several challenges due to their susceptibility to alkaline hydrolysis, risk of spontaneous combustion, possible spotting of colored fabric, and poor cost/performance. 

The three best known preformed peracids are DPDA (diperoxydodecanoic acid), H48 (magnesium monoperoxyphthalate hexahydrate), and PAP (phthalimidoperoxycaproic acid) (Fig. 11). The former two have been produced on semicommercial scale. PAP is very slow to biodegrade and has low solubility [20]. 

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