Bleach activator

Bleach activators are compounds that allow a lower washing temperature than would be required otherwise to achieve the full activity of bleaching agents in the wash liquor. Bleaching agents, usually peroxides, are usually sufficiently active only from 60 °C on. With bleach activators, this activity can already be achieved at lower temperatures. Bleach activators react with hydrogen peroxide in aqueous solution to form peroxy acids, they are a component of most laundry detergents. Peroxy acids are more active bleaches than hydrogen peroxide at lower temperatures (<60 °C) but are too unstable to be stored in their active form and hence must be generated in situ. Bleach activators are compounds that allow a lower washing temperature than would be required otherwise to achieve the full activity of bleaching agents in the wash liquor. Bleaching agents, usually peroxides, are usually sufficiently active only from 60 °C on. With bleach activators, this activity can already be achieved at lower temperatures. Bleach activators react with hydrogen peroxide in aqueous solution to form peroxy acids, they are a component of most laundry detergents. Peroxy acids are more active bleaches than hydrogen peroxide at lower temperatures (<60 °C) but are too unstable to be stored in their active form and hence must be generated in situ. The most common bleach activators used commercially are tetraacetylethylenediamine (TAED) and sodium nonanoyloxybenzenesulfonate (NOBS). NOBS is the main activator used in the U.S.A. and Japan, TAED is the main activator used in Europe. Bleach activators are typically made up of two parts: the peroxy acid precursor and the leaving group; and are modified by altering these parts. The peroxy acid precursor affects the bleaching properties of the peroxy acid: determining the activity, selectivity, hydrophobic/hydrophilic balance and oxidation potential. The leaving group influences the solubility, perhydrolysis rate and storage stability of the activator. Bleach activation is also known as perhydrolysis. Persalts are inorganic salts that are used as hydrogen peroxide carriers (examples include sodium percarbonate and sodium perborate). Persalts and bleach activators are included together in powder laundry detergents that contain bleach. In the wash, both compounds dissolve in the water. When dissolved in water, the persalt releases hydrogen peroxide (e.g. from sodium percarbonate): In a basic wash solution, hydrogen peroxide loses a proton and is converted to the perhydroxyl anion: