Sodium nonanoyloxybenzenesulfonate


Sodium nonanoyloxybenzenesulfonate is an important component of laundry detergents and bleaches. It is known as a bleach activator for active oxygen sources, allowing formulas containing hydrogen peroxide releasing chemicals to effect bleaching at lower temperatures.

Synthesis

NOBS is formed by the reaction of nonanoic acid with phenol followed by aromatic sulfonation using SO3 to form a sulfonic acid at the para-position.

Bleach activation

NOBS was developed by Procter & Gamble in 1983 and was first used in American laundry detergents in 1988. NOBS is the main bleach activator used in the U.S.A. and Japan. Compared to TAED, which is the predominant bleach activator used in Europe, NOBS is efficient at much lower temperatures. At 20 °C NOBS is 100 times more soluble than TAED in water.
When attacked by the perhydroxyl anion, NOBS forms the peroxy acid peroxynonanoic acid and releases the leaving group sodium 4-hydroxybenzene sulfonate, which is an inert by-product.