Number of Downlaods: 42
Published Date: Jan 1, 2004
Mahmood A. Khwaja
Detergents are made from Branched Alkyl Benzene Sulphonic acid (BAB/ABS, brand name Conco AAS) and Linear Alky Benzene Sulphonic acid (LAB/LAS, brand name Santomerse). These chemicals have a high production volume and more than 1, 000,000 pounds are produced annually. These ionic surfactants are found in domestic, agricultural, industrial cleaning and personnel products (including those used by children), textiles and paints. Detergents, therefore, are now competing well with soaps in terms of both quality and cost. Commercial products usually contain 60 – 90 percent, while consumer products contain 5 – 30 percent BAB/LAB. The commercial BAB/LAB products are mixtures of various alkyl chain lengths, typically from C10 to C14. The manufacturing process of BAB/LAB emits benzene, which is a known carcinogen and a known reproductive toxin.
BAB was developed in the early 1930s and being inexpensive became an instant success for use in powdered laundry detergents, replacing soaps. Soon, however, it was found that these detergents caused foaming problems in sewage/waste water treatment plants and in the environment. BAB surfactant began to accumulate in remote streams, waterfalls and fountains. These synthetic detergents were thought to be more resistant than soap to degradation in sewage treatment plants. The degradation process was found to be slow and incomplete due to the interruption of bacterial two-carbon oxidation by the branched alkyl (3-carbon oxidation) in the hydrocarbon chain (C10 – C12). This led to a search for the development of biodegradable straight chain chemicals to be used in detergents.
The light colored viscous liquid LAB was introduced in 1965 as a replacement for BAB. LAB are complex mixtures of closely related homologues and isomers. Though pure LAB solutions have average foaming properties, but the alkaline mixtures of LAB are considered almost as excellent as soap.