Synthetic Detergents Surfactants

In domestic synthetic detergents, nonionic surfactants are increasingly used, but anionic surfactants predominate. Anionic detergents, which constitute the great volume of all synthetic powder detergents, are particularly effective at cleaning fabrics that absorb water readily, such as those manufactured from natural fibers (e.g., cotton, wool, and silk). Anionic 

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Cleaning Clothes with Molecules Soap A Surfactant Synthetic Detergents Surfactants for Hard Water... 

Synthetic detergents (surfactants) may be obtained by sulfonation of suitable lipophilic compounds using oleum, chlorosulfonic acid or sulfur trioxide as the sulfonating agents. 

Detergents. The most widely used surfactant in synthetic detergents is the readily biodegradable linear alkyl sulfonate (LAS). Since the... 

The solubihty characteristics of sodium acyl isethionates allow them to be used in synthetic detergent (syndet) bars. Complex blends of an isethionate and various soaps, free fatty acids, and small amounts of other surfactants reportedly are essentially nonirritant skin cleansers (66). As a rule, the more detersive surfactants, for example alkyl sulfates, a-olefin sulfonates, and alkylaryl sulfonates, are used in limited amounts in skin cleansers. Most skin cleansers are compounded to leave an emollient residue on the skin after rinsing with water. Free fatty acids, alkyl betaines, and some compatible cationic or quaternary compounds have been found to be especially useful. A mildly acidic environment on the skin helps control the growth of resident microbial species. Detergent-based skin cleansers can be formulated with abrasives to remove scaly or hard-to-remove materials from the skin. 

In 1950 the Fischer-Tropsch synthesis was banned in Germany by the allied forces. Sinarol, a high paraffinic kerosene fraction sold by Shell, was used as a substitute. This ban coincided with the rapid development of the European petrochemical industry, and in due time Fischer-Tropsch synthesis applied to the production of paraffins became uneconomic anyway. After the war there was a steady worldwide increase in the demand for surfactants. In order to continually meet the demand for synthetic detergents, the industry was compelled to find a substitute for /z-paraffin. This was achieved by the oligomerization of the propene part of raffinate gases with phosphoric acid catalyst at 200°C and about 20 bars pressure to produce tetrapropene. Tetrapropene was inexpensive, comprising a defined C cut and an olefinic double bond. Instead of the Lewis acid, aluminum chloride, hydrofluoric acid could now be used as a considerably milder, more economical, and easier-to-handle alkylation catalyst [4],... 

Emulsion polymerisation represents the next stage in development from the suspension technique and is a versatile and widely used method of polymerisation. In this technique droplets of monomer are dispersed in water with the aid of an emulsifying agent, usually a synthetic detergent. The detergent forms small micelles 10-100 /im in size, which is much smaller than the droplets that can be formed by mechanical agitation in suspension polymerisation. These micelles contain a small quantity of monomer, the rest of the monomer being suspended in the water without the aid of any surfactant. 

The hydrophilic part of the most effective soluble surfactants (e.g. soaps, synthetic detergents and dyestuffs) is often an ionic group. Ions have a strong affinity for water owing to their electrostatic attraction to the water dipoles and are capable of pulling fairly long hydrocarbon chains into solution with them for example, palmitic acid, which is virtually un-ionised, is insoluble in water, whereas sodium palmitate, which is almost completely ionised, is soluble (especially above its Krafft temperature - see page 93). 

The first synthetic detergents had branched alkyl groups. These branched alkylbenzenesulfonates are not easily biodegradable, and they accumulated in the environment. Lakes and rivers began to foam, and wildlife suffered from the surfactant properties of the detergents, which allowed waterto wet their normally waterproof fur and feathers. 

The worldwide consumption of surfactants in 2003 is shown in Table 36.5. In many parts of the world, soap is still the primary surfactant for textile washing and personal care. Synthetic detergents are widely used in the devolved regions of the world including North America, Western Europe, and Japan. Anionic surfactants dominate the world surfactant market. Common anionic surfactants include LAS, AS, and AES. The second largest class of surfactants is the nonionics of which AE and APE are most common. The use of APE is in decline because of concerns with biodegradability and endocrine disruption. Quats are commonly used in antibacterial formulations because of their ability to lyse the cell membrane of... 

Antiredeposition Polymers. The surfactants employed in synthetic detergents are effective in removing soil and stains from the surface of the washed fabric. Under heavy soil loading, there is a tendency for these soils to redeposit on the fabric. Various charged polymers have been found to prevent soil redeposition. Sodium carboxymethylcellulose (NaCMC) is effective in reducing soil redeposition at a formulation level of 0.1-0.5 percent. 

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