Detergency alkyl sulfates

The detergent range alcohols and their derivatives have a wide variety of uses ia consumer and iadustrial products either because of surface-active properties, or as a means of iatroduciag a long chain moiety iato a chemical compound. The major use is as surfactants (qv) ia detergents and cleaning products. Only a small amount of the alcohol is used as-is rather most is used as derivatives such as the poly(oxyethylene) ethers and the sulfated ethers, the alkyl sulfates, and the esters of other acids, eg, phosphoric acid and monocarboxyhc and dicarboxyhc acids. Major use areas are given ia Table 11. 

The most widely used alkyl sulfate in shampoo preparation is lauryl sulfate. The alkyl component of this sulfate ranges from C-10 to C-18 with a predominance of the C-12 (lauryl) component. By distillation of the fatty alcohol, certain cuts can be obtained which offer the best effects in foaming, cleansing, and rinsing properties for the alkyl sulfate preparation. The range which appears to be most desirable is between C-12 and C-16. Lauryl sulfate detergents are available in various salt forms with the sodium, ammonium, and triethanolamine types being used most frequently in shampoos. 

A.lkyl Sulfosuccinate Half Asters. These detergents are prepared by reaction of maleic anhydride and a primary fatty alcohol, followed by sulfonation with sodium bisulfite. A typical member of this group is disodium lauryl sulfosucciaate [26838-05-1]. Although not known as effective foamers, these surfactants can boost foams and act as stabilizers when used ia combination with other anionic surfactants. In combination with alkyl sulfates, they are said to reduce the irritation effects of the latter (6). 

Sodium fatty acid ester sulfonates are known to be highly attractive as surfactants. These have good wetting abiHty and exceUent calcium ion stabiHty as weU as high detergency without phosphates, and are used in powders or Hquids. They can also be used in the textile industry, emulsion polymerization, cosmetics, and metal surface fields. Moreover, they are attractive because they are produced from renewable natural resources and their biodegradabiHty is almost as good as alkyl sulfates (134—137). 

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. 

Alkyl sulfates and alcohol ether sulfates have been established for use in emulsion polymerization. AOS, although it has been used for many detergent applications during the past four decades, does not find any large-scale use as a primary surfactant system in emulsion polymerization. A study by Kreis [92] has shown that AOS surfactants are very well able to produce a small size latex and have excellent foaming characteristics (i.e., foam height and stability) in latex. They should therefore be able to compete with alkyl sulfates and alcohol ether sulfates. 

The initial studies of LSDAs were carried out with oleochemicals because of their structural similarity to soap. However, since the molecular structure of an efficient LSDA is characterized by a bulky hydrophilic polar head attached to a long hydrophobic tail, it is also possible to prepare LSDAs from petrochemicals. Sulfated sulfonamide derivatives of alkylbenzenes, such as commercially available detergent alkylates, were synthesized as follows [17] ... 

Alkyl Sulfates (AS) R-O-SO3 X R=C12-C18 Laundry detergents Wool-washing agents, soap bars and liquid bath soaps, hair shampoos, and toothpastes - STPs effluents C12-15 AS between 1.2 and 12 pg L 1 [15] Fast biodegradation under aerobic and anaerobic conditions. Effective removal in WWTPs [18]... 

While raising the pH gave some improvements in lather, more improvement was needed. Various co-surfactants, including alkyl sulfates, alkyl aryl sulfonates, and fatty acid taurides were effective in improving the speed of lather when present at levels of around 5%. Cost considerations led to choosing an alkyl aryl sulfonate, particularly sodium dodecyl benzene sulfonate, as it was already widely used in the formulation of laundry detergents. 

Various detergents were examined for their effect on lather properties. It was observed that alkyl aryl sulfonates (like sodium dodecyl benzene sulfonate) and alkyl sulfates (like sodium lauryl sulfate) had the biggest impact as foam boosters. This is not surprising, as both surfactants have head groups with high charge density, which is important for achieving rapid and stable foam [20],... 

The following relation has been found for Na-alkyl sulfate detergents ... 

Conoco operated a stirred tank Pfaudler glass-lined reactor for the batch S03 sulfonation of detergent alkylate. The plant utilized over-the-fence S03 converter gas (8% S03 in dry air) having 6-8 h batch cycles (264). Allied Chemical Company provided details for batch S03 sulfonation (265,266) and Conoco also published their procedure for S03 batch sulfonation (267). Andrew Jergens Company patented a cyclic batch sulfonation and sulfation process introducing nondiluted S03 vapors into a venturi contacter that emitted reaction product into a stirred reservoir tank where it was recycled from the reservoir vessel through a heat exchanger and back to the venturi in the cyclic loop. The unit operated in a vacuum (268). Derived color quality was unspecified. 

Another class of detergents that merits attention is represented by the alkyl sulfates. These materials have been prepared by the direct sulfation of high boiling olefins resulting from the cracking of paraffin wax or the sulfation of alcohols derived from petroleum. 

Of the three main types of surfactants, the anionics are by far the most commercially important class, constituting, in particular, the major surfactant type represented in laundry and hand-dishwashing detergents. Among the anionics, linear sodium alky] benzene sul-fonaie (LAS), linear alkyl sulfates, and linear alkyl ethoxy sulfates are by far the most widely used compounds. (The industry convened voluntarily to linear alkyl chains in the mid-1960s to obtain improved biodegradabilily relative to the branched chain alkylates formerly used.)... 

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