Isethionate

A.gllsethionates. These are among the oldest of the synthetic detergents and were developed ia Germany to overcome problems of hard water. They are prepared by reaction of fatty acid chlorides with a salt of isethionic acid, ie, 2-hydroxyethanesulfonic acid [107-36-8]. These detergents have moderate foaming properties and have seen only limited use ia shampoos. 

Anionic surfactants are the most commonly used class of surfactant. Anionic surfactants include sulfates such as sodium alkylsulfate and the homologous ethoxylated versions and sulfonates, eg, sodium alkylglycerol ether sulfonate and sodium cocoyl isethionate. Nonionic surfactants are commonly used at low levels ( 1 2%) to reduce soap scum formation of the product, especially in hard water. These nonionic surfactants are usually ethoxylated fatty materials, such as H0CH2CH20(CH2CH20) R. These are commonly based on triglycerides or fatty alcohols. Amphoteric surfactants, such as cocamidopropyl betaine and cocoamphoacetate, are more recent surfactants in the bar soap area and are typically used at low levels (<2%) as secondary surfactants. These materials can have a dramatic impact on both the lathering and mildness of products (26). 

These surfactants, in conjunction with soap, produce bars that may possess superior lathering and rinsing in hard water, greater lather stabiUty, and improved skin effects. Beauty and skin care bars are becoming very complex formulations. A review of the Hterature clearly demonstrates the complexity of these very mild formulations, where it is not uncommon to find a mixture of synthetic surfactants, each of which is specifically added to modify various properties of the product. Eor example, one approach commonly reported is to blend a low level of soap (for product firmness), a mild primary surfactant (such as sodium cocoyl isethionate), a high lathering or lather-boosting cosurfactant, eg, cocamidopropyl betaine or AGS, and potentially an emollient like stearic acid (27). Such benefits come at a cost to the consumer because these materials are considerably more expensive than simple soaps. 

The viscous fatty acid chloride is mixed with soHd sodium isothionate and is heated under vacuum and agitation without water or solvent HCl is evolved, leaving the product as a finely divided powder. The direct esterification of fatty acid and sodium isethionate has been patented (69). 

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. 

Preparation of the Final Isethionate Product The diisethionate may be produced by treating a solution of the dihydrochloride with alkali carbonate, separating and dissolving the resultant base in aqueous isethionic acid and precipitating the diisethionate with acetone. The product may be purified by dissolving in hot methyl alcohol containing a trace of water followed by precipitation by the cautious addition of acetone. The diisethionate has a MP of 286°C. 

Pentamidine isethionate (Pentam 300, the parenteral form NebuPent, die aerosol form) is used in die treatment (parenteral form) or prevention (aerosol form) of... 

This drug is contraindicated in individuals who have had previous hypersensitivity reactions to pentamidine isethionate. Pentamidine isethionate is used cautiously in patients with hypertension, hypotension, hyperglycemia, renal impairment, diabetes mellitus, liver impairment, bone marrow depression, pregnancy (Category C), or lactation. 

An additive nephrotoxicity develops when pentamidine isethionate is administered with other nephrotoxic drugs (eg, aminoglycosides, vancomycin, or amphotericin B). An additive bone marrow depression occurs when the drug is administered with antineoplastic drugs or when the patient lias received radiation therapy recently. 

In addition to the soaps and fatty acids, some bars contain cocamidopropyl betaine, a mild amphoteric detergent that is added to control irritation without decreasing suds or cleaning power, and benzine sulfonate detergents such as sodium dode-cylbenzinesulfonate. Other detergents, such as sodium isethion-ate and sodium cocoyl isethionate, are also common. 

Sodium isethionate is an amphoteric detergent used in detergent bar soaps. It makes a dense lather in addition to the lather made by the soap. It is nondrying and mild on the skin. It works equally well in soft or hard water. It is also an antistatic agent in shampoos. 

Sodium cocoyl isethionate is a related amphoteric detergent used in mild bath soaps, toothpastes, and baby soaps. 

See sodium isethionate sodium-2-pyrrolidone carboxylate. See sodium PCA... 

Further auxiliary agents for the production of anionic surfactants are the sulfation and sulfonation agents oleum, chlorosulfonic acid, C1-S02-0H, air-S03 mixtures, air-S02 mixtures, sultones (especially 1,3-propanesultone (CH2—CH2—CH2—SO2), and isethionic acid (2-hydroxyethanesulfonic O-------------------1... 

As an example, the cM data of the binary mixtures dependent on the mixture composition were experimentally determined for the systems alkanesul-fonate/fatty acid isethionate, alkanesulfonate/betaine, and fatty acid isethionate/ betaine. In Fig. 31 the calculated ternary cM area of state is depicted for the mixture alkanesulfonate/fatty acid isethionate/betaine [58]. Interestingly, the... 

Sodium lauryl sulfate and/or DLAS DCOS DLMS DRMS Sodium lauryl isethionate Sulfoacetate Other surfactants... 

II. SYNTHESIS OF LIME SOAP DISPERSANTS A. Fatty Esters of Isethionic Acid... 

Fatty esters of isethionic acid were first produced by the I.G. Farbenindustrie in the early 1930s under the trade name Igepon A. A two-step synthesis is required [3]. 

CgHjNO 105-07-7) see Hydroxystilbamidine isethionate a-cyanobenzeneacetam ide (C9H11N2O 771-84-6) see Mephenytoin 4-cyanobenzoic acid... 

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