Acyl isethionates isethionate

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. 

While there was a growing number of non-soap detergents that either were already commercialized (as for use in laundry applications) or else had viable commercial potential, it was decided early on to limit the compositional search space to compositions using sodium acyl isethionates (SAI) as the primary surfactant. This decision was based on an early assessment of a prototype bar containing SAI which had been described in a 1952 French patent for which Unilever had acquired the rights [9], This prototype bar, with composition as described in Table 9.2-2, was referred to as the Monsavon bar. 

Sodium Acyl Isethionate (SAI) Detergent (lather, cleansing) 80%... 

Typical weight per cent chain length distributions based on 20 80 tallow coconut fatty acid chain distribution specified for sodium acyl isethionate specified for the Monsavon bar [9], and the purely coconut fatty acid source for SCI. 

Acyl isethionate could also be classed as an interrupted soap but, unlike ether carboxylates, the additional functionalityis added after the carboxylate and the labile metal ion are replaced with an ester, terminated in a sulphonate group. 

N-acyl methyltaurates, N-acyl sarcosinates, acyl isethionates, IV-acyl polypeptide condensates, polyalkoxylated ether glycolates, monoglyceride sulfates, and fatty glyceryl ether sulfonates [1,23]. 

Acyl Isethionates are ester-type anionic surfactants formed by monocarboxylic acids and isethionic acid HOCH2CH2SO3H. The latter is formed by reaction of 30 % aqueous sodium bisulphite and ethylene oxide at 70 C [66]. All commercial isethionates (as sodium cocoyl isethionate) are esters derived from natural carboxylic acids by esterification of the acids or acyl chlorides with sodium isethionate ... 

For a better colour it is advantageous to curry out the esterification for up to 90 % conversion and under some excess of sodium isethionate [73]. Acyl isethionates derived from acyl chloride are formed under milder conditions but contain NaCl. 

Acyl isethionate (lauryl/mirystil isethionate = IGEPON AC 78) Acyl n-methyl taurate (oleoyl n-methyl taurate = IGEPON T) Cocomonoglyceridesulfate (COONa)... 

Acyl isethionates Fatty ester a-sulphonates (R = CH3-toC4H9-)... 

Acid. Conversion to carboxylic acid and alcohol takes place. The sulphonate group may be on either of these. Thus acyl isethionates yield a fatty acid and isethionate ions, mono- and di-alkyl sulphosuccinates yield fatty alcohols and sulphosuccinic acid, and a-sulphonated fatty esters yield the a-sulphonated fatty acid and a low-molecular-weight alcohol. 

The active content of acyl isethionates in raw materials and products is determined either by titration with benzethonium chloride or by saponification. The fatty acid may be extracted after acidification for molecular-... 

Extraction of fatty acid (acyl isethionates) or of fatty alcohol (sulpho-succinates)... 

Extraction of fatty acid gives the acyl isethionate plus the acyl methyltaurate. 

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

Applications. Acyl isethionates have been used in shampoos and personal cleansers. They are also incorporated in syndet bars, together with various soaps. 

Cosmetics, Toiletry and Fragrance Association, Separation of fatty acids from acyl isethion-ates, CTFA Method A 5-1.1110 Vermont Ave. NW, Washington, DC 20005. 

Cg-Cix acyl isethionates alkyl chain length distribution... 

As a historical note, SAI for Dove was made by this acyl chloride process until a commercial process for direct esterification of fatty acid and sodium isethionate was developed by Lever Brothers Co. in the late 1950 s. The SAI made by direct esterification is generally termed DEFI, an acronym for directly esterified fatty isethionate . The DEFI reaction is follows ... 

Chemistry and general properties. Sodium isethionate is 2-hydroxyethane sulphonate, sodium salt and will form an ester with a fatty acid halide, normally an acyl chloride (Figure 4.26). 

FIG. 7 In vitro safety assessment Cytotoxicity for human keratinocyte. AGS acyl glutamate AMT acybnethyl taurate SCI cocoyl isethionate MAP monoalkyl phosphate SLS lauryl sulfate LES lauryl ether sulfate. (Erom Ref. 11.)... 

BEC titration in alkaline solution gives the sulphonated hydrocarbon plus twice the a-sulphonated fatty ester plus soap from the isethionate and acyl methyltaurate. 

Description. Sarcosinates (or salts of acyl amino acids) are the condensation products of fatty acids with iV-methylglycine (CH3-NH-CH2-COOH) (or sarcosine). The properties of sarcosinates are similar to those of isethionates. The TEA salts are more soluble than sodium salts around neutral pH. Because of the internal amide chemical function, sarcosinates undergo hydrolysis at extreme pH ranges. 

Another group of the few sulfonates based on RR are the ->acyl amino alkanesulfonates (taurates) and the - acyloxy alkane sulfonates (isethionates). - Lignosulfonate is also a sulfonate based on natural feedstock. 

These are named as derivatives of taurine (2-aminoethanesulfonic acid) and are also called taurides. The typical synthetic route involves reaction of sodium bisulfite and ethylene oxide to form sodium isethionate, reaction of the isethionate with methylamine to form sodium iV-methyltaurate, then subsequent reaction with the acyl chloride of a fatty acid to give the iV-acyl-Al-methyltaurate. Taurates have good tolerance to water hardness and find specialty applications in textiles and in detergent bars and shampoos. Taurates are sometimes classified as amphoteric surfactants. 

---