Amphoteric based surfactants

Regioselective nucleophilic attack on the cyclic sulfate 60a by O-nucleophiles gave anionic sucrose-based surfactants 61a-c in good yield, while attack by N-nucleophiles afforded amphoteric sucrose-based surfactants 61d and 61e in reasonable yield (Equation (5) Table 1) <1998CAR189>. 

Mona Industries received a series of patents in the 1980s for betaines and imidazoline-based surfactants similar to the hydroxysultaines and hydroxypropylsulfonates discussed earlier but alkylated with a propanechlorohydrin phosphate rather than the CHPS [9]. These amphoteric surfactants were demonstrably mild and were thought to have some... 

Cationic surfactants represent one of the smaller classes of surfactants, with a consumption estimated to be 700000 tons per year. Typically, reviews and market studies include in this class of materials all amine-based surfactants, whether they be charged or uncharged. In this present chapter we will use the same definition, but exclude amphoteric materials, which will be covered in the next chapter in this volume. 

It is generally known that aqueous solutions of true amphoterics can be difficult to thicken. Viscosity control is best achieved by using either the amphoteric salts or by combining with anionic surfactants. The traditional thickening aids, the alkanolamides, are not particularly effective with amphoterics. Nonionic surfactants offer the best thickening support for amphoteric surfactants, especially those based on fatty acids or alcohols ethoxy-lated with 50-200 moles of ethylene oxide, but like all nonionics, they could exert a foam depressing effect if used at a higher level. When amphoteric surfactants are combined with anionic surfactants, the traditional alkanolamides are effective. The final pH adjustment can also make a difference to the viscosity of the product. 

Thus, the Handbook of Detergents, Part E Applications, evaluates the applications of anionic, cationic, and amphoteric-containing surfactants, appraises the various factors and ramifications of the applications of surfactants in different contexts, gauges and related concerns and discusses application procedures involving surfactant and detergent formulation-based processes. 

Structurally, amino acid-based surfactants may be depicted as shown nearby. The fundamental stmctures may be considered as (1) N-acylated amino acid, which is essentially an anionic surfactant, or modified as in (b), where the carboxylic group is converted to ester or amide, as seen in cationic surfactants. The structures in (c) and (d) represent those of amphoteric surfactants, in which both amino and carboxyl groups represent hydrophilic moieties. 

Enzyme-Catalyzed Synthesis of Protein-Based Surfactants Amphoteric Surfactants... 

In order to produce the amphoteric protein-based surfactant, the incorporation of lipophilic amino acid ester was attempted using the one-step method of plastein reaction with papain at pH 9. In a system containing succinylated ttsi-casein as a protein substrate and luecine n-dodecyl ester as a lipophile, the peptide bond between Phe and Tyr of casein was first hydrolyzed, and this is followed by the incorporation of luecine n-dodecyl ester at the same position, forming a new C-terminus [34]. The structure of the macropeptide with respect to the distribution of hydrophilic amino acid residues is shown in Fig. 4 [29,34]. Amphiphilic structure consisting of hydrophilic protein portion and lipophilic luecine n-dodecyl ester was clearly demonstrated. 

Published results on the toxicological properties of different lipoaminoacids suggest that amino acid-based surfactants are excellent nontoxic surfactants for a great variety of potential applications [33-36]. Ocular irritation by Ci2ArgGly, CijArg pp, LAM, and lauryl dimethyl amino betaine (LDAB), a commercial amphoteric surfactant, has been evaluated in male albino rabbits by a double-blind method. The eyes were examined after 24 h of administration and then each day for a week. The ocular damage was evaluated in accordance with the criteria of Draize [37]. 

Protein-based surfactants are composed of two naturally occurring moieties, amino acid and fatty acid such as acylglutamate. Acylglutamates by themselves are not ultramild surfactants by any means. Their in vitro Zein values are higher than those of alkyl polyglycosides, alkylamphoacetate, amphoteric... 

Chem. Descrip. Blend based on amphoteric sequestering surfactants Ionic Nature Anionic... 

The anionic fluorinated surfactant (SPFO) forms with the nonionic or the amphoteric hydrocarbon surfactant mixed micelles containing both types of surfactants. Both systems exhibit a negative deviation from ideality. Changes of the F and H chemical shifts of the two surfactants upon mixing are consistent with pseudophase diagrams, calculated from the cmc dependence on the fluorinated surfactant mole fraction. The interpretation of data was based a modified regular solution theory and the phase-separation model. 

Shampoos based on lauryl sulfates can range from 6—17% of the active surfactant. However, though they are effective cleansers, the alkyl sulfates tend to be defatting. In an effort to make these shampoos more mild, many shampoos are now based on blends of amphoterics and alkyl sulfates or the less irritating alkyl ether sulfates. 

Baby Shampoos. These shampoos, specifically marketed for small children, feature a non-eye stinging quaHty. The majority of the products in this category are based on an amphoteric detergent system a system combining the use of an imidazoline amphoteric with an ethoxylated nonionic surfactant has been successfiiUy marketed (15,16). The sulfosuccinates also have been suggested for baby shampoo preparation because of thek mildness... 

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). 

A reexamination of so-called renewabdity has shown that advantages for oleochemicals are not sufftcientiy clear (115), especially because manufacture of surfactants ia the United States accounts for only 0.03% of aimual cmde oil consumption (62). On these bases, the primary determinants of surfactant choice will continue to be cost effectiveness and availability. The 1993 U.S. market has been estimated to be worth 3.7 x 10 (110). Approximately one-half was anionic surfactant ( 1.8 x 10 ) and one-third nonionic surfactant ( 1.2 x 10 ). The balance was made up by cationics ( 1.2 X 10 ) and amphoterics ( 600 x 10 ). The U.S. International Trade Commission (116) provides a minutely detailed breakdown of surfactant production. 

Many of the surfactants made from ethyleneamines contain the imidazoline stmcture or are prepared through an imidazoline intermediate. Various 2-alkyl-imidazolines and their salts prepared mainly from EDA or monoethoxylated EDA are reported to have good foaming properties (292—295). Ethyleneamine-based imida zolines are also important intermediates for surfactants used in shampoos by virtue of their mildness and good foaming characteristics. 2- Alkyl imidazolines made from DETA or monoethoxylated EDA and fatty acids or their methyl esters are the principal commercial intermediates (296—298). They are converted into shampoo surfactants commonly by reaction with one or two moles of sodium chloroacetate to yield amphoteric surfactants (299—301). The ease with which the imidazoline intermediates are hydrolyzed leads to arnidoamine-type stmctures when these derivatives are prepared under aqueous alkaline conditions. However, reaction of the imidazoline under anhydrous conditions with acryflc acid [79-10-7] to make salt-free, amphoteric products, leaves the imidazoline stmcture essentially intact. Certain polyamine derivatives also function as water-in-oil or od-in-water emulsifiers. These include the products of a reaction between DETA, TETA, or TEPA and fatty acids (302) or oxidized hydrocarbon wax (303). The amidoamine made from lauric acid [143-07-7] and DETA mono- and bis(2-ethylhexyl) phosphate is a very effective water-in-od emulsifier (304). 

Amphoteric surfactants are those that are an acid and a base at the same time (like water is). Cocamidopropyl betaine, for example, is used in shampoos to stabilize foam and thicken the mixture. 

In a patent survey [76] about shampoos over the period 1968-1978 the so-called cryptoanionic alkyl ether carboxylate based on tridecyl alcohol with 6.5 mol EO has been mentioned for a conditioning shampoo in combination with an amphoteric and cationic surfactant [77]. Because of the low interference with cationic surfactants no negative effect on the conditioning properties has been found [78]. 

The foam-holding characteristics of foam from surfactants in oil field jobs can be tailored by adding an imidazoline-based amphoacetate surfactant. Amphoacetates are a special class of amphoteric tensides (Figure 16-1). Imidazoles, such as 2-heptylimidazoline, are reacted with fatty acids under the ring opening. For alkylation, the imidazoline is reacted with, for example, chloroacetate [493]. 

Being internally neutralized, the amphoterics have minimal impact on the biocidal activity of quaternary ammonium salts. For this reason, like the nonionics, they often find use in antimicrobial preparations that are based on cationic surfactants. 

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