Imidazolinium amphoteric surfactants

U.S. 5968496 (1999) U.S. 5922671 (1999) Linares et al. (Procter Gamble) Tracy et al. (Rhodia) (a) Imidazolinium amphoteric surfactant (b) polyol alkoxy ester (a)/(b) = 15 1-1 1 Bis-alkyphenol alkoxylated Gemini surfactants Excellent cleaning performance and mildness improved foam stability Improved surfactant properties mild and environmentally benign... 

Synthesis of imidazolinium amphoteric surfactants was reported in a patent awarded to Manheimer in 1950 [10], in which l-(2-hydroxyethyl)-2-alkyl-2-imidazoline (hereafter called imidazoline) was reacted with sodium monochloroacetate (SMCA). The Miranol company was the first to engage in large-scale production of these products in 1947, and it was around that time when Miranol s products came to be recognized for their mildness and ability to reduce the irritation of anionic surfactants. 

Takano S, Tsuji K (1983) Analysis of cationic and amphoteric surfactants. III. Structural analysis of imidazolinium cationic surfactants. J Am Oil Chem Soc 60 870... 

Carboxy amphoteric surfactants based on fatty alkyl imidazolines (imidazolinium surfactants) make up a large part of the amphoteric surfactants. Materials of this surfactant class are based on the imidazolines obtained by the condensation of fatty acids or their esters with aminoethyl ethanol amine. 

The amphoteric surfactants are relatively expensive products compared to anionic surfactants. Thus, it is not surprising that they are primarily being utilized at low concentrations in cosmetic formulations. A review of 438 shampoos of the U.S. market reveals that appreciable quantities, for example, >5% of alkylamido betaines and imidazolinium surfactants were found in only 8.7% and 13.5%, respectively, of the investigated shampoos. Alkyl betaines were found in a limited number of cases, whereas sulfo betaines were not found in this stndy [4,5]. Since these studies were made, the market has focused on mild products. The change in the U.S. market from bar to liquid soaps has increased the use of alkylamidopropyl betaines. 

Carboxyamphoteric surfactants based on fatty alkyl imidazolines ( imidazolinium surfactants) make up a large part of the amphoteric surfactants. The very divergent interpretation of their chemical structure is partly attributable to little-developed analytical procedures in the past, but is also a consequence of special processing methods by different manufacturers. Materials of this surfactant class are based on the imidazolines obtained by the condensation of fatty acids, or their esters, with AEEA. In Figures 12.4 and 12.5, a summary of the synthesis of amphoteric surfactants based on imidazolines [4,8] is presented. 

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