Alkanolamine-based esterquats

Alkanolamine-based esterquats compose by far the largest group in fabric care applications. Three different types are used commercially, each in significant quantities (Fig. 14). 

FIG. 14 Alkanolamine-based esterquats applied in fabric care. R is Cie and Ci8, saturated or unsaturated. 

Another important class of esterquats is the betaine esters (Fig. 7), which are derived from aminocarboxylic acids and thus have a reverse ester group compared to regular esterquats based on alkanolamines [20,21]. Other examples include esterquats derived from amino acids [22,23] or dicarboxylic acids [11,24,25]. 

Softener esterquats based on alkanolamines have been extensively investigated for their environmental properties. A number of very comprehensive studies has been published [14,37,41]. All materials biodegrade rapidly and show comparatively low toxicity to aquatic organisms. It has been suggested that abiotic degradation (hydrolysis of esterbonds) contributes to the favorable environmental profiles of these esterquats [37],... 

Esterquats with improved stability and biodegradability are prepared by quaternization of a fatty acid (partially hydrogenated tallow) alkanolamine ester with an alkylating agent (dimethyl sulfate) in the presence of nonionic emulsifiers [126] or cosmetic oils [159]. This procedure avoids problems associated with the use of lower alcohols as solvents in the reaction, such as low ignition point, poor emulsifying capacity for perfume oils, poor skin compatibility, and a defatting action on the skin. Formulations of a triethanolamine-based Coco esterquat, oil, and a Ci-Cg alcohol are useful in cosmetic and sunscreen formulations [160]. 

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