Esterquats triethanolamine

The new quats generation presents readily biodegradable surfactants the long chains of which are interrupted by ester groups, thus named "esterquats" [102, 108]. Esterquats are derived frequently from the diester of triethanolamines and the partially hydrogenated tallow or oleic acid followed by a diester quaternisation. The final product, N-methyl-N,N-di[2-(Ci6-i8-acyIoxy)-ethyl]-N-(2-hydroxyethyl)ammonium methosulphate (VIII), of the formula... 

The esterquats may be considered structural homologs of DHTDMAC. Esterquats (1) and (2) contain two alkyl chains per molecule. These are direct homologs of the traditional quats used in fabric softening for many years. The triethanolamine-based esterquat (3) is a mixture and in addition to the dialkyl chain molecules considerable amounts of mono- and trialkyl esterquat are present. 

Triethanolamine-based esterquats have been found to improve the cold water dispersibility of detergent granules containing fatty alcohol sulfates [93]. 

Several esterquats have been developed commercially for hair care applications [108-110]. These products are derived from alkanolamines, mainly triethanolamine, methyldiethanolamine, or dimethylamino-l,2-propanediol [111], and preferably fatty adds of vegetable origin like oleic and palmitic sources. Some examples are given in Fig. 15. 

Triethanolamine based esterquats are a mixture of mono- di- and tries-terquats. It is claimed that for softeners and hair conditioners an esterquat with at least 50% diester content is preferred [49]. Methyldiethanolamine-based esterquats are mainly diesterquats with only slight amounts of mono-esterquat. Monoesterquats are useful as cationic surfactants in hair care formulations [124]. Solid esterquats with improved dispersibility and emulsifying properties are obtained by quaternization of fatty acid triethanolamine esters in the presence of a dispersing agent or nonionic emulsifier [125-127]. Esterquats can be used in sprayable conditioning systems for hair care [128]. 

Other complex reaction mixtures of esterquats based on triethanolamine with fatty adds and hydroxycarboxylic acids or dicarboxylic acids or polyols and dicarboxylic acids have been suggested for use in hair and body care [18,19,24,142]. Sorbitan esterquats are claimed for personal eare applications like skin and hair cleansing [143]. 

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]. 

The use of cosmetic preparations containing esterquats (i.e., quaternized fatty acid triethanolamine ester salts) and sterols as skin care agents is claimed [161]. 

Within the last 5 to 8 years, there has developed a need for efficient fabric softening agents with better enviromnental compatability than the most extensively used softening material, dhtdmac [1,5]. Several new types of fabric softener molecules which exhibit rapid biodegradation were developed [6,7], The esterquat shown in Figure 1 is based upon triethanolamine (TEA), while similar diesterquat molecules are in use based upon methyldiethanolamine (MDEA) and l-dimethylamino-2,3-propandiol (dmapd). 

Alcohol amines such as methyldiethanolamine and triethanolamine react with fatty acids to form esteramines. The esteramines have found limited utility and are mostly quaternized to yield the corresponding quats (Figure 2.3). Esterquats are used predominantly in fabric softening, paper softening and hair conditioning applications due to their substantivity and biodegradability [16]. 

Wilkes, A. J., C. Jacobs, G. Walraven, J. M. Talbot, Characterization of quaternized triethanolamine esters (esterquats) by HPLC, HRCGC, and NMR, World Surfactants Congr., 4th, 1996,7,389-412. 

---