RCO(OCH2CH2)m OH + RCO(OCH2CH2)mOOCR Ov) (v) Depending on the reagent ratio, the reaction gives predominantly monoacyl or diacyl derivatives.
The most of the ordinary European shampoos, bath and douche products comprise sodium alkyl[ethoxy• (II) where alkyl are of vegetable (lauryl, coconut, palm-kernel) or synthetic (even carbon number straight C12-14 alcohos) origin. Excellent detergency and foaming in hard water along with personal and environmental safety are among of the most valuable properties of alkylethersulphates. Of some importane are secondary alcohol ethersulphates the stability of which to hydrolysis is much higher than the stability of secondary alkylsulphates.
4. Esters as nonionic surfactants Obviously, esters between long-chain carboxylic acids and glycerol (acyl glycerols, or glycerides) are the most widespread lipophilic surfactants in food industry [42, 43] and cosmetics [44-46]. Glycerides are prepared from naturally occurring oils, fats and hydrogenated oils by alkaline, high-temperature (220 ~ or more) glycerolysis, or by reesterification of methyl esters and a direct esterification of fatty acids and acyl chlorides with glycerol: RCOCI + HOCH2-CH-CH2OH--* RCOOCH2-CH-CH2OH + RCOOCHz-CH-CH2OOCR I OH I OH I OH (II) 15 Recently, lipase-induced low-temperature (42 ~ glycerolysis with a yield of 70-90 % monoglycerides has been developed [31b].