Ester ethoxylates saponification

Lanolin alcohols are obtained by saponification of purified wool grease, a mixture of high molecular esters that is recovered in wool (qv) scouring. Ethoxylation of purified lanolin alcohols yields a full series of lipophilic and hydrophilic nonionic emulsifiers whose largest use is in cosmetic preparations. Manufacturers include Amerchol, Croda, ICI, Henkel Corporation, Westbrook Lanolin, Witco, and Pulcra, SA. 

Highly concentrated ether carboxylic acids with a low degree of ethoxylation even at room temperature can give an esterification reaction with the non-converted nonionic, especially with the fatty alcohol, to several percentage points. The result may be that a too low value is found for the ether carboxylate content. This mistake in analysis can be avoided by saponification of the formed ester [238]. Two hundred to 300 mg matter and ca 100 mg NaOH were weighed in a 50-ml Erlenmeyer glass, heated with 20 ml ethanol under reflux, and after cooling supplied with water to 100 ml. Afterward a two-phase titration was carried out. 

The amount of residual sulfonate ester remaining after hydrolysis can be determined by a procedure proposed by Martinsson and Nilsson [129], similar to that used to determine total residual saponifiables in neutral oils. Neutrals, including alkanes, alkenes, secondary alcohols, and sultones, as well as the sulfonate esters in the AOS, are isolated by extraction from an aqueous alcoholic solution with petroleum ether. The sulfonate esters are separated from the sultones by chromatography on a silica gel column. Each eluent fraction is subjected to saponification and measured as active matter by MBAS determination measuring the extinction of the trichloromethane solution at 642 nra. (a) Sultones. Connor et al. [130] first reported, in 1975, a very small amount of skin sensitizer, l-unsaturated-l,3-sultone, and 2-chloroalkane-l,3-sultone in the anionic surfactant produced by the sulfation of ethoxylated fatty alcohol. These compounds can also be found in some AOS products consequently, methods of detection are essential. 

Determination of sorbitan in sorbitan esters. This method depends on the fact that saponification of sorbitan esters hydrolyses not only the ester groups but also the ether linkage in the sorbitan itself, to produce sorbitol. The latter is a hexahydric alcohol, and can be oxidised by periodate to give four molecules of formic acid and two of formaldehyde, either of which can be measured. The method cannot be used for ethoxylates. 

HLB number of 3.8, i.e. it is suitable for a W/O emulsifier. However, in many cases, accurate estimation of the saponification number is difficult, e.g. ester of tall oil, resin, beeswax and linolin. For the simpler ethoxylate alcohol surfactants, HLB can be calculated simply from the weight per cent of oxyethylene E and poly-hydric alcohol P, i.e. 

Environmental awareness and protection have led to the development of more environmentally benign surfactants. There is a trend of substituting petrochemicals by renewable raw materials. For this reason there is currently much interest in fatty acid-based surfactants. For both fatty alcohol ethoxylates and fatty amide ethoxylates the raw material for the hydrophobic group are triglyceride oils. The triglycerides are present in plants such as rapeseed, coconuts, soya, canola, sunflour, and tallow. Fatty acids, as used for the production of fatty amide ethoxylates, are obtained from saponification of the triglycerides. Fatty alcohols, which are used to produce fatty alchol ethoxylates, need a saponification step to obtain the fatty acid, followed by a reduction, usually via the methyl ester, to obtain the alcohol. 

Esters of sucrose and fatty acids may be saponified at room temperature with ethan-olic NaOH. Derivatives of the saponification products are then analyzed by GC sucrose is determined as the trimethylsilyl ether, and the acid as the methyl ester (85). Ethoxylated sorbitan esters may be similarly analyzed, with the esters saponified with KOH/ethanol... 

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