Ethoxylated alcohols

Ethoxylated alcohol sulfates have several advantages over alcohol sulfates including lower sensitivity to hardness with respect to foaming and detersive effectiveness, less irritation to skin and eyes, and higher water solubiUty. 

Smaller amounts of the phosphate esters of the polyethylene glycol which is present ia the ethoxylated alcohol and a trace of NaH2P02 are also present. Table 13 gives aUst of commercial phosphate surfactants. 

The combination of LAS and ethoxylated alcohol has long been used in laundry powder and liquid formulations. A typical example of a phosphate version of such a formulation is shown below. The ethoxylate can be spray-dried with LAS in a complete formulation or it can be post-added to a spray-dried formulation containing LAS, phosphate, and other inorganics. 

Sulfation of ethoxylated alcohols proceeds similarly but in this case small amounts of 1,4-dioxane are formed as a byproduct during sulfation and neutralization. 

The complete analysis of alcohol sulfates is described in the Standard Methods of the International Organization of Standards (ISO) [200] and of the American Society for Testing and Materials (ASTM) [201]. These methods describe the analysis of inorganic sulfate content, chloride content, unsulfated matter, and water as well as other analytical values. Other ISO standards describe the analysis of sodium secondary alkyl sulfates [202], determination of pH [203], determination of water content [204,205], chlorides [206], total active matter in sul fated ethoxylated alcohols and alkylphenols [207], mean relative molecular mass in sulfated ethoxylated alcohols and alkylphenols [208], sulfate content... 

Dioxane is an impurity present in alcohol ethoxy sulfates formed during sulfation of the ethoxylated alcohol. 1,4-Dioxane is a carcinogen in rats and mice [312-314] and has been considered as a possible carcinogen to humans [315-317]. However, the no-effect dose in rats is equivalent to a daily intake of dioxane of 9.6-19.0 mg/kg/day, which corresponds to 0.672 g/day for humans. In other studies it has been determined that the threshold for onset of human toxicity of 1,4-dioxane lies above an intake of 76 mg/kg in adult males [318]. Although it seems to be demonstrated that amounts up to 1000 ppm of... 

ISO 6842 1989, Surface active agents Sulfated ethoxylated alcohols and alkyl-phenols—Determination of total active matter content. 

A major part of the physicochemical properties of ether carboxylic acids can be ascertained from the structure by comparing it with that of fatty acid soap, ethoxylated alcohol, and other anionics [64,73] ... 

Mengerink et al. [243] describe for the analysis of ether carboxylic acids and mixtures thereof with ethoxylated alcohols an HPLC method with the use of a evaporative light-scattering detector (ELSD). 

Falou and Thompson [10] claimed the use of IOS together with ethoxylated alcohols in detergents useful for washings fabrics. 

A lauryl alcohol ethoxylate therefore will not only contain ethoxylated alcohol with a degree of ethoxylation from 1 to 10 mol of ethylene oxide according to a Poisson contribution but due to currently typical production methods also significant amounts of unreacted fatty alcohol. 

There are some means for synthesis of defined primary or secondary esters. Monoester salts of phosphoric acid, for instance, are prepared by addition of alcohol or ethoxylated alcohol, alkali fluoride, and pyrophosphoryl chloride (C12P0)20 in a molar ratio of 0.9-1.5 0.05-1 1.0 at -50 to +10°C and hydrolysis of the Cl-containing intermediates with base. Thus, 32.3 g (C12P0)20 was treated at -50°C with 23.9 g lauryl alcohol in the presence of 0.7 g KF and the mixture was slowly warmed to room temperature and hydrolyzed with H20 and 40% NaOH to give 83% sodium monolauryl phosphate. The monoester salts showed comparable or better washing and foaming efficiency than a commercial product [12]. 

Acid ester phosphates with an alkyl chain up to C6 have little solubility whereas neutralized esters are soluble in water. In ethanol and isopropanol most of phosphoric acid esters and their salts are soluble. If the products are based on ethoxylated alcohols their solubility in water will increase as the degree of ethoxylation increases. The solubility in organic solvents like gasoline, benzene, perchlorethylene, and other apolar liquids recedes with an increase in the degree of ethoxylation but are increased by a higher alkyl chain. 

Because polarity is a dominant factor in solubility, phosphorus-containing anionic surfactants can be tested by solving them in a line of different liquids, e.g., heptane, toluene, propanone-2, ethanol, and water. From the behavior in those liquids the surfactants can be classified for an overall view on the solubility of phosphoric acid esters based on alcohols and ethoxylated alcohols in different surroundings. 

Phosphoric acid esters of alcohols or ethoxylated alcohols are recommended as surfactants which are mild to the skin. Thus they are successfully used in cosmetics such as shampoos and lotions. In analogy to alkyl sulfates and alkyl ether... 

Theoretically, the mechanism for ethoxylated alcohol sulfation is similar to primary alcohol sulfation, involving the rapid formation of a metastable product. The stoichiometry of this almost instantaneous and highly exothermic initial reaction corresponds again to more than one molecule of S03 per molecule of feedstock (Table 4). The desired ethoxylate acid sulfate product formed is... 

Dioxane forms by the chemical cleavage of two molecules of ethylene oxide from the parent ethoxylated alcohol. Dioxane is the undesirable byproduct. The amount of dioxane ranges from traces to hundreds, even thousands, of ppm (mg/kg) depending on raw material quality and sulfonation/neutralization process conditions. 

Longer EO chains in the ethoxylated alcohol feedstock, i.e., 3-EOs present higher dioxane levels than 2-EOs, all other parameters assumed identical... 

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